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Truma water heater.


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Our '97 Pilot Galaxy has the usual Truma water heater with the dump valve for when the frost strikes. Whilst in France recently I noticed that the water pump was having a little burp every now and then when the system was not being used. Investigation showed that water was dripping from the pipe under the van through which the dump valve operates. Is the valve repairable or does it need to be replaced. Your thoughts and advice would be appreciated.

AGD

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As far as I know neither the old style Truma anti-frost/safety drain-valve (that needs a 12V power supply to remain closed and is probably what your Galaxy has) nor the current valve (that does not require a 12V supply to keep it closed) is designed to be disassembled or repaired, and there’s no maintenance ‘kit’ marketed for either valve. (That doesn’t mean it’s impossible to DIY dismantle the valve and repair it if it leaks, but I’ve never read of anyone doing this sucessfully.)

 

Assuming that your valve is original it will now be 17 years old and the present fault may just be due to the internal seal’s age. If the valve has begun to leak spontaneously, it’s likely that the seal has failed.

 

If the valve had begun to leak after it was recently operated – after you had drained and refilled the heater, say – there may be some debris in it that’s preventing the seal seating properly and allowing the valve to leak when the water system is pressurised by the water-pump. Try opening the valve with the water-pump switched on, as this should blow water through the valve and clear out any debris that might be present. If the valve still leaks afterwards, it’s probably due to a damaged internal seal.

 

I expect you’ve done the obvious and tried opening and closing the valve a few times, and confirmed that the valve still leaks. If you have, it may still be worth trying the water-pump ploy I’ve just mentioned, but it’s more likely that the problem’s with the seal.

 

Replacement frost/safety drain-valves aren’t cheap, so (if you don’t regularly use your motorhome in very cold weather) you might consider fitting a Truma manual safety drain-valve instead and save some money. This would not provide anti-frost protection, but I’ve always considered the ‘automatic’ valves (particularly the 12V one) to be more of a nuisance than a benefit. My Hobby motorhome had the 12V valve and (like many other motorcaravanners) I always used to jam it shut when I was using the vehicle.

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Thank you Derek, your diagnosis is more or less the same as mine, and I did try flushing things through in the hope of solving the problem, but to no avail. I shall take some comfort from knowing that every joint, seal and junction on the system is tight and dry, but I suppose I should have looked underneath the van as my first action and not my last. My know -it -all son always points out that when you are searching for something, it's always in the last place you look.

I'm probably going to the NEC this week so I'll check out prices for replacements, but we are moving to France in February, and the Pyrenees Ski resorts are less than 2 hours away from what we francophiles call Chez Nous , so some automatic frost prevention may be a good idea.

Many thanks

AGD

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If you are going to the NEC show I suggest you discuss what’s best for you with the chaps on the Truma stand.

 

There are on-line indications that the electrical drain-valve may be hard to obtain nowadays and Truma are apparently recommending that the current “FrostControl” non-electrical drain-valve be used instead. Details of the FrostControl valve are given here:

 

http://dealer.truma.com/_anweisungen/Truma-Katalog/pdf_verzeichnis/70_000/70070_80100.pdf

 

As with the electrical drain-valve, there are two FrostControl versions, one with ‘barbed’ connectors to accept flexible water-hose attached with jubilee-clips, and another with “John Guest”-type connectors for use with semi-rigid water pipework.

 

http://www.caravanaccessories4u.co.uk/products/gas/heaters/heater-parts/truma-spare-34020-80200-frostcontrol-flexible-pipe

 

http://www.caravanaccessories4u.co.uk/products/gas/heaters/heater-parts/truma-spare-34020-80300-frostcontrol-john-guest-system

 

Whatever type of replacement valve you decide on, you’ll need to be very careful that you order the correct one.

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For the record, a Truma(UK) representative at the NEC Show confirmed that manufacture of the electrically-operated safety/drain valves used with Trumatic C-Series heaters ceased some while ago. (Retailers may still have the valves in stock, but Truma can no longer supply them.)

 

As I suggested above, Truma would expect a failed electrically-operated valve to be replaced by a “FrostControl” valve. Not needing any 12V power-supply to hold the FrostControl valve closed means that it’s more versatile and can be used with water-heating appliances other than Truma’s “Combi” (I noticed it fitted to Alde systems in Hymers.)

