Air in system every day

[Deleted member 15266]

Central heating system (conventional tanks in loft) is filling up with air daily. This is causing a tank in the loft to overflow. Strangely we have plenty of hot water and once I bleed radiators they are hot and the water stops running from overflow. This seems to coincide with new kitchen with radiators being fitted. I realise I need to get someone out but don’t want them just to bleed radiators like the last guy then disappear. Thoughts on what this could be would be appreciated.

 

[HERTS P&D]

You have a blockage in your system and it is pulling in air.

You need someone to check your pipe work in you air-in cupboard. you could try with a magnet and see where it sticks to the pipe work.

Andy

 

[Deleted member 15266]

Thanks Andy. So, for fear of being fleeced, do you think they will suggest putting chemicals in the system or powerflush? I think one is much more expensive. Don’t want to get fleeced.

 

[CBW]

If it’s a stubborn blockage, no amount of chemical will get rid if it. This would need a re-pipe.

 

[Deleted member 15266]

oh I see. That’s good to know thanks. I’ll get the magnet out!

 

[Harry Bloomfield]

oh I see. That’s good to know thanks. I’ll get the magnet out!

Failing it being a blockage, when the new rads were installed, might the pump speed have been adjusted higher? Over pumping, would introduce air to the system. Check the vent pipe, which loops up and then back down into your loft tank - ending open and above the water level. There should not be any water coming out of it at all.

 

[Deleted member 15266]

I checked with magnet in cupboard. The only one it sticks to is the slim one on the end which is hot. God knows how they’d get at it to cut it.

 

[CBW]

God knows how they’d get at it to cut it.

Looks doable imo.

 

[45yearsagasman]

Post a picture of the pump and motorised valves and the surrounding pipework. That will determine the type of system you have.

 

[ScottishGasMan]

Also what make/Model of boiler do you have. It's not a certainty yet that you have air in the system, vs the possibility of Hydrogen building up in the rads from corrosion, which would have the exact same effect.

 

[DP]

So, based on above replies, whoever comes to look at the job needs to be proactive, locate the cause and fix it.

To reiterate. When boiler is run to heat water in the cylinder, or just heat radiators of bother heating and hot water selected, there should be no dribbles from the vent pipe.

Another test. With heating or hot water off, fill a glass tumbler with water. Offer it to the vent pipe and get someone to run heating. If the pipe drinks water from the tumbler then consider repositioning the pump