# Truma dump valve



## Pudsey_Bear (Sep 25, 2008)

Hi Peeps, 

We just got back from a weekend away, with no pumped water  

The Truma automatic dump valve would not stay closed, and this in turn has screwed my Shurflo pump, now I just got a new Shurflo pump (£59.99) to fit this week if I get the time.

I was wondering if anyone had any ideas re this dump valve either what to replace it with, or someway of making it work properly, without buying new automatic one.

Well impressed with the heater though, I expected it to keep me awake, but it was whisper quiet  thank god.

Cheers Kev.


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## sideways (Jun 2, 2008)

Have you checked its got power as without it it wont close. A lt also depends where it is, mines under the bed next to the blown air trunking, But on my mates Burstner its in an outside locker im not sure whether its double floor or just a locker but it always dumping the water we have to peg it sometimes.


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## Suenliam (Mar 22, 2006)

The valve in ours won't stay closed when the temp. outside is lower than about 5 degrees. Then if you fill it up with very, very cold water it stays open. We peg it, fill up and immediately put the water heater on and all's well. (Then remember to take the peg off!)

Sorry if this does not help at all. I am not known for my technical knowledge :roll: 

Hope you can fix it soon

Sue


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## Pudsey_Bear (Sep 25, 2008)

Thanks Guys/Guyesess,

I forgot to mention in my first post, that Truma do actually do a different dump valve, which is a manual type, it is in the shape of a T with a yellow lever on the top which actuates the valve body, IE laid down you get flow to the taps etc, and raised up it dumps the water through the floor, it comes with the floor through tube attached, cost £23.99 from our local caravan parts dealer, (Dickinsons Bradford) which seems a lot for a little plastic thingy, compared to the cost of the pump

I was curious to know if anyone had tried this one above as a substitute dump valve, or if anyone had tried anything different.

Cheers Kev.


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## Telbell (May 1, 2005)

Hi Kev

Doesn't changing to a "manual" dump valve destroy the whole purpose of having the valve in the first place ie as a safety measure ( to prevent freezing pipes)it wll dump when temp drops accordingly.

There are ways round it. In this v cold weather, when I have a fair bit of water in tank, I leave the gas water heater on the low thermostat setting. As someone said, depending on where your tank is you could have a space heater perhaps....or you could use the "peg" trick to prevent the dump yourself...but again that's risky.

PS-it does no harm to heat up yr tank before putting water in, when it's v cold.


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## cabby (May 14, 2005)

On mine it will only dump the contents of the hot water tank when the valve opens, the water pump only should activate when you turn on a tap.this should alert you to a problem when nothing comes out the hot tap.

cabby


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## sideways (Jun 2, 2008)

Surely dumping the water from the boiler has the same effect as opening the tap, the pump will keep filling the boiler from the cold tank, i found this out the hard way when the leisure battery failed as i disconnected the battery to replace it the valve dumped the boiler and syphoned the entire water supply.


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## rayc (Jun 3, 2008)

sideways said:


> Surely dumping the water from the boiler has the same effect as opening the tap, the pump will keep filling the boiler from the cold tank"
> 
> There may be something odd about the design of your MH but in mine the water would have to go via the pump which will not run until a tap is switched on. Do you believe in your case that the water siphoned through the pump?


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## sideways (Jun 2, 2008)

The pump is submersible and couldnt run as battery was disconnected but still dumped all the water, also on the Burstner i mentioned before while travelling down to Spain last year they had no water even though tank was full when we left as the dump valve opened and lost all the water, As the original poster of this thread pointed out his pump ran dry as the valve opened.


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## sideways (Jun 2, 2008)

Thinking about it some more it now becomes obvious if the pump pulls water to the boiler eg is between the tap and the boiler you will not experience pressure drop without opening a tap, But if the pump pushes water to the boiler opening the boiler valve will start the pump or a syphon.


