Baxi Combi 105e DHW not kicking in.

RPW

Joined
29 Apr 2005
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Location
Leicestershire
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United Kingdom
:?:
I installed the boiler about five months ago and all has been working perfectly until last week when some 'old' pipes running up the corner of the chimney-breast started to leak (pin hole leaks). The pipes were about 30 odd years old and I put it down to the fact that previously they were part of the old ch system and they were now being used for the cold water feed and dhw output and therefore couldn't cope with the increased pressure so I changed them - they were only an intermediate part of the feed and dhw and had been used because I didnt want to distrurb bookshelves etc.
As I said, I replaced these sections and refilled the system. The CH is working fine but the diverter valve doesnt operate when I turn on the hot water.
There is also an associated noise (sounds like a restriction or air-lock) when filling the CH and when I open a hw tap.
My first thought was that I had let some solder or foreign body into the mains inlet. So I checked the filter on the inlet tap and the inlet/return manifold but both were clean.
I have subsequently removed and stripped down the diverter valve assembly and the inlet/return manifold. Both were clear - reassembled and filled the system and it is still the same problem. Before I replaced the two old lengths of pipe, there was no noise whatsoever when I filled the system or ran the HW, now there is a noise apparently coming from the i/r manifold area.

My question is, can it be possible that there is an air-lock in the boiler and if so, how do I remove it?

If it isn't an air-lock, what do you think the problem could be?

I have measured the HW flow to be about 5 litres/min.

Any help would be appreciated. Thanks
 
Thanks Gasman1015 and ChrisR.

You have probably put your fingers on it. I have done the following checks:-
CW flow at a tap =15.0 l/min
Mains in at boiler = 6.6 l/min
DHW = 5.45 l/min
DHW with CW run'g = 3.43 l/min.

The orignal pipe was 28mmsq with 15mm tapped off mains and 15mm into boiler.
I replaced it with 22mm (dont ask me why I didn't put 15mm in please) but what I also did was to take the pipe closer to the wall by replacing two curves with two 90deg on both mains IN and DHW. I am going to replace the 90deg joints with 270deg joints and see what that does for the flow.

Does this sound enough?

Cheers,

RPW
 
I have replaced the 90deg elbows and have put flexi copper in to give a lage radius.
the flow at the mains into the boiler is now 8 l/min and the DHW flow is now 6.6 l/min but the 3-way valve is still not diverting to DHW.

HELP!!!!!

RPW.
 
Kevplumb seems to show a lot of insecurity, never mind, the rest of the world can get by without that sort of attitude, perhaps he would like to discuss the control and response characteristics of high and low speed can-bus systems, if he knows what I am talking about.

Anyway, the rest of you might be interested to know that what I found confirmed other peoples thoughts, I found a blockage further up the main feed pipe and now all is working well with almost equivalent flow at the hot tap to that of the cold. Thanks for your help.

RPW
 

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