# Truma Heating/Hot Water Drain Valve



## Sharon the Cat (Nov 21, 2013)

We have one of these, the valve was held closed by a cable tie when we got it. When the weather turned colder we took the cable tie off. When we went to drain down the system a couple of days later the whole water tank was empty.

Extracts from manual:

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

I thought this was designed to empty the contents of the boiler only. Have I got it wrong and when the boiler empties the whole fresh water tank will eventually empty out as well?

If this is the case I suppose we need to keep the cable tie on when using the van but remove it when we park it up in winter???

I want to get this right because we are in the van tomorrow night & the temperature will definitely drop below 4°C outside. I don't want to wake up to no water for the kettle & no flush.


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## Siimplyloco (Nov 21, 2013)

Sharon the Cat said:


> We have one of these, the valve was held closed by a cable tie when we got it. When the weather turned colder we took the cable tie off. When we went to drain down the system a couple of days later the whole water tank was empty.
> 
> Extracts from manual:
> 
> ...



By a remarkable coincidence, this happened to us the first time we tried the boiler out. The fresh water tank empties through that valve as soon as the pump is activated by turning any tap. We went straight back to Viscount and they told us it was a common problem. They fixed it shut with tie wraps for our weekend tryout trip, and they have now fitted a manual valve.
John


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## dave and mary (Nov 21, 2013)

Can not understand why you need a cable tie on the tap, but yes when you empty the boiler it will also empty the water holding tank., as when you open the tap you are realising the presser in the system. We find that when we are using the van ( actually living in it ) have never had a problem with it freezing up but on our return home we always drain boiler and holding tank and open all taps so it can drain.

Well that is with our system.


   :drive:    :drive:


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## Sharon the Cat (Nov 21, 2013)

dave and mary said:


> Can not understand why you need a cable tie on the tap



The dealer said the cable tie was there to stop it draining accidentally.

If we don't have the cable tie on we won't have any water on Saturday morning.
:scared:
Why do Truma think that water freezes at +4 degrees C?

Ah sorry Dave & Mary - It isn't just a physical tap, it is a safety/drain valve that is held closed by a electrical coil.


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## Siimplyloco (Nov 21, 2013)

Sharon the Cat said:


> The dealer said the cable tie was there to stop it draining accidentally.
> 
> If we don't have the cable tie on we won't have any water on Saturday morning.
> :scared:
> ...



Yes, the coil fails and the water comes out! Water is at its maximum volume at 4C, just when it can do the most damage to pipes and boilers.
John


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## El Veterano (Nov 21, 2013)

On my Truma the valve only dumps the water in the boiler itself unless the water pump is left on, then it will empty the fresh water tank as well. The Truma will still give heating though without water in the boiler. I use a large spring clip on the valve to keep it shut while we use the camper in the winter.


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## Sharon the Cat (Nov 21, 2013)

El Veterano said:


> On my Truma the valve only dumps the water in the boiler itself unless the water pump is left on, then it will empty the fresh water tank as well. The Truma will still give heating though without water in the boiler. I use a large spring clip on the valve to keep it shut while we use the camper in the winter.



That was my understanding of how it should work but the manual in not clear. 
I note that the manual says Heating operation is basically possible without restriction with or without water content. so may be ours is the same as yours. The pump was definitely not on but the tank may have been low.


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## maingate (Nov 21, 2013)

From what I have read on various forums, a clothes peg is the 'must have' accessory for Truma dump valves.


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## Sharon the Cat (Nov 21, 2013)

maingate said:


> From what I have read on various forums, a clothes peg is the 'must have' accessory for Truma dump valves.



The dealer was surprised to find a cable tie and told us it would normally be a clothes peg


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## gaz2676 (Nov 21, 2013)

dave and mary said:


> Can not understand why you need a cable tie on the tap, but yes when you empty the boiler it will also empty the water holding tank., as when you open the tap you are realising the presser in the system. We find that when we are using the van ( actually living in it ) have never had a problem with it freezing up but on our return home we always drain boiler and holding tank and open all taps so it can drain.
> 
> Well that is with our system.
> 
> ...



i think they tie it shut becos i think when driving along it can rattle and be shook enough to open and empty yer tanks i seem to remember someone had same probs with theyres a few years ago same solution or change the tap....
hope you and our mary are good take care bud...


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## witzend (Nov 21, 2013)

Yep clothes peg on mine when I release it all the water comes out wether pumps on or off


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## m30 (Nov 21, 2013)

If your using the van, why would the temperature get below 4 deg? is the valve fitted externally or in a locker that doesn't get any heating?

