Truma Combi - blowing cold

[Thai Bry]

Just trying to warm up our van and have noticed a slight problem.

 

Both on electric and gas settings, our Combi just seems to be blowing out cold air.

It was working fine a month ago.

 

Any ideas would be appreciated

 

Many thanks

[Ninian]

Hi, Are you showing any fault codes.

[Thai Bry]

Ninian - 2020-12-29 10:05 PM

 

Hi, Are you showing any fault codes.

Not showing any fault codes.

Green and yellow lights - as should be on electric - and no red light when on gas only

[Ninian]

Don't know but possibly your unit has tripped and requires something to be reset. ????

 

 

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Featured snippet from the web

How do I reset my truma combi? To reset the overheating protection, allow heater to cool, re- move connection cover and press red reset button.

[Derek Uzzell]

The Truma Combi ‘overheating protection’ you’ve referred to relates only to 240V operation (see attached image), but Thai Bry’s heater is working as one might expect on its 240V and gas settings - except it does not produce hot air - and no error codes are being displayed.

 

Other than switching the heater completely off and going through the start-up routine again, and repeating that procedure several times if it has no positive effect, I doubt there is much more can be done.

 

Truma’s technical advice phone number is 01283 587960 and email: technical@trumauk.com

 

https://www.truma.com/uk/en/service/customer-service

 

See also

 

https://www.truma.com/uk/en/service/self-service/product-family/truma-combi-heaters

 

 

 

[thebishbus]

Does it have to have water in the boiler to work ? If so is there water in the boiler ? If there is water in the boiler is it heating up ok ?

Brian B.

[Thai Bry]

thebishbus - 2020-12-30 8:16 AM

 

Does it have to have water in the boiler to work ? If so is there water in the boiler ? If there is water in the boiler is it heating up ok ?

Brian B.

The Combi boiler does not have to have water in it for it to work. You can run the system with just heat around the van, and the boiler can be emoty.

[Thai Bry]

Derek Uzzell - 2020-12-30 7:10 AM

 

The Truma Combi ‘overheating protection’ you’ve referred to relates only to 240V operation (see attached image), but Thai Bry’s heater is working as one might expect on its 240V and gas settings - except it does not produce hot air - and no error codes are being displayed.

 

Other than switching the heater completely off and going through the start-up routine again, and repeating that procedure several times if it has no positive effect, I doubt there is much more can be done.

 

Truma’s technical advice phone number is 01283 587960 and email: technical@trumauk.com

 

https://www.truma.com/uk/en/service/customer-service

 

See also

 

https://www.truma.com/uk/en/service/self-service/product-family/truma-combi-heaters

Many thanks to you Derek and also to Ninian.

 

I'll look up the manual in the van later to day to check on the reset button and then let you know if this cures/ remeides the problem.

Due to the overnight cold weather here in Yorkshire , the van looks frozen over.

Thanks to all once again

[Robinhood]

Thai Bry - 2020-12-30 8:40 AM

 

The Combi boiler does not have to have water in it for it to work. You can run the system with just heat around the van, and the boiler can be empty.

It can be, but you then need to run it in "winter mode", which means selecting a mode that doesn't include water heating.

 

If you don't, the boiler will go into "failure mode" (though it isn't documented whether there are any symptoms (e.g. warning light indications) in this case.

[Thai Bry]

Robinhood - 2020-12-30 9:09 AM

 

Thai Bry - 2020-12-30 8:40 AM

 

The Combi boiler does not have to have water in it for it to work. You can run the system with just heat around the van, and the boiler can be empty.

It can be, but you then need to run it in "winter mode", which means selecting a mode that doesn't include water heating.

 

If you don't, the boiler will go into "failure mode" (though it isn't documented whether there are any symptoms (e.g. warning light indications) in this case.

Many thanks

I'm running it winter mode, so no water heating is being selected.

 

Have now found the reset button according to the manual.

I'm now running it again in winter mode, however, again it seems to be blowing just cold air.

May need to run it a little longer as it is very cold so may take some time for it to reach temperature.

 

I may turn it off, and then back on again a few times to see if this cures the problem.

 

If not, looking like an expensive visit to a dealer to resolve the problem.

It's a good job that we're not able to go anywhere- in the current pandemic - we being in Tier 3 and may go to Tier 4 later.

