Boiler Airlocked Problem

[LuckyD]

Hey guys, I'm a new member here with a problem. I have a sealed central heating system (oil). I drained my system down at the boiler to put some leak sealer in as the system was losing a small amount of pressure. I drained about 4 gallon out the stop cock at the boiler, closed it up and removed the auto air vent, put my sealer in replaced the vent and refilled my system. When I turned the boiler back on it ran for a couple of minutes and then stopped! I slackened the vent and bled the pump. I turned the pump to its lowest setting and the boiler thermo and kept turning the heating on and off. It fired a couple of times but switched off again after a couple of minutes. I bled all the house rads and strangely the upstairs rads are heating when the boiler is on and the hot water tap is flowing warm. Downstairs the radiators are stone cold and the water is cold from the hot tap. I'm out of ideas and tomorrow is sunday! (AND COLD!)

Any help is greatly appreciated

 

[Terrywookfit]

Which boiler do you have.

 

[LuckyD]

The brand is warmflow, unsure of a model no.

 

[MeldrewsMate]

Have you turned the pump to maximum speed?
Is the auto-vent open....and ejecting air?
Try running with only the hot water generation turned-on (assuming you have a conventional hot water cylinder arrangement). Wait until circulation becomes air free before opening the heating valve. Once circulation is re-established bleed the air from the upper floor radiators, remembering to re-pressurise as you go.

 

[LuckyD]

The pump I turned to lowest, I will try highest tomorrow. The auto vent I'm not sure if its working as I haven't saw it working but its newish n the cap is lose. So just try water only first

 

[LuckyD]

Just keep trying to turn hot water on and off? Till it works? And all taps warm?

 

[oilhead]

Do you have a vent on the heating return? If so, bleed there. If not, find a compression joint above the boiler and crack it . It seems you have an airlock in the return. If all fails, you could try to backfill through the drain cock you used, with a remote hose. The pressure relief valve will cope with any excess you may produce.
Also, keep venting the pump.

 

[AGAS]

The pressure relief valve will cope with any excess you may produce.

shouldn't need that much pressure to pop the prv just to get rid off air but if it does i expect he will be back on here for further help

 

[LuckyD]

Venting the pump as in bleeding it??

I’m not sure of return pipe etc. At the boiler I just have the auto air vent

 

[oilhead]

yes , venting it through the central screw. Another path to try would be to unplug the burner, and run the ststem for a few hours. This will keep the pump running and may help relieve the air lock, without the boiler overheating.

 

[Terrywookfit]

yes , venting it through the central screw. Another path to try would be to unplug the burner, and run the ststem for a few hours. This will keep the pump running and may help relieve the air lock, without the boiler overheating.

It will also fook the pump if running dry.

 

[oilboffin]

Make sure the boiler is full of water the diverter valve needs to held dead in the middle to allow water into the boiler.Bob

 

[LuckyD]

I went back to it yesterday turned pump to high and ran the boiler just in the hot water setting till it cut out. My mum (her house) had the Emersion Heater on in the am so couldn’t tell if it had heated the water tho. Turned the central heating on too and turned the boiler thermostat up, it started to heat the rads and I bled a lot of air out of the rads n the pump. The boiler cut out but started again by itself as per normal. All rads heated and working normally again! Air must somehow have moved over night to make it easier to remove. Thanks for all the help guys