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## vicdicdoc (May 14, 2005)

Kev_Behr said:


> . . Truma do actually do a different dump valve, which is a manual type, it is in the shape of a T with a yellow lever on the top which actuates the valve body.
> 
> I was curious to know if anyone had tried this one above as a substitute dump valve, or if anyone had tried anything different.
> Cheers Kev.


I 'dumped' the automatic valve & fitted one of the manual ones - no problems now [provided you remember to drain down when you put the van back in the shed.


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## vicdicdoc (May 14, 2005)

Telbell said:


> PS-it does no harm to heat up yr tank before putting water in, when it's v cold.


Which tank ? . . if you mean the Truma water heater tank then I suspect switching it on without water will do it harm [but I've never tried it so I could well be wrong . .


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## rayc (Jun 3, 2008)

vicdicdoc said:


> Telbell said:
> 
> 
> > PS-it does no harm to heat up yr tank before putting water in, when it's v cold.
> ...


The Truma C6002 Combi fitted to my MH is designed so that it can still give air blown heating when there is no water in the boiler section. If the drain valve has operated due to a fall in temperature the only way to get it to stay shut is to raise the temperature to 8 degrees by running it on heating only.


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## rayc (Jun 3, 2008)

sideways said:


> Thinking about it some more it now becomes obvious if the pump pulls water to the boiler eg is between the tap and the boiler you will not experience pressure drop without opening a tap, But if the pump pushes water to the boiler opening the boiler valve will start the pump or a syphon.


It's a bit late and I have had a few drinks but it's not so obvious to me. The pump pushes water into the bottom of the boiler which pushes hot water out of the top. If the pump is a pressure system then yes an open drain valve will cause the pump to run but I cannot see that a micro switch system will. The moral is to switch the pump supply off whilst travelling.

I am not saying that I do not believe that somehow it syphons from the water tank, through the pump and hence to the boiler where it is dumped through the drain valve. I am just asking is that what happens?


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## sideways (Jun 2, 2008)

i think that must be what happens, cheers


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## Pudsey_Bear (Sep 25, 2008)

Thank you all for your input,

I'm no wiser really, before Truma came up with the auto valve, we just drained the water when it got cold, so going manual might be a bit retrograde, at least you know what's going on, but this auto valve seems to have mind of its own.

I think it might have been better to have a more positive/stiffer off position, so it didn't move so easily and dump the water.

I wonder how many of us would actually rely on it working anyway, without checking to see if it had opened, I certainly wouldn't.

Kev


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## Traveller_HA5_3DOM (May 9, 2005)

We have one of these in our new camper and have not used it yet. Two questions please:- 
1. Does it dump the entire contents of your water supply tank or just the contents of the boiler? 
2. Can it run on both Gas or Electric to run the blown air heating without water in it?


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## Pudsey_Bear (Sep 25, 2008)

Hi,

Ours just dumps the water from the boiler I think, there is a seperate dump tap for the clean and gray water tanks, and the the boiler runs without any water in it, if I'm reading the manual correctly.

Kev.


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## Boff (May 10, 2005)

Hi Kev,

the Truma dump valve is a safety valve. It is supposed to prevent frost damage to the (stainless-steel) boiler. So if you remove it, replace it by a manual valve, or "secure" it with a peg, you will loose your warranty on the boiler (if you still have it anyway).

That the dump valve opens, can only have one of two reasons: Either it is too cold, below about +6 degrees C _at the valve_, or - if not the very latest model - it has lost electric power supply.

So, as a precaution, make sure that there is uninterrupted electric power supply to the boiler. And that the valve stays warm enough, or the boiler remains on.

BTW, it is not necessary to use a peg while filling the boiler. Just switch on the boiler first, then close the valve, then start filling. It does not do any harm heating up the empty boiler, they are designed for it.

