Truma water dump valve

[marksrv6]

I have read many threads on this subject of dumping the water at +4 degrees and allowing reseting at +8. and this is how mine works, great for protecting your equipment!

 

There are many thoughts on wedging the valve open (clothes peg being the most common).

 

I understand that when the heating is on it stays closed which is great, but I like to fill up the tank before we go off wild camping, which means no further opportunity to fill with water so if it dumps our water during the traveling we won't have any water.

 

My question is, will wedging it closed during traveling damage the electrical solenoid or run the risk of blowing a fuse?

 

Please only reply if you know and not if you are just guessing at an answer (I don't mean to be rude but I don't want to damage anything by having bad advise)

 

Thanks

Mark

 

[jenkothewanderer]

Hi I understand your query as I like to do the same when travelling to Spain in the winter. I have lifted the valve permanently with a peg or other suitable means on several occasions and have never experienced any problems. It is my understanding that if the valve did open it would only empty the contents of the boiler and not your full water tank.

 

[vindiboy]

jenkothewanderer - 2016-12-01 7:37 PMHi I understand your query as I like to do the same when travelling to Spain in the winter. I have lifted the valve permanently with a peg or other suitable means on several occasions and have never experienced any problems. It is my understanding that if the valve did open it would only empty the contents of the boiler and not your full water tank.

If your water pump is turned on the system would continue to run and empty your fresh water tank completely if the dump valve on the boiler opened, because the pump would continue to try and fill the hot water system.That is what it is supposed to do, the pump would only cut out when the system is pressurised which of course it cannot be if water is escaping from the system.

[crocs]

Have you Sen this thread?

 

http://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/cold-weather/45867/

 

Robert

[Rayjsj]

Do ANY UK manufactured motorhomes have Trumas automatic dump valves fitted as standard ? None of the ones i have owned have, Autocruise (eberspacher !) Autotrail x2, Autosleeper.

[Derek Uzzell]

Truma’s electrically-operated safety/drain valve goes right back to the original Trumatic C-3400/C-6000 combination air/water heaters that were first marketed in 1994.

 

The valve is specific to Trumatic C-Series heaters, so if the heating system chosen by any motorhome manufacturer does not include a C-Series heater, the system will not include a Truma electrically-operated safety/drain valve.

 

My understanding (based on what Truma(UK)’s technical manager told me years ago) is that the electrically-operated safety/drain valve was always an option for Trumatic C-Series heaters and, if a motorhome manufacturer wanted to fit the valve, they’d have needed to order it (and pay for it) separately. The alternative was to fit a (significantly cheaper) manually-operated Truma safety/drain valve (as fitted, say, to caravans with Truma “Ultrastore” water-boilers) that provides over-pressure protection but not anti-frost protection.

 

If you’ve come across UK-built motorhomes that have a Trumatic C-Series heater, but do not have a Truma electrically-operated safety/drain valve, the likelihood is that the UK manufacturer has either wished to make cost savings, or there are technical reasons (like the need to provide a continuous 12V power-supply to the valve) that have influenced that decision.

[marksrv6]

These are all interesting points that I have already knowledge of, but none answer my question, will forcing the switch to stay closed cause any damage to the solenoid?

[Derek Uzzell]

 

 

Simple answer - No

[marksrv6]

Derek Uzzell - 2016-12-02 2:26 PM

 

 

 

Simple answer - No

 

 

Thank You

[aandncaravan]

Like Derek says, it won't do any harm to lock it up with a Peg.

However, if you are concerned and have a Schaudt Elektroblock EBL 99 the Valves Solenoid is normally driven from the 6 way block 4, Pin 4 so you could put an inline fuse in this wire.

 

Doing this would also allow you to remove the fuse to save the power draw that the valve takes in storage.

 

If you have an Elektroblock other than the EBL 99, let me know and will see if we can provide details on that unit, like an EBL 101?

 

 

Sometimes a Peg won't grip on it's own, but curling a small elastic band around the valve 'plunger' gives extra grip.

 

The valve is standard fit on many Hymers, Burstner, Dethleffs, Geist, etc before the non electric version became standard.

 

 

[Robinhood]

aandncaravan - 2016-12-03 7:05 PM

 

However, if you are concerned and have a Schaudt Elektroblock EBL 99 the Valves Solenoid is normally driven from the 6 way block 4, Pin 4 so you could put an inline fuse in this wire.

