Central heating air problem

[Sparks125]

Hi,

Help needed please. I have an S plan system with a motorised valve on both heating and hot water circuits. When the system first fires up both valves open and rads / hot water get hot. All good you think.
Issue being that there is large volumes of air circulating around the hot water tank heating circuit causing loads of noise. I can hear it rushing thru the pump and pipes. The odd thing is that the rad circuit does not seem to be suffering with air ?. Once the hot water tank reaches temperature, that valve closes and all goes quite ?. When I run a bath the other day the air noises in the tank heating circuit went bonkers ?.
Can you have trapped air just in the tank heating circuit ?. If so how do I get it out. No bleed valves evident. By the way, both the 15mm cold feed and 22mm vent pipe to the feeder tank get very hot when this happens /.

Cheers
Graham.

 

[kbdiy]

Yes you may just have air trapped in the hot water circuit. There will be a) an auto vent, b) a manual vent or c) the pipework will have been installed such that it can vent naturally.

If a) then the vent might be stuck and therefore not operating correctly. Otherwise you will need to investigate the pipework configuration.

 

[Sparks125]

Many thanks for your quick reply.
I will have another good look tonight.
Where the feed pipe from the boiler comes into the airing cupboard there is a 22mm pipe linked in which goes up and over the top up tank in the loft. I assume this should act as the vent for both rads and hot water heating circuits ?. I suppose that could be blocked ?.

Graham.

 

[kbdiy]

All I can say to that is the vent from the boiler to the header tank must not have any restriction as it is necessary for expansion when the boiler is firing.

If it is the vent for those circuits as well then they should vent naturally without any intervention, but impossible to be sure without sight of your pipework.