FBH - How to install, test and service

[HarryM1BYT]

Originally Posted by Jakg

Exhaust (flue?) is hot (or at least it was even before it was working properly!)

Then it must be working :xmas-smiley-004:

There will be some heat in the flue, drawn from the coolant, but that would make it warm.

Hot, as in far to hot to touch, means the FBH is burning.

[HarryM1BYT]

Originally Posted by Dragrad

As requested the How to is here. If you amend or add to your OP please let me know and I will update the How To accordingly.

An excellent piece of work Harry

Thanks Dragrad....

[Jakg]

Originally Posted by HarryM1BYT

Then it must be working :xmas-smiley-004:

There will be some heat in the flue, drawn from the coolant, but that would make it warm.

Hot, as in far to hot to touch, means the FBH is burning.

Went for a ~2 mile drive today... parked up.

Coolant pipe - cold to the touch.
FBH - OWWWWWWWWWWWWWWWWWW hot.

I think it's working

[HarryM1BYT]

Originally Posted by Jakg

Went for a ~2 mile drive today... parked up.

Coolant pipe - cold to the touch.
FBH - OWWWWWWWWWWWWWWWWWW hot.

I think it's working

Excellent

[FredSpencer]

For Harry:

Show the overall image at a size acceptable for the forum (usually 800px wide so downloading doesn't take too long).

As you can see I have boxed off an area to draw attention to it. This is the area where items 1, 2 and 3 are located.

Describe this image something like, "Items 1, 2 and 3 are located within the red box marked on this image and a second image shows this area in close up and with the values for each item."





HTH

[HarryM1BYT]

Originally Posted by FredSpencer

For Harry:

Show the overall image at a size acceptable for the forum (usually 800px wide so downloading doesn't take too long).HTH

Thanks Fred, all sorted not I think, via a Photbucket account.

I'll see if I can add some photos for the FBH servicing, whilst I can still remember how to add them

[ose1665]

Quote from almost the last line of your great 'How to'

'The above might be useful to know, so you can plonk a meter straight onto the FET driver output pins, to see if the glowpin and pumps are being fired etc.. '

Could this be clarified a little more please? what does FET mean? and where are the output pins, I know this might be small beer to people who deal with electronics but even if I knew where the output pins are you still need to place the other meter probe somewhere.

just my thoughts I think this is a masterful piece of work as is.

[HarryM1BYT]

Originally Posted by ose1665

Quote from almost the last line of your great 'How to'

'The above might be useful to know, so you can plonk a meter straight onto the FET driver output pins, to see if the glowpin and pumps are being fired etc.. '

Could this be clarified a little more please? what does FET mean? and where are the output pins, I know this might be small beer to people who deal with electronics but even if I knew where the output pins are you still need to place the other meter probe somewhere.

just my thoughts I think this is a masterful piece of work as is.

FET = Field Effect Transistor, the larger three pinned devices - which you do not really need to know.

There are 4x FET's we are interested in - glowpin, Fuel pump, air and water pump.

If you look at the photo you will see these components marked up with their function in green text. You should also be able to see a green 'o' next to one of the three pins. There is an 'o' adjacent to the output pin of the three pins. If you put a volt meter between ground and each of those marked pins in trun, you can determine from the voltage measured what the FBH is doing. It simply makes it much easier to check what is happening, rather than trying to stick a probe through the insulation.

Does that help?

[ose1665]

OK I have another question on this bit...
Quote
'That gets you access to remove the burner unit and see inside the heat exchanger. Follow the two thick wires (mentioned earlier), to the glowpin, unclip the wires, unclip the glowpin - held by a spring P clip and very carefully remove it from the burner chamber. Test it by connecting its two terminals across 12v, where upon its square section end should in a few seconds become close to white hot. It is not designed to run continuously on 12v, so limit this test to a few seconds - just long enough to satisfy yourself that it glows. If it doesn't glow, then it has failed and no one has yet been able find a source for a replacement, but they are very expensive - maybe £60, even if you can manage to source one. Webasto only seem to sell them complete with the combustion chamber.'

If I understood correctly the glowpin uses quite a few amps so do you need to use a car battery to do the above test or would a battery charger 3-4amp capacity do the job?
Is the polarity of the test connection important? I would guess not but best to ask, as they are expensive and hard to get a replacement.

comments/advise would be appreciated, thanks

[ose1665]

Originally Posted by HarryM1BYT

FET = Field Effect Transistor, the larger three pinned devices - which you do not really need to know.

There are 4x FET's we are interested in - glowpin, Fuel pump, air and water pump.

If you look at the photo you will see these components marked up with their function in green text. You should also be able to see a green 'o' next to one of the three pins. There is an 'o' adjacent to the output pin of the three pins. If you put a volt meter between ground and each of those marked pins in trun, you can determine from the voltage measured what the FBH is doing. It simply makes it much easier to check what is happening, rather than trying to stick a probe through the insulation.

Does that help?

That's great thanks understand it now think I missed some points you had listed TBH, so much to take in, will try and read more times in future