Can a heating system boiler be used for domestic hot water?

LJB Chef

I am renovating and older terrace house and due to water damage throughout I have taken out the central heating system completely to be replaced with a much simpler alternative. Anyway I have, surplus to requirements, a 24KW system boiler and thought it would be good repurposed for a DHW boiler. Can anyone tell me if this is possible?

Explosive_Cornflake

Yes, just heats a coil in the hot water cyclinder

https://www.worcester-bosch.co.uk/products/boilers/explained

LJB Chef

Seems a bit inefficient. Could I not just do away with the tank altogether and just have it heating mains flow water on demand?

10-10-20

https://www.boards.ie/discussion/comment/120555016#Comment_120555016

No, you can't do it that way with a system boiler. It has to have separation as the boiler isn't safe for direct connection to the mains (due to pressure and contamination reasons).

If you want to go down that route, look up a combi-boiler instead.

LJB Chef

Mains pressure is no real issue being that it is only 1.5 bar. As for contamination, I can understand if it was hooked up to central heating still, but with it just being used to heat water does the contamination come from the heating process somehow?