 

Doing this would also allow you to remove the fuse to save the power draw that the valve takes in storage.

 

 

...no it wouldn't, Alan. The dump valve is "powered to close". When open it draws no power (and Truma's advice is to leave it open when in storage to avoid battery drain).

 

Of course,removing an inline fuse would cause it to open, but it's much easier simply to depress the "plunger" to open it. ;-)

[aandncaravan]

Robin Hood, the question from the OP was 'does locking it with a peg harm it'.

We were talking about it being locked with a peg (and elastic band) then removing the power so the OP would be at ease about any potential damage.

 

Just opening the valve, by depressing it, doesn't always stop power draw. Even in the open position some seem to drain a battery over Winter storage.

 

 

If you are going to manage it's operation manually, it makes sense to cut power altogether, no point in powering a valve being manually controlled. But do it in a way that enables it to return to 'normal' operation, like just replacing a fuse. Hence the suggestion.

 

So as it's Pantomime season :

"Oh yes it would".

 

 

 

 

 

[Derek Uzzell]

aandncaravan - 2016-12-04 1:36 PM

 

...Just opening the valve, by depressing it, doesn't always stop power draw. Even in the open position some seem to drain a battery over Winter storage...

 

 

I’m unconvinced.

 

Truma’s electrical safety/drain valve needs a continuous 12V electrical-supply for the valve’s solenoid to hold the mechanism in its closed position. If the valve opens (or is opened) no 12V power is consumed. The valve - when closed - would eventually drain the battery that provides the 12V power-supply, which is why Truma advises

 

"The safety/drain valve is held closed by an electrical coil. To save battery power, we recommend to open the valve if the vehicle is not in use for a prolonged period.”

 

Marksrv6 asked whether deliberately preventing a closed valve from opening (eg. by using a clothes-peg) while travelling might damage the valve’s electrical solenoid or run the risk of blowing a fuse. This is a perfectly reasonable question because, if the temperature near the valve drops enough, the valve will ‘want’ to open but it won’t be able to and - when that happens - there is the possibility that this might cause harm. I believe no harm will occur, but obviously cutting the 12V supply to the valve would make absolutely certain.

 

Mark’s motorhome is a Rapido 966M and I’m guessing this has a CBE-based electrical system. There will be fuse somewhere that could be ‘pulled’ to interrupt the 12V supply to the valve, but one would need to be very very risk averse to go to those lengths.

 

If Mark wants a horse’s-mouth Yes-or-No answer, the Truma(UK) technicians might be able to provide it

 

https://www.truma.com/uk/en/home/directions-trumauk.php

 

and may also be prepared to comment on the potential for the valve to drain 12V power even when open.

[aandncaravan]

The valve 'opens' on a spring, but is latched 'Closed' by a Coil in the solenoid. When power is removed the spring pulls the plunger down and opens the valve.

If the plunger is pushed down manually the magnetic latching effect of the Coil becomes ineffective, so even if powered, the Coil won't close the valve once fully opened.

 

We have seen open valves still drawing power, even with the plunger down and valve fully open. Don't know if this a fault in the valve switch or a 'feature'.

Not opened one up to see why the switch sticks, but it does. Not surprising when some of these are well over 10 years old.

 

 

On Schaudt EBL 99 powered Motorhomes, the Frost protection valve is isolated by the Cut off switch and this is the recommended shut down process when putting the van away for an extended period. I.e. removing the power, not depressing the plunger.

 

 

We don't do CBE, so can't comment on the isolation procedure for those.

 

 

.

 

[Robinhood]

aandncaravan - 2016-12-04 1:36 PM

 

Robin Hood, the question from the OP was 'does locking it with a peg harm it'.

We were talking about it being locked with a peg (and elastic band) then removing the power so the OP would be at ease about any potential damage.

 

 

..I know what the original post was about (and it was nothing about storage).

 

I was responding to your line Doing this would also allow you to remove the fuse to save the power draw that the valve takes in storage.

 

.....where the whole premise is illogical, and the insertion of a fuse (IMO, in line with my experience of these valves, and Truma's advice), an over-complication and waste of time.

 

In storage, I can think of no circumstances at all where one would want to "peg" the valve for any amount of time.

 

If there is water in the system, (not something I would recommend for storage) you would absolutely want the valve to carry out its dump function, the by-product of this would be a requirement for power to ensure the water is retained unless the temperature falls.

