Baxi combo 80e, no power to the boiler fan with DHW
- Thread starter ishaqmir
- Start date
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definitely does, everything on the boiler is ready to be fired, its that one pin on the diverter valve that hits the microswitch for the boiler fan which just doesn't go high enough if the central heating is off.
as a result, the boiler just keeps waiting for fan to come on and then eventually gives up and goes into lockout mode with a red light flashing on the triangle in a circle, which indicates low pressure/pump failure.
but the pump is 100%, the plumber opened its nut and tried stopping it, it wouldn't stop, so he said pump is still very strong and intact.
the plumber looked at boiler very closely, while testing water. he said its very strange that the pin doesn't go high enough with just DHW. he tried cleaning the assembly loads, also sprayed WD40 on external side of the pin area, but still no luck. and of course, he's changed all the parts in the diverter assembly too, and lubed up with silicone stuff.
as a result, the boiler just keeps waiting for fan to come on and then eventually gives up and goes into lockout mode with a red light flashing on the triangle in a circle, which indicates low pressure/pump failure.
but the pump is 100%, the plumber opened its nut and tried stopping it, it wouldn't stop, so he said pump is still very strong and intact.
the plumber looked at boiler very closely, while testing water. he said its very strange that the pin doesn't go high enough with just DHW. he tried cleaning the assembly loads, also sprayed WD40 on external side of the pin area, but still no luck. and of course, he's changed all the parts in the diverter assembly too, and lubed up with silicone stuff.
G
GasBod
does the boiler fire if you press the micro switch with a screwdriver while running hot water?
I suspect the domestic hot water thermistor is defective. It thinks it's as hot as the sun!
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yep, definitely does, I saw the plumber push the microswitch with the screwdriver and, Bam!!, boiler fan starts, pressure switch clicks, burner fires up and piping hot water as usual.
if it was the DHW thermister I reckon that plumber would have picked up on it, he also connected a laptop to the circuit board (well so he said, i wasn't there when he did that bit).
he has observed the boiler carefully and says its the mechanical movement of that pin that just doesn't hit the microswitch enough with DHW running alone. It definitely does move up (slowly) but not enough.
we also noted that the CH pressure has to be above the normal 1.5 bar for the assembly to work well at present. so he has set it to 2 bar and said hopefully the cleaner should work the magic.
haha, exactly, i was amazed, how can you connect a laptop to an 18 year old baxi combo boiler!! but just as he said I'm going to van to get my laptop, I had to leave for work, so I couldn't see what he did.
i've got a new boiler installation booked for this coming Friday, do you think I should cancel it and wait for any blockage to unclear? or just empty my pockets and get a new 29 CDI Greenstar installed with 7 year warranty?
The blockage will not unclear itself. Did he remove the plate heat exchanger as that would usually be the blocked part.
I would clear it easily but it is a bit messy and time consuming so I usually charge about £136. Very few engineers will bother though.
What I don't think that you should do is get that engineer to fit a new boiler ! Why should he bother to repair it ( even if he knew how ) if you will then pay him £2000 to fit a new boiler.
You should get three quotations for the same boiler. The warranty length will depend on the relationship he has with Worcester. Mad I know but if you pretty much only fit their boilers they give a longer warranty.
Whilst they think it will get installers to fit more of their boilers, they forget that others like me are uncompetitive to quote for fitting Worcester boilers in respect of the warranty length.
There are better boilers though!
Tony
I would clear it easily but it is a bit messy and time consuming so I usually charge about £136. Very few engineers will bother though.
What I don't think that you should do is get that engineer to fit a new boiler ! Why should he bother to repair it ( even if he knew how ) if you will then pay him £2000 to fit a new boiler.
You should get three quotations for the same boiler. The warranty length will depend on the relationship he has with Worcester. Mad I know but if you pretty much only fit their boilers they give a longer warranty.
Whilst they think it will get installers to fit more of their boilers, they forget that others like me are uncompetitive to quote for fitting Worcester boilers in respect of the warranty length.
There are better boilers though!
Tony
Hi Tony
thanks for reply. I had changed the DHW heat exchanger with an original brand new InterPart one exactly 12 months ago and had a magna clean and descaler fitted.
yesterday I opened up the magna clean after 8 months, and it was covered in black iron oxide, but to be honest, it wasn't very thick, so i'm assuming there is not a huge amount left in the circuit?
do you still think its the plate heat exchanger? and the Fernox F3 paste won't help? how about if i give X800 heavy duty sludge remover a go?
i wasn't going to get the boiler installed by this engineer anyway, was going to use an accredited installer, doing me a fantastic price too, a lot cheaper than £2000, with 7 year warranty. they install over 200 boilers a year apparently. but I've cancelled that appointment now anyway as i'd like to see if i can keep this boiler going.
only reason i got this engineer to look at boiler was because i wanted to give a last shot to bring it back to life. i didn't tell him i may want to change the boiler.
the fernox F3 as been in a couple of days now but no improvement in DHW with CH turned off
I would expect the blockage is somewhere inside the boiler.
I clear them by using citric acid ( or Fernox DS40 ) but ONLY in the boiler after isolating the heating circuit.
Since it can also be lime based compounds I also give it a dose of sulphamic acid as well ( Fernox DS3 ).
Tony
I clear them by using citric acid ( or Fernox DS40 ) but ONLY in the boiler after isolating the heating circuit.
Since it can also be lime based compounds I also give it a dose of sulphamic acid as well ( Fernox DS3 ).
Tony
Are you sure that he said he was going to connect it to the boiler, or are you just assuming that that was what he wanted it for?
He probably has a load of manuals downloaded to it and wanted to read the one pertaining to your boiler.
Re read the post and this was wrong so I deleted it d
dSo he hasn`t changed the top diaphragm to see if this made the pin come up and hit microswitch when only HW selected.
If you do change the boiler change it for a baxi duotec HE A 7 year warranty and fits straight onto your existing jig with no pipework alteration at all and only slight alteration to flue hole.
Better boile and more reliable than the worcester
If you do change the boiler change it for a baxi duotec HE A 7 year warranty and fits straight onto your existing jig with no pipework alteration at all and only slight alteration to flue hole.
Better boile and more reliable than the worcester
Tony, yeah u guessed it right, he's ex BG technical engineer
Gas112, he changed both top and front (larger) diaphragms including but and washer at front etc, cleaned & lubed up with silicone stuff but still, the top pin not hitting high enough to switch fan on with just DHW. The DHW does work upto 20 mins after switching CH off though.
He said he's been looking at manual and it could possibly be a water filter blocked? Is it the filter gauze in the flow regulator thing?
Gas112, he changed both top and front (larger) diaphragms including but and washer at front etc, cleaned & lubed up with silicone stuff but still, the top pin not hitting high enough to switch fan on with just DHW. The DHW does work upto 20 mins after switching CH off though.
He said he's been looking at manual and it could possibly be a water filter blocked? Is it the filter gauze in the flow regulator thing?
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