low pressure central heating

geb

Not enough pressure from tank in attic to represureise boiler in room underneath.
Just wondering why the installer did not run pipe from mains.
(Maybe it was handier as it meant no attic work when it was installed 3 years ago !!!)
The boiler pressure gauge only goes up to just less than 1/2 bar.
My main query is - should the boiler filler pipe be fed from mains as the current system is useless.
Any advice greatly appreciated.

Corkey123

Is this a small expansion tank in the attic or is the boiler being fed from the main storage tank. A close system would normally have 1 to 1 1/2 bar

geb

Hi Martin ( thanks for your input and currently using monitor i got from you last year thanks again)

Its the only expansion tank in attic that used to just feed the hot water cylinder in hot press
just beside where the central heating boiler was installed.
The pressure is just not high enough from this to repressurise boiler

JamesM

geb wrote:

Not enough pressure from tank in attic to represureise boiler in room underneath.
Just wondering why the installer did not run pipe from mains.
(Maybe it was handier as it meant no attic work when it was installed 3 years ago !!!)
The boiler pressure gauge only goes up to just less than 1/2 bar.
My main query is - should the boiler filler pipe be fed from mains as the current system is useless.
Any advice greatly appreciated.

I am not sure what you mean "repressurise". Are you talking about a bungalow, with the heating system topped up from a connection to the main water tank in the attic ? If all the rads are on the ground floor, you should not have a problem venting rads. If you have rads in the attic area (dormer), then you might have a problem topping them up. (They are on the same level as the tank). If all the rads are on the ground floor, then 1/2 Bar is quite adequate. I think that there can be a problem with some gas systems, if the pressure does not reach a certain figure, but there should not be a problem with oil systems.
Jim.

jd

JamesM wrote:

I think that there can be a problem with some gas systems, if the pressure does not reach a certain figure, but there should not be a problem with oil systems.
Jim.

I am in an apartment, and am currently trying to sort out such a problem. The pressure drops in the system -in less than a day- and the heating won't come on again (flashing light on gas boiler etc).
I was also told that fresh mains water being introduced into the closed system (by opening a valve from the mains) will eventually lead to corrosion (rust I guess) ..I can't find a leak anywhere either
jd

geb

hi jamesM
Its a two storey with gas boiler upstairs but pressure at less than 1/2 bar just not enough to heat last two rads in run - downstairs.
By repressurise i mean opening the filler stopcock (whose pipe is taken from tank in attic) to get the pressure up to 1 bar.

JamesM

geb wrote:

hi jamesM
Its a two storey with gas boiler upstairs but pressure at less than 1/2 bar just not enough to heat last two rads in run - downstairs.
By repressurise i mean opening the filler stopcock (whose pipe is taken from tank in attic) to get the pressure up to 1 bar.

Hi Geb and JD,
Once again I have to say that I do not have any experience of gas systems, especially this "flashing light on gas boiler etc". There seems to be some reason that gas boilers cut out if the system pressure goes too low.
However, Geb, I would think that if your problem is that the last 2 rads in the run downstairs do not heat, maybe you should look at the speed of the water pump or try balancing the system.
JD, if you are having to let water into the system, it must be getting out somewhere. Don't worry about the corrosion thing at this stage, but do find out why you are having to refill the system.
Cheers,
Jim.

jd

JamesM wrote:

JD, if you are having to let water into the system, it must be getting out somewhere. Don't worry about the corrosion thing at this stage, but do find out why you are having to refill the system.
Cheers,
Jim.

Cheers Jem..

I'm not too worried about the corrosion at the moment-it was more of an aside. It apparently doen't take much of a leak, and I can't find any evidence of a water leak.. Perhaps it is faulty valve-time for a plumber...

jd

jd wrote:

Cheers Jem..

I'm not too worried about the corrosion at the moment-it was more of an aside. It apparently doen't take much of a leak, and I can't find any evidence of a water leak.. Perhaps it is faulty valve-time for a plumber...

It was a leak..:eek:
It dripped into the neighbours below. To cut a long story short, the leak was found in the piping underneath the gas boiler. Luckily
1. The building contacters were still near by
2. The leak was at a join under the boiler, not somewhere under the (wooden) flooring..
Anyway all was sorted..

JamesM

jd wrote:

It was a leak..:eek:
It dripped into the neighbours below. To cut a long story short, the leak was found in the piping underneath the gas boiler. Luckily
1. The building contacters were still near by
2. The leak was at a join under the boiler, not somewhere under the (wooden) flooring..
Anyway all was sorted..

If you're having to top up, there's a leak somewhere. A good thing that it was overground. I'm glad you found it
Jim.

jd

JamesM wrote:

If you're having to top up, there's a leak somewhere. A good thing that it was overground. I'm glad you found it
Jim.

It was underground- under the floor panel in the wardrobe. The water actually spread along the pipes in the screed and dripped down into the neighbours ensuite (from a light bulb!!)
jd

rightman

Hi there!

I just wanted to ask if you know how to top up the heating system eventually?
I had to take one of the ground level rads off and flush it to make the water going through it properly. Problem is that I had to get rid of a good bucket of water from it and now my gas heater is showing me 0.0 bar!

Please help if you can as I don't want damage anything..

Thanks!

Corkey123

There should be a stop-cock or gate value close to the boiler to top up the system.

Tom Slick

MartinCorcoran wrote: »

There should be a stop-cock or gate value close to the boiler to top up the system.

Another location to look would be the hotpress, assuming you have one away from the boiler.
There may be a valve linking the mains feed to the attic with the heating system & most likely a nearby pressure gauge.