Replace silver flexi hose on expansion vessel

[Lee Robinson]

I noticed water coming out of a light socket on floor below where water tank and expansion vessels are.
Looking in the cupboard it was obvious to see the silver flexi hose that connects one of two expansion vessels was leaking and judging by the amount of water on the floor it had for a day or two.
I've isolated the water turning two wheels water inlets I assume. Turned on all the hot water taps and turned off the boiler.
I released most of the rest of the water turning the red PRV and the water went out through the tundish and then out of the house.

I simply want to replace the silver flexi hose to the white expansion vessel that connects to a PRV. This isn't a problem.
My concern is re-pressurising the system.
1) In what order do I re-open the valves.
2) Do I leave the hot taps on or off when doing this.
3) Which one of the two red wheels do I turn first.

Or does none of this matter
See two pictures of my system

I believe I'm right in saying the system pressure needs to be at 1bar when water system is cold.

Thanks for looking and hope you may be able to help.

Kind Regards

Lee

 

[FurstyFerret]

Shouldn't make any difference what order you do it in. I'd leave the hot taps closed and then crack one open afterward to let out the trapped air.

And one bar is the target pressure when cold.

 

[AL66]

The silver hose is the filling loop for the heating system - when not filling the system both the black lever valves should be off, the hose removed and caps screwed onto the connections. Frequently the hose is left in place which means it can potentially leak and also the valves at each end can let by very slightly which can result in the pressure in the heating system creeping up to that of the incoming mains supply (might be 5 bar or more).

I assume by red valves you mean the two similar looking gate valves? One labelled 'stop valve hot water' (incoming mains supply to the cylinder) and the other one at the base of the cylinder (being used as a lockshield for the heating flow through the the cylinder coil).

The first should be fully open (close back quarter turn from full open to stop it jamming open) and the second returned to whatever setting it was at before you turned it.

Closing the red gate valves and running off all your hot water was unnecessary! Would be wise to call in a G3 qualified plumber to check the system (which should be done annually anyway) as you have been fiddling with the safety devices without knowing what you're doing.

 

[Madrab]

Would be wise to call in a G3 qualified plumber to check the system (which should be done annually anyway) as you have been fiddling with the safety devices without knowing what you're doing.

+1

Any work required on an un-vented system and associated controls should be performed by a qualified engineer, just allows for the systems to be tested and checked for your safety and thereafter serviced once a year as AL suggest, just like a gas boiler.

 

[mfarrow]

The silver hose is the filling loop for the heating system

He's already taken the other silver hose to the white (hot water) vessel off.

OP, just don't, whatever you do, buy a hose with an integral valve. The connection between the vessel and the PRV on the right must never be severed in normal use.

 

[Lee Robinson]

I've decided to leave it all alone. The silver flexi hose isn't something I could buy off the shelf. Would need to wait until Monday when plumb centre shops open.
My system is serviced once a year and they just did it Wednesday last week. So I'm calling them back to buy the flexi hose and re-pressure everything back up. Seems wise to play safe.

thought I'd ask anyway - so thanks for all your advice.

I'm also informed once a PRV is used they generally become useless, so no doubt they will have to be replaced.

Regards

Lee

 

[dilalio]

What could happen...

 

[AL66]

The silver hose is the filling loop for the heating system

He's already taken the other silver hose to the white (hot water) vessel off.

OP, just don't, whatever you do, buy a hose with an integral valve. The connection between the vessel and the PRV on the right must never be severed in normal use.

OK - thought he was talking about the filling loop, wouldn't it be better to replace the hose to the white expansion vessel with rigid pipework?

 

[dilalio]

Why?