garage Compartment Temperatures?

[terryW]

For the first time I have a Combi 4 in a garage compartment. Now when I’m static in cold weather I make sure that it’s either drained, fired up or has an electric heater snuggled up to it. Now having experienced -15 to -17 this and last year I am concerned about travelling in such temperatures.

 

Is it likely that while travelling the temperature in a garage compartment could fall low enough for the automatic water drain to activate? I have a long drive to a CL coming up soon and would hate to arrive without water?

 

Anyone had a problem(?)

[Mel B]

Firstly, make sure you heat the water in your tank before you set off, it should stay hot for a long time and therefore you should have a problem with the auto valve releasing, but put something on the auto valve plunger to stop it activating anyway.

 

When I was rummaging around in the garage of our motorhome earlier this afternoon, it was actually quite snug in there and that's without any heating!

[Dave Newell]

I thought CLs had to provide a supply of fresh drinking water? Personally having just experienced a very cold weekend away where our heating failed and we awoke on Sunday to minus 8 C inside the van 8-) (thankfully I had drained the water system but it still popped a hose off a rigid pipe connection with frost) I'd say drain it down and use hand containers for drinking water.

 

D.

[Derek Uzzell]

Mel B - 2010-12-02 10:04 PM

 

Firstly, make sure you heat the water in your tank before you set off, it should stay hot for a long time and therefore you should have a problem with the auto valve releasing, but put something on the auto valve plunger to stop it activating anyway.

 

When I was rummaging around in the garage of our motorhome earlier this afternoon, it was actually quite snug in there and that's without any heating!

 

Mel

 

Rather than repeat myself, I'll refer you to my initial posting on this earlier thread

 

HTTP://www.outandaboutlive.co.uk/forums/forums/thread-view.asp?tid=21718&posts=11

 

If you look at the drawing and description on page 11 of the following

 

http://www.truma.com/downloadcenter/combi46_instruction_fr.pdf

 

you'll see that the Frost-Control drain-valve used with the latest "Combi" heaters has a very different design to the C-Series drain-valve you are familiar with and functions differently. This makes the valve trickier to 'jam' in the closed position.

 

As the standard valve is completely independent from the Combi, turning the heater on won't override the valve and prevent it opening. It's possible, if the drain-valve were sited close enough to a hot Combi, that warmth conducting from the heater would be sufficient to keep the air near the valve above the 3°C opening temperature for a fair while. Certainly, if there's a blown-air outlet in the garage (or plenty of blown-air trunking) and the heater is run in blown-air mode while travelling, the temperature in the garage should stay well above 3°C.

 

However, in present weather conditions, if a motorhome garage is unheated while travelling, I wouldn't surprise me at all if the temperature inside dropped low enough to trigger a Combi drain-valve.

 

Assuming that the valve isn't jammed shut, in order to ensure a Combi drain-valve doesn't open you'd either have to fit Truma's 12V heating option to the valve and have that operating while travelling, or make certain that the air near the valve remained above 3°C. In terryw's case, the latter would mean either running the heater while travelling or, perhaps, rigging up some sort of temporary DIY 12V heating system.

 

 

[terryW]

When I go away I think I will conduct a test and place a min/max thermometer by the heater and carry out a comparison with outside temperature. In the long term I am thinking ahead to the problems of traveling down to Spain in Jan 2012.

 

Yes the CL/CS does have water but despite their best efforts it has been known to freeze, on top of which you have to 'bottle in' to a van. Despite that, wonderful site but soon to go commercial with showers etc due to demand. All this came to a head when the local council carried out a risk assessment prior to a National Club rally and found more than 5 vans on site. Not that you would normally notice and in 15 years never heard anyone complain as it is a very large site with about 20 electric hook-ups run by a great couple.

[Mel B]

Derek, contrary to popular belief I don't read ALL of your postings!

:D

 

If, as you say, the auto valve itself was located NEAR to the boiler though it might prevent it dropping. Failing that, what about heating the water in the boiler, then letting some of it out via the valve (if that is possible), so that there is hot water in the pipe near it which may stop it popping out en-route?

 

 

[lennyhb]

But if it does dump the water you will only loose the 12 Lt in the boiler. Just make sure you reset the valve before turning on a tap or you fresh water supply will be pumped out via the boiler.

 

I found out the hard way in the spring, I thought the boiler was taking a long time to fill up by the time I had twigged what was going on - no water. Lucky there was a tap in the field about 30 ft away.

