Webasto external temp sensor

Thanks Bob, I've been on the phone to Webasto who put me in contact with their service agent here in the West, they were very helpful and told me that the plug I was looking at was for diagnostic purposes and not for an external sensor. They also asked about the positions of the inlet vent. I don't think the positioning is the problem, they are both fitted along the back wall approx 1.5mtr apart, not facing each other plus we had the door and window open.

With the help of a mate I will remove it on Monday and take it in and have it bench tested. If it tests out ok then I will look at changing the inlet position.

Noel, Is the BOG Bible accessible on this web site?

Thanks Col, every bit of info is a help. I will with the help of a mate remove the Webasto tomorrow, I will probably take it to the service agent and have them bench test it 1st, hopefully it exhibits the same as it's been doing.

We just spent two nights in the van in freezing conditions, car and van covered in ice in the morning. The Webasto barely warmed the van, it continually fired up for a short while then went into a cool period before firing up again.

Confusing info Col.
Below is an extract from the Webasto manual.
The external sensor is an option not normally fitted to caravans due to the "open space" uncluttered design that does not inhibit air flow.
The conventional rotary selection switch is a selector only, it does not contain a temp sensor.
Your installation has me puzzled.
There is further reference to the purpose of having the temp sensor on the return air side in the FAQ section of Webasto's web page.

Regards
Bob

During operation the combustion exhaust gasses flowthrough the heat exchanger charging its walls with com-bustion heat, which in turn is taken up by the heating airdelivered by the heating air fan to be routed to the ve-hicle interior.The temperature of the heating air sucked in ismeasured by means of a temperature sensor fitted tothe air intake side of the air heater or by means of an ex-ternally located temperature sensor.A temperature below the one set with the control ele-ment increases the heater performance up to maximumheat. In order to extend the burner idle period of Dieseloperated heaters during permanent operation with aheating performance in excess of 1.1 kW, the fuel dos-ing pump delivery rate is reduced every 15 minutes for20 seconds.

Ok, I took my Webasto to the service agent this morning and it was bench tested. I was shown the computer program testing my unit and the technician is convinced it's the ecu is the problem. It was producing over exaggerated figures of usage around 2000 hours and upon running the Webasto it gave the same problems I have been having with it.

I pushed submit before attaching the 2nd photo. They are of the heat sensor, it is clipped to the side of the body and has the blue wire going to it.

Confusion indeed! Maybe due to us discussing different models of Webasto heaters. That photo of yours Mick looks (I think) the same as mine, an Air Top 2000ST. That sensor is indeed a heat sensor, but an overheat sensor. If for example you block the air inlet, the machine will overheat, the sensor will detect it and turn the machine off. It is not involved in controlling the temperature during normal operation.


Bob, I'm not disputing what you say but we need to state what models we're discussing. Mine was fitted in 2008, and is an AirTop 2000ST.

This is what my controller looks like:


As you can see it is not just an ON/OFF switch.

In our van the controller is situated near the east-west bed at the front of the van. When not in bed we block this area off with a curtain, which is not ideal because the thermostat (in the controller) is effectively outside the area where we are sitting. Thus I intend to fit an external temperature control, which will be in our living area. This external control attaches to the main controller and then effectively become the thermostat.


This is what I was looking into when Mick submitted his post. It has only taken me 7 years to get around to it.

I hope this clears up any confusion. If not, I'm happy to be proved wrong. (It wouldn't be the first time).

Col

Col, I'm not exactly sure if it's a heat overload sensor or temperature limiting sensor, from what the Tech said I'm guessing the latter. He did disconnect it when testing my Webasto.

My Webasto is the Airtop 2000ST which looks a different model to Bobs PDF file