 

Thanks anyway

[Derek Uzzell]

I Think Thai Bry’s Hymer S-700G is a 2007 model.

 

If that’s correct, I’m not certain if the heater will be a Trumatic C-6002EH (often called a ‘combi’) or the Combi 6E that succeeded that appliance. If the motorhome has the former heater, there will be a pair of rotary control-switch. If it's a 2007 Combi 6E, there might be the same pair of rotary control-switches, or possibly a single CP Plus digital control-panel.

 

This may be academic in this instance, but it should show that age can matter where motorhomes are concerned ;-)

 

Assuming that the Truma heater in Thai Bry’s Hymer has the usual intake/exhaust cowl emerging from the vehicle’s side (or rear) bodywork, if gas operation is chosen it should rapidly become obvious that the gas-burner is operating as hot exhaust gasses will come out of the cowl. When the gas-burner is operating, a central heat exchanger is heated and (when air heating has been chosen by the user) air sucked into the heater from within the motorhome’s habitation area is forced over the heat exchanger and circulated around the motorhome’s interior through flexible ducts. Logically, then, if hot exhaust gasses are coming out of the cowl and the heater’s air-recirculation fan is running (and the noise that fan makes when running should always be audible) warm air should eventually come out of the outlets at the ends of the flexible ducts. There is the possibility that, if a duct became detached from the heater, warm air would be ‘lost’ near the heater, but it’s not easy to see how, if the heater is operating properly on gas, COLD air will come out of the ducts’ outlets.

 

I suggest the heater be started up on gas with air-heating selected and just left to do its own thing. It’s quite possible that - as Thai Bry has just said - there’s nothing wrong and the heater just needs time to warm up.

[Thai Bry]

Derek Uzzell - 2020-12-30 9:50 AM

 

I Think Thai Bry’s Hymer S-700G is a 2007 model.

 

If that’s correct, I’m not certain if the heater will be a Trumatic C-6002EH (often called a ‘combi’) or the Combi 6E that succeeded that appliance. If the motorhome has the former heater, there will be a pair of rotary control-switch. If it's a 2007 Combi 6E, there might be the same pair of rotary control-switches, or possibly a single CP Plus digital control-panel.

 

This may be academic in this instance, but it should show that age can matter where motorhomes are concerned ;-)

 

Assuming that the Truma heater in Thai Bry’s Hymer has the usual intake/exhaust cowl emerging from the vehicle’s side (or rear) bodywork, if gas operation is chosen it should rapidly become obvious that the gas-burner is operating as hot exhaust gasses will come out of the cowl. When the gas-burner is operating, a central heat exchanger is heated and (when air heating has been chosen by the user) air sucked into the heater from within the motorhome’s habitation area is forced over the heat exchanger and circulated around the motorhome’s interior through flexible ducts. Logically, then, if hot exhaust gasses are coming out of the cowl and the heater’s air-recirculation fan is running (and the noise that fan makes when running should always be audible) warm air should eventually come out of the outlets at the ends of the flexible ducts. There is the possibility that, if a duct became detached from the heater, warm air would be ‘lost’ near the heater, but it’s not easy to see how, if the heater is operating properly on gas, COLD air will come out of the ducts’ outlets.

 

I suggest the heater be started up on gas with air-heating selected and just left to do its own thing. It’s quite possible that - as Thai Bry has just said - there’s nothing wrong and the heater just needs time to warm up.

Hi Derek

 

My Truma is indeed the C 6002EH version.

I've now done as you suggested, by running the system on the gas setting. Even checked that the main gas bottle was full, which it was.

I went outside to check the external cowl, and after a few splutters, hot exhaust was coming out of the cowl.

I've let the system run a little while, and indeed, warm air was coming out of all the outlets within the van, including the two in the garage.

I've now turned off the system, and as usual, I get the normal warm air overrun from the Trauma.

 

I'll let the system cool down a little before, trying it on electrics.

 

Many thanks for your advice.

[Thai Bry]

Afternoon Derek

 

Tried it on gas, and all seems ok.

Let the system cool right down, put it on EHU, and the same problem persists.

Only cold air blowing, yet I can hear the fan working.

 

A visit to a Truma expert beckons me thinks.

