# Truma boiler & Dometic fridge problem



## 97721 (Feb 15, 2006)

Last weekend we experienced problems with our Truma hot water system dumping water via. the dump valve opening up even though we were on 240v hook up and the temps got nowhere near 4/8 degrees which sets off the anti-frost system.

We had to refill the water tank three times (apologies to anyone close to the MVSP at CC's Carsington site for the continual presence of a Knaus Sun Ti on Friday evening & Saturday morning & evening!). 

Last night I hooked up, reset the red dump switch, primed the taps and switched on the hot water system. Everything was fine until I switched the water heater off and then the dump valve opened up depositing hot water all over our hardstanding! 

Our fridge has also had an intermittent fault when it won't switch on. I'm told that both the Truma heater & fridge are on the same electrical circuit. I don't think that it's a fuse as the system does work sometimes.

Any ideas as to what the problem may be?

We also have a problem with the flat screen TV in that it continually scrolls and we only have 50% of a picture (the other half is blue). We don't think it is a reception/aerial problem as we can "see" the programme in the background. Could this be related to the above apparent electrical problem?

The van is booked into Lowdhams next week for them to investigate but "forewarned is forearmed"!!!


PilgrimPhil


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## ingram (May 12, 2005)

PilgrimPhil said:


> I don't think that it's a fuse as the system does work sometimes.
> 
> PilgrimPhil


I now nuzzing except that from the above comment; maybe it could be a loose fuse causing intermittent problem.

Harvey


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## 97721 (Feb 15, 2006)

As an update to my original posting on my "Trumas"!

Lowdhams have found what appeared to be a faulty terminal block within the control panel and have re-routed the supply and now the fridge appears to work OK and the water heater appeared to be OK too at the time but........

the Truma heater is still dumping it's water even during the middle of the day! Surely this shouldn't be happening at this time of the year? If so I'm surprised more people haven't been complaining!

Lowdhams have suggested that I test electric supply & fuse to the red dump switch to see if the supply is constant or not. This I will do but fear that I may need a new dump switch altogether.

How do others cope with holding the water in the system in the middle of winter? Does the heater have to be on 24/7 to stop it dumping the water?

A frustrated PilgrimPhil who doesn't want to keep having to do a round trip of 180 mile + fuel for what may (hopefully) be an easy problem to sort

PS the TV screen is still knackered and we await replacement from Germany


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## sergeant (Jun 7, 2006)

Hi Phil, You dont say specifically what the problem with the fridge was but the water heater & picture problem both point almost definitively at a low voltage problem. You say you were plugged in but was the battery charger on & have you checked the 6amp mcb which controls the charger as there have been a lot of defective ones in the system in the last 2 years.,Steve


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## 97721 (Feb 15, 2006)

Hi Sargeant/Steve,

The problem with the fridge was that it kept failing intermittently i.e. no lights on the panel even when switched to gas. The rewiring by Lowdhams on the control panel seems to have worked though.

The TV problem is again intermittent. On Friday last weekend it worked fine (although we had nil TV reception at Orford but the DVD worked OK - perhaps it was those large BBC world service masts about half a mile away blocking reception!!!!) but on Saturday the fault had come back.

We were on 240v hook up all the time. Battery level is fine and all the other 12v systems are OK (i.e. fridge when switched to 12v).

I attempted to check the in line fuse & electric supply at the dump valve last night but by the time I had got some panelling off to gain access, it was dark & raining! Plus the fuse is right under the boiler with little slack and the cable is very thin. Given my noted heavy handedness I will need to do this with care!!

On checking this morning, the valve had held overnight.

PS the CL site at Raydon Hall at Orford is recommended - very quiet (even the sheep moved to the other side of the adjoining field to continue their baaa-ing!)


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## sergeant (Jun 7, 2006)

Hi, From experience i would still say you have a battery/wiring problem as you had just driven there thereby charging your leisure battery which started to drop again on Saturday. I would physically check the voltage at the battery as i dont think your charger output is reaching the battery, Steve


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## 97721 (Feb 15, 2006)

Having spoken to Truma on Friday and described the symptoms, they seem to think it is a 12v problem (either too low or high voltage). Lowdhams suspect the same, so at least both are singing from the same hymnsheet!

But as we can still use the 'van with the clothes peg holding the dump valve closed, we will continue to get away at weekends and will only get it fixed when the TV screen arrives from Germany and Lowdhams can have the 'van for a whole day.

