# No Hot Air - Bathroom (1994) Hymer B644



## devjb (Dec 16, 2010)

As the title says, I get no hot air from the air vent in my 1994 B644. All the other air vents are fine.

I have checked the four air outlet pipes on the bottom of the combi boiler (Truma c6000) and they are all secure. Looking into the bathroom hot air vent with a torch, it does not seem to have an air pipe connected to it, more a channel made from wood between the dinette and bathroom wall. My guess is a hot air pipe has become detached from this wooden channel, somewhere under the raised floor tray.

I can't see anyway to check the route of the bathroom hot air pipe and how it connects without stripping out the sink, toilet, cupboard and bathroom floor tray. 

I,ve found a disconnected hot air pipe at the bottom of the wardrobe floor, that seems to go outside under the floor to the waste water tank. I presume (when connected) this is to stop the waste water tank freezing. Does this also provide hot air to the bathroom? I tried to blow hot air from a hairdryer into the open end of this waste tank pipe and also, into the bathroom vent, but can't trace any air route.

The rest of the van is lovely and warm, but the bathroom is freezing


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## devjb (Dec 16, 2010)

Can anyone help?


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## ardgour (Mar 22, 2008)

Hi
going by our 2003 644, the pipe leaves the boiler goes into the floor, across the back of the waste water tank at the point where the back lounge/bed is (slightly raised floor on ours) it then supplies 3 places on ours. Rear lounge (probably not relevant if yours is rear fixed bed version) the underfloor half garage on passenger side of vehicle and finally bathroom. It is a branched pipe with 3 outlets.
We could try getting some photos of ours if it would help

Chris


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## SilverF1 (Feb 27, 2009)

Is it possible that there used to be a t-piece (to the bathroom) off one of the duct tubes, and this has been removed by a previous owner?

If there is an outlet for the heating in the bathroom, it should have a duct tube connected.


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## JeanLuc (Jan 13, 2007)

On mine, the garage and bathroom are supplied by the same pipe, and I think the waste valve & tank are on the same branch. Perhaps difficult to compare as ours is a garage model but here is the layout. From the Truma, which is below the wardrobe on the offside, the pipe runs across the front of the garage beneath a ply-wood box section. Then a T-junction takes a feed into the garage and the shower room (nearside) and the pipe continues outside and down to the waste tank.

Have you checked to see if the tank gets hot air when the system is running (or perhaps it has been frozen given current temperatures)? Is there an obvious point to which the loose pipe in your wardrobe should be connected?


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## devjb (Dec 16, 2010)

Thanks for the replies

It sounds a similar set up to yours Chris. It is an end lounge model. 
I have 3 pipes that run back from the Truma, under the rear lounge false floor, to heat the end lounge, half garage, window vents etc.. One of these then provides air forwards to the dinette and behind the drivers seat (LHD)

Is your bathroom vent on the front wall of the bathroom, towards the front dinette. How is the pipe routed from the false underfloor area in the end lounge, through the bathroom to the bathroom vent on the oppersite wall. I suspect this pipe has become detached or has been removed for some reason. I can't see any route for it around or outside under the bathroom, so i guess it goes under the shower tray/bathroom floor within the bathroom

I get no heat to the waste water tank. I think i have worked out where the waste water tank pipe should connect, as one of the pipes under the wardrobe floor as been cut and rejoined with tape. I think this must have had a T join at sometime.


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## ardgour (Mar 22, 2008)

Hi

Our bathroom vent is on the wall between bathroom and rear lounge next to the toilet near to the internal 'door' wall of the bathroom. the vent is well above floor level. The forward side of our bathroom is a swing wall shower room without heating vents. The heating pipe gets to the bathroom from below the rear lounge floor coming up into a small extra little 'box' on the lounge floor that covers a right angle bend in the ducting that then goes into the bathroom.

We have a separate pipe just above/at rear of waste water tank that then passes into the dinette seat and heats the dinette.

hope that helps - we can photograph our pipes tomorrow if it helps.

John (Chris's OH)


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## Bill_H (Feb 18, 2011)

I had problems with airflow in my B564, and it turned out to be a butterfly valve in a junction where pipes joined, butterfly had closed. It was not obvious from the outside that there was a 'valve' in the junction, and I only discovered when I pulled the pipework apart.


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## devjb (Dec 16, 2010)

Hi John & Chris

It sounds like the design has been changed on the newer models, but it has given me the idea to fit another bathroom vent on the back/lounge wall of the bathroom served from one of the existing air pipes under the false floor. That seems an easier option than sorting out the existing vent on the opposite wall and lifting the shower/bathroom floor pan.

Thanks
John


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