 

Thanks for your advice anyway

 

 

[Derek Uzzell]

The relevant trouble-shooting section of Truma’s C-6002EH Operating Instructions say

 

Electrical operation 230 V

 

The green indicator lamp on the control panel illuminates when the unit is switched on, the yellow indicator lamp on the power selector switch does not illuminate and the heating does not become warm

 

– No supply voltage. – Check 230 V supply voltage and fuses

– Device fuse defective. – Check device fuse (see Maintenance)

– Overheating switch has triggered – Reset overheating switch (see Maintenance

 

Does the yellow indicator lamp on the power selector switch illuminate in your case?

 

(It may be that, when 230V-only heating is selected, even if the heating elements aren’t working the warm-air fan may run.)

 

[Thai Bry]

Derek Uzzell - 2020-12-30 3:36 PM

 

The relevant trouble-shooting section of Truma’s C-6002EH Operating Instructions say

 

Electrical operation 230 V

 

The green indicator lamp on the control panel illuminates when the unit is switched on, the yellow indicator lamp on the power selector switch does not illuminate and the heating does not become warm

 

– No supply voltage. – Check 230 V supply voltage and fuses

– Device fuse defective. – Check device fuse (see Maintenance)

– Overheating switch has triggered – Reset overheating switch (see Maintenance

 

Does the yellow indicator lamp on the power selector switch illuminate in your case?

 

(It may be that, when 230V-only heating is selected, even if the heating elements aren’t working the warm-air fan may run.)

Hi Derek

Yes, when on EHU, both the Yellow & Green lights show.

It didn't do at 1st.

I may have to check the fuse on the Schaudt unit.

[Thai Bry]

Sorry, not the fuse on the EBL unit, but the fuse on the actual boiler.

 

I've looked at this, however, due to the tight placing of the unit, under the wardrobe area, I'll have difficulty in accessing the fuse area.

[Thai Bry]

Derek Uzzell - 2020-12-30 3:36 PM

 

The relevant trouble-shooting section of Truma’s C-6002EH Operating Instructions say

 

Electrical operation 230 V

 

The green indicator lamp on the control panel illuminates when the unit is switched on, the yellow indicator lamp on the power selector switch does not illuminate and the heating does not become warm

 

– No supply voltage. – Check 230 V supply voltage and fuses

– Device fuse defective. – Check device fuse (see Maintenance)

– Overheating switch has triggered – Reset overheating switch (see Maintenance

 

Does the yellow indicator lamp on the power selector switch illuminate in your case?

 

(It may be that, when 230V-only heating is selected, even if the heating elements aren’t working the warm-air fan may run.)

I've had the system on gas for the last couple of hours, and it's as warm as toast in the van.

 

I'll let the system cool down before putting on the electric part to see if this works, and check for the yellow and green lights on the top indicator.

Fingers crossed.

If not looking like a fault on the electric side of things.

[Robinhood]

I had the equivalent 240v fuse go on a Combi 6E, and it was a devil to get at, given that the unit was built in against the wall. A small mirror and a large amount of swearing allowed me to replace it (after several days of running on gas only).

 

Knowing the layout of the connection board on a C6002EH may help if "fumbling in the dark". (Power Off Please :-S )

 

The fuse in question is the T10AH one (which is a slow blow/delayed action fuse, not entirely common, but also not entirely difficult to source).

 

The picture, as it is a good one, is unashamedly pinched from "elsewhere". ;-)

 

[peterjl]

Hi.

 

This is probably a silly question but is your EHU actually providing power? The fan will work off the battery.

 

I had some weird issues with my system in September and the problem wasn’t always made clear by the warning lights which gave some random results especially giving low battery warnings when the battery level was fine.

 

Peter

[Thai Bry]

Robinhood - 2020-12-30 5:22 PM

 

I had the equivalent 240v fuse go on a Combi 6E, and it was a devil to get at, given that the unit was built in against the wall. A small mirror and a large amount of swearing allowed me to replace it (after several days of running on gas only).

 

Knowing the layout of the connection board on a C6002EH may help if "fumbling in the dark". (Power Off Please :-S )

 

The fuse in question is the T10AH one (which is a slow blow/delayed action fuse, not entirely common, but also not entirely difficult to source).

 

The picture, as it is a good one, is unashamedly pinched from "elsewhere". ;-)

Thanks once again Robin.

I'll see if I can get a mirror on a stick to squeeze down the back of the unit.

Looking really difficult- if it's the fuse that needs replacing.

