A twist on the gas boiler selection question.

[AMEdinburgh]

Please could I benefit from the experience of the forum answering this question?

18 months ago we changed to a biomass heating system which heats a large internal tank in tank, from which we draw DHW from the inner tank and CH from the primary circuit

I retained my elderly Worcester 350 to act as a back up system boiler having rerouted the DHW to the new tank. It has now expired.

The back up is only used if the biomass boiler is down so that we always have DHW and CH. Just like a car I presume boilers like being used regularly but in our case we would only perhaps be putting it on for a few hours each month to keep that part of the system ticking over and ensure if called upon it could take over from the biomass.

I am looking for a 30KW (approx) system boiler for this function. Is there a model/brand that is particularly good or indeed bad for such intermittent use.

Thank you in advance for any helpful replies

 

[Dan Robinson]

Any boiler can function this way. Stick it on a 7 day timer set to come on fire an hour a week... or whatever.

Intergas would be my choice .


Leave it permanently powered and it will look after its own pump.

 

[AMEdinburgh]

Thank you Dan,

Unfortunately the biomass boiler is meant to be physically isolated when another source of heat is used for metering the RHI, so we have a changeover switch to call the heat from the boiler of choice and close a gate valve on the other circuit, although with a non return valve in each circuit and no pump running, that is probably overkill

Thank you for the Intergas tip. I shall look at that.

 

[ianmcd]

Most new boilers have a function called "daily pump kick" sometimes referred to as anti-seizure when the boiler is not used the pump will run for a very short period every 24 hours when the boiler has not been used, not all boilers use this but in your situation I would recommend you fitting a boiler that has this function

 

[AMEdinburgh]

I'll look out for that, thank you.

 

[Agile]

Pity you are so far away!

I have a used heat only Worcester Greenstar 42cdi only a few years old which would have been ideal as a backup1

How is your pet's jacusi?

Tony

 

[AMEdinburgh]

Doing fine, Tony, thank you. Put in a 10KW heat exchange from the biomass system, so in effect now using wood cat litter to heat the pool.