Truma S3002 electric heating not working

[ecliptic]

To the problem.

I cannot get the heater to blow hot air using the electricity mode - the elements do not heat up.
The control unit is side-by-side with the hot water controller and that controller works. This might help eliminate a question of local overheating causing problems.
I removed the control wire from the fan speed selector on the top of the heater front panel and on re-inserting found the green light had come to life in the heating control unit. Perhaps an oxidised contact cleared? But still no heat.
Checking the question of power, I turned on the Ultraheat switch (240v) - yes, fuse is OK, and checked the voltage on the heater side of the box behind the heater. 240v from both black wires to earth, nothing else.

I am now seriously pondering the thermostat question.
Removing the composite material cover from the back of the fan I discover what has to be a thermostat, This fits thru a hole into the fan housing. Now, is it a max temp cut-out or a temperature sensing unit. Have photo but cannot see how to attach to this post. The lack of apparent connection to the box at the rear base of the heater lends weight to it being a max-cutout sensor.
Video on the Internet showed the fix was to remove the gas fire and replace thermostats. There is nothing showing re thermostats in any exploded schematic diagrams of the heater, and I do not see a thermostat on any wiring diagram, so perhaps this one is the culprit. However, disconnecting the 240v for a period did not change the situation.
The wiring from the ultraheat wattage and heat control goes to the control box close to the floor at the rear of the heater. If there is another thermostat then it must be inside the heater box cover and yes, I would need to remove the gas fire to access.

Because the van was not built here, local support is nil from dealers and such.
Truma EU referred my request for assistance back to their local Aust. agents who declined to assist -" heater not registered within Australia".

Your thoughts are encouraged, please.

Some folk will tell me, here in Australia, that I made a mistake taking a UK van back to Australia. My 2004 Lunar Quasar 525 has better quality fittings and finish compared to the local varieties and towing 1050Kg is easier than 3000kg. Just finished replacing the front floor section and will prepare a booklet regarding the process.

 

[Damian]

Have a read of this from over 9 years ago:
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.

 

[Damian]

In addition to the above information, you need to treat the heating system as three separate units which work entirely on their own or in combination.
The gas heater is one part, the electric heating is the second and the fan unit is third.
Each will work on their own or in combination with the fan.

If when the fan is selected (which works entirely on 12v DC) it runs then there is nothing wrong with it.
As for the electric heater unit, it has two cutouts mounted on the control box behind the gas fire, a lower limit cutout and a higher limit cutout.
Both are known weak points and if going as far as replacing them, then it is sensible to replace both at the same time.

Have a look here at temperature control and limit : https://www.leisureshopdirect.com/gas/caravan-gas-fires/truma-ultraheat-electrical-supplementary-heater-spare-parts
However, access to the control box usually means taking out the gas fire which in turn involves breaking gas joints and breaking the flue seal.
It is highly important that on reassembly a new flue seal is fitted and that all gas joints are tested for soundness and pressure tested.

It should also be noted that the thermostat for the electric heating is part of the control switch , which if mounted near the fire, or above the fridge, it can be fooled into thinking what the temperature is as the back side of the control switch is in a cavity which is heated and does not cool down as quickly as the main van.
The answer to rectify this is to fit a remote thermostat if one is not already fitted.
If one is fitted it will be usually attached to the gas fire sensor bulb at the front base of the gas fire just behind the front cover.

 

[ProfJohnL]

Hi

I understand from your posting and your status this is a 2004 Caravan.

Have you only just acquired this caravan?

Has the electric heating worked for you previously?

Was it sold you as working, if so you may have some redress against the seller if you purchased it in the UK even if you bought it to export. Our Consumer rights act does not require the buyer to be resident in the UK. only that the contract and transaction took place in the UK. Whether its worth trying a long distance complaint is a decision for you.

There are some common failure modes that Damian has explained. As for obtaining spares, I am surprised that Truma's Australian agent is reluctant, but perhaps that becasue of local liability laws on such things.

If its only thermal switches you need, I pretty sure you would be able to order them from a UK or EU seller.

I concur with Damaian that contacting Gary art Arcsystems would be good step.

 

[Hutch]

Ah the old Grey Cells are reviving,.
Nothing bad meant ! Thanks for digging in.

Thats why this Forum is so helpful..