Best Regards,
Gerhard


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## Pudsey_Bear (Sep 25, 2008)

Brilliant answer Boff  

It's a shame that they didn't use similar wording in the Truma manual, just one question remains, how can you tell if the valve is duff, there is probably a simple answer, but it eludes me.

BTW, my engine battery went flat, but the leisure one was OK, maybe that's why it opened.

Cheers Kev.


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## tincan (Jul 31, 2006)

Kev,
you seem to have a couple of issues here. (a) the boiler/ valve and (b) the pump
why have you had to change the pump? I only ask as we had a similar experience last year when the dump valve operated causing the pump to run for a couple of days, unnoticed, but the pump was still fine- believe it or not. Our dealer says he has never replaced one of these pumps, so they must be fairly sturdy. We use the peg normally only when travelling as road vibration has caused it to drop the contents all over the road even in summer but we have been known to forget to remove it occasionally. I was not aware that loss of power could also activate the valve, thanks Boff will keep an eye on this in future

Noel


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## Pudsey_Bear (Sep 25, 2008)

Hi Noel

We went away for the weekend, and the pumps just ran, with nothing coming out of the taps, not even a gurgle, despite the tank being full to the top, no leaks as far as we could tell, so I can only assume that the impeller or whatever moves the water is damaged, I'll soon know if thats thecase as soon as the new pump is fitted.

Cheers Kev


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## TJ101 (Oct 12, 2008)

Good Thread

My valve was in "dump" , open mode most of the week, and now the temperature is below freezing,,and the valve won't stay shut of its own accord !! Guessing, just like it should be, due to ambient temp rather that low power, (on hook up) 

Switched on the water heater, and within a few seconds, the valve will stay shut no problem,


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## Pudsey_Bear (Sep 25, 2008)

It might be a good idea if someone on here who really knows his stuff re wintering campers, could tell us just what we really need to do. my method is to just empty everything and leave all the taps open, but maybe this isn't really the way to go.

You'd think, being on our third camper, we would know the score, but they've all been different types as far as water and heating is concerned.

Kev


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## Boff (May 10, 2005)

Hi again!



Kev_Behr said:


> how can you tell if the valve is duff


I have never heard so far of a Truma valve going duff, but:

First make sure that there is 12 volts supply to the boiler. Boiler switched off. Now shut the valve. If the temperature is above 3-8 degrees, it should stay shut. If temperature is lower, then it will open again.

In this case, make sure that gas is turned on, and fire up the boiler. Now try again to shut the valve. It now must stay shut, no matter the temperature.

If it does not perform like that, or opens spontaneously even while the boiler is on, then check the cable and contacts between valve and boiler. If that still does not help, then the valve is most certainly broken.

Best Regards,
Gerhard


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## Pudsey_Bear (Sep 25, 2008)

Thanks again Gerhard,

I'll try it in a couple of days, I'm off work today, Hospital tomorrow, but I should be OK by the weekend, and I'll check it out while I'm changing the Shurflo pump.

Kev


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## leseduts (Jun 3, 2008)

If our valve dumps, it empties all the water from the clean water tank. I understand that it is because it causes a syphon effect due to a submersible pump. Has anyone any thoughts on how we can stop it emptying the tank.


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## vicdicdoc (May 14, 2005)

If anyone is after an automatic dump valve - I've got my old one in the shed . . make me an offer !


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## Boff (May 10, 2005)

Kev_Behr said:


> ...and I'll check it out while I'm changing the Shurflo pump.


Another hint: If you have a pressurised water system, like with your Shurflo pump, then *always* switch off the pump while driving, or while leaving the MH alone!

Not only because the Truma valve could trip. Just imagine what would happen if a water pipe connector broke, or a hose fitting went loose. The pump would then transport the complete content of your fresh water tank into your van's habitation area! 8O

Best Regards,
Gerhard


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## Pudsey_Bear (Sep 25, 2008)

Thanks again Gerhard,

As we've been having pump problems, and because of the failings of previous campers, I do tend to turn everything off, more for peace of mind than anything else, as you tend to hear too many horror stories of people leaving stuff turned on, and coming back to a disaster.

