Fortic Primatic Tank Internal Bell Exchanger Airlock style?

[DIWHY]

Thanks for being interested, I've got one in the loft.
I'm sure its an indirect fortic primatic works kindof similar to a diving bell

I used to have a diagram explaining how this worked (ex mech engineer must have diagrams) which gave me the bottle to work on it, now I've lost it.

I've done a few hot water tap change jobs but know this doesn't require a full drain.
I now need to remove rads and am sure this does.

Although I did a full tank drain 16 years ago when a carpet fitter nailed a 22mm feed pipe I now keep reading how this is fraught with refill difficulty and difficulty 16 years later is an unwelcome guest.

I honestly don't remember it being too hard but them I didn't drain the rads, only the tank.

Is there an easier way to remove rads without a drain down, I read about bunging the feed pipe at the bottom of feed tank with blue tack and this stops the water draining.

Any help Any diagrams AnyOne

 

[kevplumb]

you cant bung a primatic
see if i can find a pic

this might help

 

[DIWHY]

Cheers Kev, so gotta drain it all then as the rads are ground floor, any advice on refilling ?

Diagram looks similar to last one I had but probably more mod design.

Mine is open topped cold tank (feed) and I think the vent drops into there as well.
Don't recognise the vent? on ranges diagram above the bell heat exchanger could be a new idea.

 

[kevplumb]

all works the same marra
filling just let it and vent as normal

 

[chrishutt]

Before you refill, fit isolating valves to central heating flow and return pipes from boiler. Then in future you will only need to shut these to carry out any work on CH side. You have checked that you don't already have such valves, haven't you?

 

[ollski]

Refill it nice and slowly and it won't blow the air bubble out....about 3 hours to drain it and refill it.

 

[CopperCylinderMan]

Just to confirm what Ollski said - keyt to refilling primatic systems is to fill them slowly.