John Rumm wrote:
wrote:

Hi, I have a Isar HE30 combi boiler and a few things are begining to
get on my nerves.....

1) During CH mode the boiler pump runs on for 4 minutes after the CH
demand has gone. It's a good idea to equalise the water temp around the
system, but not so good if your programmable thermostat turns the
boiler on every 10 minutes to regulate the room temp. The flame only
lights for 30 seconds - then it's 4 minutes of overun. Aaagh!

Given the pump ought to be almost silent, who cares?

2) During the overun above if the system recieves a DHW demand - BANG,
the changover valve switches mode whilst the pump is still running.
Hydraulic nightmare!! Anyone else seen this problem?

No, the diverter will make a audible click when switching - but I would
not describe it as a "bang". There is little difference in its
activation sound from the boiler being in standby or CH mode IME at the
time of the HW demand.

3) Air, air and more air whilst in DHW mode. 4 months and the system is
still boiling of air! or is it I don't know?

Air where exactly? Coming out the hot tap?


--
Cheers,

John.

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| John Rumm - john(at)internode(dot)co(dot)uk |
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Hi John,

1) The pump ain't silent it rumbles. It's in the kitchen and it's
annoying.

2)When the diverter valve switches over the water is at full flow too
and from the boiler.... so it hits the back of the claosed valve and
bangs - water hammer. The whole central heating system convulses so
it's a bang audable throughout the house. The pump stops when the valve
is changing from DHW to CH but obviously doesn't when changing from CH
to DHW, Ideal aren't interested.

3) The air is in the boiler closed circuit - it clears when the system
switches to CH as it can be heard entering the first rad. When DHW runs
again the air slowly builds up... Again Ideal aren't interested.

Mark