Truma dump valve again (1 Viewer)

Duck Truck

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I think the elbow would help
If not much heat coming through it the small amount of warm air is coming in above the dump valve
Hot air rises so it probably isn't warming the valve.
Fit the elbow it's got to help
Kev
 

Lenny HB

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I still do not see how and area that is inside a van that is in use is going to get down to 3 deg, my money is still on a faulty valve.

Hopefully when the OP logs back on he will let us know night time temps etc.
 

two

Aug 4, 2011
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Whilst I like the facilities all together, as you have in your locker, the dump valve is going to operate in cold weather if there are any draughts through the locker. You may have a 2” have a hole for the EHU socket – I’d check that. As hot air rises, I’d extend the warm air outlet to the base of the valve. Lagging may do the trick as long as you draw enough hot water to keep the valve warm. I’d prefer lagging to strapping the button in because the valve will still work should you forget to remove it.

I don’t know much about the electrical override option, but think it may only function with mains (EHU) available, so not so good when running on gas alone.

A draught can freeze the water in a pipe. I’ve experienced that at home after removing an outside tap and leaving a ¾” hole unblocked. The incoming air came past some pipes in a cupboard and froze them, even though the place was heated. Moving water is unlikely to freeze, though.

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Lenny HB

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Lagging may do the trick as long as you draw enough hot water to keep the valve warm. I’d prefer lagging to strapping the button in because the valve will still work should you forget to remove it.
Drawing hot water won't help as no hot water flows through the valve it will only cause the boiler to fire up, which I think we have already established is too far away.
You may have a 2” have a hole for the EHU socket
Certainly doesn't help the situation, I assume there is a flap that closes after the lead is plugged in?
I don’t know much about the electrical override option, but think it may only function with mains (EHU) available, so not so good when running on gas alone.
The heater is a low current 12v device which only operates when the boiler is on.
 
Last edited:
Oct 29, 2008
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Whilst I like the facilities all together, as you have in your locker, the dump valve is going to operate in cold weather if there are any draughts through the locker.

I don’t know much about the electrical override option, but think it may only function with mains (EHU) available, so not so good when running on gas alone.

Wrong. The dump valve is designed to protect the boiler and will not operate as long as the boiler is switched on if it has the electrical connection.

This is not just for use on EHU and works all the time. My last van had it and was faultless for the 7 years I had the van.

If the valve is fitted away from the boiler in a double floor it should have the electrical connection. If it doesnt it should be fitted close to the boiler.
 

two

Aug 4, 2011
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Any idea what current the 12V option draws and is it on all the time?
Whether the dump valve gets warm from the flow of hot water will depend on how it's been plumbed and the water will only flow past the back anyway. But that may be enough.
At the end of the day, the mission will be to prevent the temperature of the dump valve from falling below its trigger point (3°C?).
 

Fletton

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I still do not see how and area that is inside a van that is in use is going to get down to 3 deg, my money is still on a faulty valve.

Hopefully when the OP logs back on he will let us know night time temps etc.

It was about -5 at 12am but may have gotton colder later... temp in locker showing below 5 on gauge in there...

The other thing is ... if water is on and DV operates.... As water syphons out and empties fresh tank - boiler kicks in - trying to warm water as cold passes through... Have used 34ltrs of LPG in 7 days with two DV water dumps!!!!...

I've bought some domestic "overflow" pipe and a couple of elbows for £2.50.. to try... although its slightly smaller i can make it fit... and see.... but I'm aware that with no heating on.... it may (will) still dump!...

I'm begining to think that because the valve in on the "lower" part of the double floor - coldest part... I may have to consider getting the heater.. because when living area reaches temp and turns heating off... locker may (will) be cooler than Hab area.. sort of thing..

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two

Aug 4, 2011
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Agree that, whist your arrangement provides a neat collection of services in one place, it's not the best solution for winter time. Especially if you visit the locker for something.
 

Duck Truck

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John
In winter when we go away in order to stop the dump valve operating it's important to leave the heating on 24 x 7
not just the hot water. During the day when we are out skiing we set the heating to low, the temp during the day is usually warmer.
When we are sat in the camper in the evening the heating is cranked up. When we go to bed we turnthe heating lower but enough to ensure the heater blows most of the night if the temperature drops.