 

If there isn't water in the system (as would be the case after winter drain-down) the valve can quite safely be opened, avoiding (as Truma says) any current draw.

 

In either case, there is no need for any further in-line interruption.

 

====

 

As to the original question, I can answer empirically.

 

My recent 'vans have had the newer "passive" dump valve, but I've had the powered valve before that, and we invariably use our 'vans throughout the year.

 

Subject to me not expecting temperatures to fall even lower, I've regularly used a peg to hold the valve closed in the interim "above freezing but below dump" range, both for filling prior to journeys, and during the subsequent day's travelling.

 

In general, the boiler has been in an area of the 'van that has received some vehicle-generated heat during travelling, removing any risk of freezing, but there has always been a slight risk that the valve would not be maintained above "dump temperature".

 

On-site, and/or during long absences from the 'van, the peg has been removed, relying on (at least water-) heating being used to stop it dumping, and allowing it to do so if failure of the same caused a risk of freezing.

 

This practice has never led to any problems with the valve.

 

 

 

[aandncaravan]

Sorry guys but you are talking about new valves and how they operate according to the theory of the Truma book.

 

We are talking about real World and what we have seen. These are valves that are maybe not as young as they were and possibly not operating as expected, as many items don't when they get tired?

 

 

 

We have not suggested pegging the valve in storage, only in use agreeing with what Derek had already suggested, but that cutting the power would allay any anxieties the OP might have about it being powered while he was doing this.

 

The fuse also stops the valve being powered while locked closed by the peg, saving power which isn't required because of the peg.

 

It can ALSO save power in storage, but that was not the primary reason for the fuse.

 

We make the point of doing it the suggested 'fuse' way so that it can be operated exactly as 'normal' by just replacing the fuse.

At no point have we suggested a peg in storage, or suggesting it should be used contrary to all sensible drain down guidelines, so not sure where you have got that from or why you go on about it in such great detail?

 

 

[Derek Uzzell]

Allan

 

CBE-made distribution boxes carry a low-amperage fuse the purpose of which is defined as “...for the gas power supply (fridge, kitchen, boiler valve, etc.)” So, if the distribution box is reasonably accessible (which it is on my current Rapido, but definitely was not on my previous Hobby motorhome) removing the box’s cover and this fuse should cut 12V power to the Truma safety/drain valve.

 

However, as Mark’s concern was over any potentially damaging effect from forcibly holding the valve in its closed position while travelling and we both agree that doing this will cause no harm, there seems little reason to advocate fuse-removal as well. Truma states that the electrical safety-drain valve's 12V ‘drain’ is just 0.035A, so (for Mark) fuse-removal prior to travelling to provide 12V power-saving will hardly be a major issue.

 

Given Truma’s advice about saving battery power by opening the valve when the vehicle is not being used, it can be assumed that this action should reduce the 0.035A value and, logically, the reduction should be to zero. If a valve still draws 12V power when the knob is in the open position and water will drain through it I’m sure Truma would diagnose this as a fault not a feature.

 

For paranoid control freaks the simplest solution is to ditch the 'frost-sensing’ valve (electric or non-electric) and replace it with a Truma manually-operated one. Over-pressure protection will be retained, but the valve will only be opened or closed when YOU want it to be.

 

(I vaguely recall asking on this forum whether anyone had ever had a Truma safety/drain valve open itself and had been glad this had happened. There were no replies...)

[aandncaravan]

Derek, I agree that the move away from a 12v powered valve to a mechanical one was a step in the right direction, and a reasonable mod for any older Hymer, Burstner, etc. Shame it is so expensive.

 

We are agreed that locking up the valve plunger using a peg or something won't do any harm to the older 12v powered valves.

 

But the OP had already read elsewhere that this was safe to do, yet STILL had concerns.

My reply said we agreed with you, but IF they still had concerns then removing 12v power was an option that would completely remove any worries they may have still had. We wrote, "However, if you are concerned....".

 

 

We get emails asking the best way to remove power from the valve. These are often from owners who want to lock them up and manage the drain like most British built Motorhome owners do. Some having had Swift Group vans previously. They don't want the limitations of the 12v 'semi automated' option.

 

I took advantage of the Post to publish what we think is the best way to do this on an Elektroblock EBL 99, one of the most common units fitted with this device.

