Truma Thermostat

[dougie201]

Hi Folks

Can anybody tell me a website or retail outlet that sells Truma thermostats? My heater is not very good on the 240volt setting and have been told the thermostat could be to blame.

Thanks in advance .

Dougie....

 

[gary]

It very often is the thermostat or rather it's situated in the control switch where it is then directly affected by heat from the fire or another heat source.

However, it maybe the man control board is at fault, these use three simple relays to switch the elements on and off, contacts bun out over time and prevent the elements working.

A quick check with fan off, is to switch the heater too 1000w and number 9 on the dial, now feel the heat coming directly from the fire.

Switch too 2000w and you should now get a large increase in heat, if not the at least the 2kw relay is not switching on.

If though all seems ok then fitting a remote sensor will usually sort out the system, you can get one of those directly from me at less cost than anyone else sells them! and mine work better than anyone else's?! www.arcsystems.biz

Other reasons for poor performance is how your using it and or how it's installed, below is my take on how to get the best from it;

The Ultraheat's wattage settings are there so you can make use of low amperage hookups, 500W for 6A, 1000W for 10A and 2000W for 16A hookups, their not there to adjust the temperature of the van.

The Ultraheat is thermostatically controlled, therefore the wattage used will simply mean the fire is heating for shorter or longer periods. Where the problems arise then is if the temperature control is not working correctly, this is often due to the heat from the elements directly affecting the sensor itself, it's within the control switch. This means the heat brings the temperature sensor up to that set on the dial and the elements switch off, you and the vans are still cold but the sensors toasty and takes forever to cool before switching the fire back on!!

Due to this and particularly overnight, it's become something of an urban myth to set it at 500w or 1000w, this or that number on the dial and fan speed setting. In truth what's happening is the available heat is not capable of reaching the set temperature so never switches off, it's a useful work around but not how it should work.

The real solution is to fit a 'remote' temperature sensor and attach it to the gas fires sensor, if a remote is already fitted, it to will usually react better if moved to this location.

Setting the fan on manual speed means the fan runs at this speed regardless of the amount of heat being produced, I would suggest manual fan is only for use without heat for cooling in summer, if infact it has a use?!

Setting the fan to 'A'utomatic allows the heat produced to control the fan speed 'up' to the speed set on the dial, you can then, keep this set maximum low and therefore quiet over night perhaps

Automatic means the fan will run slowly initially and speed up as the air passing through gets warmer, doing it this way allows heat and fan to be switched on together and doing away with waiting xx minutes as often suggested.

I would suggest as a start and during the day, the wattage selected is as high as the hook up allows and then fan speed set to maximum on Automatic.

This provides the maximum heat if required and the fans speed will respond to change in temperature, ie, fast when heat cycle is on and slow when heat is off.

After that you can fine tune to suit your own needs

Other heating problems concern the control board, the elements are switched on and off by relays and the contacts burn out, particularly the two 1kw relays. If this happens you may think you have it set to 2kw but only one element is working, finally perhaps leaving you with just 500w working when both 2kw and1kw settings no longer work.

(Note, relays will still be heard to 'click' but unless you have heat, their not working)

The 12v for control also comes from this board and the transformer sometimes packs up, apart from no heat, you will lose the green light in the switch if this happens

Lastly and also if no heat is forth coming, there are two safety thermostats, one at least of these has a habit of self destruction which stops all heating on electric! If the lower 125C thermostat trips, it automatically resets when it cools. However, the 175C limit stat is a 'self hold' and cannot reset once tripped until the mains supply to the heater is switched off, once mains supply is off, it will then cool and reset automatically.

The control switch itself seems generally reliable but the odd one does fail.

The numbers on the dial represent roughly 4degs and 9 is 32degs or thereabouts, this in theory makes 6 or 7 'normal' but it's what feels comfortable that matters not the number.

Another problem not caused by the heater itself is long runs of un-insulated blown air pipe running outside under the floor, insulating this will improve matters considerable.

Everything installed and working as it should, there is no good reason why the electric heating should not work very well and keep an even temperature to suit your needs.