 

[shoz09]

Hi I am on holiday just now, electric heater was working fine, funny click/clunky and green light on electric heater control gone off no longer creating heat. Fan still working and so is gas which I have had to use. I don't know where to find the thermostat you all mention? I haven't yet taken off front of fire....is it likely to be behind there? I also wondered if it could be a fuse but main fuse box appears to be ok, so should I be looking for another fuse somewhere else? Had van for 3 years so not a problem I have experience of, but it's a 2006 swift so it might be something old needing replaced? I would appreciate advice on where to look to solve green light on control knob not working/thermostat or control panel. Feeling a bit lost on this problem.

 

[shoz09]

Hi I am on holiday just now, electric heater was working fine, funny click/clunky and green light on electric heater control gone off no longer creating heat. Fan still working and so is gas which I have had to use. I don't know where to find the thermostat you all mention? I haven't yet taken off front of fire....is it likely to be behind there? I also wondered if it could be a fuse but main fuse box appears to be ok, so should I be looking for another fuse somewhere else? Had van for 3 years so not a problem I have experience of, but it's a 2006 swift so it might be something old needing replaced? I would appreciate advice on where to look to solve green light on control knob not working/thermostat or control panel. Feeling a bit lost on this problem.

 

[ProfJohnL]

May I suggest you enjoy your holiday for now as you do have the gas if you need heat, and wait until your home where you can either investigate further or call an expert to resolve the problem.

If the heating element has failed, the gas heater will need to be removed to access the element, and that should only be done by someone who is gas competent.

 

[Grey13]

Damian...

Does this control have some sort of temperature measuring device built in or how does it adjust temp levels when you select say 2 or 6 ?

 

[Dustydog]

If you have a multi meter you can easily check the continuity of the mains supply. Same with the element. The Thermal Overload Devices are at the very rear low down. As Damian said they do fail and can be hard to remove in situ. Enjoy our holiday. Glad to say we don't need our heaters here at the moment

 

[Damian]

Damian...

Does this control have some sort of temperature measuring device built in or how does it adjust temp levels when you select say 2 or 6 ?

Yes it does at the back of the inner dial which is why many users find that the heater does not respond to changing temperatures in the van as quickly as it should, as that control is usually mounted into a space behind the wall, such as a wardrobe wall, or similar, where the temperature takes a lot longer to drop compared to the main body of the van, and is why a remote sensor is advised, fixed to the gas temp sensor bulb at the base of the gas fire.

As far as the question is concerned and the loss of the green light on the control panel, that suggests that the transformer which supplies that light, situated on the PCB behind the gas fire in the Ultraheat control box has failed.
To effect any repair will need the gas fire to be removed as it is usually impossible to do anything to the Ultraheat with the gas fire in place, and that means gas tightness testing, new flue seal etc etc.

 

[Grey13]

Hi Damian Thanks for that, do you know what it is, thermocouple, PT100 or bi-metal thermostat or ?

 

[Damian]

Sorry, I have absolutely no idea or have any interest in what they use, as long as it works.

 

[Grey13]

Having checked I found it is a thermocouple.

 

[Gunny]

Have a read of this from over 9 years ago

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.

As our heating has got worse and in fact we have no heat now (still have green light at control switch) I'm thinking all the relays have gone in our 2003 Ace Jubilee Statesman (swift)
So where actually are the relays/control box ?
Is it the white rectangular box I can see with truma on the top at the back of the fire ? This is looking down the back of the fire from the wardrobe above

 

[ecliptic]

In addition to the above information, you need to treat the heating system as three separate units which work entirely on their own or in combination.
The gas heater is one part, the electric heating is the second and the fan unit is third.
Each will work on their own or in combination with the fan.

If when the fan is selected (which works entirely on 12v DC) it runs then there is nothing wrong with it.
As for the electric heater unit, it has two cutouts mounted on the control box behind the gas fire, a lower limit cutout and a higher limit cutout.
Both are known weak points and if going as far as replacing them, then it is sensible to replace both at the same time.

Have a look here at temperature control and limit : https://www.leisureshopdirect.com/g...t-electrical-supplementary-heater-spare-parts
However, access to the control box usually means taking out the gas fire which in turn involves breaking gas joints and breaking the flue seal.
It is highly important that on reassembly a new flue seal is fitted and that all gas joints are tested for soundness and pressure tested.