[Thai Bry]

peterjl - 2020-12-30 5:28 PM

 

Hi.

 

This is probably a silly question but is your EHU actually providing power? The fan will work off the battery.

 

I had some weird issues with my system in September and the problem wasn’t always made clear by the warning lights which gave some random results especially giving low battery warnings when the battery level was fine.

 

Peter

There is power going to the unit, the lights on the dials say so. At least the gas system of the unit works.

If no heat on Electrics, and due to the tightness of the unit against a wall, looking like a visit to a Truma agent to have the problem resolved.

Sadly an expensive task me thinks, but on the bright side of things, we've had the van from new since 2007, so all in all not too bad, and there are worse problems others are facing in this current pandemic.

[Thai Bry]

Derek Uzzell - 2020-12-30 3:36 PM

 

The relevant trouble-shooting section of Truma’s C-6002EH Operating Instructions say

 

Electrical operation 230 V

 

The green indicator lamp on the control panel illuminates when the unit is switched on, the yellow indicator lamp on the power selector switch does not illuminate and the heating does not become warm

 

– No supply voltage. – Check 230 V supply voltage and fuses

– Device fuse defective. – Check device fuse (see Maintenance)

– Overheating switch has triggered – Reset overheating switch (see Maintenance

 

Does the yellow indicator lamp on the power selector switch illuminate in your case?

 

(It may be that, when 230V-only heating is selected, even if the heating elements aren’t working the warm-air fan may run.)

Hi Derek

 

Just checked & sadly I can confirm that the Yellow light on the dial does not come on when I'm on the electric side of things.

Just the green light is showing.

All working OK on the gas side of things.

I've also got a e-mail in to Truma technical help.

As Robin, has stated, my unit is very tight against the wall of where it's housed, so unable to fumble about to replace a fuse if this is the case. Looking like a visit to an authorised Truma specialist, nearest one according to the Truma website is in Bradford.

[Derek Uzzell]

Robinhood - 2020-12-30 5:22 PM

 

...The picture, as it is a good one, is unashamedly pinched from "elsewhere". ;-)

I can’t see your picture - all I get is a small picture-frame with a red cross on it (1st image attached below), but I’m not sure what the cause is.

 

Anyway, I think the photo you acquired is the 2nd image I’ve attached below, with the position of the fuse arrowed in green.

 

A Trumatic C-6002EH has two black ‘boxes on its sides. One box protects a complex PCB that deals with most of the heater’s 12V functionality and the other box (that has a sliding section on it that covers the red 230V ‘reset' button) protects a much simpler PCB. Although managing to slide up the cover and press the reset button may be fairly easy (if one is lucky!!) removing the protective ‘boxes’ may prove impossible while the heater remains in situ.

 

This 2007 forum thread discussed the 230V fuse and the difficulty gaining access to it on a Knaus motorhome.

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Truma-Combi-6002EH-Fuse-Blown/6599/

 

(I remember Truma technicians complaining bitterly about how difficult it could be to work on Trumatic C heaters when motorhomes were brought in for repairs, with one saying that they dreaded the arrival of a Hymer motorhome as accessing the heater often involved major furniture dismantling.)

[Robinhood]

Thai Bry - 2020-12-30 6:01 PM

 

Thanks once again Robin.

I'll see if I can get a mirror on a stick to squeeze down the back of the unit.

Looking really difficult- if it's the fuse that needs replacing.

I know the Combi6E is different, but the arrangement is very similar. TBH, I managed with a mirror, and then by feel, in a very tight space. BUT, the fuse is considerably more easy to remove than to replace under those conditions.

[Robinhood]

Derek Uzzell - 2020-12-30 6:31 PM

 

(I remember Truma technicians complaining bitterly about how difficult it could be to work on Trumatic C heaters when motorhomes were brought in for repairs, with one saying that they dreaded the arrival of a Hymer motorhome as accessing the heater often involved major furniture dismantling.)

It's not quite the same picture, but almost, and I suspect from the same source ;-)

 

I had recall work done on a C6002EH in my Rapido maybe 12 years ago at TrumaUK. The "techs" were extremely grateful Rapido had put a service hatch for the unit in the exterior wall, as it was well-buried somewhere in the kitchen. Almost had it done before I'd finished my bacon sarnie in their canteen ;-) .