CH (old open system) re-fill, after removing rad?

24 Dec 2011
Reaction score
United Kingdom

Had to change a leaky radiator valve (went ok) but when connecting back up I got a banging noise from the boiler- out of water or air lock I'm guessing.

The system is an old open type with tank in the loft. Boiler is a late 90's gas Baxi Solo 2PF.

How should I get it running again? Really don't want to call someone out this time of year.

Cheers for any advice & happy Christmas!
Sponsored Links
Thanks- seems to be working ok (lets water in when you push down).

I tend to think it needs bleeding somewhere- maybe the pump?
Bleed radiators, bleed pump , bleed air vent in air ing cupboard.

Then turn on heating controls and turn pump from speed 1 to 3 and then back down and up again, to push air around system

Sponsored Links
You may have a restriction/blockage in the cold feed pipe where it joins the primary circuit. Sometimes if you give it time the level will correct itself by slowly passing the restriction. If not try backfilling the system with a hose mains pressure to fill to the correct level.

refill procedure :

turn water supply back on and allow header tank to refill

bleed all the radiators - you will hear the air being pushed out and the header tank ball valve will open again to top up the tank as water exits into the system. Do this on each radiator until water comes out of the bleed valve.

bleed pump

bleed boiler (if you can - some systems have a drain valve below the boiler and its advisable to open this and let some water flow out.

Turn on CH and HW and over ride temperature controls by turning thermostats up to an un-achievable temp.

Turn pump onto maximum for a few minutes until heat is felt throughout the radiators and HW cylinder flow and return pipes.

Turn off HW and CH

Bleed radiators again, and also pump.

Continue this procedure until no air is coming out of the radiators.

Job done (unless its air locked or blocked up)
Cheers for the advice...

Did the above and the CH & HW have been running at full heat for a good 15mins now with no ill effects, fingers crossed! Before the boiler would clonk after a minute or two, overheat light would come on and then shut down.

Think I'll let it heat the water before I touch anything again :LOL:
Surrey, United Kingdom? You eventually managed to escape The Village, then.

Be seeing you.

Orange alert, orange alert...

Boiler seems to switch itself on and off every few minutes- no idea if its always done this as I've never taken any notice of the system until now! Only lived here just over a year as well (since escaping the village!).

Hot water/heating are fine.

(we want information...!)
its supposed will turn on and heat the water in the system upto whatever the boiler stat is set to (probably 80 degrees ish) and then the burner will go out. Once the water drops in temp it will turn back on and heat it up again.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links