Propex Heater

Hi

Following on from my zig control panel question, next on my list is the propex heating.
I followed the instructions and turned on the gas, opened the inline gas tap, turned the thermostat fully anticlockwise, positioned the 3 way switch to the left but no red power light came on.
Now this is were I am stumped, does the ignition work on 12v or 240v, I was trying it with 12v supply on.

Thanks
Pat

Well I am new to all this but if it is like my Trophy the 12v has to be on. Hope that helps

JerseyTrophy wrote:Well I am new to all this but if it is like my Trophy the 12v has to be on. Hope that helps

12v is on

Check fuses in Zig panel, under right-hand cover. If not one of those, there may be a fuse in the thermostat panel.

I've checked the fuses in the control panel and they were all ok (I gave all the connections a clean just in case), I also opened the thermostat and don't see anything but transistors, no fuses. 
I also opened a black box next to the heater unit which again only held a circuit board and no fuses. 
I have a multi meter but to be honest I ain't got a clue how to use it to check if power is present.

I am totally stumped, due to the fact I was getting no sign if life whatsoever from my propex heater I assumed that I was getting no power to unit.
I started checking from the fuse box in the zig control panel all the way to the propex heater itself and I am getting power all the way.
Power at the fuse, power at the thermostat, power at ghe heater and in the black box that's attached to the heater.
Also checked that gas was getting through but still no sign of even attempting to ignite, no sign of life at all.
Anyone got any ideas, the only thing I have not done is remove the heater unit and open it.
Forgot to say, there is plenty of power at the battery.

But still no red light? Odd. Have you checked both sides, i.e. is the earth continuous too? The fan should run anyway, before it tries to ignite.

It needs plenty of volts. If the battery is anywhere near flat it won't work. Measure the voltage across the terminals at the heater itself - maybe you've got a bad connection somewhere and the voltage is dropping when it tries to start.

Hope you get it fixed - ours is brilliant. Bit noisy though.

Hi Patbhoy, You say you dont know how to use the meter ?
You need to get someone to read the voltages at the battery and at the heater.
I am sure the gas side is waiting for the electrics.
Let the forum see the voltage readings for more help.
regards

mike

My 1994 vintage Propex heater has two 1/2" disc thermal cut outs (normally closed self-resetting thermostats) inside. In my unit both these failed and needed replacement. The guy from Propex I discussed this with acknowledged this as an issue.

Can't remember how the problem manifested itself in terms of indicators etc.

Replacement was relatively straightforward but nevertheless requires removal and disassembly of what is a gas appliance and so, legally, I believe it has to be done by someone who is CORGI qualified.

Bartfarst

mikethebike wrote:Hi Patbhoy, You say you dont know how to use the meter ?
You need to get someone to read the voltages at the battery and at the heater.
I am sure the gas side is waiting for the electrics.
Let the forum see the voltage readings for more help.
regards

mike

I put the probes of the multimeter across the poles on the battery and it read 13v so I'm assuming all is ok there.
At the thermostat I put the probes on the live and earth terminals and the meter read 15v but started dropping.
Don't know if this is just me not knowing what I am doing with the meter or is there a drop in voltage at the thermostat.
I contacted Propex and they have told me to bridge certain wires to see if the heater unit tries to ignite and if it does then it probably points to a faulty thermostat.

Hi Patbhoy, Thanks. Something not right with those figures.
13volts is not right off charge. 12.6 or so is good.
15 volts eisewhere is definitly not right. 
Your scale reading could be wrong!
Need to double check these readings please.
regards

mike

Assuming your multimeter is a cheap one, than 13V is near enough for the battery voltage. As Mike says, a bit high, but I'd put that down to the meter. But if there's 13V at the battery, then no way can there be 15V at the thermostat. I'd say that's likely to be 15 milliVolts, so effectively zero.

I think you're looking at no power to the thermostat, especially as the red light doesn't come on. On mine (88 Rapport so very similar), although there is a fuse on the control panel, the power supply actually comes direct from the battery via a separate cable. Have a look for a separate fuseholder near the battery terminal. That was what was wrong with mine - or one of the things anyway!

Also, measure the voltage between the earth at the thermostat and the van body - if there's any more than a few hundred millivolts there then you've got an earthing problem.

Our Propex heater wasn't working so I phoned Carvers and asked about a replacement. 'You don't need a replacement' the man said. 'Bring it into us and we will have a look'. They did and in a couple of hours it was working for the fraction of the price of a new one. Their service was brilliant

Bartfarst - an engineer doesn't have to be Corgi registered. The Corgi scheme is no longer, it has been replaced by Gas Safe. For motorhomes the engineer has to prove competency and this is usually done by the AcOPS qualification which is specific to Caravans an Motorhomes.

Hi

I contacted Propex and they gave me the following advice.

Coming from the heater will be two cables. One goes to the little black box and the other about 12" long will go to a connector that then goes to the thermostat and your power supply.  Disconnect the heater from everything else at that point and you will be left with four colours in the cable. Red, black, orange and purple.  Put the red and orange together and connect direct to a 12v +. And put the black to 12v - . Do not connect the purple to anything. 

If the heater now runs and tries to fire then your thermostat is faulty,  if still nothing then it is something in the heater and it will need to come to us to be looked at.

I tried this and success the heater ignited and ran great so it looks like it must be the thermostat.
I tried putting power direct from the battery to the thermostat and there was nothing so it looks like a replacement from Propex for £40 unless anyone here can advise me in some other way.
I've heard of people buying thermostats from B&Q for £9.99 and fitting them.
Before I fork out the £40 any last words please.

If you are competent and you are resigned to buying a new one anyway there can be no harm in taking it apart and having a look. 
It could be something as simple as a broken track or poor soldering that can be fixed.

I bit the bullet and ordered a new thermostat from Propex this morning.
Let's hope this will be problem solved 

I used to have a propex in my old van bit late now but i used to use a cheap home stat on it i think i had +12 on the red wire -12 on black then the orange went to one side of the stat with a +12 to the other side of the stat. I think the propex one looks neater and smaller than home stats.

Mike

Fitted the new thermostat this morning but my problem has not been solved  

I am thinking of going down the road of rewiring, is it simply a case of running a positive and negative from the battery with an inline fuse on the positive then the same from the thermostat to the heater without the fuse and run new orange and purple wires from the thermostat to the heater?

Seems simple or have I got it wrong.

Hi.   

patbhoy wrote: I am thinking of going down the road of rewiring,

Ohh. I wouldn’t start rewiring until you know what’s wrong. You could spend a lot time unnecessarily and end up with a right bodge to boot.   

You know from the contact with Propex that 12V on the orange wire is the signal for the heater to turn on.

You also know that the heater works when you connect the orange wire directly to 12V at the heater end. I think the next thing to do is the same thing at the thermostat end.

My suggestion would be:

Measure the voltage between the red and black wires at the connecting blocks on thermostat and on the heater. They should both read 12v (measure directly on the connectors not using the vehicle body as negative).

Then disconnect the orange wire and connect it to the red wire at the thermostat end. If the heater bursts into life the wiring is OK. If it doesn’t and you can measure 12V on one end of the orange wire and not on the other the orange wire is broken.

To check that the new thermostat is working disconnect the orange wire and then turn the thermostat up full (i.e. on). Measure the voltage between the black wire and the connection for the orange wire in the thermostat housing. If it’s substantially less than 12V it’s time to get back on to propex.

Brod.