It should also be noted that the thermostat for the electric heating is part of the control switch , which if mounted near the fire, or above the fridge, it can be fooled into thinking what the temperature is as the back side of the control switch is in a cavity which is heated and does not cool down as quickly as the main van.
The answer to rectify this is to fit a remote thermostat if one is not already fitted.
If one is fitted it will be usually attached to the gas fire sensor bulb at the front base of the gas fire just behind the front cover.

Hello Damian, thank you for your information. This ungrateful person apologises to you for not acknowledging your information and effort in the input.
I have the problem continuing and shall remove gas fire once more, check all electrical connections, resistance across heating element, and conductivity of the two thermostats. If all else checks out then the finger looks like being pointed at the PCB (ouch)

 

[JMC]

Hello Damian, thank you for your information. This ungrateful person apologises to you for not acknowledging your information and effort in the input.
I have the problem continuing and shall remove gas fire once more, check all electrical connections, resistance across heating element, and conductivity of the two thermostats. If all else checks out then the finger looks like being pointed at the PCB (ouch)

Also in Oz and have a small 2007 Swift that was recently imported. I was looking for something with a bathroom but still light enough to tow with the car, seems only the UK vans can do this! For space heating it has a Trumatic S 3002P (gas) and Ultraheat (electric). I could not get the electric element to heat at all. Discovered I had to have the temp dial all the way up to maximum 9 (31c) before the relay clicked. Ambient temp was only 22c so lower settings should have activated but didn't . Next my Ultraheat would cutout within 10 mins, more so when set to 1000W or 2000W with or without the Trumavent fan on. If I reset the Ultraheat at the circuit breaker it would work again for another 5-10 minutes. Next I removed the gas heater as gas wasn't piped in. Likely the importer's gas certifier required it be disconnected from heater. I found the remote sensor wire (option) was fitted to the control box thermostat and was tied to the base of the gas heater. Apparently it is meant to work better in that position. After removing the gas heater I was left with an opening in the floor that I sealed up to prevent cold air and bugs getting in, but I left a 5mm gap to push the thermostat wire through to the underside of the van! Underneath I coiled and secured it so it wasn't too exposed. Heater now works on 500 or 1000w for couple of hours with no cutouts and can now get the van very warm. My remote sensor must have been too sensitive even at the recommended spot. Moving it to the much cooler position under the van has done wonders. I did consider unplugging the remote sensor wire from the control box and removing it completely but that would force the control box thermostat to take its readings locally, and that box is sort of close to the element. I think having my (faulty) remote sensor in a cooler spot underneath is better. It still cuts out on the 2000w setting so that must be a different issue, possibly the 175c overheat safety thermostat is faulty. Yeah I have no gas heating and electric that only works on 500 or 1000w ...but still better than nothing. Good luck with yours.

 

[ecliptic]

H JMC, thank you for your insight.

Have to admit I have been caught up with other projects along with the Covid-19 issue and accompanying travel restrictions. Now the restrictions are easing my attention has turned to the caravan heating issue again. Shall try your trick of turning the temp dial all the way up.
At least I have gas for heating but electric when on a powered site is so convenient.

Options beyond this are to send the PCB back to a repair facility in the UK, and discover how to site the temp control thermister away from the current (destructive) location.

 

[ecliptic]

OK, update.

I had been having a struggle with a non-functioning fridge when on 12v (connected to tug).

Resolved that this morning but making the earthing at the tug connection plug more definite (tighter screws) and on impulse thought I should check the electric heating (240v).
Knock me over with a feather - it works. No idea why, but it works.

First law in fixing things is - if it works, leave it alone!!

Many thanks to you all for your considered input and suggestions.

We have a great community here and I am most appreciativie of it.

I did a major reconstruct of the van when I finally managed to limp into Perth WA and shall be putting together a pictogram of the problem and rebuild on one of my websites -- will advise through appropriate forum when ready.

