Fuel Burning Heater

Chas2008 · 23rd November 2013, 21:12

Today, using a page from the Webasto Thermo top C E & Z Installation Manual I set about testing the Combustion Air Fan and the Circulation Pump to check their operation.
Why, because my FBH is not operating as it should. When pin 3 is earthed the Water pump runs for 124 seconds then stops, no other activity happens.
The PCB has been repaired by FrenchMike, a new Dossing pump has been fitted and primed, and a new Landrover Temp Sensor has been fitted inside the front bumper.

In the diagram above, X5 is the Circulation pump power feed and X4 is the Air fan feed.
These are the same as the labeled picture below (thanks to FrenchMike)

Both the Air fan and Circulation pump powered up when given a 12v feed.

Why then won't the FBH fire up and run normally when powered up?

All posts I can find on the forum say that when powered up the Air circulation fan kicks 1st, not so in my case.

Other than taking the PCB out and returning to FrenchMike to be checked again I'm at a loss.

Has anyone any thoughts on this please?

Charles

23rd November 2013, 21:12	#1
Chas2008 Avid contributor Rover 75 Connoisseur SE 2.0 CDT Join Date: Jul 2012 Location: Wirral Posts: 171 Thanks: 25 Thanked 15 Times in 10 Posts	Fuel Burning Heater Today, using a page from the Webasto Thermo top C E & Z Installation Manual I set about testing the Combustion Air Fan and the Circulation Pump to check their operation. Why, because my FBH is not operating as it should. When pin 3 is earthed the Water pump runs for 124 seconds then stops, no other activity happens. The PCB has been repaired by FrenchMike, a new Dossing pump has been fitted and primed, and a new Landrover Temp Sensor has been fitted inside the front bumper. In the diagram above, X5 is the Circulation pump power feed and X4 is the Air fan feed. These are the same as the labeled picture below (thanks to FrenchMike) Both the Air fan and Circulation pump powered up when given a 12v feed. Why then won't the FBH fire up and run normally when powered up? All posts I can find on the forum say that when powered up the Air circulation fan kicks 1st, not so in my case. Other than taking the PCB out and returning to FrenchMike to be checked again I'm at a loss. Has anyone any thoughts on this please? Charles __________________ [SIGPIC][/SIGPIC] Last edited by Chas2008; 23rd November 2013 at 22:39.. Reason: Correct mistake made.