Baxi 105he rads not hot enougth

has the pcb been worked on at any time ? its easy on these to put the PCB in withe the potentiometers 180 degrees out so when the front dial says max its actually at min
That's a very good point. The pcb was taken out to dry. As there were signs of water near the mechanical time switch. So that could of easily happened yeh!
Although as above mentioned he removed divertor ( front end at a guess) and he said it worked after that for a short while.
Basically what he never told me until today is that the heating worked , but only got warm. Then it got to the point where is wasn't getting warm at all!! But I've gotta take info with a pinch of salt as always! Further digging gets completely conflicting info from my experience with customers or friends.
For example it's working but it's not working....ehhh?
Anyway I'm gonna go , check everything's where it should be! Valves , pump , micro switches, etc. Then I'm gonna remove pump and change the back end of divertor. My guess now is that there's debris in heating differential or that it's sticking so hopefully that'll do it.
Thanks for your help
 
remove the pcb and gently turn both potentiometers to min with a screwdriver, dont force anything, then turn both knobs to min and refit the board, very easy to get it wrong with that boiler
 
Well I'm finally here and When I'm running hw the heating flow is getting hot Divertor then. All parts were changed out apart from the big brass bypass and the push rod and spring on the ch differential. So I guess that's the issue. And good clean out.
Do these small sensing pipes block commonly also
 
We'll flow doesn't get hot with hot water on now but still the pump sounds like it's full of air and very hot if I run hot water the airation noice stops, then it kicked in for heat went high the low rate then turned off
 
Expansion was empty and seems to be a lot of air in pump it's doing my head in
 
Expansion was empty and seems to be a lot of air in pump it's doing my head in

Isolate flow and return, turn hot water on and bleed air carefully form the pump. It’s probably not that but it will rule it out. They can air lock like little *******s
 
It's drove me silly. It's very strange and must be a coincidence but I stuck a pcb in that I kept from getting scrapped from a house refurb, but a known good one .
The air died down from pump instantly.. very weird. It stated on for few mins got to 80' and shut off.
When it does come on is doesn't go like the wind to 80 it creeps up then hits 80 makes a slight air noice then shuts down very calmly.
I pulled the overheat stat and tested it . It showed continuity at 0 ohms! When I put it back on the bugger kept flashing first two lights. I mean ffs what next.
And the auto air vent is completely fubar I was getting tired and isolated flow return and slackened Allan screw, and pop! water in face.
I still not 100% on divertor but today it's been cleaned and all new parts replaced so I should be confident it's good . I mean they look exactly the same apart from diaphragms look a little different in rubber quality. Apart from that good.
Anyway any help appreciated
 
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You've been told already....many ebay diverter repair kits are sold for particular boiler models but they often fail as there are slight differences between the pushrods etc.
A very well known boiler spares company trading on ebay package the wrong parts in their refurb kits. I'm talking about mm differences.
It's much safer to buy the genuine repair kit from the boiler manufacturer (if they do one) or a complete new diverter and swap the front (of the back) section over.
Get someone in that knows what they're doing...no one in the trade would even touch the isolating valves...there's no need.
Stick a new AAV on...that should have been done with the diverter "repair". Did the vessel get pumped up or is there another problem lurking there.
You might find in heating mode the system water is bypassing round the plate as the diverter is not shutting off the DHW circuit fully...and hence poor heating.
 
Get someone in that knows what they're doing..
very good advice,your boiler has well known hydraulic workings. same hydraulics on many imported boilers but your boiler has an additional secondary heat exchanger which just needs a little more fault finding consideration.

Tbh the attached central heating system needs to be checked before blaming the boiler and vice versa,for a boiler repair technician its an easy repair. just find a boiler repair technician who is familiar with your type of boiler or cut your losses and exchange the boiler (n).

Shame to scrap a decent basic baxi boiler, which with some decent servicing (not flue prodding) will outlast many newer plastic component boilers,it's your choice.

:idea:
 
Expansions been recharged .
I'll tell him to get new AAV and divertor or a kit.
 

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