Daily bleeding

[moosehead]

We have a fully pumped system - Potterton Suprima. System was extende two years ago into an extension. pirping used in extension is Hep2o. Rest is copper.

Have a bisque radiator in the bathroom which seems to need bleeding every day as do two other but to lesser extent. The bathroom rad is the one nearest the pump. I have noticed a small amount of corrosion on the outside of the radiator close to where a pipe weld would be.

Question is why should we need to bleed so often. I have seen here before the possibility of air getting into the system, how would I trace this or could it be the rad is corroded allowing a little bit of air in which then accumulates over the day.

P.S. SHoudl rads and pump be beld with system operational or off?

Tks as usual.

 

[Softus]

We have a fully pumped system - Potterton Suprima. System was extende two years ago into an extension. pirping used in extension is Hep2o. Rest is copper.

Have a bisque radiator in the bathroom which seems to need bleeding every day as do two other but to lesser extent. The bathroom rad is the one nearest the pump. I have noticed a small amount of corrosion on the outside of the radiator close to where a pipe weld would be.

Was a chemical inhibitor added to the system at any time?

Question is why should we need to bleed so often. I have seen here before the possibility of air getting into the system, how would I trace this or could it be the rad is corroded allowing a little bit of air in which then accumulates over the day.

Air would not be drawn in through a hole in a rad unless the pump is creating negative pressure in the region of the hole.

P.S. SHoudl rads and pump be beld with system operational or off?

Hmm. Off, to be safe, but see previous answer. As a general rule I switch off the system when venting, but this is because generally I'm only venting when refilling and don't want the pump to be running dry for even a moment.

 

[ollski]

Turn the pump off, there is no point trying to bleed the system while you are whizzing the air around the pipes plus as already mentioned its possible that the system may be piped up to allow the pump to pull air in. Also worth finding out where your new rads have been teed into the existing system.

If you have a leak the system will be introducing fresh water constantly which will dilute your inhibitor, release oxygen and cause corrosion of the radiators and hydrogen to collect in the rads. Although I'm pretty sure it will be, make sure the plastic pipe is barriered otherwise air will permeate it into the system.

 

[moosehead]

Thanks for the replies.

Chemical inhibitor added recently after another drain down to re-route some pipes and cut out a dead leg. Thsi was done in the last three weeks.

Ollski - not sure what you mean by 'barriered'. If it is something technical and involved a degree of work I am pretty sure the plumber didn't do it.

I'll suspend the expansion tank and see if the level goes down, but I am not aware of any leaks in the system. How else woudl I be able to trace an air leak?

There is one other thing one of the bedroom rads - furtherst from pump, at best gets only luke warm and whilst the system isn't 100% balanced this surely is not right. I wonder if sludge could affect just one stretch of pipework on the flow?

Tks as usual