Truma Heating/Hot Water Drain Valve

[Sharon the Cat]

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.

 

[Siimplyloco]

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.

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

 

[dave and mary]

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:

 

[Sharon the Cat]

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.

 

[Siimplyloco]

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.

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

 

[El Veterano]

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.

 

[Sharon the Cat]

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.

 

[maingate]

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

 

[Sharon the Cat]

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

 

[gaz2676]

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:

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...

 

[witzend]

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

 

[m30]

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

 

[Tezza33]

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,

Without heater operation, 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

 

[oldpolicehouse]

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

 

[philstoke]

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.

 

[Siimplyloco]

Hello

I don't understand all this cloths peg and zip tie business.
SNIP
I think you have a fault and the dealer is spinning you a tale. As they do.

Blue Skies

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

 

[Deleted member 8180]

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.

 

[Tezza33]

Hello

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


Blue Skies

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

 

[windysurfer]

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:

 

[onion]

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