 

 

I have to confess to not liking the device at all. Even when it is mechanically perfectic the way it works by dropping Water at + 3 degrees and then not closing again until + 8 degrees, in my view, is less than ideal. But all too often it isn't mechanically perfect.

We have seen units drawing permanent power yet won't lock. Units without power that won't drop, units with open circuit solenoid coils, valves drawing power unexpectedly and several drawing significantly more current than Truma quote.

 

They also lead some owners to think the entire Water system is protected when it only protects the Boiler. So you still need to take manual action to drain down the system

If you want to save the battery running down in storage, again you have to take manual action.

 

To me, a flawed, semi automated device that creates confusion and requires so much manual intervention, is worse than a totally manual option.

 

 

 

The fact that so many people do lock the plunger up using clips, pieces of Aluminium with a slot cut in it, a piece of string nailed to the roof of the cupboard, a bungee, a very sophisticated plastic oblong cut in such a way that it slides under the Plunger, hundreds and hudreds of pegs, etc, are all very good indications of how poor it is in real use.

 

Some of the solutions we have seen are genius, with a lot of effort put into the solution. You have got to be very unhappy with something to go to that much trouble.

 

Like you say, when they have dumped Water, it is rarely at a time it is actually appreciated, so, to me, it doesn't seem to meet it's design intention on any aspect.

 

 

Sorry to disagree with you on the use of one of these, because I have great respect for you and Robin Hood, but I think they are better managed totally manually.

With the power disconnected, via a way where it can easily be reinstated if desired.

 

.

 

 

 

 

 

 

 

[marksrv6]

Thank you for all your replies and I think I can safely stop it from dumping the water when required, But I would still like the frost protection as well so I won't bypass it.

 

Not fully understanding how the valve worked was the problem, I thought the 12v supply was constantly trying to open it thats why I thought it might cause damage.

 

Now my understand is (if I am correct) the 12v holds it closed until it is told by the frost sensor to open it, it then shuts off the 12v supply allowing the spring to pop it open.

 

So buy wedging it closed, it just means that when below 4deg but still above freezing (when using the motorhome so I am able to keep an eye on the outside temperature) it will stay closed with no 12v supply therefor not resulting in any damage.

 

I am not worried about the power drain because I am fortunate enough to have it at home (hooked up) and never really go more than 3 weeks without a few days away.

 

Thanks again

Mark B-) B-) http://forums.outandaboutlive.co.uk/forums/images/emoticons/icon_cool.gif

[Robinhood]

aandncaravan - 2016-12-04 3:41 PM

 

At no point have we suggested a peg in storage, or suggesting it should be used contrary to all sensible drain down guidelines, so not sure where you have got that from.....

My response was nothing about the peg, but entirely about the totally unnecessary insertion of an extra fuse in the valve circuit, and the fact that the valve (unless it is faulty) shouldn't cause any current draw in storage (if left open, as would largely be the case).

 

aandncaravan - 2016-12-04 3:41 PM

 

.........or why you go on about it in such great detail?

 

Given our relative contributions to date, that's a bit rich, Alan - are we still in Pantomime mode? I'll do my best to redress the imbalance. ;-)

 

You often conflate the results of your experience with some rather (IMO) "off the wall" views on technical matters. As you write them up, they sometimes set hares running (maybe through misunderstanding).

 

My own motive in responding to this thread was to correct impression that I (and it appears others) certainly got from your text that you were stating without qualification that the (older, electric) dump-valve was in danger of draining the leisure battery when in storage. It is clear to me that this is/should not be the case, as an opened valve should not (unless faulty) cause any such drain.

 

If the valve is indeed faulty, then it would be better to give this some attention lest it malfunctions in an undesirable manner, rather than putting an extra isolating fuse somewhere in-line.

 

Even if as a 'paranoid control freak'* you wished for some such protection, in many circumstances, the "base" fuse could easily be "pulled" from the existing electrics (as Derek has set out for CBE equipment, and which would be extremely easy on my EBL99 - were it fitted with an electronic valve on the designated circuit, rather than the passive one it has!).

 

aandncaravan - 2016-12-04 3:12 PM

On Schaudt EBL 99 powered Motorhomes, the Frost protection valve is isolated by the Cut off switch and this is the recommended shut down process when putting the van away for an extended period. I.e. removing the power, not depressing the plunger.

...the above is another example of where your wording, either through incomplete thought or poor expression, might cause hares to start running.

