Potterton combi80 fan running ?

[mattfair]

I've just replaced the modulator board on a combi 80 and now there is a constant running noise as soon as I switch it on at the mains. Even putting it into standby wont stop the noise. I don't think it's the pump, could it be a fan running? Any ideas how I could stop this/ adjust the timing?

Thanks for any advice.

 

[DP]

Can you say why you replaced the modulation board?

 

[mattfair]

I think one of the pins for a plug on the board wasn't making good contact. This caused the whole boiler to lose power intermitently and finally the arcing melted the board.

 

[ChrisR]

If it has a permanent pilot, the fan is meant to run slowly all the time, speeding up when there's a demand for heat. I can't remember if there were any combi 80's with a permanent pilot though!

 

[kevplumb]

combi 80 is electronic chris (that long since i fitted one had to look first)

 

[Agile]

I thought the Combi 80 E was electric and the Combi 80 P was permanent pilot with the slow running fan.

The poster will know if he has a permanent pilot because he will see a small blue flame all the time even when the boiler is not on.

Tony Glazier

 

[Slugbabydotcom]

Try disconnecting pl9 {2 orange wires} on the modulation board if this knocks the fan off suspect dhw flow switch

 

[mattfair]

Disconnecting pl9 made no difference.

I can't see a permanent pilot light through the inspection window. Sorry I can't be more exact about the type of combi80. I'm sure it didn't make a constant noise before though.

The board I was supplied with has a few less components on it than the old one ( resistors etc), I was told this was simply an improved version.
I now wonder if the shop could have given me the wrong type, ie the one for a permanent fan ?

I'd love to know if there's any numbers to identify which is which.

Thanks for all your suggestions so far.

 

[gazthepottertonengineer]

pcb part nos should be 21/18867 for permanent pilot model
the only differance though is link 1 indicated on the board by LK 1 this shouldnt be there for electronic model so ifyou have got permanent pilot board you simply need to cut it its just below where the Fuse holder is

 

[ChrisR]

Yer out of date gaz, I think??
Ye olde puma/combi 80 boards were the same but for a link, but later ones are different. The Electronic ignition board 21/18601 has more components on, bottom left corner around PL10. The Perm Pilot board 21/18867 has one component the E boards hasn't, capacitor C17. LK1 is missing on the E board. It's missing about 2 dozen of the E's components.

I intend to put the capacitor C17 in an E board and try it in a P boiler with the link cut, sometime.

So our reader, it could be that you have a P board in an E boiler.???
There's a little sticker atop one of the relays to say which is which.

I'd seek assurance that putting the wrong board in doesn't bust theboard, but if you have a P board and you need an E I'll swap it if you pay the postage. Bit rash, but...

 

[doitall]

There's an offer i can't refuse

Dinner in Crickelwood is Tuedays Night the 7th June

john

 

[ChrisR]

Jolly good - anyone else fance a curry with a bunch of anoraks?

You just have to bring a rivetingly interesting bit from a boiler, or .......

 

[gazthepottertonengineer]

trust me just cut link 1 i always do and it works fine
chris dont take any notice if they have one or two differant components as its a fact that pcbs always have alot more components than they actyally need on them as the manafacturers find it cheaper to leave them on there than to remove never worked that one out myself just wot ive been told by Frank Hyland who develops these things

 

[kevplumb]

have to admit never seen a perm pilot combi 80

 

[ChrisR]

Gaz if that was right why would they be producing the 2 different boards. 25 odd components - doesn't sound right to me.