Combining feed and vent to prevent pumpover advice please!

[Rusty89]

The arrangement in post #11 might be your best bet/.

Regarding my pic in post 10 -

Could I put a 22mm Equal tee in on the horizontal line, just above where i've marked it, then run 22mm pipe back to header tank. Then cut the 15mm pipe downstairs in the airing cupboard and put a stop end on it?

I'm confusing myself

 

[Rusty89]

Here's the loft view. I don't get why it's pumping over at all (lid off header as im replacing float valve)

 

[Johntheo5]

What is the diameter of the feed pipe??.

 

[Rusty89]

Regarding my pic in post 10 -

Could I put a 22mm Equal tee in on the horizontal line, just above where i've marked it, then run 22mm pipe back to header tank. Then cut the 15mm pipe downstairs in the airing cupboard and put a stop end on it?

I'm confusing myself

What is the diameter of the feed pipe??.

15mm cold feed sir

 

[Rusty89]

Close up

 

[Johntheo5]

OK, thanks, your suggestion may work but in view of the fact that you are getting severe pump over I would definitely look at doing it like post #11.

We know that the 22MM vent is clear because of the pump over, so you could remove and cap the 15mm cold feed with a compression stop just in case you have to reverse the change or fit a manual air vent (thumb screw type like the one at your HW cylinder) then connect the vent into where the cold feed was taken off, no need have to drill a hole in the tank bottom, I would be very surprised if this didn't work, only requires a partial drain down.

 

[Rusty89]

OK, thanks, your suggestion may work but in view of the fact that you are getting severe pump over I would definitely look at doing it like post #11.

We know that the 22MM vent is clear because of the pump over, so you could remove and cap the 15mm cold feed with a compression stop just in case you have to reverse the change or fit a manual air vent (thumb screw type like the one at your HW cylinder) then connect the vent into where the cold feed was taken off, no need have to drill a hole in the tank bottom, I would be very surprised if this didn't work, only requires a partial drain down.

@Johntheo5 I like what you're saying but I'm a bit stupid . Now this is my to-do list -

1) Remove 15mm cold feed pipe from my F+E Tank, cut the other end 15mm pipe in my airing cupboard near where it joins the main circuit. Put a compression stop on it.
2) Make hole bigger in F+E tank and use compression tank connector for 22mm.
3) Cut down the 22mm vent pipe that runs along the loft ceiling.
4) Re-use that 22mm vent pipe - attach one end to the new tank connector
5) Connect the other end to where I cut the 22mm pipe (where I marked in my image in post 10, but a bit higher so it is horizontal from F+E tank).

If I've got this totally wrong, would ye mind correcting me please? my kids are out of house tomorrow so good time to get it done.

Massive thanks indeed

 

[cross thread]

Cut 15 mm old cold feed and fit a manual vent,
then as you stated alter the 22 mm vent so it’s connect in 22 mm to the header tank in place of the 25 mm connector
pipe in cupboard is ok as is.

 

[Johntheo5]

As above, but in 1 above, cut the 15mm pipe ~ a foot above where it joins the main circuit in the airing cupboard and fit a manual vent.

I would also strongly advise installing a 15mm gate valve on the mains supply to the F&E tank as the system (especially after a full drain down) has to be filled very slowly, this is easy to do with the isolating valve rather than messing around with a bit of string to fill the system slowly via the ballcock.

 

[Rusty89]

As above, but in 1 above, cut the 15mm pipe ~ a foot above where it joins the main circuit in the airing cupboard and fit a manual vent.

I would also strongly advise installing a 15mm gate valve on the mains supply to the F&E tank as the system (especially after a full drain down) has to be filled very slowly, this is easy to do with the isolating valve rather than messing around with a bit of string to fill the system slowly via the ballcock.

What does the manual vent do, and when would I open it? Is it the same thing as I already have in my airing cupboard on the stalk?

I will also buy a 15mm gate valve. Just going to Toolstation now. Thank you so much.

 

[denso13]

I will also buy a 15mm gate valve

Don't get a gate valve for mains water to the cistern, get a stopcock or full bore ball valve.

 

[Johntheo5]

What does the manual vent do, and when would I open it? Is it the same thing as I already have in my airing cupboard on the stalk?

I will also buy a 15mm gate valve. Just going to Toolstation now. Thank you so much.

You open it and keep a eye on it when you commence to fill your system very slowly, try opening the one in your airing cupboard to see.

 

[Johntheo5]

Don't get a gate valve for mains water to the cistern, get a stopcock or full bore ball valve.

I've never had a problem with gate valves, some are 40 years old some < 2 years old, no problem with tight shut off or gland leakage, a ball valve will obviously do the job as well but no need for a full bore as you will/should be filling the F&E tank slowly and once full will "never again" need filling until the next drain down.