Thanks for your help/suggestions

PilgrimPhil


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## Denboy (Oct 11, 2005)

*Truma water heater dump valve*

To all fellow sufferers of this problem I can only add my experience.
When I collected my Burstner T 680 in December last year , the van being handed over next to mine ( a new Elegance ) suddenly dumped it's heater water on the tarmac. I overheard the ' below 8 degrees C ' explanation but noted to myself that it was 12 C outside , and I thanked my lucky stars that it was not our new van.
However in the next ( winter ) months I experienced the tendancy to dump several times and assumed that the sensor was doing it's job as it was always overnight.
Then in July , during the day and in a temperature of 22C it dumped again whilst I was at Chelston. They fitted a new valve there and then . Was that the end of the problem---I don't think so.
Today I noticed the tell tale puddle under the heater , temperature no less than 14c last night , so here we go again.
I haven't tried the clothes peg fix yet and I am reluctant to do so as I am forgetfull and it's bound to freeze within hours of me doing so.
I will be watching the situation closely.
Denboy


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## Denboy (Oct 11, 2005)

*Truma water heater dump valve.*

Well. I'm replying to my own post if that's allowed.
I opened my Burstner Owners Manual today to find that if the leisure battery voltage falls below 10.5v , all appliances are switched off EXCEPT the safety drainage valve.
On another page it states that when the battery voltage drops below 10.8v the function of the safety drainage valve cannot be guaranteed.
So there's a contradiction .
As it happens I am currently checking the performance of my leisure battery, 10 months old because it seems to have a limited performance compared to any leisure battery I have ever had.
Sure enough mine was below 10.6V , ( after 6 days from fully charged without use ) , and this is presumably the reason why the drainage valve operated ---if the second statement in the handbook is the one to take seriously.
In my case it's a case of RTH ---refer to handbook , but it's not always a remedy as we well know.
Denboy


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## Robin (May 1, 2005)

Denboy / Pilgrimphil
Ha - yes the battery voltage. I had the same problem yesterday when I disconnected the battery - the Truma frost valve dumped. And I couldn't stop it when I reconnected the battery. Also the fridge was completely dead. This was at the dealers, and after some head scractching we reset the 12 volt system and all was (is) well. We have a Weinsberg, which is pretty much the same as the Knauss Sun Ti, and there is a red removable isolation key on the battery charger - turning this on and off resets the system. Your problem with the Knauss sounds a bit more complex though. 
I think the frost valave is a veritabel pain in the wotsit, I would dearly love to find a way of disabling it ANYONE??? -
8 degrees C is not very cold - I don't know why they set it at this. I am vert caoable of draing the water system when it is cold enough.
I read somewhere that a clothes peg over the red button thing works - It doesn't - it just springs off. 
Someone must have solved this one :?: 8O


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## sergeant (Jun 7, 2006)

Hi , re the dump valve it is dead easy to change it to a manual one for a few quid,Steve


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## Robin (May 1, 2005)

sergeant said:


> Hi , re the dump valve it is dead easy to change it to a manual one for a few quid,Steve


Any chance of a bit more info Steve? - on the Truma website I can only see what they refre to as the Electrical safety/drain valve listed for my heatert (C6002EH)
Robin


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## sergeant (Jun 7, 2006)

Hi Robin, any dealer can get the part from truma for you or just go to your local plumbers merchants as it is only an inline tap you need but check the pipe size & type as it can be 1/2" flexible,10mm or 12mm semi rigid on push fits, Steve


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## buzz7639 (Jul 20, 2005)

Hi, I was sick of losing the hot water from my hymer with atruma heater, bought a manual valve from a caravan dealer for £12, an hour later i had changed it, no more problems


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## 97721 (Feb 15, 2006)

Having spent a day at Lowdham at Nottingham yesterday, I hope that all our Truma troubles are history! They have re-wired the dump valve direct to the leisure battery, so providing the battery holds it's charge and the temps stay above 4 degrees, we shouldn't be having such frequent trips to the MVSP on sites!

Also the TV screen has been replaced and appears to work OK.

So the next test of the system will be two weekends time when we are staying at the CC site at Abbeywood in readiness to see the Tennis Masters at the Albert Hall on Saturday afternoon.

Must report that Lowdhams service dept. have been fine even though there has been a couple of months delay in getting everything sorted as the TV had to come from Germany and they wanted to wait till it arrived to go through our maintenance list. 

Hopefully we can go back to enjoying our new motorhome now!

PilgrimPhil


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