New install condensing combi system

[John]

As far as I'm "happy" with any modern (accountant engineered) product they are well built, at least they use stainless steel and plastics properly rather than aluminium in contact with acidic condensate. I'd not classify them as a two man lift by any stretch of the imagination but I suppose I've been around long enough to expect bags of cement to weigh a hundredweight (approx 50kG) not these namby pamby 25kG bags that are the norm nowadays. I have installed an Isar in the past so by way of comparison I can say it was much heavier and not as easy to install

[Pete C]

Oops, meant to say burner/fan, the pump would best be left running.

Bit unnecessary for a non modulating boiler I would have thought.

cheers, Pete.

[Andy Hall]

Except that the Keston Celsius 25 is a modulating boiler........

.andy

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[Pete C]

Ooops, I'm not a boiler spotter :))) Does the temperature control affect CH as well as DHW? I'd have thought it only affects DHW, and the rest of the time the boiler operates in condensing mode where possible.

For DHW it could be useful to have a lower output temp for bath filling, this could be done with a preset and changeover relay.

For more control something could be done with the flow and return thermistors.

cheers, Pete.

[Andy Hall]

It isn't a combi either.

I have this functionality on my (MAN Micromat) boiler.

has an outside temperature sensor as well as an indoor one, and programmable curves for CH operating temperature vs. environmental temperatures. It will thus modulate the CH temperature down to around 40 degrees and 3kW if there is not a great heat demand.

For DHW, there is a temperature sensor in a pocket in the cylinder which starts a hot water reheat cycle when a rapid drop in temperature is detected. In this mode, the boiler is run up to full output to reheat the cylinder rapidly.

.andy

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