 

Truma does, in fact, offer a 12V heating element (about £30) that can be fitted to a Combi’s FrostControl valve. This is described in Combi Operating Instructions as follows:

 

"Truma supplies a heating element (part no. 70070-01) as an accessory, which is inserted into the FrostControl and fixed in place with a retaining bracket. This heating element heats the FrostControl to approx. 10°C when the Combi is switched on. This means that the boiler can be filled after a shorter time, irrespective of the temperature in the installation compartment."

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FWIW, though I like the idea of no current draw, the newer, non-electric valve is a real PITA.

 

I use my van throughout the year, draining down between use in cold weather.

 

Previously, when I wanted to refill, and the weather was cold enough to trip the valve, the electric valve could be immediately held closed either by turning on the heating, or by judicious use of a clothes peg.

 

The new valve has no electrical connection, and its shape precludes the use of anything simple to hold it closed. Hence, the area in which it is has to be heated for some time to raise the temperature above the "dump point", otherwise I can't fill.

 

I have ultimately resorted to the use of a long piece of wood jammed between the button and an adjacent wall, though the shape and action of the button makes this somewhat unreliable.

 

I'm prepared to leave well alone, but frankly, if I were replacing, and prepared to handle the risk of non-automated drain down, (it's only ever happened in mine when I didn't want it to!) then I'd consider using a simple manual lever operated drain-down cock (which would also be much, much cheaper!)

 

 

 

 

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Agree Robin the old valve was mounted by the tank and would be fine with just the hot water on for a few hours a day. Like yours the new one is remote from the tank, although close enough to be OK if the heating is running not sure how it will cope with just the hot water on.

The new valve is supposed to open at 3 deg, the old one was 5 deg many a time I found the water dumped on the old van when the temperature inside the van was nowhere near as low as 5 deg.

 

Only had the new van a few months so don't know how it's going to perform, but if is does not dump until down to 3 deg should be OK when outside temperatures are below zero and that doesn't happen too often down here.

Hopefully with the fresh water tank lower than the valve it won't drain the fresh water tank like it did on the last van, a pain in the butt arriving at destination to find an empty water tank thinking you had a full one.

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lennyhb - 2014-10-18 12:49 PM

 

Like yours the new one is remote from the tank, although close enough to be OK if the heating is running not sure how it will cope with just the hot water on.

 

...not quite; my current van has the dump valve right next to the boiler.

 

My understanding is (and it always seemed to work for me) that, for the previous electric valve, turning on the boiler in any of its modes kept the solenoid on the dump valve energised, and thus maintained closure.

 

Whilst I preferred to use a peg on my previous van (since this operated in transit without the heating), it was useful sometimes to simply put the heater in heating only mode so I could immediately fill up.

 

Neither of the above are available on the new valve (though it should be possible to fashion something to replace the peg approach (maybe a business opportunity ;-) )

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Robinhood - 2014-10-18 1:31 PM

 

 

My understanding is (and it always seemed to work for me) that, for the previous electric valve, turning on the boiler in any of its modes kept the solenoid on the dump valve energised, and thus maintained closure.

 

Nope, the old valve required permanent power to keep it closed, if power was lost it would dump. There was only 2 wires to the old valve for the 12v power & 2 situations when it would dump, low temp or no power.

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Derek Uzzell - 2014-10-18 2:49 PM

 

Robinhood

 

I believe you’ve overlooked my earlier posting of 18 October 2014 7:39 AM that mentions the Truma 70070-01 heating option for the Frostcontrol valve - though jamming the current valve closed is another matter.

 

Sounds dangerous to me, forgot you switched it on temp drops overnight to -10, boiler full of water doesn't dump = wecked boiler.

 

At least jamming a bit timber in there each time you will probably remember it, with the electric heater there is a tendency to leave it on all the time.

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Derek Uzzell - 2014-10-18 2:49 PM

 

Robinhood

 

I believe you’ve overlooked my earlier posting of 18 October 2014 7:39 AM that mentions the Truma 70070-01 heating option for the Frostcontrol valve - though jamming the current valve closed is another matter.

 

....no Derek, I saw that (and I already knew about it), but another £30+ to resolve an issue that wasn't there with the previous valve is a bit steep.

