Low Pressure Indicator on Airston Combi Boiler - advice please.

merton69 · 8 Jan 2024

Hello All.

I have just changed by 3 way diverter valve and all is well for the hot water.

But when switched to the heating, the boiler tries to start up but after 15 seconds or so, the red LED Low Pressure appears.

The pressure is at a good pressure.

Please can anyone advise how to get around this and for the heating to work?

I have attached some images to help.

Thank you.

ianmcd · 8 Jan 2024

Try bleeding the pump, large screw on the front just crack it open till water comes out you have air in the boiler

merton69 · 10 Jan 2024

Thank you for the suggestion ianmcd.

I have already done this as well as checking the impeller was working.

I have also bled all the radiators.

merton69 · 10 Jan 2024

LATEST!

I replaced the new 3 way valve with the old one just to see if the new part was faulty or could tell us something else.

The old part, obviously still leaking, worked both the hot water and the heating.

I turned it off and left it to have a meal.

Some time later, I tried the heating again, as the house was so cold. It didn't trigger the heating. Just some whirring sound then silence, then the red LED came on as in the above image, just how the new part performed.

Any suggestions on what to do or try please?

I did forget to mention, the boiler was serviced fully okay, a few weeks back.

How is it saying low pressure when the pressure is correct on the dial please?

At present it is nigh on impossible to find an engineer available in our area!

I feel it is something simple, especially as the old part was working for a period of time, when re-installed.

merton69 · 11 Jan 2024

Tried it again and only the hot water works. Still the low pressure LED comes on.

Any suggestions please?

merton69 · 12 Jan 2024

Hello.

Just tried the heating side again, after putting in the new part again as the leak was getting worse and I am away for a day or so.

The heating started! Well, the boiler kicked in with the burners activated and then all of a sudden a huge clunking came form within the system, that sounded like air, the pressure dial went up and down quickly a few times then settled then the boiler went out and nothing until the red low pressure LED came on.

I am sure there is air is somewhere where it shouldn't be.

Can anyone suggest what to do to get rid of any air and the pressure built up by water only please?

We are due for some really cold weather next week and would very much like to get it sorted for then.

Hope you can help please.

merton69 · 20 Jan 2024

Hello.

I still have no heating side of the boiler.

The update is the pressure light no longer comes on when striking up the heating side.

I have a YT clip to show and sound the problem.

I believe there is air in the system but I am no expert.

Any advice to sort the problem would be gratefully recieved.

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Low Pressure Indicator on Airston Combi Boiler - advice please.

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