wrote:

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

In the same room as the boiler I can't hear the pump over the fan of the
boiler. Could there be a fault with the pump?

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.

I must admit to never having listened carefully to exact switchover
sequence on my HE35 to know if it is doing the same as yours. However, I
have never been aware of anything more than the polite "clunk" of the
diverter valve and the speed up in the fan when switching from CH to HW.

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.

Is it air or hydrogen? (i.e. does it burn if you try to ignight the gas
as you bleed it from a rad).

If it is air, and you are sure that it is only/still getting into the
system while in HW mode[1], then that would indicate the fault in the
boiler I would have thought, since the primary heating loop is only
running through the main and plate heat exchangers, the pump and the
diversion valve.

If it is hydrogen, then that would indicate a fairly active corrosion
problem. Is there sufficent corrosian inhibitor in the primary circuit?

Is it loosing water - how often do you need to top up the pressure?

[1] Could it be that air is getting in all the time, but you only become
aware of it in HW mode because a slug of it is released in one hit,
rather than being fed in over time?


--
Cheers,

John.

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