Dumb Question - Primatic Cylinder

[dontknowitall]

Please excuse the ignorance.

I don't know how to isolate the hot water (for a tap change) from a primatic cylinder - I know how to drain one down but not how to turn off the hot water.

I'm assuming I will be facing a primatic cylinder. Cylinder with a tank above it (all combined into one unit) with an F&E cistern above it. Two pipes at the front for heating.

There's no visible isolation valve before the cylinder but there is one after the Tee to the F&E.

So, how do I turn off the hot water? As always, any hints gratefully received!! (Although perhaps not a "Get a plumber in"!!)

 

[Guest123]

Are you sure it's a Primatic cylinder? Primatic cylinders are a pig to work with. If you drain down you risk losing the internal bubble when refilling. I'd leave well alone. If no valve is present, why not just freeze it and fit a full bore iso valve?

 

[aqualogic7]

are you talking about a fortic combined cistern/cylinder in which case there is normally a gate valve on hot water outlet if no valve then have to drain down cistern

 

[dontknowitall]

Thank you to you both. I mean't to mention fortic as it could be one of these!

Just googled fortic and it's one of those!

So it looks like a drain down (which I've done before when replacing an immersion heater).

Thank you, again!!

 

[kirkgas]

you dont need to drain a combined primatic and risk losing the bubble to change a washer, turn off the cold supply and open the hot tap till the water stops flowing, which will leave the hot part of the cylinder fulll of water and will maintain the bubble, when refilling keep the tap open and fill slowly this will minimise airlock on hot water draw off

 

[Guest123]

It's not a Primatic he's working on mate.