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- 20 Dec 2004
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Hi,
i was browsing this site last night in the hope i could diagnose the problem with my mothers central heating.
Equipment:
potterton combi80 with 3 rads upstairs and 4 downstairs
Fault Description
HW - works great, no probs
CH - upstairs rads have gradually got colder and colder (over last year), now they are stone cold, but downstairs are hot, the closer to the boiler you go the hotter they are as a general rule.
tried bleeding, checked the rad "check valves" are open upstairs and even tried closing all the downstairs check valves (except small bathroom) but still no heat got upstairs (im sure there is no air lock too).
Combi seems to work fine, CH is demanded 24hrs and flame comes on, pump running fine, fan running fine, however the flame quickly modulates down compared to when HW is demanded. Eventually after a few mins pump stays running but flame goes out, then comes back on every 5-15 mins for a few mins.
My Diagnosis ? ?
1st
thought it was the pump, but i think that has been ruled out by what i am reading in other posts..
2nd
Divertor valve or WAX assembly ? ?
if it is this, can i do any tests to verify if it is the valve or the WAX assemblt ? can it be possible it is only letting enough CH water to circulate around downstairs and not upstairs ?
can i replace the wax on its own or is it better to replace both together ?
the part number for the valve according to the manual is Baxi part 929651 or G.C no 289 718
is this correct and does it contain the WAX assembly ?
Oh, and any idea how much the parts will cost and how much it will cost to install ? ?
Thanx very much for any assistance
Stewart
i was browsing this site last night in the hope i could diagnose the problem with my mothers central heating.
Equipment:
potterton combi80 with 3 rads upstairs and 4 downstairs
Fault Description
HW - works great, no probs
CH - upstairs rads have gradually got colder and colder (over last year), now they are stone cold, but downstairs are hot, the closer to the boiler you go the hotter they are as a general rule.
tried bleeding, checked the rad "check valves" are open upstairs and even tried closing all the downstairs check valves (except small bathroom) but still no heat got upstairs (im sure there is no air lock too).
Combi seems to work fine, CH is demanded 24hrs and flame comes on, pump running fine, fan running fine, however the flame quickly modulates down compared to when HW is demanded. Eventually after a few mins pump stays running but flame goes out, then comes back on every 5-15 mins for a few mins.
My Diagnosis ? ?
1st
thought it was the pump, but i think that has been ruled out by what i am reading in other posts..
2nd
Divertor valve or WAX assembly ? ?
if it is this, can i do any tests to verify if it is the valve or the WAX assemblt ? can it be possible it is only letting enough CH water to circulate around downstairs and not upstairs ?
can i replace the wax on its own or is it better to replace both together ?
the part number for the valve according to the manual is Baxi part 929651 or G.C no 289 718
is this correct and does it contain the WAX assembly ?
Oh, and any idea how much the parts will cost and how much it will cost to install ? ?
Thanx very much for any assistance
Stewart
