Truma dump valve again (1 Viewer)

[Andrew gill151]

Hi all,

After a bit of info regarding what I am to expect from the Truma dump valve.

I filled my van with 90% water yesterday and drove to site this morning, the temperature was ok as I had a heater on in the van overnight. just been out to the van to find the dump valve has activated and water is all under the van, this is what I expected however, the water level in my fresh water tank has now dropped to 50%. The water pump is off and no taps are switched on, any ideas on why water has come out of my fresh water tank as I believed the dump valve only empties the hot water tank?

Cheers.

Andy

 

[Phaeton]

Surely if the hot water tank drain is below the cold water tank level (which must be normal) it will simply siphon the water out ?

 

[Lenny HB]

It's normal as the hot tank empties you get a syphon effect which draws water into the hot tank, on our last van it could on occasion competly empty the fresh water tank.

^{_{Subscribers  do not see these advertisements}}

 

[rosalan]

As you do not want the water to drain at this time, you could temporarily hold the switch up with a clothes peg. The real danger here is that if you forget the peg and the heater unit actually freezes, the cost of repairs will make your eyes water.

 

[Lenny HB]

As you do not want the water to drain at this time, you could temporarily hold the switch up with a clothes peg. The real danger here is that if you forget the peg and the heater unit actually freezes, the cost of repairs will make your eyes water.

That is on the older ones you need to wedge the button in with a stick or something on the mechanical valves can't always be done due to position of the valve. Not such a problem with the mechanical valves as they don't dump until temp is down to 3 deg.

 

[Andrew gill151]

Forgot about syphoning effect, just put my heating back on full so should be able to close valve, mine hasn't got the popup on top its the one with a turn toggle on the top with a blue button on the front bottom.
Think this is a poor design as now I am away from good clean water for 4 days and my precious clean stuff draining into the dirt!

^{_{Subscribers  do not see these advertisements}}

 

[GJH]

As you do not want the water to drain at this time, you could temporarily hold the switch up with a clothes peg. The real danger here is that if you forget the peg and the heater unit actually freezes, the cost of repairs will make your eyes water.

Or do as we do. Leave the water heater on. Once the water is up to temperature it doesn't use much gas keeping it there and the dump valve won't operate when the water heater is on.

 

[Andrew gill151]

GJH,
Think that's going to be my default technique, spend 4 days in the van and 4 out at home, so keeping it warm shouldn't be too much of a cost.

 

[Zigisla]

I actually use the dump valve to empty all my water. As I could be bothered to lift cushions and throws and move the table out of the way to get to the Fresh tank dump v/v, all I do is turn the Truma dump v/v to open and lift taps to mid position. All water goes.

^{_{Subscribers  do not see these advertisements}}

 

[Larrynwin]

In between frequent trips if a risk of frost I set heating at 15degs so warm blown air prevents truma dump. I am on hook up in drive.

 

[lorger]

We had an issue on our last van, after some investigating I found the valve had a little bit of grit in it. I took valve off and cleaned out, no other issues.

 

[Duck Truck]

I reckon it siphoned the water as well.
Not sure how close your dump valve is to the boiler
but it sounds like the temp around the dump valve dropped low enough to cause the valve to dump.
That's why people peg them closed.
Remembering to remove the peg and drain before leaving the van in cold weather.

Kev

^{_{Subscribers  do not see these advertisements}}

 

[Lenny HB]

Forgot about syphoning effect, just put my heating back on full so should be able to close valve, mine hasn't got the popup on top its the one with a turn toggle on the top with a blue button on the front bottom.
Think this is a poor design as now I am away from good clean water for 4 days and my precious clean stuff draining into the dirt!

That is the mechanical valve, has to be very cold outside before they dump. Just using the heating in the evening normally leaves enough latent heat in the van to prevent them dumping overnight.

 

[jezport]

Forgot about syphoning effect, just put my heating back on full so should be able to close valve, mine hasn't got the popup on top its the one with a turn toggle on the top with a blue button on the front bottom.
Think this is a poor design as now I am away from good clean water for 4 days and my precious clean stuff draining into the dirt!

Where is the valve fitted? If its away from the boiler it should have an electrical connection designed to keep it closed if the boiler is on. If its fitted next to the boiler it doesnt need it.
I was told this directly from Truma .

 

[DBK]

Am I the only one to read the thread title as "Trump duma valve..." which is a sort of reverse spoonerism I suppose. Still not sure what sort of valve it is, but probably gold plated whatever it does.

^{_{Subscribers  do not see these advertisements}}

 

[adonisito]

After filling the van, did you put all hot water taps on to fill the Truma , and then wait until water was running through all other taps? That's what we do, although I use a clothes peg while priming as the temperature is often low. Then whack the water heater on for a bit.

