Always lots of air in our CH system

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Discuss Always lots of air in our CH system in the Central Heating Forum area at PlumbersForums.net

Alucard said:
Hi apologies
The expansion copper pipe is 15mm not 25mm...finger trouble :)
Click to expand...
The vent pipe is/should be 22mm and the cold feed is 15mm, are you sure its not the cold feed you are looking at.
Is the pump located upstairs in the hot press and the boiler downstairs, if so, and if you have zoned CH and HW then you will have at least two motorized valves fairly close to the pump, they may be located above the pump or below it, between the pump and these you might see something like the above arrangement (without the air jec).
Also go to the attic and have a look at your small cistern (Feed & expansion or F&E cistern for short) and see where the vent goes up and over it and also the cold feed which will come from the side or end of this cistern, you can then follow it and see where it is teed into the system.

Might look something like this: (This pump is pumping downwards)

1709661238401.jpeg
 
Last edited:
Apologies for the delay in replying.
F&E tank photo attached plus images of:
Grundfos pump set at lowest speed
2-way Motorised valve and controller also shows 15mm F&E feed.

Do you recomend the "glass" of water test on the 22mm vent pipe.

I presume that if the water is sucked into the vent that is where the air gets in.

Any other thoughts?
Thanks
 

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For clarification
15mm F&E pipe
22mm vent pipe
Gas boiler is downstairs, pump upstairs in the hot press.
Zoned CH and HW with a 2-way Motorised pump and controller.

Thanks again.
 
That Drayton 3 way mid position valve installation doesn't look right to me, can you check that the direction (up or down) the pump is pumping, there should be a arrow on the pump body, also there may be AB stamped on one the valve body ports and maybe a A & a B on the other two, B should go to the cylinder heating coil inlet (top) and A should go the the rads.

1710350944082.png
 
Hi good evening,

TheGrundfos pump arrow on the front is pointing anticlockwise so is pumping up.

I removed the Drayton 3 way mid position motor controller to check if marked A or B and it was not marked.
 
Alucard said:
Hi good evening,

TheGrundfos pump arrow on the front is pointing anticlockwise so is pumping up.

I removed the Drayton 3 way mid position motor controller to check if marked A or B and it was not marked.
Click to expand...
See image sent. The arm is shown in the down position = Central Heating. Whin the controller moves the arm a 1/4 turn up it is in the Domestic Hot Water position.
 
Still looks wrongly plumbed to me, it should, IMO be like shown below.

The pump outlet might be connected to the CH

Can you confirm or not that the cold feed is teed in to where I have the labeb, if it is then definitely plumbed incorrectly.

Others might comment??

EDit: I can't post a photo either so

Can you confirm that the pipe teed into what you caal the CH pipe is the cold feed, if it is then plumbing definitely incorrect.

Will try and post photo later.
 
I can confirm that the 15mm pipe on the Left side is the F&E cold. This is T-eed into the CH 22mm pipe from the left side of the 3-way Drayton midposition valve.

The boiler feed comes through the floor to the bottom of the 3-way Drayton midposition valve.

The DHW to the cylinder coil comes from the top of the 3-way Drayton midposition valve .

How would this configuration cause the excessive air in the Central Heating system?

Thanks
 
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