 

I know Lenny uses gas - invariably when the temperatures are low I am on hook-up, and if there is any possibility of very low temperatures, I simply leave the boiler on its lowest water setting overnight to avoid any issue. (something I've also done on gas on the odd occasion we're off-grid). Between trips it is drained anyway (and I also wouldn't mind if it dumped then).

 

My major issue is the inconvenience when wanting to refill at ambient temperatures less than 7C.

 

Mine would warm reasonably quickly (but not immediately) with the heating on, but anyone with a remote location for the valve could have a far greater issue (and the heated valve option might be more attractive).

 

lennyhb - 2014-10-18 3:24 PM

 

Sounds dangerous to me, forgot you switched it on temp drops overnight to -10, boiler full of water doesn't dump = wecked boiler.

 

At least jamming a bit timber in there each time you will probably remember it, with the electric heater there is a tendency to leave it on all the time.

 

Whilst instructions are a bit difficult to find, I believe the function added is logically (if not physically) similar to the previous, electric, valve, in that the switching is provided by the heater being turned on in any of its modes - hence, even if it were forgotten, the heater should be warm enough not to freeze the contents.

 

 

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Robinhood - 2014-10-18 3:50 PM

 

Whilst instructions are a bit difficult to find, I believe the function added is logically (if not physically) similar to the previous, electric, valve, in that the switching is provided by the heater being turned on in any of its modes - hence, even if it were forgotten, the heater should be warm enough not to freeze the contents.

 

 

I don't see that as the valve's dump action is solely mechanical, if is kept heated above the dump temp it will never dump.

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As Robinhood says, the 70070-01 option is intended to heat the Frostcontrol valve only when the Combi heater is turned on and (presumably) won’t be vulnerable to frost damage. The option sidesteps predictable problems when refilling the heater at low ambient temperatures and is perhaps the only logical approach when a non-electrical 'temperature-sensing’ drain valve is involved.
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I thought I had got this sorted, until you lot joined in, now I'm not so sure. Whilst we still live in the UK the van stands by the side of the house and I run a power cable to it with which I charge the batteries and run a 500 watt oil heater with a thermostat. I drain the tanks as best I can, and so far I have had no problems. When we move to SW France we will still be able to store the van by the house and run a power cable to it, and the climate is really not much different to Berkshire in winter, so when the van is not in use it will be pretty much the same as now. The difference will be that at last we will be retired. No commitments, so as we are only a couple of hours from the ski slopes, and about the same from the coast, or from Spain, we could easily be tempted ,at the drop of a hat, to jump into the van and go somewhere at any time, and we could encounter some temperatures cold enough to freeze things, and now I'm worried about the water heater freezing up whilst we are on the road, because the back of the van gets pretty cold,( we peg a blanket up behind the cab seats when it's cold so we keep lovely and warm but the back of the van is really cold.) How much of a problem is it?

AGD

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Assuming that you were planning to fit Truma’s “Frostcontrol” drain-valve, you can find English-language installation and operating instructions (respectively) here (Page 15)

 

http://dealer.truma.com/_anweisungen/Truma-Katalog/pdf_verzeichnis/30_000/34020_09600.pdf

 

and here (Page 12)

 

http://dealer.truma.com/_anweisungen/Truma-Katalog/pdf_verzeichnis/30_000/34020_05100.pdf

 

You’ll note that the Frostcontrol valve should be installed “in the immediate vicinity” of the heater and is designed to open automatically "If the temperature around the drain valve is below about 3°C”.

 

To provide realistic anti-frost protection the valve must open before there’s any likelihood that the water in the heater has begun to freeze - hence the 3°C valve-opening temperature.

 

If you are asking whether it’s possible, when driving your motorhome when the outside temperature is well below freezing, for the vehicle’s living-area water system to freeze up, the answer is of course “Yes” - if the temperature of the water at any point in the system reaches freezing-point, the water will freeze. A Frostcontrol valve should drain the heater before damage can occur, but it won’t prevent water in the rest of the system from freezing.

 

Only a relatively small percentage of motorcaravanners will habitually drive their vehicles in very cold weather. I don’t know how many of these have had water-system freezing problems when so doing, but I’m guessing it will be few as the potential problem is plain and some measures can be taken to guard against it (eg. choosing a suitably ‘winterised’ motorhome and/or maintaining an above-freezing temperature in the vehicle’s interior when travelling).