I don't think I mentioned in this post but the van is a Laika Ecovip 7RG, and both the Truma and the Shurflo trailking 7 pump are under a fixed but lifting bed in the rear.

Cheers Kev


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## sideways (Jun 2, 2008)

leseduts said:


> If our valve dumps, it empties all the water from the clean water tank. I understand that it is because it causes a syphon effect due to a submersible pump. Has anyone any thoughts on how we can stop it emptying the tank.


 If you find out let me know as i have same camper same problem.


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## Roger7webster (Oct 10, 2006)

You could 'T' in a vent cock in any convenient area to stop the syphonic effect


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## sideways (Jun 2, 2008)

can you elaborate a bit on that please i,m quite handy but dont understand what it actually is or entails.


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## Pudsey_Bear (Sep 25, 2008)

I think a T cock means, put a T peice in line, which would stop the syphoning by allowing it to suck air instead of draining your tank, but it has been said before that sometimes I get things wrong, so take no notice of me at all, whatsoever, ever.

My own solution to the syphon problem might be to just put a tap in the way, but maybe an empty tank in winter is not a bad idea, or is it just better not to have a completely full one to allow the water to expand when it freezes.

Also puzzling me, if I do drain everything down, should I leave any or all sink taps open, and how about the tank drain tap? open or closed? as open would allow small bugs etc to crawl in, wouldn't it?

Kev


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## Boff (May 10, 2005)

Hi Kev!



Kev_Behr said:


> My own solution to the syphon problem might be to just put a tap in the way, but maybe an empty tank in winter is not a bad idea, or is it just better not to have a completely full one to allow the water to expand when it freezes.


You should not have a syphon problem. Membrane pumps, like your Shurflo, do not allow a flow when not running, so syphoning can not occur. This is different with certain immersion pumps.



Kev_Behr said:


> Also puzzling me, if I do drain everything down, should I leave any or all sink taps open, and how about the tank drain tap? open or closed? as open would allow small bugs etc to crawl in, wouldn't it?


At least all sink taps should be open. Otherwise any remaining water might destroy them when freezing. About the tank drain tap, this is up to you. There are not too many bugs crawling around at times of frost. Nevertheless there is no reason not to close it again, as long as tank and drain pipe are completely dry.

Best Regards,
Gerhard


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## Roger7webster (Oct 10, 2006)

As Gerhard says syphonic problems should only occur if your van is fitted with a submersable pump in the water tank and probably micro switch operated taps. 
If this is your system the tank will empty when the Truma dump valve operates. 
One way to overcome this problem is to fit a T piece into the coldwater feed pipe and connect the third connection to a valve and for a Rolls Royce job a ball/float operated air vent as fitted to your domestic central heating system This will act as a syphon breaker and solve the problem 
Hope this helps. Email me if you need more info 
Roger


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## Pudsey_Bear (Sep 25, 2008)

*Truma dump valve and Shurflo water pump*

Well I finally fitted the water pump, the hardest part was to to get at two of the mounting screws, as they'd fitted the Truma boiler after the pump and made it a little awkward to get at them, the pipes were all push fit, and the wiring was those weird screw cones (they'll get replaced this weekend) I took the oportunity to clean the little in line filter, it was'nt full of muck and gunk etc, which you might expect on a 2001 van, but had a few strands of what looked like the drillings from the water tank, but it's in now, it took a while for the water to flow correctly, but after I'd turned the shower tap on it all worked fine, the pump now turns off within two seconds.

Oddly the pump switch no longer glows red, I'm sure that must mean something even if it's only that the bulb has blown, does anyone know anything about that?

Thanks to everyone who has posted replies to this and other posts of mine, and I hope that each and every one of you has a great Christmas and a Happy New Year.

Cheers Kev n Liz


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