 

There is indeed a recommendation from Schaudt as to how to decommission the electrics for (long-term) storage. It runs to a few more words than you use, but obviously as a byproduct of fully isolating the 12v supply, the dump valve should operate (and the Schaudt documentation warns of this).

 

This in no way carries any recommendation in respect of the correct opening of the dump-valve. Truma's instructions are to manually depress the plunger.

 

I suspect that many winter users of 'vans will dump the water by manual use of the valve between trips, and not bother to isolate the 12v electrics. I also suspect that most users who do isolate the 12v on putting their 'vans into long-term storage will dump water manually long before any such isolation of the electrics.

 

I wouldn't want anyone thinking they were working "against official recommendations".

 

=====

 

FWIW, I find the dump valve somewhat of a pain as an all-year-round 'vanner, but, on balance, given the cost of a new Combi, I think I'd rather have it than not. Contrary to some opinions, however, I would prefer the older electric valve to the newer passive one. As discussed in this thread, the older model could be held for filling by turning on the heater, or by use of the dreaded peg. The newer model excludes any hold by putting on the heating, and is significantly more difficult, but not impossible, to use the mechanical peg-equivalent approach.

 

 

*© Derek Uzzell

 

 

[aandncaravan]

Robinhood - 2016-12-05 4:53 PM

 

aandncaravan - 2016-12-04 3:41 PM

 

At no point have we suggested a peg in storage, or suggesting it should be used contrary to all sensible drain down guidelines, so not sure where you have got that from.....

My response was nothing about the peg, but entirely about the totally unnecessary insertion of an extra fuse in the valve circuit, and the fact that the valve (unless it is faulty) shouldn't cause any current draw in storage (if left open, as would largely be the case).

 

aandncaravan - 2016-12-04 3:41 PM

 

.........or why you go on about it in such great detail?

 

 

 

 

 

So you didn't write,

 

"In storage, I can think of no circumstances at all where one would want to "peg" the valve for any amount of time. If there is water in the system, (not something I would recommend ....", etc. etc.?

 

 

 

 

I have always followed the advice that once you have drained down the water, you then close the Drain valve to prevent the ingress of any creatures/debris which might then lead to the valve not sealing correctly when recommissioned at a later date.

There is also a line of thought that leaving it open causes the seal to shrink/dry out leading to leaks, which closing the valve helps to reduce.

 

I thought that was what most people did? Most owners I speak to do.

 

I know there is contrary thinking that leaving the valve open allows any 'Ice expansion' to take place, but if the drain down is thorough and Sink taps are left open, as generally advised, there is no advantage in leaving the Drain valve open.

 

Anyone who follows that general practice of closing the 12v powered Frost valve after draining, regardless of how it is closed, will be consuming power throughout the Lay-up period. Even if it is closed using a peg, unless a deliberate effort is made to also cut the power.

 

That is a lot of potential people not taken account of in your argument, isn't it?

 

 

 

If you look at the EBL 99 wiring diagrams you will see there is no fuse for the Frost protection valve, unlike the CBE Derek speaks of. Hence our advice to fit one.

 

 

Your drain down process is interesting, but I would cut the power first, if only to check the valve was working and did indeed dump the water as designed. Better to test it at drain down than find out on a minus 20 degree trip it is stuck hard closed?

That is my interpretation of the Schaudt documentation, which loses much through translation (like the battery isolation switch which isn't) based on what we know, have seen and sensible use.

If Truma advise depressing the plunger, when it is a perfect opportunity to test the valves operation, then, IMO, it should be rewritten.

 

 

You advise the repair of any faulty 12v powered Frost protection valve yet they are not cheap. When the automatic function is so very dysfunctional, is that cost effective when manual management gives more desirable operation?

That is backed up, not only by your own use, but by the fact that Truma have completely changed the design of it's replacement.

 

Every single person we have encountered with a faulty valve has elected to manage it manually, usually because, ' we already do'.

 

 

[Robinhood]

aandncaravan - 2016-12-05 9:33 PM

 

So you didn't write,

 

"In storage, I can think of no circumstances at all where one would want to "peg" the valve for any amount of time. If there is water in the system, (not something I would recommend ....", etc. etc.?

 

...demonstrably I did, but the prime context was that of not requiring the extra fuse because the the valve wouldn't naturally be pegged, and would be open and not drawing current, rather than a discussion of the peg itself.

