Air in radiators/tank overflowing - problem solved

[sharpo]

Had the pump replaced a few weeks ago, now the system keeps getting air bubbling round and into the radiators and the header tank overflows. The ballcock valve does work.

Seems the pump is more powerful than the old one and at times I can feel air drawn in through the pipe above the header tank. The pump is on the slowest/least powerful setting.

The radiators all seem to work, except of course when air gets in & lowers the water level.

Any ideas on this?

 

[Razor900]

Which way is the arrow on the body of the pump pointing; towards the vent or the valve(s)?

Are both the pump isolation valves on

 

[sharpo]

Which way is the arrow on the body of the pump pointing; towards the vent or the valve(s)?

Are both the pump isolation valves on

Can't see any arrow on the body of the pump????? Not an expert on this but I think the vent is connected via a T connector below the bottom valve.

Isolation valves are open (water flowing) if that is what you mean.

Thanks for reply, hope mine makes some sense to you.

 

[doitall]

Maybe a pic of the pump and surrounding pipework.

 

[sharpo]

Maybe a pic of the pump and surrounding pipework.

Here's a pic. The diagonal pump at the front is just cold water pipe to wash basin, so ignore that. Valve to left of pump is to rads & upper one is to hot water tank. The header tank for hot water is in this airing cupboard, the one for heating system is higher up in the loft. Hope the pic helps.

 

[doitall]

Unclear from the pic, if you get a mirror and look down the back of the pump you should see the arrow.

I know which way it looks like it should be, so see if you agree.

 

[sharpo]

if you get a mirror and look down the back of the pump you should see the arrow.

Found it, on the black part at the back - it points up, which seems correct to me.

 

[doitall]

if you get a mirror and look down the back of the pump you should see the arrow.

Found it, on the black part at the back - it points up, which seems correct to me.

Hey we'll decide what is correct or not


You are right though

 

[doitall]

Can you ID the cold feed and vent in the pic, or another, and where does it join the flow pipe.

When he drained down did he clean the header tank first.

Can you drain a 10 or so ltrs of water from the draincock and see if the header tank is refilling.

There's a tee directly above the pump, can you tell where it goes or is it just a vent.

 

[sharpo]

Thanks guys, got sidetracked, sorry about time taken to reply.

Excuse the drawing, I'm no artist! Missed off one of those automatic vents connected via a T connector a foot above the top Honeywell control valve.

I've marked in RED the pipes which are hot & from the boiler, the black are the return/overflow/feed pipes.

As I was trying to draw the plan, it sounded like air hissing by the pump, which stops when I press my hand against the side. I've tried covering it with a damp piece of plastic bag to see if it is drawn to the pump - it sticks but maybe because it is wet and not attached by suction. Can a pump draw air in?

 

[doitall]

Can you show the cold feed and the black pipes a bit clearer, hust single lines is fine.

Looking at the drawing so far the cold feed is in the wrong place, so Yes, it will suck in air, an easy test is to hold a glass of water under the vent and turn the pump on.

 

[sharpo]

Less complicated drawing this time

Hot water tank showing the outlet pipe to boiler, the auto vent is a foot or so above the hot water tank. The cold supply from header meets it at floor level.

I can't get the red pipes on same drawing without confusing myself, but hope it is clear to you.

When the pump was changed by BG the supply was just shut off either side of the pump, nothing else drained.

 

[davebgas]

Probably never know the answer but I wonder if the old pump was set on a slower speed as by looking the whole head and body has been replaced here. Just changing the pump by shutting valves wouldn't entrain much air.

Sorry to jump in so late on the thread btw

 

[doitall]

Ok much better drawing can you add the vent, pump and valves to it now.

The arrow on the back of the pump is facing up, Yes.

 

[ollski]

what boiler have you got as the lack of a bypass may not be helping matters.