Baxi 105e- no hot water, not diaphragm?

[lektra]

Hi all, hope someone can help! I have a Baxi 105e boiler and without warning we have no hot water. The central heating is working fine.

Thinking it might be the diaphragm, I checked to see if the pin was coming out to hit the microswitch when the hot water was turned on. The pin isn't coming out of the housing at all. However, when I bypass this by manually pushing in the microswitch pin, I can hear the microswitch clicking on but I still get no hot water.

I've called around to find a boiler engineer, but no one is available for at least 3 days so I'd like to tackle this myself, if it's within my capabilities. Can anyone advise what the next steps are to track down the problem?

 

[45yearsagasman]

By doing that to the microswitch you fire the boiler but the diveter has not changed over to the hot water position and all the heat will go to your rads.
The action of the diaphragm is not only to close the microswitch but to allow the diverter to change over the internal valves to divert the heat energy to the plate heat exch.In short check an dreplace the diaphragm.

 

[lektra]

Ah, that makes more sense!

I may as well get the diaphragm kit and replace the nut as well but apparently there are 2 diaphragms on this boiler. Do you happen to know the part number I'd need? I think it's 5111137, but not sure.

Thanks for the help!

 

[45yearsagasman]

I'm not sure of the part number.If you go to your merchant with the GC number of your boiler they will be able to ID the correct part. GC numbers for baxi combi's are 47-075-??.This info is on the boilers data badge.

 

[mysteryman]

One of the diaphragms - the smaller one I think - is for the primary circuit. The larger one needs replacing in your case. Don't try it unless you are confident - it's not that easy.

 

[lektra]

Just an update, I managed to get a diaphragm kit from eBay for £8 which was delivered the next day. Even a novice like me managed to fit it within 20 minutes and we now have hot water again. Thanks to both of you for the help!

 

[45yearsagasman]

No worries, and thanks for the thanks.