 

As you are bound to know when you are driving how cold the weather is outside and are familiar with your Pilote Galaxy’s water system and its insulation properties, you should be able to decide at the time what the chances are of the water system being harmed. First thing to do, I would have thought, is to make sure that your motorhome’s cab-heater is functioning as well as it can (admittedly usually not very well with older Boxers/Ducatos) so that you can dispense with the comfort blanket...

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....much will depend on how much of the vehicle heater's output will find itself to the vicinity of the boiler (and such things as pipes).

 

It doesn't take much to maintain an ambient temperature above freezing, and (at least with my various 'vans) I haven't been too concerned about filling up and travelling whilst the outside temperature is hovering around zero. (continental temperatures may drop somewhat lower on a regular basis)

 

As already said, though, I do drain down between uses (since I don't heat the 'van on the drive) because, although the (expensive) heater is largely protected by the dump valve, other plastic parts (such as taps, etc.) are vulnerable to freezing and cracking, and tend to retain water unless "blown through".

 

This is why I liked the previous valve better, since, as discussed, it had both a mechanical and electrical method of immediately closing it ready for rapid refilling (and, if confident about the level of in-transit heating, a peg used to close the valve could be left in situ whilst travelling, otherwise it would dump well above zero).

 

I think somewhere up the thread Derek mentioned that you might still get an "old stock" original valve if you searched.

 

There is one here:

 

http://www.caravanbreakers.net/www.caravanbreakers.net/info.php?p=2&pno=3&pid=2978699&cat=66209&ack=9&search=&sought=

 

...which, though from a breakers, purports to be new, and is somewhat cheaper than I can find the new-type valve online.

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Robinhood - 2014-10-20 10:14 AM

 

....much will depend on how much of the vehicle heater's output will find itself to the vicinity of the boiler (and such things as pipes).

 

It doesn't take much to maintain an ambient temperature above freezing, and (at least with my various 'vans) I haven't been too concerned about filling up and travelling whilst the outside temperature is hovering around zero. (continental temperatures may drop somewhat lower on a regular basis)

 

As already said, though, I do drain down between uses (since I don't heat the 'van on the drive) because, although the (expensive) heater is largely protected by the dump valve, other plastic parts (such as taps, etc.) are vulnerable to freezing and cracking, and tend to retain water unless "blown through".

 

I have never had any problems when in use as I found that if the heating has been on during the evening there is normally enough latent heat in the van so as not to cause any problems.

 

I have recently fitted a CP plus controller, which makes life a lot easier if going out for the day and it's below zero, I can set the heating to come on at say 8 or 10 deg, it will take the chill off the van without wasting too much gas, likewise could always set a predetermined temperature overnight.

 

 

 

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  • 1 month later...

Just had the coldest night of the season so far, we were recording 3.5 deg about 9 am this moring check local weather station (about 2 miles from us) they recorded a low of +1.8 deg at 7:20 am.

Check the van dump valve closed, the old van with the electric valve with outside temperatures of + 5 to 6 deg.

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The 3.5°C temperature you mention should (in principle at least) not cause a current Truma FrostControl safety/drain valve to open. Truma’s advice about the valve is

 

"If there is a risk of frost (at approx. 3°C ambient temperature), the FrostControl opens automatically and releases the water in the boiler to the outside via a draining connection.

 

The drain valve can only be closed again manually and the boiler filled again at an ambient temperature of around 7 °C.”

 

The equivalent temperatures for the previous electric valve were slightly higher. Truma’s advice was

 

"If the temperature at the safety/drain valve is less than 4°C, the water contents may discharge on its own accord if the appliance is not in operation (also if there is a failure). To avoid water loss, switch the device on (Summer or Winter mode) and close the safety/drain valve at the control knob by raising it up.

 

Without heater operation, the safety/drain valve can only be closed again at temperatures above 8°C”.

 

As Robinhood has pointed out, an advantage of the electric valve over FrostControl was that, if it were wished to fill the water system when the air temperature at the valve was 8°C or lower (when an open valve would not stay closed), it was a simple matter to close the valve by turning on the Truma C-Series heater or by temporarily holding the valve’s control-knob in its raised position (eg. via a clothes-peg). To do similarly with FrostControl means adding a Truma heating option to the valve or somehow managing to jam the valve’s push-button in its closed position.

