Truma c 6002 EH Not Heating up.

[coach2000]

Due to go on my travels next week and sods law something does not work. On turning on my truma today it would not ignite on gas. It has been working ok all the time the cold snap has been on.

The green light comes on the switch, the fans turn, the solenoids operate but it does not get warm. I changed the gas bottle in case the pressure was down but no joy.

My next thing is to try and check the fuses but the are not easy to get at. Does any one know how to get under the covers?

Any ideas to get the heat on please.

 

Clive.

[weldted]

Heater, if you turn it on to hot water only does the water get hot. Does the green light turn red, if it does and it blinks that is low battery, if it is red and fixed it is a gas problem. There is a red reset button at the top of the black box check that that is reset, if the fans runs for a while then stops the green light stays on it and you have turned the temp dial up to 9 check the wires are connected at the temp sensor looks like a small black button fitted in different places according to model on my Bessacar it is low down near the hab door. Hope this helps?

[coach2000]

Thanks, I have no water in the system for now and cannot try that side of it. There is plenty of battery power and I do not get any red lights. I wonder if it could be the igniter as the gas solenoid seems to open. Will have a closer look at the weekend. It is under the fixed bed, so I will lift the mattress and put more light on the job.

 

Clive.

[Derek Uzzell]

coach2000 - 2010-12-30 11:34 PM

 

Thanks, I have no water in the system for now and cannot try that side of it. There is plenty of battery power and I do not get any red lights. I wonder if it could be the igniter as the gas solenoid seems to open. Will have a closer look at the weekend. It is under the fixed bed, so I will lift the mattress and put more light on the job.

 

Clive.

 

In principle, if there's any problem at the gas-ignition stage, the heater should shut down and the red 'fault' monitor light should illuminate steadily on the heater's Contro Panel. If the igniters weren't working, then the gas wouldn't light and the heater should shut off its gas supply and shut down.

 

The initial start-up sequence on these heaters is audible (or it is with mine!).

 

Let's assume you have selected 'gas operation' on the Power Selector Switch, turned the Control Panel's temperature-setting rotary dial to '9' and selected one or other of the 'Winter' settings (ie. blown-air heating).

 

The heater's blown-air fan should begin to run relatively slowly, then, after a short while, you should hear the gas-feed solenoid-valve click open followed by the sound of the igniters 'firing' (a sort of low-pitched electronic 'squeal'). If the gas doesn't light, then the igniters should stop firing, the solenoid valve should click shut and a red light should illuminate on the control panel.

 

As I understand it, your heater seems to perform gas-ignition successfully, but no warm air emerges from the blown air outlets. Logically, that's impossible, as, if the heater's gas-burner has lit and the blown-air fan continues to run, warm air MUST eventually emerge from the outlets.

 

If I were in your position, the first thing I'd do is confirm what I had selected on the heater's Power Selector Switch and Control Panel. I'd then listen to see if I could identify anything odd happening during the start-up procedure. If everything seemed OK, the heater kept running, but no warm air was produced, then I'd seek advice from Truma(UK) on 01283 586020

 

I have never removed my C-6002EH's protective covers, but I did remove the cover of my previous C-3402. If you can actually access the covers to remove them, then I'm pretty sure the method of removal will be obvious.

 

As you are probably aware, C-6002EH heaters have two 12V slow-acting fuses - a 6.3A and a 1.6A - located beneath the protective cover shielding the main electronics printed-circuit board. I don't know what these fuses are for and, consequently, I don't know what effect fuse failure would have. Based on Truma's C-6002EH trouble-shooting list, I would have thought that failure of either fuse would stop the heater working, but who knows? That's why I'm suggesting you contact Truma(UK) before attempting to remove the covers.

[coach2000]

Hi Derek, I'm going to have a look this afternoon as I cannot stop thinking about this problem. I tried to get hold of Truma UK this morning, no joy.

After the solenoids operate to open they do not click again after to indicate closing, also outside the van at the outlet cowl it is cold air blowing all the time.

Thanks for that reply.

 

Clive.

[Dave Newell]

This is just a guess but there is some education behind it. I think it may be the combustion air fan motor has failed. The symptoms are that you hear the gas valve open but it doesn't try to ignite and goes to a fault light on the control. What actually happens is the gas valve snaps open but closes immediately as without combustion air it would not burn properly so the system shuts down. When you said you heard the gas valve open but not close again leads me to suspect this.