Stu


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## Tezza33 (Nov 21, 2013)

On my Hymer it is inside the wardrobe where the hot water/heating system is, as others have said it empties the fresh water tank but I always have 1/4 of a tank left when this happens, it doesn't empty it all because the dump valve is higher than the bottom of the tank so it cannot empty any of the water that is below that level, it has only happened once when I have been using the van and it was because we were low on gas so the previous night we didn't heat the water or the van and the temperature dropped too much.
 I always peg mine now when we are travelling because sometimes we have to pay for water or the taps are frozen and you cannot get any,


			
				 Sharon the Cat said:
			
		

> *Without heater operatio*n, the safety/drain valve can only be closed again at temperatures above 8°C!


 Because I have some water left I switch the heating and water on, as soon as I do that the valve can be closed and I can then pump water to the hot water tank


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## oldpolicehouse (Nov 21, 2013)

Hello

I don't understand all this cloths peg and zip tie business.
The valve is there to protect the boiler from freezing in very cold conditions. It should not empty your water tank unless you have left the pump on.
In our Rapido the manual says it will operate when the temperature falls to 3 degrees in the van.
If you are away using the van this will not occur unless you are really hard. We have been skiing in the Alps with nightime outside temperatures down to -20 and this valve will not open. Yes it does work because I've left the van outside my house in cold weather and found it has opened.
You should be able to just fire up the heating and it will reset after a short time. You do not need water in the boiler to fire up the heating.

I think you have a fault and the dealer is spinning you a tale. As they do.

Blue Skies


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## philstoke (Nov 21, 2013)

Thats interesting to know than you can run the heating without any water.
I had a look at my 03 Rapido the other day and had it plugged into the mains and went to switch the heater on and the lights did not come on in the control dial.
Looked at the valve and it has opened, I pulled it closed, tried the heating again and it fired up, but I was worried because steam started to come out of the vent, obviously from a little water in the system.


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## Siimplyloco (Nov 21, 2013)

oldpolicehouse said:


> Hello
> 
> I don't understand all this cloths peg and zip tie business.
> SNIP
> ...



I understand it because as pointed out earlier, it's a common fault, and the commonest way to prevent the electrically operated valve from opening is with a cable tie or a clothes peg! We now have a manual valve which I must remember to operate from time to time....
John


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## Mastodon (Nov 21, 2013)

this is what you need... The valve is supposed to trip at or below 4 deg c. When ours goes the boiler empties and the water tank siphons out as well. Probably depends on the tank setup. We gag ours to prevent accidental dumping.


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## Tezza33 (Nov 21, 2013)

oldpolicehouse said:


> Hello
> 
> It should not empty your water tank unless you have left the pump on.
> 
> ...


Maybe that is true on yours, on the Hymer the valve is situated on the pipe from the fresh water tank to the heater so when it opens it drains both, but as I said on mine it is higher than the bottom of the fresh water tank so I get left about 40ltrs

If you have a pressure activated pump it will empty the fresh water tank whatever your set up


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## windysurfer (Nov 21, 2013)

I have the same safety valve fitted to mine, it normally just drains the boiler and hot water taps but on the odd occasion it does empty the fresh water tank. I think it may be dependent on how much water is in the tank as I think it may syphon out the water if there enough in. Only explanation I can think of:idea:


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## onion (Nov 21, 2013)

I have this in my laika the only time it's a problem is filling from empty but just put the heating on when filling & it's fine, I keep the water heater on at low in this weather all night, as the boiler is under the bed & keeps it nice& warm& doesn't use much gas, 2 nights away this week I used £1.08 in gas & water was not of


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## Brian the snail (Nov 21, 2013)

Haven't had the Truma Frost control drain the tank, mainly because I had already drained it but our tank sits inside the van on the same floor level as the Truma and a combination of gravity and syphon would definitely cause the tank to dump most of its contents. We don't have a pressurised pump system so that wouldn't affect the situation. 
Normally for winter use we are only out a couple of nights so as soon as frost is forecast we drain the system and carry a 10 litre bottle of water, generally satisfies our needs.


Clive  :juggle:


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## Touringtheworld (Nov 21, 2013)

*Funny you should say that......*

I went around ours on Tuesday opened all the taps on everything. As a precaution rang the van builder about the Truma and its ability to dump at 4 degrees, he replied "don't worry about that we have fitted a manual tap because they are a pain the bum, just flick it up, jobs a good 'un" The van was brand new this year, I'm glad I phoned them. 

I await any other little mods as they come along.


