Whats the big boiler upstairs for?

Cardew

philnicandamy wrote: »

Ours is Gas fired thermal store(boilermate).......(small boiler on kitchen wall...large control boiler in cupboard)

I wasn't aware of that - thanks.

To be honest I can't see the reason why a gas fired thermal store would be used - although obviously there must be one.

The normal use of a thermal store is for heating systems that cannot produce enough 'instant' heat to cope with the central heating for the whole house e.g. a heat pump.

Even physically small gas fired boilers can produce a very large heat output, so it seems strange to have a large tank full of hot water.

Premier_2

aaronoxf wrote: »

Im glad I asked the question then, let me explain a little better. downstairs against the kitchen wall is a small boiler, gas controlled which when we stick heating on or hot water on, this fires up and hot water comes through.

Upstairs in the back bedroom in a cupboard there is a larger tank with a smaller tank above it, this has two switches, one inside the cupboard and one outside the cupboard, these switches are switched off as we dont often need hot water as shower come through hot and when washing up we use a kettle

This sounds like a conventional central heating system.

With a thermal store, it's not normal to be able to turn hot water only on at the boiler; the system works by having the boiler constantly available to maintain the water in the cylinder at the required temperature. Domestic hot water is heated by it (usually mains pressure) passing through hot water cylinder. Radiators are heated by circulating the hot water in the cylinder direct to the radiators
This is effectively opposite to the way a conventional system works.

With a conventional system, when the boiler heats the hot water (which is user controlled), it heats the water in the cylinder. This water then gets delivered to the taps. A separate circuit independent of the cylinder heats the water to the radiators (heating).

If as you describe, your cylinder has a smaller container on top, this is the expansion tank and should negate the need for a separate water tank in the loft.

Either way, it does sound like you have electrical immersion heater(s) on the cylinder. These are not required other than for backup in case of boiler failure ... or should you decide to use them in summer rather than the gas boiler. (With the relative high cost of electricity, you're probably best off using the gas boiler all year unless possibly you have Economy 7 too)

If you could post a photo of the cylinder and switches, we could probably give you more definite advice.

penrhyn

It would help if OP could take the make and model numbers off their appliances.

Cardew

penrhyn wrote: »

It would help if OP could take the make and model numbers off their appliances.

Both the OP and philnicandamy!

I am wondering if the 'thermal store' is really just for domestic hotwater - a fancy name for a hot water tank.

The conventional explanation of 'thermal store' is to have a supply of hot water to pump around the radiators for central heating.

So for the life of me I cannot see the purpose of having a 'thermal store' when you have a gas boiler.