 

 

[Dave Newell]

Time to get sensible folks! The frost protection valve (often referred to as the Truma dump vavle) is theree to protect the boiler from freezing.

 

If the boiler is subjected to freezing temperatures when it is full of water and cannot dispose of its contents before it freezes it will obviously freeze up itself. If this happens it is going to cost a big wad of cash to sort out!

 

As water freezes it expands and if there is no room for the expansion it will burst, or at the very least severely damage the boiler casing rendering it as scrap metal and leaving you with a big bill for repairs. An Ultrastore water only heater will cost you about £400 plus installataion, a C series or Combi and you're talking over a GRAND!

 

I've already seen two motorhomes that are probably going to need new C series heaters due to frost damage.

 

If there is any chance of frost causing damage to your heater or water heater for goodness sake drain it and don't block the auto drain valve by any means.

 

In edit, I forgot to say this :

Which is less grief, a weekend away in sub zero temps having to use a hand container for drinking water and using a kettle for hot water or coughing up several hundred pounds for a new water heater or more for a combi unit?

 

D.

[terryW]

So far I have had two Combi 4's the last one was fitted internally and not a problem but in both cases the dump valve was in close proximity to the heater so a tank of hot water should give some protection but probably not for a full days driving.

 

With regards to the drain being restricted to10 litres, that is probably true in my case, even if the 'self priming pump' does not prevents the full tank being siphoned I think my heater is slightly higher than the fresh water tank.

 

I suppose the complete solution would be to change the regulator type and run the heater on the move but I'm not sure I would be happy with that.

[Mel B]

Agree Dave, but the question was in relation to whilst travelling and not losing water in the process. The assumption was that when on site the 'van would be connected to the electric hook-up and therefore the boiler would be kept on so it wouldn't be in danger of freezing. If, however, there was any risk of the boiler being frozen, then of course it should be emptied.

[sshortcircuit]

Dave

 

"As water freezes it expands and if there is no room for the expansion it will burst, "

 

I thought it was the converse, in as much as it expands when it thaws, with the same result unfortunately

 

Edit

 

Just checked, which I should do before posting, but water expands 9% when freezing but the burst only shows when it thaws

[Dave Newell]

sshortcircuit - 2010-12-03 10:40 PM

 

Dave

 

"As water freezes it expands and if there is no room for the expansion it will burst, "

 

I thought it was the converse, in as much as it expands when it thaws, with the same result unfortunately

 

Edit

 

Just checked, which I should do before posting, but water expands 9% when freezing but the burst only shows when it thaws

 

I rest my case M'lud!

 

D.

[Brian Kirby]

terryW - 2010-12-03 9:08 AM When I go away I think I will conduct a test and place a min/max thermometer by the heater and carry out a comparison with outside temperature. ..................

I think this is an excellent idea - providing you do it with the boiler dry.  You will presumably have the cab heating on, and the exterior of the van is insulated.  Bulkheads between van interior and garage are not, generally, insulated, so the garage/heater enclosure should be warmed by heat from the van interior, albeit not very efficiently.  By how much will depend on internal van temp, efficiency of insulation, and distance between van heater and Truma.  My guess would be that it won't go that low, but a test is by far the best way to find out, ideally in conjunction with a thermometer placed somewhere in the interior, so that the actual temperature drop can be calculated.  Most vehicles these days seem to have an external temp warning, or thermometer, so you should get the full picture.  Won't translate for anyone else's van, because too many of the parameters will be different, but a good working guide to what to expect on yours.

[Derek Uzzell]

Mel B - 2010-12-03 9:03 PM

 

...Failing that, what about heating the water in the boiler, then letting some of it out via the valve (if that is possible), so that there is hot water in the pipe near it which may stop it popping out en-route?

 

 

You could do what you've suggested, but you would only be 'storing' a tiny amount of hot water in the drain-valve and the water pipework near it. I can imagine this working for a while, particularly if you swaddled the valve with towels (or something) to reduce heat loss from it as much as possible, but I would not be confident that the ploy would be effective during a long journey if the temperature in the motorhome's garage really dropped.

 

(By the way, I wasn't implying that I expected you to have read my earlier posting: it was just simpler and easier for me to refer you to the earlier thread than to rehash what I had said previously.)

[lennyhb]

When it's cold we always warm the van up by running the Truma for 20 min before driving off, not only is the van nice & warm we also have a tank of hot water so the cupboard where the heater is keeps nice & snug all day with no danger of the water being dumped.

