Ravenheat CSI 85T constant refiring

[psarinuk]

Hi

I've a Ravenheat HE85T boiler, very similar to CSI85T model.

Recently, the boiler has been constantly re-lighting on both CH and DHW and sometimes the red (overheat) light comes on. I checked the thermisters, they were OK. Replaced the DHW (wet pocket type) with a known good thermister as I thought it might be some hard water damage, still same problem.

The pump works OK, the fan can be heard to go high speed.

The water gets hot, then lukewarm, then hold or cold again before the boiler starts refiring every few seconds.

I replaced my existing fan PCB (which fails every year on boiler) FROM:
http://www.ebay.co.uk/itm/Ravenheat...ooling_Air&hash=item2575e9e5cc#ht_1086wt_1456

TO:

http://www.ebay.co.uk/itm/Ravenheat...Cooling_Air&hash=item1c2ba9712d#ht_958wt_1397

It worked OK for a day before going to the same state as described above. As you can see the new one has lot more electronics on its circuit board compared to my previous one. However the part number 0012CIR06010/0 is exactly the same. Does this matter?

My worst fear is ignition control board (main PCB) and I hope that never comes true..

I hope I get some quick replies and many thanks in advance for that..

 

[Agile]

Hi,

My old trusty Potterton Profile 50e boiler has just been moved to a newly extended wall in the garden (approx 3.5 meters).

I've another plumber coming around but I just want to be armed with all the information so we can sort this quickly when he arrives.

Thank you.

You seem to have a lot of boilers!

When we read about the "plumber coming but want to be armed" we expect that means that a DIY repair is planned!

When someone asks about several different boilers then we think that they are asking because they are doing boiler repairs when not gas registered!

 

[psarinuk]

how many boilers equates to "You seem to have a lot of boilers!"

Maybe I can make it easier for you, If I've 2 houses, how many boilers do I ought to have?

P.S. Hope you enjoyed the old fan PCB that I sent to you (@NW10).

 

[Slugbabydotcom]

They tried a lot of different manufacturers. If the part number is the same then it's ok.
Here's a pretty pink one

 

[Agile]

P.S. Hope you enjoyed the old fan PCB that I sent to you (@NW10).

Yes, thanks very much for that!

Its apparently a very common fault but the first opportunity for me to see exactly how it worked and what went wrong.

All they do is put a couple of parallel connected capacitors in series with the fan to slow it down.

Its very simple and cheap to do ( until it fails! ).

Tony

 

[psarinuk]

All they do is put a couple of parallel connected capacitors in series with the fan to slow it down.

Yes I worked that out. If you short pin 9 and 10 (black and brown), the fan would always run at high speed. Wonder why they wanted to slow down the fan (something related to efficiency)?

Also if you notice the second board in my links above, the part number on the board itself is 0012CIR06030, not 0012CIR06010 as it has been sold to me. So I ask again, is it a right replacement? As with this board, things are running fine for some time before they go pear shape again (constant on-OFF firing).

For some reason, I bought another one of first link, which is a "true" 0012CIR06010 and the fan did not come on at all, high speed or low, as pins 3 and 5 on the board (green and yellow) were always showing 0.45V. This lead to high temp warning lamp (RED) ON every time I tried with DHW and/ or CH and the flue never came on.

With the 0012CIR06030, pins 3 and 5 show the correct voltages for now... 0.46 when the fan is not ON, 1.46 when the fan is high speed and 1.14 when the fan is low speed.

I've left it like that (with 0012CIR06030) till it starts the ON OFF cycle again..

Please help!