 

aandncaravan - 2016-12-05 9:33 PM

 

I have always followed the advice that once you have drained down the water, you then close the Drain valve to prevent the ingress of any creatures/debris which might then lead to the valve not sealing correctly when recommissioned at a later date.

There is also a line of thought that leaving it open causes the seal to shrink/dry out leading to leaks, which closing the valve helps to reduce.

 

I thought that was what most people did? Most owners I speak to do.

 

I know there is contrary thinking that leaving the valve open allows any 'Ice expansion' to take place, but if the drain down is thorough and Sink taps are left open, as generally advised, there is no advantage in leaving the Drain valve open.

I think we're going round in circles here, and this is where I came in several posts above; patently there is an advantage in leaving the drain valve open because, as Truma advise "The safety/drain valve is held closed by an electrical coil. To save battery power, we recommend to open the valve if the vehicle is not in use for a prolonged period."

 

aandncaravan - 2016-12-05 9:33 PM

 

Anyone who follows that general practice of closing the 12v powered Frost valve after draining, regardless of how it is closed, will be consuming power throughout the Lay-up period. Even if it is closed using a peg, unless a deliberate effort is made to also cut the power.

 

That is a lot of potential people not taken account of in your argument, isn't it?

 

..well, it might be, (naturally I don't know everyone else's practice) but I choose to follow Truma's own advice as above which is simple and clear, and avoids all the issues. No need to isolate the power, no need to use a peg. Such advice seems fairly natural to me, and also a byproduct of the design, whereby, if power is also isolated in the vehicle during lay-up, the valve could only be held closed by non-Truma design means (i.e. the peg).

 

aandncaravan - 2016-12-05 9:33 PM

 

If you look at the EBL 99 wiring diagrams you will see there is no fuse for the Frost protection valve, unlike the CBE Derek speaks of. Hence our advice to fit one.

 

..yes, I'm sorry and I'll give you that. I've mis-read the circuit diagram, and with a passive valve in my unit, I have had no reason ever to check it out. (though my habitual practice of manually opening the valve whilst not in use would render it a non-sequitur anyway). My 'vans that have had the older drain valve were all CBE equipped.

 

aandncaravan - 2016-12-05 9:33 PM

 

You advise the repair of any faulty 12v powered Frost protection valve yet they are not cheap. When the automatic function is so very dysfunctional, is that cost effective when manual management gives more desirable operation?

That is backed up, not only by your own use, but by the fact that Truma have completely changed the design of it's replacement.

 

Every single person we have encountered with a faulty valve has elected to manage it manually, usually because, ' we already do'.

 

...actually, I chose my words very carefully - I advised "attention", not necessarily repair (If the valve was using current when open, against design expectations, I would be concerned about its overall state, and certainly wouldn't want to rely on it functioning) . As I've posted above, on balance I would prefer to have the automatic protection, so I would repair/replace with similar (or given lack of availability, the newer 'passive' version).

 

If I wanted full manual control, however, then I'd simply replace with a manual drain valve, at significantly lower cost, and bypass any current drain issues completely (whilst, of course losing any protection from automated dumping).

 

The redesigned valve doesn't, of course, add any new "manual" function as might be inferred from your text above. It is another automated valve that simply doesn't rely on electricity to hold it. The function is much the same (albeit trigger and reset temperatures are slightly different), and similar issues about unwanted dumping exist (and are, IMO, more difficult to bypass with the new design, which I suspect arose from a matter of simplicity and cost of manufacture and installation, rather than anything else).

 

====

 

It seems to me that you're over-complicating what should be a very simple procedure, realising little or no added-value in the process.

 

Follow Truma's advice and leave the valve open during storage and there should be no current-drain issues (or if there are, you'll get a warning that the valve is not working as designed and needs checking out).

 

Any electrical isolation or not can then be dealt with entirely independently of the draining process.

 

(Of course, the great majority of this is irrelevant for those who have the newer, passive, frost control valve)

[Derek Uzzell]

I don’t recall coming across anywhere ‘official’ advice that, after a Truma safety/drain valve (whatever its type) has been opened to drain a motorhome’s water system, the valve should be reclosed to prevent insects/debris finding its way into the drain-tube and on to the valve. Nor ‘official’ advice that leaving the valve in its open position causes the valve’s seal to shrink, which may result in the valve leaking. Both are, of course, possibilities, but I've never heard them mentioned until now.