 

 

[Guest JudgeMental]

truma water heaters are not insulated so heated water does not stay hot for THAT long..... having a fully winterised double floor van (like me) where truma heating circulates below the floor gives peace of mind winter camping......

 

If your van not designed for winter use, best not to use water boiler or run the risk of breaking it.

[Derek Uzzell]

terryW - 2010-12-03 10:30 PM

 

...With regards to the drain being restricted to10 litres, that is probably true in my case, even if the 'self priming pump' does not prevents the full tank being siphoned I think my heater is slightly higher than the fresh water tank...

 

If a motorhome has a water-pump that operates by sensing a drop in pressure in the water system then, if the pump happens to be switched on when the drain-valve opens, the pump will empty the motorhome's fresh-water tank.

 

If a motorhome has a water-pump submerged in the fresh-water tank and operated by tap micro-switches, if the drain-valve opens then the fresh-water tank may be completely emptied by siphonic action even though the pump may have been switched off at the vehicle's control-panel. I don't believe that the heater being above the fresh-water tank would necessarily prevent this happening, as there's a good chance that siphoning of the tank will begin immediately when the drain-valve opens but before the heater starts to empty. You'd need to test to be sure and, if only the heater drained, be confident that would always happen.

 

If a motorhome has a 'hybrid' system (like my Hobby's) with a pressure-sensitive pump operated by tap micro-switches, then just the heater should empty as the pump (even if switched on at the motorhome's control-panel) will not run when the drain-valve opens and, because the inactive pump will act as a check-valve, siphoning of the fresh-water tank's contents won't take place.

[Derek Uzzell]

Dave Newell - 2010-12-03 10:25 PM

 

Time to get sensible folks! The frost protection valve (often referred to as the Truma dump vavle) is theree to protect the boiler from freezing.

 

If the boiler is subjected to freezing temperatures when it is full of water and cannot dispose of its contents before it freezes it will obviously freeze up itself. If this happens it is going to cost a big wad of cash to sort out!

 

As water freezes it expands and if there is no room for the expansion it will burst, or at the very least severely damage the boiler casing rendering it as scrap metal and leaving you with a big bill for repairs. An Ultrastore water only heater will cost you about £400 plus installataion, a C series or Combi and you're talking over a GRAND!

 

I've already seen two motorhomes that are probably going to need new C series heaters due to frost damage.

 

If there is any chance of frost causing damage to your heater or water heater for goodness sake drain it and don't block the auto drain valve by any means.

 

In edit, I forgot to say this :

Which is less grief, a weekend away in sub zero temps having to use a hand container for drinking water and using a kettle for hot water or coughing up several hundred pounds for a new water heater or more for a combi unit?

 

D.

 

I agree.

 

In terryw's case, the logical strategy would seem to be to drain the Truma appliance before setting off and to refill it when he arrives at the CL.

 

This would ensure that the heater was frost-protected while travelling, but he would still have a full water-tank to commence his CL stay. The 10 litres of water that's normally stored in the Combi would be 'lost'; there would be a need to remember that the water system was out of action during the journey, and the water system would need to be 're-primed' at the campsite., but this would address the concern about the drain-valve opening during transit.

[lennyhb]

JudgeMental - 2010-12-04 9:29 AM

 

truma water heaters are not insulated so heated water does not stay hot for THAT long..... having a fully winterised double floor van (like me) where truma heating circulates below the floor gives peace of mind winter camping......

 

If your van not designed for winter use, best not to use water boiler or run the risk of breaking it.

 

If we have had the heating on in the evening so the hot water is only at at the lower temp, 9 hours later in the morning we still have warm water.

 

 

[terryW]

My thanks to everyone for their thoughts on the subject. I now have a better idea of what do do and plan as follows:

 

1 I have a mains heater in the compartment and will need to use that to bring the dump valve temperature up so I can fill it before I leave.

 

2 Heat the tank prior to departure

 

3 Switch the pump off so if the valve operates then I won't drain the whole system.

 

4 Take a hot water bottle so I can warm the valve up to allow it to be closed again on arrival, if necessary.

 

Can I say as I look out on snow field in splendid isolation that this Forum is great not only as a means of tapping into the wealth of knowledge and experience out there but also for just stimulating your own ideas on a subject. many thanks folks

 

 

[Derek Uzzell]

lennyhb - 2010-12-04 10:11 AM

 

JudgeMental - 2010-12-04 9:29 AM

 

truma water heaters are not insulated so heated water does not stay hot for THAT long..... having a fully winterised double floor van (like me) where truma heating circulates below the floor gives peace of mind winter camping......