 

D.

[Brian Kirby]

Except, dear Dave, that Coach has no red lights up, and he says he gets cold air blowing from the flue, which must surely indicate the combustion air fan is running.  Bummer!

However, I wonder if it may be a problem with the hot air circulation fan, as he says no air comes from the heater vents at any temperature. 

Although whether that would allow the start up sequence to run and just shut off, as though the stat were satisfied, without red lighting, I know not.

Just typing this made me wonder if the stat may be the problem, either at the control panel, or at the thermistor (I think?) sensor on the wall?  If either thinks the van has reached the set temperature, the fan would not run, so no circulating air, and the heater would not fire, but no red light would come on because the control logic would be satisfied.

So, is Coach possibly using a supplementary heater in his van, and is that under the temp sensor, so it detects warmth and doesn't fire the heater?  Or, has the temp setting on the controller accidentally been turned right down, and is its lowest setting effectively an "off" setting, so that it is just waiting to be turned up to tell it to generate some heat?

[Derek Uzzell]

Dave Newell - 2010-12-31 12:16 PM

 

This is just a guess but there is some education behind it. I think it may be the combustion air fan motor has failed. The symptoms are that you hear the gas valve open but it doesn't try to ignite and goes to a fault light on the control. What actually happens is the gas valve snaps open but closes immediately as without combustion air it would not burn properly so the system shuts down. When you said you heard the gas valve open but not close again leads me to suspect this.

 

D.

 

Dave

 

The snag with your theory is a) Clive's heater evidently does not shut down and no red 'fault light' illuminates on the Control Panel and b) Clive says "outside the van at the outlet cowl it is cold air blowing all the time", which one would expect not to be happening if the burner-fan had failed.

 

These appliances have lots of safety interlocks and I'm fairly sure that, if you put the heater into gas-only blown-air mode, if either of the fans had failed the heater would shut itself down. The fans (both of them) run for a while before the gas-valve opens and gas ignition is attempted, and I would expect the heater to shut down during that preparatory period if either of the fans had packed up. Similarly, if the gas-valve has failed, or the igniters have failed, the heater should shut down.

 

If my own heater is representative of the breed, the gas-valve can clearly be heard closing, so, if Clive's heater's valve were opening then closing immediately after, I'd expect to hear a 'double click'. (It would be worth switching the heater off while its running to check whether the sound of the gas-valve closing can be heard.) It's reasonable to assume that the gas-valve is actually shut - otherwise you'd surely smell gas at the intake/exhaust cowl? Conversely, if the gas-valve is shut, the heater really shouldn't be running at all in gas-only mode.

 

A C-6002EH can safely be operated empty of water, so it would be worth putting Clive's heater in gas-only water-heating mode to see what happens at the gas-ignition stage. The advantage of doing this is that the blown-air fan won't be operating and, consequently, it should be possible to hear the burner-fan running and be easier to hear sounds made by the gas-valve and igniters.

 

If it's not possible to contact Truma(UK), then I guess checking the heater's on-board fuses is the logical next step.

 

 

[coach2000]

Well Derek, Brian and Dave. A real head scratcher. Just to clear a couple of points up before I go on. No other heating is used to affect the stat. There was cold air coming out the heater vents and the controller was set at 9. Dave you could have been right about the combustion fan as I could not hear it running seperate to the circulation fan.

However, it has now decided to work again, when I first tried it again today, no joy. I lifted the mattress base. Dismantled part of the woodwork and disconnected a couple of heater pipes to get at the unit covers. If you cannot get a front access to the electronics box it would be next to impossible to work on, if not about 4-6 inches minimum sideways.

On taking the cover off the electronics module all the pc board came out as well and you have to disconnect the 12 volt supply spade terms. to get the cover off. Checked both the fuses and all connections, could not see anything wrong. Visual inspection of board(looks like inside of a laptop) nothing. More fun then trying to get cover back on with pcb in correct position.

Well, time to try and see if I had disturbed anything. The green light came on, the fans started, 30 second delay, solenoids clicked, then another low clicking sound which I took tobe the ignitor and then the solenoids operated and the red light came on. What have I done now I thought and then I realised that's how its meant to work.

