Truma Ultraheat stats

[Dustymil]

Hi all,

Sorry, another Truma Ultraheat cry for help.

Our heating works fine on gas, but when I switch to, or start with, electric, it all works fine until it reaches the temperature set on the room stat, but once the stat cuts in, the system cools and then refuses to heat again, no matter what I do.

I've read somewhere that it could be an internal stat/temperature control, but I've no idea where to find it, or how to test it if I could!

Any advice, or pointers would be gratefully received. Thanks for your time.

 

[Grey13]

From what you say, heating element must be fine otherwise it would not heat on Elec.
They have a fixed surface mounted stat shown in this picture, the little thing hanging on wires
http://www.qis-uk.co.uk/Pics/Truma_Heating_Element_Thermostat.JPG
These are bi-metal switches preset and can give trouble and stick like you explain.
The heating element has 4 bolt holes and goes on the tank and the stat on the other 2 studs shown
http://www.qis-uk.co.uk/Pics/Truma_Steel_Vessel.JPG
Where are they you ask
Looking at the bare tank, you can see where the two water pipes come out, then figure out where the heating element and stat sits
http://www.qis-uk.co.uk/Pics/Truma_Ultrastore_water_heater.JPG
have fun!

To test what I did was. All testing done with power OFF.

See the black cable in the picture, stapled to the floor entering the heater near the outlet pipes, well I first disconnected the plug in the cable, tested the circuit going to the heating element, which includes both the heating element and stat. It showed continuity. Then heat it up and when it will not heat again again open the plug and test. If you now have an open circuit it is almost certainly the stat.
PS This should be done by a qualified electrician! Do not electrocute yourself!

 

[Jaydug]

From what you say, heating element must be fine otherwise it would not heat on Elec.
They have a fixed surface mounted stat shown in this picture, the little thing hanging on wires
http://www.qis-uk.co.uk/Pics/Truma_Heating_Element_Thermostat.JPG
These are bi-metal switches preset and can give trouble and stick like you explain.
The heating element has 4 bolt holes and goes on the tank and the stat on the other 2 studs shown
http://www.qis-uk.co.uk/Pics/Truma_Steel_Vessel.JPG
Where are they you ask
Looking at the bare tank, you can see where the two water pipes come out, then figure out where the heating element and stat sits
http://www.qis-uk.co.uk/Pics/Truma_Ultrastore_water_heater.JPG
have fun!

To test what I did was. All testing done with power OFF.

See the black cable in the picture, stapled to the floor entering the heater near the outlet pipes, well I first disconnected the plug in the cable, tested the circuit going to the heating element, which includes both the heating element and stat. It showed continuity. Then heat it up and when it will not heat again again open the plug and test. If you now have an open circuit it is almost certainly the stat.
PS This should be done by a qualified electrician! Do not electrocute yourself!

I think the OP is asking a question about his room heater, not his water heater.... hmy:

 

[Grey13]

Comes with getting old, better to just keep quiet! Anyway it also may help some with water heater problems.!

 

[Jaydug]

Hi all,

Sorry, another Truma Ultraheat cry for help.
.

Your problem certainly sounds as though it could be one of the overheat devices. Trouble is they are situated right in the base of the electric part of the fire and to get to them, the gas fire needs to be removed. Unless you are 'competent' you should leave it to a caravan engineer. Four years ago the devices were about a fiver each. Now Truma are selling them for £25. Here's a picture of them.

 

[Grey13]

Why are there 2 of them?

 

[Damian]

One is an overheat the other is a temp limiter

 

[Dustymil]

Hi Grey13

Thanks for your silly reply and time spent. The pictures, are they for the Ultrastore water heater? My problem is that the Ultraheat heater cuts out and doesn't cut back in?

Sorry if I've misinterpreted your reply?

Thanks

 

[Damian]

Quote " The pictures, are they for the Ultrastore water heater? "

Yes they are, nothing at all to do with your space heater.

Before you start buying lots of bits which you then find are of no use as they do not fix the problem, start at the beginning!!

As I understand your heating works initially to the selected temp ,then cuts out and does not come back on.

First thing to check is if you have a remote thermostat fitted, which will be attached to the gas temp sensor at the bottom of the fire, behind the front cover (the gas temp sensor is the copper tube, the remote if fitted will be attached to that with a cable tie)
If there is not one fitted then that is where the problem is.

 

[Dustymil]

Great info all the same Grey13, I hope that I never need it, but I'm sure someone on here will!

Damian, is the remote stat a modification or standard fitting?

Apologies but I cannot recall exactly what model Truma is fitted to my Abbey Vogue 215, but I'll check all details when next set the van

Thanks again all

 

[Dustymil]

Grey13, I've just read my reply to you earlier, bloody predictive text a put "silly reply"!!, I've no idea what the word should have been, but definitely not "silly". I hope that I've not offended you. Sorry!

 

[Grey13]

I don't get offended easily, no problem!

 

[Dustydog]

This is the classic TOD, Thermal Overload Device , failure as described by Damian.
One fails at 165deg C , may be lower, cools and resets, the other fails permanently at185deg c. Two years ago I paid a fiver each for oem. £25 each :woohoo:
If you remove the entire heater change the flue o ring without fail or you face the chance of CO death If you don’t understand that get a professional engineer in. Never mind that you also need to break the gas input seal which also needs correct testing once reinstalled . If you don’t know how to test don’t do the job!

 

[Damian]

Great info all the same Grey13, I hope that I never need it, but I'm sure someone on here will!

Damian, is the remote stat a modification or standard fitting?

Apologies but I cannot recall exactly what model Truma is fitted to my Abbey Vogue 215, but I'll check all details when next set the van

Thanks again all

The remote is a modification as the result of the standard fitted one being placed too close to either the heater or other heat source.
The original stat is part of the control switch which is usually located near the fire, typically in a wardrobe wall or similar.
What happens is the van heats up, including the area into which the control switch is situated.
The fire then cuts out a the required temp is reached.
The main part of the van cools down, but the area where the control switch is, does not so the fire will not start up again until that area has dropped in temp, which may be several hours after the van has cooled down.

The remote is relatively easy to fit, a bit fiddly but as it is only a jack plug going into the fire control box at the base of the Ultraheat, as long as you can get to that.
The sensor is then cable tied to the gas sensor.

This is the item: https://www.leisureshopdirect.com/gas/caravan-gas-fires/truma-fires/trumatic-s5002-gas-heater-spare-parts/remote-sensor-truma-ultraheat