 

If your van not designed for winter use, best not to use water boiler or run the risk of breaking it.

 

If we have had the heating on in the evening so the hot water is only at at the lower temp, 9 hours later in the morning we still have warm water.

 

 

Nevertheless, JudgeMental's observation is correct - the water reservoir of Truma combination air/water heaters has minimal insulation.

 

Let's imagine that the water in a C-Series (or Combi) appliance is heated in the evening as a by-product of the air-heating (which is what I understand you are saying), then the water should attain a temperature of at least 40°C.

 

If none of that water were used overnight, then the temperature of the water will fall no lower than the temperature of the air around the heater. In a heated motorhome, and with the heater imprisoned in a cupboard, that air temperature could easily remain above 20°C and, consequently, the water the following morning will still feel relatively warm. However, this is not because the heater has good insulation.

 

If you were to heat the water to 40°C with the appliance (hypothetically) exposed outside the motorhome's protective environment where the ambient air temperature were, say, 0°C, 9 hours later the water temperature would be extremely cold.

 

Truma markets the 14litre-capacity 230V-only "Electroboiler". This is very heavily insulated and claimed to lose heat at just 1°C per hour. Presumably some caravan/motorhome manufacturers fit the Electroboiler (otherwise Truma wouldn't bother to make them!) and, if one always used campsites with EHUs, it might offer a viable (and less expensive) alternative to a gas/230V Ultrastore boiler.

 

[Mel B]

Derek Uzzell - 2010-12-04 9:01 AM

 

By the way, I wasn't implying that I expected you to have read my earlier posting: it was just simpler and easier for me to refer you to the earlier thread than to rehash what I had said previously.

 

Don't worry Dezza (aka Yoda ... not that you look like him I'm sure :$ ) - I know you weren't doing that. :-D I do try to keep up with a lot of the stuff to do with motorhomes but wasn't aware that the new Truma boiler had a different valve set-up ... it's good to learn things! :->

 

One thing I did wonder though, is as the insulation on the Truma boilers isn't that great, would it be possible to add extra insulation, safely, to make them better, I'm thinking maybe cutting down a domestic hot water tank cover might do it? What do you think? :-S

[Derek Uzzell]

Mel B - 2010-12-04 10:51 PM

 

One thing I did wonder though, is as the insulation on the Truma boilers isn't that great, would it be possible to add extra insulation, safely, to make them better, I'm thinking maybe cutting down a domestic hot water tank cover might do it? What do you think? :-S

 

I think you may be referring to Truma Ultrastore water-boilers, rather than Truma combination air/water heaters. I don't know what an Ultrastore is like inside, but Truma's drawings of the appliance seem to suggest that it is better insulated than the combination appliances.

 

An Ultrastore's design would make it much easier and safer to 'blanket' than a combination-heater and I can't find anything in Truma's Ultrastore Installation/Operating instructions about not doing this, or about any requirement to leave clearance around the appliance. So I'd guess that covering the thing should be OK.

 

I understand your thinking, but I would wonder about the practical need.

 

We use the water-boiler part of our C-Series heater primarily to provide hot water for showering. Once we've showered, we won't normally fire up the boiler again until we take another shower (usually not until the next day), hence maintaining the temperature of the water in the boiler during the interval doesn't really concern us.

 

I would not want to try adding an insulating cover to a 'combi' but, even if we had an Ultrastore instead, I don't think I'd bother. A cover should save a small amount of gas during the heating stage and would help to keep the water hotter for longer, but neither of those factors would matter much to us.

 

You might try e-mailing Truma(UK)'s technical people about this - it would be interesting to find out what their advice would be.

[terryW]

I wouldn't insulate a Combi without confirmation from Truma, my main concern is the printed circuit control board may overheat and fail.

 

In my view the gap round appliances should always be no less than that specified in the installation instructions.

 

My last one was under the wife's 3/4's of the bed, kept her warm in the Winter and she made a good gas monitor, plus a carbon monoxide monitor in the compartment of course.

[lennyhb]

As I have said I don't have a problem with my C6000 keeping the water hot, it stays warm as long as you don't draw off any water. With such a small boiler if you draw off 4 litres that will be replaced with 4 Litres of cold water which is a third of it's capacity. So I also think it would be a waste of time insulating it might be be a different case if it were a 50 Lt boiler.

 

Last weekend we were at Setthorns in the New Forest we turned the thermostat down to min & left the heating on all day while we were out walking. At that setting it only just kept the chill off the van but enough to stop the water dumping and fairly economical on gas.