Low pressure

[Fediuld]

Hi,


Yesterday I saw that the pressure was low (below 0.5 bar) on the central heating. That occurred after the radiator didn't started last night with the broken flame symbol.

I spoke to one of my neighbours and told me to refill the central system, and which valve it is under the combi boiler.

I turned it on, the gauge jump to 1 bar, left it for 5 minutes and turned it off. Then dropped back again bellow to 0.5 bar, while the boiler stopped working again. After few tries dismayed a friend of mine told me to leave the cold water on, and turn on all the radiators in the house.

I live in a two storey house, and I have the top rads off for many years since I am not using the top bedroom, nor the ground floor.

After 2 hours, while the heating was still on, and the cold water also decided to close it. The rads started warming up after I turned off the cold water while the pressure remained just above 0.5 bar. (at least had some heat).

Now, I had a look around the house and I cannot see any leaks. In addition the top floor rads one gets barely warm the others not at all.

Tried to bleed them with the key, one of them had bit air in there, needed around 15 minutes to stop air coming through, the others are dead empty.

I am completely new to this area of DYI and I would like your feedback how to solve the problem.

More info.
Since last night when I had the water on, I can hear water movement inside the rads, the ones that were working fine all those year.

When the boiler is working now hits the 1 bar, when stops drops below 0.5

The house is 2007 build and bought it from new in 2008, before the divorce, where I stayed on the house on my own. (hence not warming the top bedrooms).

The boiler is LPG one, since the whole estate is on a central LPG tank-supply.

Now reading the sticky above it says to turn off the boiler completely and turn on the water until it hits 1+ bars. Is that correct?
However when my boiler is off, no water can be heard from the cold water pipe (which is pretty hot right now when is working on with the rad).

I should have a pump working upstairs, but cannot hear it at all, while the cupboard where it is, there are too many pipes around and I have no clue what is what.

Thank you for your assistance.


EDIT

Took some pics of the system.


Boiler (ground floor). The valve that seems is working is the left one

Cupboard with the rest of the plumbing

 

[roguetrader]

It's not a combi boiler.
Leave to valves under the boiler on. (Inline with pipework, not at right angles.)
Fill heating system using the filling loop beside the red expansion vessel in the photo. Pressurise to approx 1.2 bar, then go round and vent rads. Top up again when pressure drops. When finished, make sure pressure is on approx 1.2 bar.
Start heating, further venting maybe required.

 

[Fediuld]

It's not a combi boiler.
Leave to valves under the boiler on. (Inline with pipework, not at right angles.)
Fill heating system using the filling loop beside the red expansion vessel in the photo. Pressurise to approx 1.2 bar, then go round and vent rads. Top up again when pressure drops. When finished, make sure pressure is on approx 1.2 bar.
Start heating, further venting maybe required.

Thank you for the advice.

Could you tell me how to fill the heating system using the filling loop? Do I have to switch with a screw driver the second nob shown here?

Because switching the valve near the flexy pipe doesn't seem to work. (moved the red nob on the top few times and hear some water noise last night but not since).

EDIT Found it

It has a black switch on the other side.
I fill it up to 1.2.

However the gauge on the boiler displays 1.8 bar now, while not working.
(it said 1 to 2.5 operational).

Knowing that there are some empty rads that will go down.

 

[roguetrader]

Leave the red knob if at all possible.
You've filled the pressure now, so you need to create a demand (ensure programmer on and room stat turned up). Your boiler may need a manual reset, either on the boiler or a quick off and on.

 

[Fediuld]

Leave the red knob if at all possible.
You've filled the pressure now, so you need to create a demand (ensure programmer on and room stat turned up). Your boiler may need a manual reset, either on the boiler or a quick off and on.

Hi,
It didn't need a reboot, but just set up the thermostat.

Bleed all the rads, the 4 on the top bedrooms, had plenty of air in there and the pressure drop by almost 0.4 bar, I topped it back to 1.1 bar where the gauge on the red expansion and everything seems working fine.

Only issue when I tried to bleed one of the small rads on one of the en-suites the whole screw (where they bleed) got unscrewed not the centre bit only, and is dripping slowly.

Turned it off, I will cut off all the water to that one and going to see how to repair it.

Thank you very much

 

[roguetrader]

No problem. Glad you're up and running again.

 

[Fediuld]

No problem. Glad you're up and running again.

Sorry for bothering you. But quick question regarding the leaking rad.

It has a TRV on one side, which I turned OFF.

On the other side is the only radiator in the house with a Terrier Lockshield valve (the one with the screw on top) and isn't moving by griping the white plastic head (both directions).

However the screw can be tightened. Is this correct?

The rest of the house has standard universal valve caps (no screw).

Again thank you, you helped me a lot

 

[roguetrader]

Undo the screw, lift off the white cap, turn brass square clockwise with small adjustable spanner. This will stop the flow to the rad. Unscrew bleed plug, it may have a rubber o-ring. Couple of wraps of ptfe should sort it.

 

[Fediuld]

Undo the screw, lift off the white cap, turn brass square clockwise with small adjustable spanner. This will stop the flow to the rad. Unscrew bleed plug, it may have a rubber o-ring. Couple of wraps of ptfe should sort it.

Thank you