New Boiler - Should it be connected to the mains or not?

FrankN1

Hi there,

Im replacing my boiler that seems to have poor pressure. One company said it should be connected to the mains when getting the new boiler installed but the 2nd company says this isn't common practice and can be very dangerous.

Curious to see if anyone knows what's best practice?

Thanks in advance.

John.G

Is it a combi boiler??

FrankN1

https://www.boards.ie/discussion/comment/118451573#Comment_118451573

Yep I believe so, Gas boiler for rads and water.

ongarite

Combo boiler are usually installed in the UK & replace the hot water tank in hot press (hot water is on demand).

You sure it's a combi & what model are you getting installed

FrankN1

It's probably not a Combi boiler then? Looking at the Bosch Worcester model.

John.G

If not a combi then the only role that the mains plays is to top up the boiler pressure and is the normal(and only) way to top up.

Curious_Case

How do you know you have low pressure? are the rads slow to heat?

Clogged pipes or faulty circulating pumps can cause problems, independently of the boiler.

FrankN1

It could be clogged pipes too, it's most likely a combination of both but the boiler needs to be replaced.

If it is replaced with a new one, is there any need for it to be connected to the mains? Does it pose any safety risk by connecting it to the mains as the plumber mentioned this can in very rare circumstances lead to a pipe exploding due to blockage which is obviously hugely dangerous.

Sleeper12

Gas boilers shouldn't be connected to the mains supply in Ireland according to the building regulation, Irish Water & local By Laws. Plenty are connected & the function OK. I'd imagine this is why you got conflicting advice between the two companies. Personally I'd be engaging the services of the company insisting on following the building regulations & best practice

cruizer101

The connection to main is kind of a temporary one.

There will be a filling loop which consists of a non-return valve and a valve that can be opened/closed. So when the system is commissioned the valve will be opened to fill to a certain pressure and then closed and shouldn't really be required to be opened again unless something else goes wrong or if work is done on system e.g. rad drained to move it.

So it is technically connected to the mains but the connection closed off.

There are also open vented systems with separate tank in attic but I don't think any newer systems are those.

Curious_Case

https://www.boards.ie/discussion/comment/118454116#Comment_118454116

Completely agree . . .