Replacing external oil boiler with a combo

Calahonda52

Boiler is cracked so needs too be replaced. Am thinking about a combi and remove the immersion cylinder.

The rad heating loop is through the wall into the house, under the concrete floor.

Top up loop is from the rising main which has a good pressure.

Just wondering to where the hot water feed from the combi need to be brought, kitchen sink is inside the window.

Just thinking about this, for showers, will the combi boiler need to fed from the header tank, rather than the rising main?

Thanks as always.

(storage is temporary pending getting boiler sorted, circulation pump on ground is a spare)

standardg60

It's against regulations but i dare say you'll find a plumber who'll be happy to connect the combi to the top up loop mains feed. Just a matter of bringing a new feed for the hot to the kitchen sink then, connect it to the current hot water feed to the sink and use that in reverse to supply and connect to the bathroom hot water feeds where the existing cylinder is.

Bear in mind that this feed will be pressurised in contrast to the gravity fed cold in the bathroom taps, but setting the thermostat on the boiler to only heat the water to your preference eliminates the need to mix in any cold anyway, if you have a mixer shower or tap.

Calahonda52

Thanks so the regs here are different to UK where they supply from the rising main

Calahonda52

Case closed, DHW storage on an oil fired combi is between 30 and 50 litres, much smaller on a gas boiler.

This 30 litres is always at 81 degrees on the Grant I looked so not energy efficient for intermittent use.

Case closed on combi, will replace with standard boiler