Central Heating Bypass Pipe?
- Thread starter James Holland
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Thanks for everyone's replies so far!
I get the feeling that the majority think it shouldn't be there, but I'm a little concerned that a minority think it's ok. The last thing I want to do it block it and cause more issues.
I'm considering cutting into the red area and adding a 22mm isolation valve. What are people's thoughts? - And would you suggest turning it fully off or leaving some restricted flow?
Thanks
James
I get the feeling that the majority think it shouldn't be there, but I'm a little concerned that a minority think it's ok. The last thing I want to do it block it and cause more issues.
I'm considering cutting into the red area and adding a 22mm isolation valve. What are people's thoughts? - And would you suggest turning it fully off or leaving some restricted flow?
Thanks
James
Only Tony thinks it is alright and it isn't.
If you turn the valve off you will have problems. The system needs checking and altering to accordingly.
If you turn the valve off you will have problems. The system needs checking and altering to accordingly.
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I don't mean close the current valve, I mean add a new isolation valve in the red dotted area of the diagram (across the bypass area) to make it a conventional layout.
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you have a bypass, but no bypass valve,
some boilers don't need one but most do,
what could happen is that both 2 port valves will shut when satisfied (no call for heat) but the pump will still run (pump over run, this helps disperse the heat away from the boiler), so there needs to be a path for that water to circulate, auto bypasses are sprung loaded so it stays shut when the valves are open, but open up when the pump is pumping water but no valves are shut (if that makes sense)
also if you have a system with full TRVs they could potentially be all shut down, but the 2 port valve for the heating open, and there would be nowhere for the heating water to circulate, then the auto bypass would open.
some boilers don't have a pump over run and the pump will shut down at the same time the boiler stops firing.
either way you need something on that pipe
some boilers don't need one but most do,
what could happen is that both 2 port valves will shut when satisfied (no call for heat) but the pump will still run (pump over run, this helps disperse the heat away from the boiler), so there needs to be a path for that water to circulate, auto bypasses are sprung loaded so it stays shut when the valves are open, but open up when the pump is pumping water but no valves are shut (if that makes sense)
also if you have a system with full TRVs they could potentially be all shut down, but the 2 port valve for the heating open, and there would be nowhere for the heating water to circulate, then the auto bypass would open.
some boilers don't have a pump over run and the pump will shut down at the same time the boiler stops firing.
either way you need something on that pipe
I would not attempt to say if the drawing is correct or not based on the picture.
But if the drawing was correct then I would wish to add an auto bypass valve along that bypass pipe and set it to about 3 m.
You should also have a pressure release valve somewhere on your system ( as well as the filling valve which you presumably do have although not shown ).
But some others are saying they think something else is wrong but without specifying what!
Tony
But if the drawing was correct then I would wish to add an auto bypass valve along that bypass pipe and set it to about 3 m.
You should also have a pressure release valve somewhere on your system ( as well as the filling valve which you presumably do have although not shown ).
But some others are saying they think something else is wrong but without specifying what!
Tony
Look up the three tee rule, return back to the boiler should be from boiler.
By pass, hot water, heating. Otherwise you would get reverse circulation unless someone had fitted a check valve
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3 Tee rule applies to open vented, is this not a sealed system?
Still causes problems on some systems Shaun. Had it a few times.
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It can but its not the 3 tee rule, purely reverse recirculatio from where one has teed...
Ok then the two tee rule 
as its a sealed system obviously the first tee (feed and vent) dont count but the position of the next two tees still need to be correct, the return from the cylinder should be the last connection before the boiler.
as its a sealed system obviously the first tee (feed and vent) dont count but the position of the next two tees still need to be correct, the return from the cylinder should be the last connection before the boiler.This one is shown as both returns at the same point on his drawing.
I would say that would work fine if it really was like that.
BUT the OP will not understand the very important significance of the exact positioning of the actual return connections!
I would say that would work fine if it really was like that.
BUT the OP will not understand the very important significance of the exact positioning of the actual return connections!
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