Propex Heater

[t3convert]

The Propex heater on my 87 T25 Autosleeper has never worked since I bought the vehicle 2 years ago so I finally decided to prise the unit out (no easy task) and wondered if anyone knows anywhere locally I can take it to have it tested/ repaired (I live in Brighton E.Sussex). Also, the flexible aluminium inlet and outlet pipes seem to have been jointed to the box with white powdery cement. Is this asbestos?

[Cobra88]

Pretty sure you can send it back to propex to be serviced

They are in Ringwood i think

[Mocki]

yes send it to propex.... and no its just exhaust paste

[937carrera]

Propex are fairly close to you in Ringwood.

Before you send it, how do you know that the problem is with the main unit ?

There could also be a problem with the power supply, gas supply or control unit.

Is the unit just completely dead or is there a series of flashing lights when you try and use it.

[Oldiebut goodie]

Normally people don't use paste on the joints and what you are seeing is aluminium oxide. I see it every day on Webasto heaters especially on exhaust outlet spigots. Moisture in the joint and the warmth soon creates it. Severe cases on aluminium heat exchangers will ruin an otherwise serviceable exchanger. Having two dissimilar metals doesn't help either. Use of paste can keep it at bay for longer than without.

[t3convert]

to 937 Carrera.
To be honest, I don't really know where to start with this.
I've discovered that the thermostat at the back of the van seems to be working (the red light comes on and the fuse inside the Labcraft unit looks fine) but I haven't been aware of any flashing lights on the Propex box itself because they might be on the side and you can only see the front when it's attached up. I'll try hooking it up outside the cupboard (but without the gas pipe attached) and let you know.
Regards

[Cobra88]

are you sure its not just locked out ?

cant remember the procedure but they have a safety lockout that sometimes needs to be reset

look at manual to see how

Rick

[t3convert]

To Cobra88,
Thanks Rick. I'll see if I can get hold of the manual online.

[Cobra88]

which model of propex ?

[937carrera]

I'll bet it's a Propex 1600

https://www.propexheatsource.co.uk/wp-c ... ions_2.pdf

Unfortunately you can't test things properly without gas connected because of the safety devices.

Can you upload pictures of the unit and more importantly the control unit ?

[t3convert]

to 937 carrera
It is indeed a Propex 1600.
I've taken photos but I'm unable to upload them

[937carrera]

You can attach photos directly to a post, but they have to be smaller than 140kb and there's an unknown size restriction, 640 x 480 is fine I think.

Alternatively, you can upload to techpowerup.org - free and no registration needed

[937carrera]

What happens when you switch the heater on

Any lights come on at the thermostat

Does the fan run ?

Does the fan stop running after 30 seconds and then some lights flash ?

[t3convert]

to 937 carrera
No joy I'm afraid.
Have re-attached the gas pipe and turned on the gas (although the cylinder might be empty).
The red light comes on at the thermostat but only when I switch on the ignition.
No sign of life at the box (no lights flashing) and nothing from the fan.
It's as dead as a doornail.
I've noticed that the purple wire from the box has just been looped back so it's not connected.
Will eventually send a picture.
Thanks for your help so far

[937carrera]

So at this point it seems like you have a basic wiring problem, let's try and fix that first

Do you have access to a digital multimeter - using one will make diagnosis much simpler.

We can use the operating mode diagram on page 7 and the wiring diagram on page 5 in combination to solve this.

Next step for you is to figure out how to upload photos - we'll probably need some.