However, it must be remembered the van needs to be warmed through thoroughly, not just the air, before the heating is turned down. While the vans cold it will constantly drag heat from the air and this in turn needs constant topping up or the van will always feel 'draughty'. It's most useful then while particularly cold to use gas as well for the first couple of hours, also, if the heating is off during the day to turn it back on at the first sign of a chill.

 

[James_374408700]

Gary,

Does the use of gas and electric together ever trip the 175c stat?

Jim

 

[James_374408700]

Gary,

Does the use of gas and electric together ever trip the 175c stat?

Jim

Should have said 125c thermostat

 

[trucker]

Gary, what a fantastic reply, lots of things in there this old dog didnt know.

Thank you

Kevin

 

[gary]

Thanks Kevin although most of it is a pre-written stock answer I've often repeated!

I'm surprised then someone's not copied it by now and flogging it on ebay! like some of the manuals on ebay that are free to download from my website?

As for the stats Jim, their directly behind the gas flue pipe so presume measure it's temperature, this would suggest the 125C stat will cut off the electric heating if the fire and electric together is to much.

I have to say the exact answer is one I've been meaning to ask of Truma, never seem to get round to it though!!

 

[James_374408700]

Gary,

That is what I believe happens. When I have used both gas and electric together for a decent time then switch off the gas, the electric elements do not appear to work. Presumably the 125c stat has to cool down before the elements will reheat.

This means the van can cool too much so I don't leave the gas on at the same time for too long as it can defeat the purpose of heating the van.

Thanks for you words of wisdom as always!

Jim

 

[gary]

I might add then, the 125C stat will reset by itself quite quickly once it cools down, the 175C however will not by itself reset, it first needs action by you to isolate the mains supply to the heater, only then can it cool and automatically reset.

 

[James_374408700]

Gary,

Are you saying you just switch off and on immediately then let it cool or switch off, let cool then switch on again?

Jim

 

[gary]

The latter, the stat is of the 'self hold' type and contains an internal element, when it trip out the supply is cut to the main elements but it also connects the internal element to keep it switched off.

It does away with manually pressing a reset button but still demands your intervention in switching off the mains supply to allow it to reset.

The problem is if you switch off and then switch back on to early, the thing reheats more or less instantly, you then need to switch off again and wait the original time plus some more!

 

[James_374408700]

The latter, the stat is of the 'self hold' type and contains an internal element, when it trip out the supply is cut to the main elements but it also connects the internal element to keep it switched off.

It does away with manually pressing a reset button but still demands your intervention in switching off the mains supply to allow it to reset.

The problem is if you switch off and then switch back on to early, the thing reheats more or less instantly, you then need to switch off again and wait the original time plus some more!

Thanks Gary, that has clarified matters.

 

[dougie201]

Thanks for all that info Gary. Hopefully will cure my problem. You listed info i never knew. Thanks again.

Dougie....

 

[SBS]

If using gas and electric heating at the same time, the rewcommendation is that the fan is switched on. This will pull cooler air over the overheat thermostats and so make them less likely to trip out.

Mike

 

[chris_374398963]

I had the same problem with my electric water heater. It work fine when i put the gas on but when i tried the electric it would not work. So i turn everything off drain the system then waited for a hour then i refill the system turn the electric water heater on and it worked but also my force air heating worked as well. I hope this is some help

 

[gary]

Yes Chris, the Truma water heater users the same type of self hold thermostat, albeit of a different make, disconnecting the mains supply to either though is the only way they can reset themselves.

I've heard tell the waters heaters design is only good for a few trip outs before it needs expensive replacement!

Whether this is true or not, better to get into the habit of switching the hot water off early and hopefully prevent forgetting while your pre-occupied with packing to leave site.

 

[stephnsons]

Very informative thread.

 

[bertieboy1]

If you can get the thermostat out or if you can get a name/model number from it that would be a good start to do an internet search.
Years ago we had a problem with tap microswitches,managed to take one off and get the manufacturers name and the switch part number.
Got onto the manufacturer (turned out they made similar switches for the military)anyway they recognised the switch and kindly sent us a couple of samples and the problem was solved.

 

[keato1981]

Could you tell me where the relays are located please?

 

[Damian]

This topic is over 9 years old and refers to two different heaters, the water heater and the electric fire part of the space heater.
What part do you want info on?
the water heater or electric space heater?

