Open vent system problem

[andrewhottap]

Hi
I was fixing a radiator for a client. I refilled the system there is no flow on the return to the boiler (V old Potterton profile) I have flushed the system through.
the pump is working OK and both zone valves are working fine.
I'm not to happy that the pump is in a horizontal position but the system has been working.
could it be the heat exchanger is full of junk in the boiler?
Any ideas to help a stressed plumber.
Cheers
Andy

 

[Goldspoon]

You might have an airlock?

Have you tried turning the pump up to max to try and push any airlock out?

Have you bled the pump?

You could attach a hose to the drain plug of a lower floor rad and drain off for a good while - can send air out the hose...

Failing that send water into same drain point via a hose (mains pressure) and push water into F&E tank.

Pump could be knackered also?

 

[Nige F]

I had one like that - Years ago- I could take you to the poxy house now - burned into my brain,it was There was a hidden Air vent -manual one . on the floor of a built in cupboard , off a bedroom. Good Luck

 

[andrewhottap]

Thank you for all your comments. I have tried every way to remove an air lock. Didn't think of hidden air vent . First thing I'll do is look at the state of the pump which seemed to be working and venting OK.

Will let you know how it goes.
Cheers!

Andrew

 

[mickyg]

don't wanna teach you to suck eggs, but might be worth checking it has properly filled and c'feed hasn't blocked up, especially if the header is mucky.

 

[andrewhottap]

don't wanna teach you to suck eggs, but might be worth checking it has properly filled and c'feed hasn't blocked up, especially if the header is mucky.

Not at all at this point I'll take any suggestions. I took the header tank out and cleaned it and connected the cold main to the feed to flush it through.
drained the system twice!! Opened two drain cocks on the ground floor and then turn the mains on to flush through with full mains pressure!!! Water ran clean!!
Used wetvac on the vent when system full to see if that would shift an air lock!!
I am going to try to cut into the system as close to the boiler as I can on the return then flush through there. I have managed to get hot water to the flow side but not the return.
I bet I get there it'll heat up no probs and I'll be none the wiser.

Andrew

 

[g20]

It aint circulating, almost definatly an air lock, vent the boiler, cylinder and if its solid floors and drops then look for air vents on the pipework.