# Truma Frost Protection Valve - Warning



## Nosha (Nov 25, 2008)

As you may know Truma water heaters have a frost protection dump valve.

Well on Saturday night we were 'wilding' at a wedding reception, at about midnight I walked back to the m/h to go and switch the heating on, it was around -1c as I walked across the carpark I heard the sound of running water, as I got to the van I realised that the valve had opened, not normally a problem when parked up at home with the electric turned off, but with the van in use and the electrics on; the water pump had sensed the drop in pressure and had kicked in.

My warning is:- had I not returned a) we could have run out of water - not a real problem, but b) the pump could have run for hours and possibly burnt out!!

I don't know if my water pump can run dry, but it must surely be rated for intermittent use rather than continuous, so next time I'll turn the elecrics off when it's that cold!


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## bevo (Nov 26, 2008)

*dump valve*

hi nosha
           my heater has one of those dump valves, but when i bought the van the salesman showed me a little red platic circlip that you insert in the dump valve whem it is in the closed position.
 works everytime for me.
 live long and prosper.


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## Hymerman (Nov 26, 2008)

Hi there

On the dump valve there a red button that drops down to dump the water, I've got a clothes peg on my one to stop it dumping water!!  Just need to remember to remove it if you're not using the van..

With regards you water pump you can install a switch so that you only turn the pump on when you need it, plus that also stops it cutting in and out during the night if the water pressure drops..  Winner!!:


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## cipro (Nov 26, 2008)

Nosha said:


> As you may know Truma water heaters have a frost protection dump valve.
> 
> Well on Saturday night we were 'wilding' at a wedding reception, at about midnight I walked back to the m/h to go and switch the heating on, it was around -1c as I walked across the carpark I heard the sound of running water, as I got to the van I realised that the valve had opened, not normally a problem when parked up at home with the electric turned off, but with the van in use and the electrics on; the water pump had sensed the drop in pressure and had kicked in.
> 
> ...


 
I got cought on that one but luckly the water pump on the control panel
was in off mode so only lost about 15 lts of water ( well that is what I think the tank holds ) .


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## Nosha (Nov 26, 2008)

Yes thanks, I've also used the clothes peg trick as I was once in catch 22. It was so cold the valve opened, then I dare not put the heater on as there was no water in the boiler to close it off again!!!

So I will either use the peg when I'm out, or try and remember to switch the pump off before going out for the evening!


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## rsvman (Nov 29, 2008)

If you have a truma combi, you can run the heating without any water in them, also if the heater is turned on the auto dump valve will not dump your water out...


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## Kev_Behr (Nov 30, 2008)

*Truma dump valve problems*

Hi Everyone, Newby here,

I just saw that section of thread below, and I would love to know where I could get one of these plastic circlips as mentioned from, as these auto dump valves are a pain in the rear when they don't work correctly.

Cheers Kev



bevo said:


> hi nosha
> my heater has one of those dump valves, but when i bought the van the salesman showed me a little red platic circlip that you insert in the dump valve whem it is in the closed position.
> works everytime for me.
> live long and prosper.


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## cipro (Nov 30, 2008)

Kev_Behr said:


> Hi Everyone, Newby here,
> 
> I just saw that section of thread below, and I would love to know where I could get one of these plastic circlips as mentioned from, as these auto dump valves are a pain in the rear when they don't work correctly.
> 
> Cheers Kev


 
I believe the dump valve can differ from heater to heater although the same make, you can use a clothes peg however on mine the clearances is to small so I use a chain circlip oh yes I now but it works for me.

The other thing about this auto dump pain in the **ss is I like to drop all my water to save fuel on the way home and if you turn off the12v supply the valve will open!!!! ah you say but this only happens when the ignition is off and of cause you are stationary as I found out while in a petrol station, water everywhere did any one else find this out the hard way. No some are saying because since then I have relised that you can atchually just push the cap down manually at any time so that it now the brides job


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## bevo (Dec 22, 2008)

*dump valve*

hi
   i would use a peg also as the circlip i use on mine can be a bit fiddly( no good if youv'e had a drink).
 i'll do that in future.


live long and prosper


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## smifee (Dec 22, 2008)

i knew about the automatic dump valve before i bought my van. one of the first things i did was to have the automatic valve disconnected & a manual valve fitted.

just have to make sure some heat in the van when it gets near freezing.

manual valve about £20 from truma


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## Deleted member 72935 (Jul 31, 2018)

*truma frost protection valve*

hi,

my valve is dropping water no matter what I do with the top valve lever, is it broken. keep reading things about pegs and circlips not sure what or where you would 
put this to stop the water drop. anyway the problem I had while on holiday filled my freash water tank pump did not work. tested pump with live feed it works but cannot fill system because this valve dropping water, so I assume that's why no back pressure, have checked all the micro switches on the taps ect.
would think when power up system pump would run a little before relising no back pressure or keep running this is not happening which also make me think I have other problems or ther is somekind of pressure sensor in line some where which I have not tracked down /.

any help or advice would be good ..


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## witzend (Jul 31, 2018)

The dump valve is usually close to the heater the control nob has to be raised to stop it from dumping water a clothes peg fitted below the knob will stop it dropping if the power is disconnected like in hab batterys removed or disconnected it will also dump the water. A split pin or metal R clip even a length of wire through the hole will also do the job I don't expect the red plastic clip  was intended for the valve. In my van when it dumps, most of the water tank is siphoned out as well so not much water left


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## Fazerloz (Jul 31, 2018)

It makes me wonder why they bother fitting a frost protection valve if everybody stops them from operating. Strangely I never do or have had need to.


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## Deleted member 71750 (Jul 31, 2018)

Bigjohn998 said:


> hi,
> 
> my valve is dropping water no matter what I do with the top valve lever, is it broken. keep reading things about pegs and circlips not sure what or where you would
> put this to stop the water drop. anyway the problem I had while on holiday filled my freash water tank pump did not work. tested pump with live feed it works but cannot fill system because this valve dropping water, so I assume that's why no back pressure, have checked all the micro switches on the taps ect.
> ...



Top valve lever, are you sure you have an automatic valve? Sounds like you have a manual dump valve. Picture might help


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## 2cv (Aug 1, 2018)

I must be one of the 10% with no common sense who has a manual valve as fitted by the van builder and dumps the boiler contents themselves when there is a chance of them freezing.


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## Deleted member 38440 (Aug 2, 2018)

*Dumping at 0°*

If it didn't dump at higher than zero that would be better.


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