The mention of relays indicates it is the electric part of the space heater and the relays are on the PCB behind the gas fire.

 

[DaveA1]

Nine years old or not, this is a very informative thread.

 

[jamestaylor18]

Yep a very useful post! My ultraheat dial is next to the door, and the duct is under the dial. This obviously effects the performance of the heating. I’ve picked up a remote thermostat today and will have a go at fitting it this week. I am going to attach it to the gas thermostat and see if that helps at all.

 

[Damian]

Fitting it alongside the gas thermostat is the correct place for it.

 

[jamestaylor18]

Thanks Damian, I will see how i get on

 

[samskip]

I recently tackled the overhaul of my Trumatic s3002 Gas Heater with Ultraheat Electric Heater, a horrible job because of poor accessibility. I acknowledge the expertise of Gary of www.arcsystems.biz, without whose notes on this forum I wouldn't have known where to start.

I attach the following notes and photos from my experience and prior research which might assist others. My caravan is a 2001 Elddis Avante 482.

OVERHAUL OF TRUMATIC S3002 GAS HEATER WITH ULTRAHEAT ELECTRIC ADDITION

Isolate gas, and 12v and 230v supplies.

Remove the fire front by pulling the top forward till it releases, then pulling upwards. The gas temperature control knob pulls upwards to remove, and the electrical connections pull off.

Fire front removal and replacement is clarified in this video:

View: https://www.youtube.com/watch?v=yPIui6wAQNU&app=desktop


Unfortunately the retaining springs get bent and don't hold the front securely. Owners often put small screws through the top to hold it in place (I had previously done this).

Disconnect the gas fire flue (retaining ring has 1 screw). The 53mm diameter rubber seal (10030-26500) should be discarded. It must be replaced with a brand new one on re-assembly - otherwise poisonous carbon monoxide could leak into the van when the gas heater is used.

Disconnect the gas pipe underneath the caravan. Remove the complete s3002 gas heater after removing 5 large wood screws that secure it to the floor. The gas fire is not attached to the dimpled sheet metal backing (the ‘Installation Box 30040-16800’). Only the Ultraheat electrical items are mounted on the Installation Box.

Reaching behind the Installation Box, remove the fan motor assembly. It is fixed by 3 self-tapping screws to the Installation Box. The fan motor assembly has open-ended slots for the screws, so it is theoretically possible to loosen the screws and rotate the body slightly to remove it, like a bayonette light bulb. However, if it is too difficult to do this in practice, the screws will have to be removed. No need to remove the ducting from fan the motor assembly.

Now the installation box, complete with Ultraheat electric element and printed circuit box, can be removed after unscrewing about 7 tiny woodscrews.

Check the heating element is securely attached to the backing plate with all 4 fastening plates (30030-95700).

Check the warm air ducts are connected properly to the fan motor assembly without air leaks. There should be two self-tapping retaining screws retaining each duct. Take the opportunity of cleaning any dust off the fan blades.

If appropriate, seal up any gaps that would allow draughts from the adjacent fridge enclosure to affect the back of the heater. The heater should get its air input via the 40 mm gap at the bottom of the fire front, not from the fridge enclosure. (However, obviously, combustion air for the gas burner comes from under the floor, with flue gas exhausted to the roof cowl.)

Plug the jack of a remote electrical temperature sensor 30030-7100 into the Ultraheat printed circuit board in its plastic box. On reassembly, attach the sensor end of the wire to the gas temperature sensor using two cable ties.

If necessary, replace both the 125C temperature control device (30030-65100) and the 175C temperature limiter (30030-65200) if they are thought to be faulty.

Rebuild, using LPG jointing compound on the gas connection. When replacing the fire front, make sure the earthing spring makes good contact. A useful modification is to add a proper earthing wire between the body of the gas fire and the fire front, making the earthing spring redundant and ensuring a good spark from the gas igniter.

To ensure safety compliance, get the gas and electrical systems tested by qualified persons before switching on and testing.

 

[ProfJohnL]

All well and good, but this is a job that should be done by qualified fitter with the necessary gear to check the the appliance functions correctly and most importantly safely which requires skills and tools most DIYer's simply do not have.