Another Truma Combi 4 e question?? Smelling hot and 402 h error code

[Taylornewtonfarm]

Hello and hope that someone can help. I have a Combi 4e, it is pretty new has been used for about 20 nights so far. It has started to smell hot, you know that kind of electrically sort of hot smell, when it is on hot water. The smell appears after a couple of minutes, Error code 402 h has appeared a couple of times, I have 4 vents all fully open and no blockages. The smell is coming out of the ducts and there is no smell at all in the cupboard where the heater unit is. It is the same no matter if we are on gas, electricity or mixed. If we are on heating and hot water all seems to be ok.
Has anyone got any ideas or had a similar issue?
Thanks in advance.
Bill

 

[Riverbankannie]

It could be just the newness of it smelling. Do you have the (in my opinion) fairly confusing rotary controls? When you say when on hot water setting it smells, could it be that you have turned on the higher electric element? Error code 402 says getting too hot and to check for blockages in pipes or pipes not connected.

 

[MikeD]

As above error 402 is:

#402

Warm air temperature exceeded: - Not all warm air ducts are connected - Warm air outlets blocked - Circulated air intake blocked

- Check whether the 4 warm air ducts are connected - Check the individual outlet openings - Remove the circulated air intake blockage

 

[Taylornewtonfarm]

Hello fellow van enthusiasts,
Here is the response from Truma. Very comprehensive and I am posting it in case anyone else encounters this issue.

It is not unusual under certain conditions for the Combi Boiler to emit hot odours from the duct outlets.
There are several reasons why this may occur;
When used on ‘’Summer’’ setting (water heating only) very high temperatures are created within the boiler, natural convection can take place which causes cool air to be brought in via the low level ducts causing high temperature air to convect through the high level ducts at a very slow speed raising the ducting temperature. Any dust or debris that may be in the duct and plastic materials in close proximity to the duct become hot and can cause an odour.
When used on ‘’Winter’’ setting (blown air heating) the temperatures are much lower within the boiler and ducting therefore it is less likely to experience the hot odour issue.

Fault code 402 is just a warning code to indicate that the unit is in a cool down phase, this will occur when switching from water heating to space heating, it is nothing to worry about and will disappear when the heat exchanger of the heater has cooled a little.

 

[Chris22]

Hello, we have a truma combi 6e which also brings up this warning code w402h. Runs fans up cools and resets after about 2 minutes. Truma say it is normal, how often does yours bring up the warning message? Ours is about couple of times a week. When were away. Only happens if heating comes on just as water has finished heating. Thanks Chris.

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[Emmit]

It could be just the newness of it smelling. Do you have the (in my opinion) fairly confusing rotary controls? When you say when on hot water setting it smells, could it be that you have turned on the higher electric element? Error code 402 says getting too hot and to check for blockages in pipes or pipes not connected.
View attachment 438581

Good Morning Annie and to the OP,

In our 'Brand New' (to us???) Burstner we have the above diagram.

I can tell you, after 7yrs of owning the Hobby, these instructions came as a breath of fresh air.
Without fail, in the past, we had to pour over the 'old' instructions to work out which dial went up, which one went down etc.

Then followed the obvious waiting to find out that Truma's instructions were less than clear and the inevitable grumblings when we had to wait even longer for heat/water etc. The translation wasn't in colloquial English

With those instructions, (above,) I've found that the 'Up' arrows and 'Down' arrows make it much more user friendly. OK? it's still not sunk in and I don't just go to the dials without them but the right transaction is performed without fail.

To the OP. I can say that we had that 'Electrical' smell every time we used the Heater for Hot Water in the Hobby. It was our signal that the water was hot enough for a shower. Enjoy

 

[mitzimad]

if we put ours on the high setting it smells hot aparently this is normal

 

[Riverbankannie]

Good Morning Annie and to the OP,

In our 'Brand New' (to us???) Burstner we have the above diagram.

I can tell you, after 7yrs of owning the Hobby, these instructions came as a breath of fresh air.
Without fail, in the past, we had to pour over the 'old' instructions to work out which dial went up, which one went down etc.

Then followed the obvious waiting to find out that Truma's instructions were less than clear and the inevitable grumblings when we had to wait even longer for heat/water etc. The translation wasn't in colloquial English

With those instructions, (above,) I've found that the 'Up' arrows and 'Down' arrows make it much more user friendly. OK? it's still not sunk in and I don't just go to the dials without them but the right transaction is performed without fail.

To the OP. I can say that we had that 'Electrical' smell every time we used the Heater for Hot Water in the Hobby. It was our signal that the water was hot enough for a shower. Enjoy

I read you purchased a new MH - congratulations!

 

[Emmit]

I read you purchased a new MH - congratulations!

"New"??? To us, Annie. To us.