Baxi 105e instant Problem !?

[Chumley2]

Hi Guys,
Hope you can help me with a problem on the above boiler

The problem noticed first was that the hot water was not getting as hot as it used to, it starts off hot and then only lukewarm.

When standing next to the boiler i notice that when a hot tap is opened it seems to go through all the correct procedures and then the pilot light will go out and cut back in after approx 30 seconds?

I also noticed that the central heating fires up and then cuts out after 2/3 seconds and then will not fire up at all?

I have checked the ch sensor which gives me a reading of 3.6kohms the dhw sensor gives me 8.4kohms and the ch overheat gives me 0.005ohms.

I have also taken off the microswitches to reveal the brass plungers underneath and both of these operate correctly!

Anybody got any ideas please?

Regards
Chumley

 

[combiman1]

Hi Chumley
as the problem is common between H water and C htg it would point towards the Air pressure switch faulty when the boiler starts the Fan puts pressure down the positive pressure pipe and flicks the air pressure switch over and then the burner lights however if this switch closes again usually within 30 seconds [if faulty] then the burner will go OFF and water cools down I have seen this fault many times on Baxi s and it always boils down to the Air pressure Switch The sensor readings you have given fall within accepted parameters so you can rule those out
I hope this reply will be of help to you

combiman1

 

[Boilerman2]

Get an RGI to check the Plastic Venturi (that the APS hoses attach too these can melt with very little excuse - if ok suspect APS not a DIY job though!!

 

[Chumley2]

Hi Guys,

Thanks for your quick responses to my question & apologies for my slow response !!!

I will look into the possible answers you have given me and investigate further and will give a postive or negative response to help others who may have a similar problem !

I say this because i notice on a lot of forums questions are asked with many replies given, but there seems to be a lack of response once the problem is solved, thus leaving others to guess at a possible 5,6,7... suggestions from you guys !

Again thanks guys and i will post back with the RESULTS !

Regards
Chumley

 

[WilkyWay]

The diff valves and divertor valves often clog up on these. Sounds like the pin that is in the divertor valve, but operates the diff valve is stuck or choked up and it's going off because the boiler is reaching temperature but not transfering all it's heat to the DHW.
You could pull the diff vlave off and try and free it up if you fancy. Or get an engineer to do it.

 

[gaswizzard]

I have checked the ch sensor which gives me a reading of 3.6kohms the dhw sensor gives me 8.4kohms and the ch overheat gives me 0.005ohms.

Suggest you check them again.