Next door neighbour has just had their HW tank replaced under
maintenance contract by BG. The old tank was copper but I think the new
one is SS - it is certainly very flat topped (still open vented).

They transferred the immersion heater (the immersion heater is not used
and is a back up for boiler failure only) and thermostat from old tank
to new but now they seem unable to get satisfactory HW temperature.

One minute it is scalding hot, reduce the thermostat setting by 1Deg and
the water ends up dropping to luke warm before the boiler wakes up to
warm it up.

When moving the thermostat manually there is about a 5C "backlash"
between switch on/off operations.

Any suggestions as to whether this is

1) a thermostat that didn't like being moved and has failed due to the
disturbance

2) Lack of thermal connection between the new tank and the thermostat
(should there be any form of heat transfer compound between them) - I
think this would be my first point of call if it was my tank)

3) Incorrect positioning of the thermostat

4) any other ideas.

He has the maintenance contact with BG so they will be called in to fix
it but he would like some confidence that the problem can be fixed.


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Chris B (News)