Baxi 105e instant problem!!

[Frizz]

Hi
I have a baxi 105e instant combi.
My issue is that the when the pre heat is on its heating the rads and the hot water is not very hot. I've turned the preheat off. But when a hot tap is turned on the rads start to get hot again and the waters only Luke warm and it seams to run on for ages??
I replaced the pressure differential valve but this doesn't seam to have made any difference. ( think that's the correct name. 3 ports and a pin in center)

Could it be the diverter valve? I replaced this last year??

This must be the worst boiler out there saving for a valliant ecotec 838 hopefully this is worth the cash.
Many thanks for any advice and help.

 

[McCombi]

Yes sounds like the diverter valve passing again.
I suspect the problem isn't the boiler but the quality of the system water.

If the system is dirty and isn't cleaned it will keep happening.

 

[Frizz]

Yes sounds like the diverter valve passing again.
I suspect the problem isn't the boiler but the quality of the system water.

If the system is dirty and isn't cleaned it will keep happening.

Ok cheers ill change the diverter for the new one later see if that sorts it.
Are you referring to the water in the boiler system? Is there a cleaner I could add after emptying and refilling??
The diaphragm in the 3 way valve was ok also.

 

[McCombi]

Search the wiki on this site for flushing system it will tell you how, alternatively call a plumber.

 

[Frizz]

Ok I've replaced diverter valve with new one. I've also replaced hot water temp sensor( I had a new one in tool box so thought it can't hurt)
I'm still getting some hot water going down the ch pipes when hot waters on.
???

 

[davebgas]

Plate heat ex full of rubbish... Forces the heat down the flow

 

[Frizz]

Plate heat ex full of rubbish... Forces the heat down the flow

Easy fix??
Replace or remove and flush out??
Any advice welcome please.

 

[davebgas]

Remove and clean would be my first try, it costs you nothing and they clean pretty well usually. Unless they are choked that us, but you'll soon see how bad it is.

I never liked the instant. Wasn't a great idea to start with.

 

[Frizz]

Ok do I just drain boiler down remove and flush out with hosepipe?
Any tips on removal ?? It looks tight at the back bottom.

 

[Corgigrouch]

I realy dislike working on the instant, before you remove the secondary heat exchanger, get the flexible seals for it..... they can turn to gloop akin to a several month old fruit pastile that your kids dropped down the back of the sofa

Seriously.... They do decompose in fresh water (Best reason I can think of for drinking Scotch)

 

[bazdaman]

Just drain ch and hw side of boiler, two screws hold the plate heat exchanger in, as said use new lip seals on pop some x800 in plate ch side only! Give it some hw from kettle and shake it empty drain repeat several time or leave to soak, just remember to put something over pcb on removal as these things only needs to hear running water for pcbs to fail!

 

[Frizz]

Ok looks like I'm stripping the plate heat exchanger down in the near future.
How many plates is it on the 105e instant? 16? 21?
Any part numbers are a great help please.
And for the 4 rubber washer seals.
Many thanks.

Easiest way to drain down the boiler fully and remove the exchanger please.
Many thanks.

 

[bazdaman]

Manufacturers part no. Is 1002249.00 they are a chaffoteaux part that is cheaper but same as baxi, parts center number is 432000 they are 2.42 retail price + vat follow instructions on page 38/39 of link for instructions on replacing and draining. http://www.baximarketing.co.uk/disc...-boilers/Baxi-Combi-instant-HE-80-105-ins.pdf

 

[bazdaman]

Sorry they are instructions for the he version but they are the same anyway turn off cold water to boiler and use drain off on bottom right hand side of boiler to drain ch side

 

[gas112]

And use brick acid to clean it flushing with a hose will do nothing