DIY Doctor UK DIY Forums

I have purchased a new house with an oil fired boiler which is located in the garage. Some of the radiators do not get hot. The system has a blue vessel built into the pipe work close to the boiler. I do not believe the system is toped up by a cold storage tank. Does this vessel help to maintain the system pressure – the vessel is not fitted with a water top-up facility and does not have a gauge, it is manufactured by Grunfos.

Can you please give me an explanation of what the purpose of this vessel is?

Should the boiler have some sort of frost protection because it is outside of the house?

Thanks for any help

glr,
The vessel is probably a pressure chamber which has a ballon in it filled with air, this allow the system to expand and contract. Pressurising the system is done by using mains water and you may find the mains is already plumbed into the system but it should be isolated by two valves.
Recommend that you fit a pressure gauge or use a filling loop which incorporates one, aim for about 1.5 bar.
Yes the boiler should have a frost stat so that it fires when the temperature drops to near freezing.
end

Soneboy thanks for the clear information,

My oil fired system is fitted with this vessel (Grunfos) and I have been told that the preesure is toped up constantly from the header tank in the loft, so as I see it, the system is an 'open system'. Why in this case do they also install this vessel?

glr,
Have you been into your loft and checked to see if you have a header tank.
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