 

[Lenny HB]

After filling the van, did you put all hot water taps on to fill the Truma , and then wait until water was running through all other taps? That's what we do, although I use a clothes peg while priming as the temperature is often low. Then whack the water heater on for a bit.

OP has the newer valve, clothes peg won't work on that, can hold the button in but fiddly easier to put the heating on for 15min.

 

[Fletton]

I leave my water on 24/7 at mo.. Regardless of whether I put (or leave heating on overnight).. Never has it dumped yet..

But I did put a thermometer in the service hatch area... For curiosity ... It seems to stay around 10 Deg in there at this time of year.. However, the boiler is adjacent to the service area with lots of room for warm air from boiler body to seep in and around the valve...

^{_{Subscribers  do not see these advertisements}}

 

[Allanm]

I had a frost control heating element in my Autosleeper fitted with a Truma water heater. It enables you to close the valve at lower temperatures so you can fill the system without resorting to pegs or other things to keep the valve closed.
In the years we have had motorhomes, I have never emptied the heater because of the cold. We use the van all year round, if it gets cold, we leave the water heater on. It's on now, last night the temperature dropped to -1 c, too much bother to keep emptying out and filling.
We also leave the fresh water tank full, its onboard next to the water heater so no chance of anything freezing.

 

[Duck Truck]

Hi Lenny
Sorry I haven't had a van that couldn't be pegged.
Maybe worthwhile giving a blow by blow about how the new ones work
Makes interesting reading even for us with the old type.
Kev

 

[Lenny HB]

Hi Lenny
Sorry I haven't had a van that couldn't be pegged.
Maybe worthwhile giving a blow by blow about how the new ones work
Makes interesting reading even for us with the old type.
Kev

It has been covered on several threads before, here is some info on it.
Has been fitted to Combi 6 & Combi 4's from about 2007.

^{_{Subscribers  do not see these advertisements}}

 

[Fletton]

Well... sod's law prevails...
Just got up for a wee... NO FLUSH!!!

So turned on bathroom tap thinking airlock (had been out for gas and diesel earlier).. nothing!..

Checked level on dial... NOTHING!!

Tracky bottoms and flip flops on ... armed with torch went outsude to find a frozen water trail on the tarmac....

Water Heater had been on and set at 60 and heating left on at 11....

And to top it all... I can't get the service door open to reset because the water vapour from heater flue has created a huge icicle from top to bottom of hatch and its solid....

I knew I should have washed those firkin pots n' pans before retiring!!!

Oh well... should learn to keep gob shut!!

 

[Cal54]

@Fletton, only gave you a 'funny' because of the information regarding washing the dishes and keeping your gob shut!! Hope you get it sorted this morning. These dump valves are a bloody nuisance as it has happened to me at the NEC, but I guess no water is better than a hefty repair bill.

 

[Fletton]

@Fletton Hope you get it sorted this morning. These dump valves are a bloody nuisance as it has happened to me at the NEC, but I guess no water is better than a hefty repair bill.

I can't understand why it would do it ... as the boiler had been on perm 24/7 at 60.. except for the time it took me to nip out and fill with LPG yest... and then it was straight back on ... Heating too.... so no chance of boiler freezing IMO !.. Also it didn't "throw up" the previous night when it was firkin cold... odd!.

Will investigate temperature in service bay area when I can get the hatch door open!..

Might have to invest in that heater attachment thingy... can't have this occurring randomly ...

Edit:::

^{_{Subscribers  do not see these advertisements}}

 

[Duck Truck]

On the old valves pegging stopped this happening
So what do you do on the new valves to prevent it?

 

[Munchie]

something way wrong here, no way should it dump if water heater is on!

 

[KeithChesterfield]

A plastic cable tie looped from the back to the front over the valve to hold in the button (B) works in cold weather - just flip the cable tie up and off when not required - put it back when required.

^{_{Subscribers  do not see these advertisements}}

 

[Lenny HB]

I wonder if you have a faulty valve, ours has never dumped when using the van and we never leave heating or water on overnight.
Which type of valve do you have?
The blue mechanical ones dump at 3 deg, the red electric it's 4 deg but I have known them dump at 6 deg. If you have been using the van and heating on in the evenings inside the van shouldn't drop below 12-13 deg well ours doesn't unless it is in an unsheltered spot with gale force winds.

 

[Fletton]

something way wrong here, no way should it dump if water heater is on!

Well it certainly did... any ideas welcome ...

Edit: Is there any way to test valve for faults?

 

[Lenny HB]

Well it certainly did... any ideas welcome ...

Edit: Is there any way to test valve for faults?

Take it off reset it in a warm environment put it in a cold place with the sensor from one of those cheap electronic thermometers taped to it and monitor the temp it opens, you could use the fridge and open the door to check it every 5 min, should be able to work out if it is OK. If it is the red one you will need to connect it to a 12v supply.

^{_{Subscribers  do not see these advertisements}}