where to place automatic bottle air vent?

Andy From Sligo

Boiler : Grant Euroflame Condenser Boiler - open vented system .

Just moved into house and experiencing quite a bit of air in central heating system - keep bleeding radiators, and manual air vent in the hot press and manual air bleed screw in return pipe of outside boiler, still got air though in system.

The return pipe inside my boiler has a bleed screw but its a manual one (uses radiatior key to bleed) I was thinking of placing a Bottle type AAV in the return pipe and leaving the vent cap open what do you reckon?

I know the general consensus is that in an open vented system there should be no need at all for any AAV's at all in the system (if the system is working correctly) but now its the only way I can think of getting rid of the air in the system once and for all.

I have been up in the loft and the CH expansion pipe that goes into the CH Tank is free of blockage and not immersed in the water.

I did rent a house once where it had an ouitside boiler and that was open vented but even that had an AAV on a 15mm pipe inside the outside boiler.

the AAV in the diagram for the boiler:





The Manual vent in Hot Press:

Would it be useful to change the manual air vent with a bottle AAV there also as well as one in the boiler? - You see in the picture that the manual air vent is after the expansion pipe to loft tank, is that correct, just wondering, or should a manual vent/aav be placed before the expansion vent pipe ?




The outside boiler has a hexagonal nut on the boiler part. it says "Central Waterway - do not remove plug" - could I tap a 15mm thread into this and then put a 15mm vertical pipe with an AAV at the top would this do anything to alleviate the air in the boiler/system?

Sorry for all the questions. and thanks.

Dtp1979

Andy From Sligo wrote: »

Boiler : Grant Euroflame Condenser Boiler - open vented system .

Just moved into house and experiencing quite a bit of air in central heating system - keep bleeding radiators, and manual air vent in the hot press and manual air bleed screw in return pipe of outside boiler, still got air though in system.

The return pipe inside my boiler has a bleed screw but its a manual one (uses radiatior key to bleed) I was thinking of placing a Bottle type AAV in the return pipe and leaving the vent cap open what do you reckon?

I know the general consensus is that in an open vented system there should be no need at all for any AAV's at all in the system (if the system is working correctly) but now its the only way I can think of getting rid of the air in the system once and for all.

I have been up in the loft and the CH expansion pipe that goes into the CH Tank is free of blockage and not immersed in the water.

I did rent a house once where it had an ouitside boiler and that was open vented but even that had an AAV on a 15mm pipe inside the outside boiler.

the AAV in the diagram for the boiler:





The Manual vent in Hot Press:

Would it be useful to change the manual air vent with a bottle AAV there also as well as one in the boiler? - You see in the picture that the manual air vent is after the expansion pipe to loft tank, is that correct, just wondering, or should a manual vent/aav be placed before the expansion vent pipe ?




The outside boiler has a hexagonal nut on the boiler part. it says "Central Waterway - do not remove plug" - could I tap a 15mm thread into this and then put a 15mm vertical pipe with an AAV at the top would this do anything to alleviate the air in the boiler/system?

Sorry for all the questions. and thanks.

Generally not on the return as they can also suck Air into the system if left open, depending on pump location. If you're continuing to get air then it could be a leak somewhere or piped incorrectly and drawing in air

Andy From Sligo

UPDATE: the central heating circulating Pump (grundfos) at the back of the boiler was on number 3 speed and I have turned this down to number 1 and it has really helped to quieten the noise of the air rushing in the rads and pipes. I hope by putting the pump to number 1 speed though this will not cause damage to the boiler or cause it to overheat. I will keep an eye on it.

On a connected note, the circulating pump is on the return side. Just wondering why these are designed in this way. What I mean is that the central heating expansion tank is in the loft , and wouldnt the gravity be enough on the return without use of a pump on the return? - I know in the old days they used to put CH pumps on the flow side for the rads - mind you, I havent checked but most probably this system/tank piping is more than likely combined feed and vent maybe thats why they put the pump on the return side

Tom44

Great idea :eek:



Quote.
The outside boiler has a hexagonal nut on the boiler part. it says "Central Waterway - do not remove plug" - could I tap a 15mm thread into this and then put a 15mm vertical pipe with an AAV at the top would this do anything to alleviate the air in the boiler/system?



Eh ?
Read the lable.

K.Flyer

If you are renting this house you should not be tampering and making alterations to a central heating system that does not belong to you, especially as you don't know what you should or should not be doing to it
Ask your landlord to send out his plumber if you feel there are issues with the system.

Andy From Sligo

K.Flyer wrote: »

If you are renting this house you should not be tampering and making alterations to a central heating system that does not belong to you, especially as you don't know what you should or should not be doing to it
Ask your landlord to send out his plumber if you feel there are issues with the system.

OK will do, was just trying to get some ideas