Gas boiler installation

In July 2022 I had a Worcester Bosch Greenstar 18i system gas boiler installed by Bord Gais. The pressure gauge barely moves above zero, and never into
the green area of the dial which I assume would indicate the required pressure for efficient running. Although I have no plumbing expertise it seems to me
that it is fed from the attic tank, whereas the manual seems to indicate that it should be a sealed system which can be topped up from the mains. There does not
appear to be any way to top up the system although the company has videos on utube demonstrating how to top up with a mains water connection.
I brought the low pressure to the attention of the installer was told it was not a problem, not to worry.
I understand that in England attic tanks are a thing of the past, and wonder if this particular boilers is being correctly installed in this country.
I wonder if the low pressure greatly affects the boiler efficiency, and also shortens the life of the boiler.
Has anyone had this boiler installed and had a similar experience? I changed from an old Ideal boiler to this condenser boiler in the interests of greater
efficiency but wonder am I losing out.

Have you tried these steps to identify which filling system you have?

My boiler is fed from the attic tank, not the mains. If you follow the path of the pipe from the attic to the boiler, you come to a small external filling loop with two black taps like the first picture. You can open the taps to top up the pressure.

Can you take a picture of the pipes at the base of your boiler?

learnwell said:

I wonder if the low pressure greatly affects the boiler efficiency, and also shortens the life of the boiler.

Click to expand...

Makes no difference, once there is enough pressure to stop by the boiler thinking there is no water.

Thanks for replies. I don't appear to have any of the top up methods shown. Since my system has never been topped up I figure this has to mean that it is open and self regulating, otherwise it would long since run out of water. It seems that it depends on the head of gravity from
the attic tank which is insufficient to maintain it at the recommended pressure.
Corola, is yours a Worcester Bosch Greenstar? Is the gauge in the green area? You say your boiler is fed from attic tank. Is there
an external pump anywhere in the feed? My previous boiler was fed from attic via pump in hot press, but the pump was removed my the
installer of the Greenstar, who said it was not required. I don't understand how your system can reach the recommended pressure if fed
from the attic tank.
I attach a picture taken from the underside of the boiler.

No, it's not the same model. Like yours the manual says it should be fed from the mains, but it's not - it's fed from the cold water tank in the attic. The installer said he kept the tank so we could still have showers / flush toilet when the mains water goes off, which is frequent in my area. There is an external pump from the attic to the boiler in the hotpress, to boost the pressure. It's a sealed system and the pressure stays in the green area with normal use. It needs topped up after bleeding radiators.

I don't know about open vented systems.

Ours has the topup in the hotpress! So maybe look there for taps

Hi Joe Roberts, thanks for reply, is your boiler the same make/model as mine, is it fed from attic tank or rising main? There are no top up taps in our hot press. Is your boiler in the vicinity of the hot press, if not I presume you need someone to observe the pressure gauge when you top up.
From the reply of Corola I'm wondering if my installer should have removed the pump from the circuit.

It's a baxi condenser boiler out in the garage. There is a pressure gauge in the hotpress, looks like it is fed from tank upstairs.

Thanks to all for replies. I had hoped to hear from someone who had the same make/model as mine installed by Bord Gais but no luck on that score.

Maybe try Boards.ie and Reddit?

Thanks, will give that a go

as others have mentioned, my refill loop is in the hot press, I turn 2 valves, give it a few seconds then close them. My boiler (a Baxi) won't run once the pressure goes below 0.6 bar and I top it up to between 1 and 1.5 bar maybe every 6 months.

I don't know whether low pressure affects the efficiency - we had ours serviced a couple of weeks ago and the guy said it was running at 90% efficiency, and the pressure was already quite low on it (I topped it up subsequently). Have you not had it serviced since 2022?

It is serviced annually by Bord Gais, required as part of the 10 yr guarantee. At the moment the needle is flat on zero, boiler has been running for two hours. The service engineers don't see it as a problem nor did the installer when I rang him after I first noticed it. To be fair the rads get as hot as they did with the old boiler. Anything I read online states that the pressure should be one to one and a half bar. It makes me wonder what is the point of having a pressure gauge. Perhaps it does not affect the efficiency but I can't help thinking it must affect th longevity of the boiler.