Two more tries and success it ignited and stayed lit the rest of the day even after switching off and restarting.

I have still not got a clue what it was but will have to keep my fingers crossed. I have not put all the screws back just in case.

Thanks for all the suggestions, just a pity I did not find anything.

 

Clive.

[Brian Kirby]

Possibly, just completely disconnecting power when you removed the pcb caused a full reset, and that was all it needed.  One or two people seem to have been having problems after the cold, so maybe there is a fine film of condensation on the pcb that has been causing trouble.  Whatever, glad its working now!

[sshortcircuit]

"so maybe there is a fine film of condensation on the pcb that has been causing trouble. "

 

Come on Brian, that's a real clutch at straws. Condensation results in "bang"

 

Its working now but why ?????

[hallii]

Modern circuit boards will be coated in synthetic resin to prevent any leakage paths being formed by condensation, but if not coated a film of condensation can produce some strange effects.

 

Most likely is that removing the cover and board has cleared a high resitance contact somewhere. The somewhere could be the connectors, or it could be a

high resistance joint on the board caused by the failure of the solder to "wet" either component leads/pins or the copper circuit board.

 

Time will tell, if it's a poor solder joint it will happen again, and they can be a real pain to find. I used to swap a circuit board costing £600 because it was the best way to solve this sort of problem.

 

Then on the bench the fault coluld be sorted and the board made ready for the next time. Shhh! Don't tell the customers.

[Brian Kirby]

sshortcircuit - 2010-12-31 11:54 PM "so maybe there is a fine film of condensation on the pcb that has been causing trouble. " Come on Brian, that's a real clutch at straws. Condensation results in "bang" Its working now but why ?????

As hallii implies above, the currents on pcbs are far too low for the result to be a bang.  Even low voltage (sorry extra low voltage :-)) currents passing along fine conductors in close proximity can leak if there is a trace of surface moisture.  Even if the board is well designed, and coated to prevent this, there is still the possibility a blob of solder may have spread further than it should.  So yes, it is a bit unlikely, and I agree the greater probability is that a poor connection was rectified in the process of inspection. 

However, as I said, there seem to have been a few recent failures apparently relating to the cold weather, so one might think there is some, cold related, common factor.  Condensation somewhere critical is such a possible common factor.  It would be interesting if Coach were to contact Truma technical when they get back to work, to see if they have an explanation for what he experienced.

[coach2000]

Going to ring Truma on Tuesday. See if they answer the phone. the only other possible fault I could have disturbed would have been removing the 2 small fuses to check. If one of these had not been inserted properly before.

 

Clive.

 

[Robinhood]

Brian Kirby - 2011-01-01 12:31 PM

However, as I said, there seem to have been a few recent failures apparently relating to the cold weather, so one might think there is some, cold related, common factor.  Condensation somewhere critical is such a possible common factor.  It would be interesting if Coach were to contact Truma technical when they get back to work, to see if they have an explanation for what he experienced.

In the process of fitting a Nature Pure filter to my previous 'van, I managed to spray water over the control box of a similar unit.

On completing the work, I tested the heater, and lo and behold, it didn't function. (I can't remember if I got any lights or not on the panel).

I removed the cover, and carefully dried all the PCB and connections (yes, the water had intruded), and once complete, it worked first time.

Not exactly 'condensation' but there was obviously some short-circuiting taking place, and since it worked until I exchanged the 'van some years after, it doesn't look like it caused any damage.

So, condensation may be a possibility. 

[Brian Kirby]

coach2000 - 2011-01-01 1:20 PM Going to ring Truma on Tuesday. See if they answer the phone. the only other possible fault I could have disturbed would have been removing the 2 small fuses to check. If one of these had not been inserted properly before. Clive.

Their technical guys have always had the reputation for being very helpful, and have previously answered the odd query for me, so you shouldn't have any problem getting in touch.  Let us know what they say, Clive, I'm intrigued as well!

[coach2000]

Just returned from France and rang Truma. They could not give a reason. The only thing they could think of was that the ignitor block was slowly breaking down. They did confirm that by removing the 12volt connection would give a proper reset. The technician was very helpful and answered other questions that I had.

I have been away for a month using the Truma everyday and it has not happened again. I have had other problems but will start a new thread for this. Once again, thanks for al lthe suggestions.

 

Clive.