Do you know where the internal temp sensor is located?
If that is located in a particularly warm area
the heating may not come on very often allowing the area around the dump valve to get cold and trigger the dump valve.
I bought from Lidl £3.99p a frost alert the sensor hang on its wire near the dump valve the led screen is in the camper and shows the temp near the dump valve if the temp drops close to freezing an alarm sounds loud enough to wake you. Just an extra precaution. Handy when your gas runs out overnight.
However I stress you need to leave the heating on and not just hot water
Kev
 
Last edited:
Oct 29, 2008
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Agree that, whist your arrangement provides a neat collection of services in one place, it's not the best solution for winter time. Especially if you visit the locker for something.
It wouldn't be a problem if the correct dump valve was fitted

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Fletton

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John
In winter when we go away in order to stop the dump valve operating it's important to leave the heating on 24 x 7
not just the hot water. During the day when we are out skiing we set the heating to low, the temp during the day is usually warmer.
When we are sat in the camper in the evening the heating is cranked up. When we go to bed we turnthe heating lower but enough to ensure the heater blows most of the night if the temperature drops.

Do you know where the internal temp sensor is located?
If that is located in a particularly warm area
the heating may not come on very often allowing the area around the dump valve to get cold and trigger the dump valve.
I bought from Lidl £3.99p a frost alert the sensor hang on its wire near the dump valve the led screen is in the camper and shows the temp near the dump valve if the temp drops close to freezing an alarm sounds loud enough to wake you. Just an extra precaution. Handy when your gas runs out overnight.
However I stress you need to leave the heating on and not just hot water
Kev

The temp sensor is above door...

I will investigate frost alert :)

IMG_2898.JPG
 

Zigisla

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From the Truma web site, there is only one type of valve fitted and it is the one you have and it is only manual and SHOULD be fitted near the boiler and inside the MH. As yours is fitted in an outside locker, there is an electrical heater that your can get, that connects from the combi and attaches to the DV to keep it warm enough not to operate. As I see it now, without this heater or another way of keeping the DV above 3deg i.e. keeping your heating on and the blown air vent directed to the DV, you will continue to loose water overnight.(n)
 

Fletton

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From the Truma web site, there is only one type of valve fitted and it is the one you have and it is only manual and SHOULD be fitted near the boiler and inside the MH. As yours is fitted in an outside locker, there is an electrical heater that your can get, that connects from the combi and attaches to the DV to keep it warm enough not to operate. As I see it now, without this heater or another way of keeping the DV above 3deg i.e. keeping your heating on and the blown air vent directed to the DV, you will continue to loose water overnight.(n)

Yup :( ... that much I've sussed :)

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Duck Truck

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zig I think you are right
the photograph also shows the temperature sensor fitted at the highest point over the door.
So hot air rises and the temperature around the sensor is likely to be many more degrees above that in the locker.
 

Duck Truck

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john
do you keep your heating running over night
or just the hot water?
 

Fletton

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john
do you keep your heating running over night
or just the hot water?

Both if its cold.... usually set thermostat to tween 10 and 13... before retiring... but I'm aware the blower (heating) in Moho Living area would then go off immediately.... until temp in van dropped significantly... and by that time the temp in service locker may (or is) dropping considerably more... hence the DV operating... and my comment in an earlier post saying i'd probs have to raise temp in accom area for overnight... which is not my bag... I prefer it "cool".. rather than hot for sleeping ;)

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Duck Truck

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The heating in the hab area
can you click the outlet flaps to closed.
That way the temp will drop in the habitation area. The sensor will pick up the drop in temp and kick the heating on. However the blown hot air will be greatly restricted from going into the hab area and more hot air will be blown into the service locker.
You may have to jiggle a bit with the temperature setting and how many flaps open or closed or partly closed till you find the right balance.

Or if you like it cooler to sleep
Sleep outside and let the camper get cosy for the morning:xrofl:
 

Fletton

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The heating in the hab area
can you click the outlet flaps to closed.
That way the temp will drop in the habitation area. The sensor will pick up the drop in temp and kick the heating on. However the blown hot air will be greatly restricted from going into the hab area and more hot air will be blown into the service locker.
You may have to jiggle a bit with the temperature setting and how many flaps open or closed or partly closed till you find the right balance.

Or if you like it cooler to sleep
Sleep outside and let the camper get cosy for the morning:xrofl:

Actually... the "flappy" things sounds like an interim plan... until :) ....

And I said cool... not ferkin freeeezin!.. ;)
 

two

Aug 4, 2011
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If you start closing flaps off, there is a possibility that your boiler will overheat. It must be allowed to shed the vast amount of heat that it can produce or it may start to melt things.
Try to prevent any draughts within the locker. I'm sure that's where the greatest heat loss is.
You have found a warm air outlet. There ought to be a return (but I don't suppose there is) else there is nothing to complete the circuit. I think it would work better if you could create a return for the air to circulate within.

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Duck Truck

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I did say balance
don't shut them all why not half close them all and see what happens
You are going to have to do the trial and error bit
and not just sit there and wish it was different
 

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