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## Sharon the Cat (Nov 22, 2013)

onion said:


> I have this in my laika the only time it's a problem is filling from empty but just put the heating on when filling & it's fine, I keep the water heater on at low in this weather all night, as the boiler is under the bed & keeps it nice& warm& doesn't use much gas, 2 nights away this week I used £1.08 in gas & water was not of



Might try that tonight as it's under my side of the bed.


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## oldpolicehouse (Nov 22, 2013)

philstoke said:


> Thats interesting to know than you can run the heating without any water.
> I had a look at my 03 Rapido the other day and had it plugged into the mains and went to switch the heater on and the lights did not come on in the control dial.
> Looked at the valve and it has opened, I pulled it closed, tried the heating again and it fired up, but I was worried because steam started to come out of the vent, obviously from a little water in the system.



Hello
Yes it's definitely no problem.
I've bought 2 Rapidos from Wokingham Motorhomes
I went out to the van one cold and frosty morning and the boiler safety valve had opened.
I scratched my head for a while wondering how I was going to get it to stay shut.
I rang Paul (a really helpful guy)at Wokingham Motorhomes. He said straight out " fire up the heating " I said "but there is no water in the boiler"
Does'nt matter he said.
I don't think he would have given me this advice on a fairly new motorhome still under warranty unless he was sure it was ok.

Blue Skies


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## Sharon the Cat (Nov 22, 2013)

oldpolicehouse said:


> Hello
> Yes it's definitely no problem.
> I've bought 2 Rapidos from Wokingham Motorhomes
> I went out to the van one cold and frosty morning and the boiler safety valve had opened.
> ...



It is quite clearly stated in the manual.

We want to fill our tank today, so we closed the valve & to keep it closed we have upgraded to the deluxe clothes peg and binned the mkI cable tie.


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## daveg (Nov 23, 2013)

I've just suffered from the system draining down on our, new to us, Hymer. A large'ish wire paper clip, opened out a bit, fits nicely in the groove at the bottom of the drain button and holds it shut. I couldn't find a deluxe peg strong enough to hold it


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## seadogjon (Nov 23, 2013)

hi all,,is this drain valve usually right by the boiler.cant find it any where ,theres a pipe sticking out under van ,like adrain but seems to disapear under the boiler.after a hard frost last night (minus 1 in static) no water was dumped out,got a drain valve on fresh water tank but cant find the boilers,,going wild all december so dont want to knacker it now.any clues,


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## iampatman (Nov 23, 2013)

*Same van, same problem*

Hi Sharron,
I think we have the same van, a Lunar Premier 592? Exactly the same thing happened to us a week or so ago. We were in France and the van was parked up for a few days at our daughter's house with the water tank empty. We filled up before we left and it was pretty cold, an hour or so down the road we stopped for a cuppa and water was pouring out. Lifted the bed, hit the switch and it just kept popping up again!!! Eventually it closed but we'd lost nearly a tank full. We filled up a few villages down the road and it hasn't happened again 'cos we're living in the van and it's not been below 4deg (although it's pretty nippy tonight in Gandia just  It's funny, when we bought the van there was a clothes peg on the floor next to the switch and I thought it must have just fallen in there somehow.
Pat


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## Sharon the Cat (Nov 23, 2013)

iampatman said:


> Hi Sharron,
> I think we have the same van, a Lunar Premier 592? Exactly the same thing happened to us a week or so ago. We were in France and the van was parked up for a few days at our daughter's house with the water tank empty. We filled up before we left and it was pretty cold, an hour or so down the road we stopped for a cuppa and water was pouring out. Lifted the bed, hit the switch and it just kept popping up again!!! Eventually it closed but we'd lost nearly a tank full. We filled up a few villages down the road and it hasn't happened again 'cos we're living in the van and it's not been below 4deg (although it's pretty nippy tonight in Gandia just  It's funny, when we bought the van there was a clothes peg on the floor next to the switch and I thought it must have just fallen in there somehow.
> Pat


Hi Pat
Yes same van. To reset the valve when temp is below 8 degs just switch the heating on. It works without water.
I downloaded a copy of the manual from the Truma site.


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## lotty (May 4, 2014)

Our Truma boiler recently dumped the water on a cold night a couple of weeks ago. I didn't realise until I used the van and filled up with water only for it to come out from under the van as it was filling, lol. 
We pulled up the drain switch, filled up and off we went. 

The problem we have now is that it doesn't seem to have sealed? Every time I use a tap or the toilet flush, water comes out of the boiler under the van?? Can anyone advise on what I can try to stop it? 

It is not effecting the use of the heating or taps, just p-ing water out?

Thanks 
Lotty


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