PROPEX PROBLEM

[Plasticman]

so are you saying you have it on the bench and it runs when wired as it would in the van,that is with stat/switch connected.and have you also had a gas supply feeding it on the bench to confirm ignition
mm

[Oldiebut goodie]

Seems to me you have an earthing problem with your wiring to the Propex as it still won't work especially if you have low volts at the heater still. Get this with Webastos a lot, also check that your cabling is up to size especially if you have long runs. (earth and power ones) You could still have high enough volts if you measure to a different earth point whilst you are checking but low to the heater's earth. Especially as you said "Checked volts only 11.15v at control unit and 10.5v at heater"

[jeffj]

Fully connected on bench with gas. Heater runs and pumps out heat. Thermostat kicks in and everthing works as it should.

Going to rewire with heavier wire and renew earths.

[Plasticman]

good, proving the unit in its entirety functions as built takes a lot of the guess work out as you no know where the problem lies, .you could wire it inthe avn and stick the bench gas on it ,and im sure it will fail to woirk which leaves as said earlier the van lecky.
nice monday job and i bet its nice at the seaside today....busy?
mm

[CovKid]

Try using heavier gauge wire from power to Propex. Ghost123UK spotted this weakness in mine which would fire but not run for long. Basically there was only just enough voltage to fire it up but as soon as battery dropped even slightly, the Propex voltage sensor would shut the thing down. They like good quality cable - comparable to that used between thermostat and unit as a minimum.

Once I upgraded cable, the Propex ran all night quite happily. They also don't like running off car batteries I found. They prefer leisure batteries because of their stamina.

[jamesandtheopenroad]

Sorry to jump in on this thread, but my propex won't fire up when the lights are on. Turn them off and no problem. Thing is, they're only leds, so don't have much current draw. The leisure battery is only a couple of years old and really hasn't been used that much. What should I be looking at?

[ghost123uk]

What should I be looking at?

A new battery

Joking aside, measure the voltage on the terminals of the leisure battery after it has been stood overnight (with nothing of consequence turned on) and see what it says, it should be a bare minimum of 12.6 volts. Many leisure batteries are past it at 2 years old, esp if you have ever let it run down below about 11 volts.

You could also fire up the Propex, then test the voltage in 2 places, the battery and the live and earth at the Propex end. There should be no more than about .1 or .2 of a volt difference. If there is more than that difference then the wiring needs upgrading (or connections like relevant earth(s) etc checked)

Let us know...

[jamesandtheopenroad]

Ta. Will do

[jeffj]

Rewired heater today after sparky (mark) diagnosed fault yesterday.

Ran larger cable from leisure battery direct to thermostat and bypassed the zig unit. Also added earth from heater earth to body inside cupboard.

Now works fine. Left disconnected at moment because I need to buy and fit a 5amp in line fuse.

The previous live supply to stat had been taken from one of the zig unit fuses and was only 300 mm long but think just not enough juice coming through to fire heater?

The switched live and earth supply from stat to back to heater left as was.

Problem solved. Water pump had also stopped working so fixed this as well. Cable connection was broken on back of zig unit fuse.

Productive day.

[Thorgills]

Awesome! So round to yours when it's next chilly on a site Dude!

[Mark Foss]

Glad it worked

[Sleedale]

But if you and Mark fancy more Propex practice, my van wouldn't mind some heating

Well done chaps, persistence and hard work paid off.