 

I would have thought that, as there’s no advice from Truma about reclosing the valve after ‘out-of-service’ draining (though there is advice that “the draining socket of the electrical safety/drain valve must always be kept clear (free from slush, ice, leaves etc.) ) general pratice among motorcaravanners will be to leave the valve open after draining rather than reclose it.

 

I wouldn’t contemplate reclosing the valve as a) with the Elasi electric valve it’s going to use current unless the valve’s power-supply is interrupted, b) if the power-supply is not interrupted and the weather gets cold, the valve will open itself unless it has been ‘pegged’ shut, c) even if the water system has beeen carefully drained, if the valve is reclosed and ‘jammed’ there’s every chance that residual water will find its way into the valve’s internals and, not being able to drain through, will freeze in cold weather and cause damage and d) it just seems a perverse thing to do!

 

As there will be plenty of forum members who own motorhomes that have a Truma Elasi or FrostControl safety/drain valve, a poll of what they do regarding reclosing the valve after draining, or leaving it open, may be educational.

 

There’s a lot of intriguing stuff on-line and in motorhome manuals about the Truma valves. It would appear that the 12V supply to the Elasi valve is sometimes provided via the motorhome control-panel’s main On/Off switch, and an (ancient) Chausson manual I have advises that an Elasi valve’s 12V supply should be turned off if the motorhome is to be out of use for more than three days (though the manual does not reveal how to do the turning-off!)

 

While it’s well recognised that, if an Elasi or FrostControl valve spontaneously opens and a motorhome’s pressure-sensitive diaphragm water-pump is switched on when this happens, there’s every chance that the vehicle’s fresh-water tank will be drained as well as the heater. Even if a motorhome has a submersible water-pump triggered by tap microswitches, the water-tank may empty through the drain valve via siphonic action. Motorhomes with a ‘hybrid’ system (with a pressure-sensitive diaphragm pump triggered by tap microswitches) may be OK, with just the heater draining (My Hobby had that type of water system and there was no evidence of tank-siphoning taking place when the valve opened) but ‘jamming' an Elasi valve closed (photo attached) is the usual preventive ploy.

 

The approach described on this French webpage may be of interest

 

http://www.casa-trotter.com/phpBB3/viewtopic.php?t=119

 

A microswitch is employed to ‘sense’ when the valve opens. The water-pump’s 12V power is interrupted, preventing it from pumping the water-tank dry. This won’t address water systems where siphoning can occur (you’d need to have a shut-off valve in the water hose between tank and drain-valve to stop that) but it might be worth being aware of.

[aandncaravan]

People lock the solenoid up, that is established.

For just one person leaving it locked up all winter, by forgetting it's on, could cost them an £80 battery. That dead battery could in turn kill the mains charger and potentially the Alternator. Having a simple way of cutting power when it is locked, can prevent that as well as other benefits.

 

 

Robin Hood, you write,

" It seems to me that you're over-complicating what should be a very simple procedure..........".

 

 

I am not sure spending 5 minutes, and I mean less than 5 minutes, putting in a fuse holder like the one below (literally snipping the cable, stripping the insulation off the ends and then using 2 block connectors to attach it) is very complicated?

It can literally be done in 5 minutes and is so simple I am sure my 6 year old could do it?

The cable carries less than 0.3 amp so doesn't need anything other than the most basic of connections.

 

Isn't the omission of a safety fuse well worth correcting on it's own?

 

 

This whole additional text and discussion is about the merits of spending 5 minutes adding a fuse or not. I just suggested adding a fuse to be able to provide a very simple method of cutting the power when the user wants too in addition to managing it manually.

Just exactly as almost every British built Motorhome and Caravan owner does.

It's not radical, ask a Swift owner.

 

You say it's complicated, I say it's easy, effective and flexible.

 

We clearly see things from a very different perspective.

 

 

 

[Derek Uzzell]

Yes, but that assumes that the ‘average' motorcaravanner will be/feel confident enough to carry out the task you’ve described and that the task itself will actually be as simple in practice as you suggest.

 

You could do it, Robinhood could do it, I could do it, but there will be many motorcaravanners out there who are not DIY and Truma heater-literate and would need much more detailed guidance as to which cable to insert the fuse in, how to make the connections, etc. There will also be Truma heater installations where access to carry out the modification will be far from straightforward.

 

(Out of curiosity I’ve added a poll to the forum to try to establish how motorcaravanners generally treat these valves.)