 

Conversely, a major advantage (for Truma) of FrostControl over the superseded electric valve is that, while the latter was designed to be usable only with Truma C-Series combination air/water heaters, the manually-operated FrostControl valve can be employed to frost/protect all Truma water-heating appliances, including “Combi” air/water heaters and Ultrastore, Electroboiler and Alde Compact boilers.

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  • 2 months later...

As a new motorhomer we find ourselves in a Lunar Champ with a Truma 14 litre, gas only water/air heater. In cold weather the electric cutoff dumps the water contents of the heater, as expected, but on several occasions the entire fresh water tank has been dumped too, presumably through the heater.

 

I haven't got to the bottom of this but it either does so regardless of electrical power, or may require power to the heater to pump the fresh water overboard. Is this normal? If not, any idea where the fault might lie?

 

We have experienced this while travelling, with the heater off (as we don't have the cowl extension). It's a bit disconcerting to arrive somewhere and discover no water on board. On site, with a hookup, we use a stand-alone electric heater instead of the gas heater, which heats the accommodation space, but may not adequately heat the Truma unit to prevent it dumping...

 

Any clues, gratefully accepted.

 

Newbies_who_live_in frigid_Scotland_and_wish_to_winter_camp...Keith

 

 

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Welcome to the Out&AboutLive forums, Keith.

 

You haven’t provided details of which model of Lunar Champ you own and its year of manufacture, but I’m guessing that its air/water heater is a Truma C-Series ‘combination’ unit, either a C-3402, C-4002 or C-6002.

 

These heaters all have a 12-litre water capacity and the flue that includes the heater’s gas-burner air-intake and burnt-gas exhaust is normally led through the motorhome’s side (or sometimes rear) bodywork. The intake/exhaust flue can be led upwards within the motorhome’s interior to come out through the roof, but this is much less common than the flue emerging through the motohome’s side (or rear) ‘wall’. Consequently, I’m a mite perplexed by your mention of a “cowl extension” as, although extensions are available for a roof-mounted flue, they would not normally be fitted when the vehicle is being driven, and no extensions are available when the flue is wall-mounted.

 

If a motorhome is fitted with a Truma combination air/water heater and the water system includes a submerged water-pump (ie. the pump is within the freshwater tank itself) rather than a diaphragm-type pressure-sensitive pump, then there's every chance that, when the Truma safety/drain-valve opens, water will commence siphoning from the main water tank. As water flows from the heater through the safety/drain valve, water will simultaneously be ‘pulled’ from the motorhome’s freshwater tank to be lost through the safety/drain valve. It's possible that, with some water systems, the siphoning process would cease when the heater has emptied, but received wisdom seems to be that siphoning usually continues until the freshwater tank is completely drained.

 

This has been discussed on the forum (and in motorhome magazines) in the dim past, but (other than swapping the submerged water-pump for a diaphragm type) there seems to be no optimal solution to prevent siphoning happening. You could (as many people have done, including me) jam the safety/drain valve closed while the motorhome is being used (not the best idea though if the weather is really really cold) and switching the heater on will (should!) prevent the electric safety/drain valve opening.

 

Inserting an on/off valve in the water hose leading from the freshwater tank to the safety/drain valve would allow the tank to be isolated and would prevent siphoning should the safety/drain valve open, but this approach would undoubtedly prove to be a nuisance in practice (and you’d need to remember to always close the supplementary on/off valve when the weather was cold).

 

The electric safety/drain valve is designed to open if the temperature at the valve is less than 4°C. If the safety/drain valve has opened, unless the heater is then turned on, the valve can only be closed again if the temperature at the valve is above 8°C.

 

As a ‘valve jammer’ I was very careful to un-jam the safety/drain valve when my motorhome was out of use during the winter (when I would also have completely drained its water system, of course) and I never used the vehicle for things like skiing trips. So jamming the valve closed wasn’t really a cause for concern for me. My Hobby motorhome’s water system was also of an unusual type that, even if its diaphragm water-pump was switched on, only the Truma heater would drain if the safety/drain valve opened. Consequently, even if I had not chosen to jam the valve shut, the worst that could have happened is that the heater would have drained.

 

Realistically then, if you want to ensure your Champ’s freshwater tank does not empty in very cold weather and don’t want to alter the water system, you'll either need to have the heater operatiing or jam the safety/drain valve closed.

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