Baxi 80E Combi boiler

[jeddyboy]

Hi Guys think i have found the problem with my baxi 80e
just not quite sure about the fitting of preferential valve diaphragm,
do i turn off the mains water, open hot water tap, put towel under boiler make sure boiler is turned off at the mains.
then remove micro switch on the top and remove screws to reveal diaphragm
any advice welcomed thanks.

 

[45yearsagasman]

View media item 31064Turn off cold supply to boiler and open hot tap. Undo the two nuts and disconnect both tubes from valve. Loosen the 2 screws at the back of the housing and remove the valve from the boiler. It's easier to dismantle on a bench. Pay attention as to how it comes apart to ensure correct reassembly, and clean and lube the push rods with silicone grease. Do protect the pcb housing from water. Reassemble in reverse order.

 

[gas112]

Ignore 45gaaman thats for changing whole valve .

Yep cold off open hot taps to drain

put a towel in front so any water doesnt go into control panel
undo little nut at top and then the 6 screws
when you take front off watch out that spring doesnt shoot out

 

[jeddyboy]

Thanks guys , but on my pressure differential valve there are only 4 screws to undo and also microswitch screw,is this correct?

 

[jeddyboy]

sorry it is not the front part(diaphragm)
it is the one further back at the top, all connected to three way valve system,
this also has micro switch on the top,with just 4 screws,
Any ideas thanks..

 

[picasso]

Whats the actual problem with your boiler ?

I think this is what 45years was on about.

https://www.youtube.com/watch?v=FEh4jEWUPGk

 

[jeddyboy]

Picasso thanks for reply, believe i need fitting instructions for central heating diaphragm, which is located above the diverter valve and toward the back a little,
problem with boiler is this smaller diaphragm not working properly causing the pin to remain open,having to close pin manually to fire up the boiler..

 

[jeddyboy]

believe it is the pump proving diaphragm..

 

[gas112]

you will need to drain the central heating side of the boiler to change that one the diaphragm will prob be ok its just the pin that gets gunged up and needs cleaning

 

[jeddyboy]

Gas112 Thanks for your fast response is it a easy job to drain?
any help would be appreciated thanks.

 

[45yearsagasman]

Thanks Picasso, at least you read my post correctly unlike gas112.
It now transpires that it was not the dhw diaphragm but the pump proving diaphragm, which will of course mean a different method. The pic was to assist the OP. Having said all that I can't remember having to change many of the smaller diaphragms. I'm curious to know the symptoms.

 

[jeddyboy]

Thanks Picasso, at least you read my post correctly unlike gas112.
It now transpires that it was not the dhw diaphragm but the pump proving diaphragm, which will of course mean a different method. The pic was to assist the OP. Having said all that I can't remember having to change many of the smaller diaphragms. I'm curious to know the symptoms.

Little pin sticking and having to manually press it down to make boiler fire up..how do i drain system? thanks.

 

[picasso]

Does your boiler work on central heating?

 

[ChrisR]

Point is, it very probably isn't just a diaphragm at fault.
eg, a slow/blocked pump, or ....
Is it exactly the same on CH as HW?

How do you drain a system - well you open something to let the water out ( )
Exactly what and how, depends.....

 

[jeddyboy]

Does your boiler work on central heating?

yes central heating works ok, but if i do not push the pin manually do not get any hot water because boiler will not fire up.