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tbh these days seal the system unless its ropy like the one im doing
and some boilers have flow switches in dont fire unless theres flow
and some boilers have flow switches in dont fire unless theres flow
Discuss Feed and Vent fun :DDDDD in the Plumbing Jobs | The Job-board area at PlumbersForums.net
Why not seal without pressurising. Use the header as top up, with gate and non return fitted. Sealed system controls as required with heat only or system boiler ( Worcester Cdi used to not need minimum pressure to operate, but check with them).
Non return is to stop the water backing up into the header. Therefore system controls required, i.e PRV and expansion vessel required either external or internal to boiler (system). Doesn’t need filling loop as header acts as top up vessel. Works a treat without stressing existing pipe work.
Have got two systems like this operational now in their sixth year and no problems.yea but would it open under gravity and not stick
Have got two systems like this operational now in their sixth year and no problems.
Top of system for header. Followed by gate or lever in downfeed, so you can turn system of and for easy replacement of check valve. I positioned them in airing cupboard. Check valve can be anywhere between isolation valve and where it tees into the system.
Not sure how to read that?Trying to work out how much head you have
Does the gate valve stay open in normal operation?Use the header as top up, with gate and non return fitted.
I converted mine about 20 years back. Old cast iron floorstanding boiler, gravity HW, pump next to boiler, pumping downwards. No controls. Cold feed to boiler return.I am actually having the same problem trying to decide how I convert a gravity hot water/pumped rads to all pumped on a very old system, without pump over or corrosion.
Gate valve stays open. Ans yes you can just seal, add vessel and PRV and have virtually no pressure. Its just convenient using the existing header instead of a filling loop if its already there.Does the gate valve stay open in normal operation?
I can't see how this differs from just having an expansion vessel, but with pre-charge pressure somewhat lower than normal.
Still need to put the expansion vessel connection in the right place, to avoid having negative pressure somewhere.
OK thanksGate valve stays open. Ans yes you can just seal, add vessel and PRV and have virtually no pressure. Its just convenient using the existing header instead of a filling loop if its already there.
I converted mine about 20 years back. Old cast iron floorstanding boiler, gravity HW, pump next to boiler, pumping downwards. No controls. Cold feed to boiler return.
Scrapped the boiler and installed wall-mounted condensing. Moved the pump to the airing cupboard, added diverter valve (system W), open vent, cold feed and DV in the airing cupboard. Added cylinder and room stats. Re-used the gravity 28mm pipes as pump suction and cylinder return.
Still working OK.
In my case the F/E tank is almost directly above the airing cupboard, so open vent and cold fill no problem. I chased the wall in the hall for the roomstat, and it was fiddly getting the lead through to the airing cupboard. Eberle roomstat, because it was cheap, but no complaints, has anticipator heater and gives excellent control. I guess you'll use a radio-controlled roomstat so won't have the cabling problem.That is exactly what system I have to work on!
Cast iron oil boiler with 28mm gravities to cylinder and 28mm pumped (pump is also on return pipe) to rads. No controls.
The feed pipe joins in at tee at return at cylinder.
Your new pipe up arrangement would be nearly what I would ideally do, but difficult on this house. I might risk trying to seal the system - but at a low charge.
As to Vee’s point about sealing the system using gravity feed from f&e tank and non return valve, - I have came across systems done that way, some of which are fed from the cwt cold supply.
Personally I don’t like it because risk of contaminating cwt, also disadvantage that the sealed system will keep being topped up in an event of a bad leak, like nail through a pipe. Although constant top up has also advantages.
Sorry Shaun, you've lost me. What works brilliant?My very scientific experiment
34" of head
1" single check valve
22mm feed
1 Williams f and e tank
Result
It works brilliant
Sorry Shaun, you've lost me. What works brilliant?
With the suggested scheme the valve needs to close to prevent upward flow, if I understand correctly. Does it have a spring-loaded flap? Unlikely it will close otherwise. Or maybe use 2 90° bends so the valve is in a horizontal section, if it's the right type of valve. Or maybe 2 return bends so it's vertically down, but that gets a bit messy.Didn't think there was going to be enough head to open the check valve
That's looks like low-head check valve. Am I right?
With the suggested scheme the valve needs to close to prevent upward flow, if I understand correctly. Does it have a spring-loaded flap? Unlikely it will close otherwise. Or maybe use 2 90° bends so the valve is in a horizontal section, if it's the right type of valve. Or maybe 2 return bends so it's vertically down, but that gets a bit messy.
OK, looks like you have about 1.2m opening the valve on your rig. There should be more than that when installed.yes its spring loaded in the closed position
OK, looks like you have about 1.2m opening the valve on your rig. There should be more than that when installed.
System Boiler?
Looks nice! Does everything work OK?Job done I think it looked ok
Took 5 hours to fill tho (due to no head f and e tank about 2" above the rads)
Looks nice! Does everything work OK?
3bar @ 82deg C otherwise it should not be used.I'd like to think pushfit can with Stand 1bar!! Although I dispise the stuff.
I’d recommend an expansion vessel & blow off as its a sealed system.heat only
Can you not see the massive expansion vessel in his picture then no?I’d recommend an expansion vessel & blow off as its a sealed system.
Reply to Feed and Vent fun :DDDDD in the Plumbing Jobs | The Job-board area at PlumbersForums.net
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