Truma Blown Air Heating

winks

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Water works perfectly on this C3402 model but I can't get the heating to fire up.

Turn outer ring of control to heating only then turn temperature control up to full. The air circulator fan runs at a low speed, which I'm given to understand should be the case initially, but the main burner doesn't fire up and eventually the air circulator fan gives up. It has worked previously but with a mind of its own on occasion.

Hoping to get a local service fella to take a look but if anyone has a magic answer I'd be obliged. I have a Roseann who is greatly affected by heating or the lack of it. Can't believe she's a bona fide Jock.

Cheers

H
 

Mike Duhig

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Hi, we have the self same problem but on a B694.
Can get hot water on all four settings, water and heating options but no heating!
We have a very good Caravan Doctor, did a diagnostic test and said the main burner had a fault, wouldn’t fire up for the heating.
Then problems started…..Truma no longer support this model boiler, suspended spares in summer ‘21!
New burner like hens teeth, finally secured one two weeks ago, £395, fitted all fired up and worked for 30 minutes then stopped, water only again.
Specialist company in Cannock suggested PCB might be faulty, we’re in Wiltshire, sent board tested all fine.Awaiting PCB for refitting.
No ideas what to test next?

Like you my better half cannot cope without full central heating therefore unless we are hooked up’van cannot be used.

Would welcome any suggestions as to what to do next please and I wish you luck with your problem.

Mike
 

gypo

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Water works perfectly on this C3402 model but I can't get the heating to fire up.

Turn outer ring of control to heating only then turn temperature control up to full. The air circulator fan runs at a low speed, which I'm given to understand should be the case initially, but the main burner doesn't fire up and eventually the air circulator fan gives up. It has worked previously but with a mind of its own on occasion.

Hoping to get a local service fella to take a look but if anyone has a magic answer I'd be obliged. I have a Roseann who is greatly affected by heating or the lack of it. Can't believe she's a bona fide Jock.

Cheers

H
Does the light flash on the on off switch? Mine will flash in different patterns depending on the error message, for eg if the power supply isn’t enough for it I think it flashes in a 3 burst Pattern?
 

Mike Duhig

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Don’t have flashing lights system on my heating, green and orange lights come on, orange goes off once temperature reached. Green stays on.
 

winks

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Does the light flash on the on off switch? Mine will flash in different patJust as Mike says in terns depending on the error message, for eg if the power supply isn’t enough for it I think it flashes in a 3 burst Pattern?
Just as Mike says in the previous post, only green light and orange for when water is up to temperature. I have seen a red on it in the past but can't remember what caused that.

Cheers

H
 

maingate

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Like most gas boilers there is a system of safety features (in series) that it goes through on start up. The fan you hear is the first of them, it allows 12 volt power to the next stage which should be the ignition sequence. This starts the boiler by opening the gas valve and could be where your trouble lies. Do a visual check for wiring problems. Normally the fan will run for a set time and if there has been no ignition then you should get the red light when the boiler shuts down.

The switch to start the boiler seems OK as the fan starts up. Don't be offended .... but did you remove the external cover on the exhaust? Years ago when I had the same boiler I kept forgetting to do that. :giggle:
 

winks

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Like most gas boilers there is a system of safety features (in series) that it goes through on start up. The fan you hear is the first of them, it allows 12 volt power to the next stage which should be the ignition sequence. This starts the boiler by opening the gas valve and could be where your trouble lies. Do a visual check for wiring problems. Normally the fan will run for a set time and if there has been no ignition then you should get the red light when the boiler shuts down.

The switch to start the boiler seems OK as the fan starts up. Don't be offended .... but did you remove the external cover on the exhaust? Years ago when I had the same boiler I kept forgetting to do that. :giggle:
I’d guessed it was start of a pre ignition set up to have the fan running. On the flue point, this has a circular balanced flue and I’ve cleared some debris from the intake side but the burner for the water works perfectly. We had the rectangular shaped flue on our Hymer so I know what you mean.

Cheers

H
 

Martin P

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I ended up taking our old Truma out and replaced it with a new Combi 4e.
Looking back if I had done that straight away I would have saved a couple of hundred quid on repairs and had a warmer few weeks in Scotland. The new 4e is a much better bit of kit
I think once the old trumas start playing up they become a money pit
 

Martin P

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Our fault (same symptoms) started with the main fan motor . The fan would turn slowly then shut off. The brushes were worn so the control unit not happy to fire up combustion. New motors are not available. Dont fit the motor from from the 4e as this will take out the transistor on the main circuit board. It is possible to open the motor and fit (adapt) brushes to fit.
 

winks

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Just been having a look at the 4E. Can be bought for around £1500 but let’s hope that it go that far.

Cheers

H
 

Mike Duhig

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Just been having a look at the 4E. Can be bought for around £1500 but let’s hope that it go that far.

Cheers

H
Yes indeed, I’ll keep you posted on how my repairs go, still waiting for the PCB to return.
Mike
 

Martin P

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Yes just searched still available but a bit expensive! Nobody ever said maintaining a motorhome was cheap!!!
I got our boiler working for a while but when it started playing up again we just decided to bite the bullet and cut our losses. Our main 3 week holiday is just too precious to us to risk.
Changing the boiler was quite a big job. I managed to position it so the gas line just needed moving slightly ( it came with a new fitting) and the exhaust piping was long enough to reach the outlet. Water pipes were easy to change and heater blower pipes were simple. The big problem is the control cabling as it has extra wires than the old model. Quite a lot of work to lay in plus the new 240v line.
The new control panel is bigger so needs cutting in..
Truma problems are a nightmare. I feel your pain!
 

Mike Duhig

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I got our boiler working for a while but when it started playing up again we just decided to bite the bullet and cut our losses. Our main 3 week holiday is just too precious to us to risk.
Changing the boiler was quite a big job. I managed to position it so the gas line just needed moving slightly ( it came with a new fitting) and the exhaust piping was long enough to reach the outlet. Water pipes were easy to change and heater blower pipes were simple. The big problem is the control cabling as it has extra wires than the old model. Quite a lot of work to lay in plus the new 240v line.
The new control panel is bigger so needs cutting in..
Truma problems are a nightmare. I feel your pain!
I’ll keep my fingers crossed for a successful repair in the first instance!
 

winks

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Mobile man has been and there is no output to the fan from the pcb, which is impossible to access without stripping out at least one cupboard, but not impossible. Having talked to him I feel much more confident about going a bit further myself. In fairness the boiler has not been "serviced" since we took ownership of the van so I'll take the bits I can apart, non gas carrying that is, clean up edge connectors and the like and see what comes next. Worst case I have a company I've used previously who will change the unit for a 6E thus giving us leccy heating as well for £2000.

Only took £20 off me for his diesel, so that's good.

Cheers

H
 
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