Hot water problem with a CELTIC PLUS combi boiler

16 May 2006
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United Kingdom
can anyone help my daughter fathom out her problem please. she lives in a hard water area in chippenham and has a celtic plus combi boiler.
the BAR pressure showing on the boiler is 3.4 out of 4
even though the hot water dial is turned up fully, the heating meter shows only 34 degrees (it can go up to 120) when trying to get hot water upstairs to the bath and toilet sink, and the water is warm to cold during the running of these 2 items.

also it only shows 40 degrees when supplying hot water to the sink taps in the kitchen alongside the boiler. the water to the kitchen sink is at least warm to hot.

before all the above, during last week, at least the hot tap in the toilet (where the bath is) gave some degree of hot water out, now though it is the same as the bath hot tap, coldish/warm.
last week the bath hot water went from warm to cold to warm again etc. now it is just coldish/warm.
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kev, thanks, could you tell me where the changeover valve is situated, i am printing out the whole booklet on this boiler from the internet as we write.
is this something a layman can do or should i tell her to get a plumber in and any idea what it would cost her to replce this item (approx).
it will probably be a scaling problem as it has come on slowly and she is in a hard water area

c.o.v is at the bottom front right

its in the book

not to difficult to change

can't remember if you can get a service kit of a full valve

but you should be able to get a diaphram

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