Just came cross this idea of using two smaller boilers in parallel connection instead of single large boiler (say 36kw), so in case one boiler failed the system can still operate albeit in lower capacity. The additional one-time installation cost does not seem to be unaffordable but in practise, not sure if it's worth it for the redundancy it provides?
Dual boiler worth it?
- Thread starter Sup9
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A good idea on very large properties if you've got space, or situations where maintaining some heating capacity is essential, but not necessary for normal domestic usage. Is this a theoretical question or are you looking to have a new boiler or boilers yourself?
As above not unusual on large properties or commercial work.
We fit out large restaurants (200 covers plus) always use two boilers as maintaining hot water is a absolute must.
We fit out large restaurants (200 covers plus) always use two boilers as maintaining hot water is a absolute must.
Friend has two boilers in a large Edwardian property, often don't use upper floors so that boiler sits idle most of the time.
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Might it be sensible when considering two boilers, to think of one larger and one smaller? That way, it allows the smaller boiler only, to run at best efficiency when their is reduced demand for heating, only calling on the larger unit when the smaller one cannot cope.
Yup , I've seen it also in large houses - I suppose it might be cheaper to have two domestic grade boilers rather than one large commercial grade one.
The house I live in had two gas boilers decades ago
The large heating boiler in the utility room and the smaller hot water boiler in the linen room with the hot water tank so in this case they were two totally separate systems rather than as I've seen in other large houses merely two boilers on the same system. So the heating boiler was never used between the spring and autumn.
I've no idea how dual boilers on the same system are controlled so that they both don't start "fighting against each other" in terms of call for heat etc.
The house I live in had two gas boilers decades ago
The large heating boiler in the utility room and the smaller hot water boiler in the linen room with the hot water tank so in this case they were two totally separate systems rather than as I've seen in other large houses merely two boilers on the same system. So the heating boiler was never used between the spring and autumn.
I've no idea how dual boilers on the same system are controlled so that they both don't start "fighting against each other" in terms of call for heat etc.
2 or more boilers typically use sequence controls and low loss headers. Boilers not necessarily same fuel.
Look at the cost of two 18kW, try to find a sequencer and cost that, deduct the cost of a 36kW unit, that will be the price of you redundancy backup. There may be an infinitesimal saving in fuel if you use a sequencer but running in parallel, no.
I’m indeed looking to have a new boiler and heard of this dual boiler setup from a chat group. My boiler is probably 20+ years old so not very efficient, it’s only failed once though in the last 5 years due to the pilot light(?) not ignite.
Use heat engineer.com software to do a proper heat loss of your house, 36kW is a lot. It'll cost a tenner and take 2-3 hours, you'll learn a lot and there'll be no ambiguity in boiler requirements.
What make & model is it?
Ideal Mexico 2
thanks, will check out the software
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