Cheers

 

[Beachball]

Also in Oz and have a small 2007 Swift that was recently imported. I was looking for something with a bathroom but still light enough to tow with the car, seems only the UK vans can do this! For space heating it has a Trumatic S 3002P (gas) and Ultraheat (electric). I could not get the electric element to heat at all. Discovered I had to have the temp dial all the way up to maximum 9 (31c) before the relay clicked. Ambient temp was only 22c so lower settings should have activated but didn't . Next my Ultraheat would cutout within 10 mins, more so when set to 1000W or 2000W with or without the Trumavent fan on. If I reset the Ultraheat at the circuit breaker it would work again for another 5-10 minutes. Next I removed the gas heater as gas wasn't piped in. Likely the importer's gas certifier required it be disconnected from heater. I found the remote sensor wire (option) was fitted to the control box thermostat and was tied to the base of the gas heater. Apparently it is meant to work better in that position. After removing the gas heater I was left with an opening in the floor that I sealed up to prevent cold air and bugs getting in, but I left a 5mm gap to push the thermostat wire through to the underside of the van! Underneath I coiled and secured it so it wasn't too exposed. Heater now works on 500 or 1000w for couple of hours with no cutouts and can now get the van very warm. My remote sensor must have been too sensitive even at the recommended spot. Moving it to the much cooler position under the van has done wonders. I did consider unplugging the remote sensor wire from the control box and removing it completely but that would force the control box thermostat to take its readings locally, and that box is sort of close to the element. I think having my (faulty) remote sensor in a cooler spot underneath is better. It still cuts out on the 2000w setting so that must be a different issue, possibly the 175c overheat safety thermostat is faulty. Yeah I have no gas heating and electric that only works on 500 or 1000w ...but still better than nothing. Good luck with yours.

Hi JMC Welcome to the forum

 

[ecliptic]

Update.

I contacted the Truma main dealer here in OZ to see if they could supply or repair the PCB and had a prompt call back to advise me the heater - gas and electric - was illegal and I need to install an Australia certified one.
Hmm, with a price tag of $2195 plus install I think I will risk the hand on the shoulder.
Odd, though, for when I had the van checked for a gas certificate there was no quibble about the heater.

The fact that I did have the heating run once on 240v tells me that I have a problem with the PCB rather that the temp control diode. This chance operation followed my solving a power supply problem with the fridge on 12v connected to the tug (motor running).

Suggestions invited, including where I can get a PCB for the Truma 3002s EL heater. Repair is also an option but where?

 

[ProfJohnL]

Update.

I contacted the Truma main dealer here in OZ to see if they could supply or repair the PCB and had a prompt call back to advise me the heater - gas and electric - was illegal and I need to install an Australia certified one.
Hmm, with a price tag of $2195 plus install I think I will risk the hand on the shoulder.
Odd, though, for when I had the van checked for a gas certificate there was no quibble about the heater.

The fact that I did have the heating run once on 240v tells me that I have a problem with the PCB rather that the temp control diode. This chance operation followed my solving a power supply problem with the fridge on 12v connected to the tug (motor running).

Suggestions invited, including where I can get a PCB for the Truma 3002s EL e sheater. Repair is also an option but where?

During this pandemic, many businesses are using postal sales to keep things moving a little. You might find a UK or EU caravan dealer might have the part in stock or might be able to order it, and they might be prepared to post it to you.

I don't know how the AU regs cover private imports for foriegn visiting vehicles. However I'm a bit of a stickler for following regulations, and I have to add you should follow the local codes regarding works.

 

[ecliptic]

Hello ProfJohnL.

Firstly, I agree with you regarding regulations.

However, there is nothing that I can see that contradicts the local regs - which are there to keep us safe.

All systems protected by fuses and earth return sensing.

Sometimes the call is to protect local industry or the current Country master dealership.

I can get the part from leisureshopdirect but they want a large amount of roubles for postage. When I asked why it was because of the value of the part .... Beats me, so need to shop around.

Getting the part into my hands is not a problem - no border regulation control of end use of item.

Regards

 

[Damian]

When I asked why it was because of the value of the part .... Beats me, so need to shop around.

The reason for the cost of postage is that in the UK , the Post Office including Parcelforce, have a sliding scale of charges that include Insurance, the more expensive the item, the more the postage, plus of course the distance it would have to travel, which increases the possibility of loss, all comes into the final price.

Just looking at their prices for Global Express is £43.50 with the amount of cover for the item.

 

[ecliptic]

Thank you for the figure, there, Damian. It equates to $79 here in down under. Sigh.

Bullet biting called for

Many thanks to you and ProfJohnL for your explanations.