Gravity Fed Air In System

[plumber.]

Hi All,

I've just added four new radiators to a property.
System: conventional heating system
Conventional Potterton Suprima boiler

I've bleed the air from the radiators correctly, starting at the bottom then upstairs.

All the radiators seem to be getting hot, but the boiler seems switch on and off every 3mins or so.

What could be wrong?

 

[ambrosia]

sounds like air in the system
the best way to clear it is with a wet vac, 2nd best is use the pump, but you dont have one on a gravity system which unfortunately leaves back filling

Back filling is when you connect a hose pipe from the mains to the last rad and fill till it starts coming out of f and e tank

 

[Bunker]

Look for air vents in the airing cupboard or by the boiler.

 

[hammers4spanner]

wet vac all day long ,

why do you think its gravity??

 

[Bunker]

I think you guys are off track, I don think he means gravity CH, thats just a mistype on the title, Im presuming its grav HW..probably me being wrong

 

[plumber.]

Look for air vents in the airing cupboard or by the boiler.

I can only see a bleed key vent, but no air vent. I opened the bleed key, no air or water came out.

 

[plumber.]

sounds like air in the system
the best way to clear it is with a wet vac, 2nd best is use the pump, but you dont have one on a gravity system which unfortunately leaves back filling

Back filling is when you connect a hose pipe from the mains to the last rad and fill till it starts coming out of f and e tank

Where should I connect the wet vac to? Also would I need to bleed the pump in the airing cupboard?

 

[kay-jay]

i took it to mean gravity hw/open vent heating too. if so did you open zone valves on drain/refill?

 

[diamondgas]

It wont be gravity chaps ... boilers for fully pumped only! I assumed the op mean't 'open system' when mentioning "gravity"? Regards the issue I'd think it would need a visit from someone GSR. Fault could lie within the appliance..?

 

[kay-jay]

It wont be gravity chaps ... boilers for fully pumped only! I assumed the op mean't 'open system' when mentioning "gravity"? Regards the issue I'd think it would need a visit from someone GSR. Fault could lie within the appliance..?

More likely to be overheating due to a circulation problem given that hes drained and refilled an open vent system imo.

Unless of course boiler was knackered before and his customers are trying to tuck him up.

 

[diamondgas]

More likely to be overheating due to a circulation problem given that hes drained and refilled an open vent system imo.

Unless of course boiler was knackered before and his customers are trying to tuck him up.

I agree kay-jay ... could well be and seems most likely considering the previous drain and fill. I wouldn't rule out issues with the boiler though, it is a Suprima

 

[plumber.]

i took it to mean gravity hw/open vent heating too. if so did you open zone valves on drain/refill?

It's open vented with a pump in the airing cupboard. I didn't open the zone valve on draining down or filling. I'm guessing that's the problem?

It doesn't have an automatic air vent anywhere in the airing cupboard either, which isn't helping.

 

[kay-jay]

It's open vented with a pump in the airing cupboard. I didn't open the zone valve on draining down or filling. I'm guessing that's the problem?

It doesn't have an automatic air vent anywhere in the airing cupboard either, which isn't helping.

Try cracking the nut on the top tapping for the coil on the cylinder to bleed out any air

 

[plumber.]

Thanks for the help and tips so far everyone.

Should it not have a bleed key, but a auto air vent instead?

I read somewhere it's better back filling the system from the bottom, instead of the top. Would it be better to fill the system with mains high water from the drain off point, or low pressure?

 

[kay-jay]

backfill from low point drain off with hose connected to outside tap or washmac valve. if it is a regular customer, while drained stick manual air vent on the coil and any high points in system eg do heating pipes go up and over into loft....

 

[galaxy_plumbing]

could get blockage when refilling, probably lots of stuff in F&e so there is not enough water in system