Air sucked in from vent pipe

[nsudace]

Hi All

I am looking for some advice regarding my open vented CH (rough schematic knocked up in MS Paint attached)

For some time I have had issues with needing to regularly bleed radiators as well as gurgling of air around pipes and rads.

I have notice a couple of issues with the header tank; a) water rushes out of it when the pump stops, and b) air is pulled in when it starts (I have confirmed this by holding a jar of water under the vent which all got sucked up).

Yesterday I removed a load of sludge from the point marked 1 on my diagram, but this does not seem to have solved the problem.

The only other possible oddity I can see with my system is that the vent and cold feed pipes both have a horizontal run of about 2 metres in the loft space, as the header tank is not directly above the airing cupboard.

Is this likely to be the cause of my problem and are there any easy fixes other than moving the header tank? Would increasing the vertical height of the 2m horizontal run help (currently the horizontal run is about parallel with the height of the water in the tank)?

 

[lightning]

Depending on heating system and boiler why don't you seal it

 

[75pete]

Have a look at FAQs 8. Good starting point for your problem.
Also, have a look at FAQs Heating/Boilers 12. If you then think it's could be blocked.
I've used this simple flush with success.
Pete

 

[nsudace]

Depending on heating system and boiler why don't you seal it

Certainly an option I will keep in mind. Boiler is a Suprima 70. I was hoping I might be able to employ a quick and cheap fix whilst I work out what I want to do long term.

Have a look at FAQs 8. Good starting point for your problem.
Also, have a look at FAQs Heating/Boilers 12. If you then think it's could be blocked.
I've used this simple flush with success.
Pete

Thanks for this. I had the pipework apart where the cold feed meets the flow into the pump and removed a load of sludge, but the problem still remains.

Next was going to be to increase the height of the U-bend on the vent pipe as per suggestions in the FAQ, but interested to know whether the long horizontal run on the vent pipe is a bigger issue I should address first.