or nrv wrong way around ?
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View the thread, titled "New radiator in loft causing problems" which is posted in UK Plumbers Forums on UK Plumbers Forums.
or NRV is faced wrong way
S
Stevemarch1969
Just done a little test.
loft rad off at Trv all other radiators ok.(ie not hot)
as soon as Trv switched on on loft rad, other rads below get red hot but flow and return of loft rad are not hot and loft rad not hot. When loft rad on, return pipe with Trv on gets hot but only up to one way valve which stops it entering system.
steve
S
Stevemarch1969
TRV is on return side and has one arrow pointing into rad and one pointing down at return pipe.
NRV is on return pipe and allows flow away from rad only.
other side of rad has standard lock shield.
NRV is on return pipe and allows flow away from rad only.
other side of rad has standard lock shield.
You have let the air out have you ?
S
Stevemarch1969
S
Stevemarch1969
its weird because flow is from ch side of 3 port so assumed correct.
The only thing "wrong" I suppose is that the loft rad return is teed into the cylinder return.
Maybe as someone else has said the only way to resolve is to make the loft rad return enter the ch return system somehow and not the cylinder retUrn which will prove difficult.
i may just get the NRV removed and go back to how it was. Not ideal but at least the rad worked (even if it seemed to be filled from the retUrn of cylinder and the HW was on constantly as it was filling the rads as well as the cylinder!). But if I use the Trv in the loft effectively hopefully this will stop.
steve
Post photos
S
Stevemarch1969
Flow pipe is upper one teed from ch side of 3 port valve.this goes to lock shield on right of rad.
return pipe is lower pipe with NRV fitted and teed into return pipe which comes from the HW cylinder to the right. This goes to Trv on left of rad.
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Post few more photos to the right hand side whet 3 port and cylinder is
It seems simple enough. The plumber has made a stupid mistake, if I am picturing it right.
As you have said, the return to the cylinder is where he went wrong. That shouldn't be joined into for the rad unless you also joined the flow to the hot water flow & at least the rad would work when hot water only on & not effect the other rads.
What is happening at moment when only hot water on, is the flow is going through cylinder coil & then out through the return pipe the plumber has wrongly connected - then through the rad & into the flow he connected to the main rad circuit.
Simple! And it really just is the usual mistake - 2 connections to the main return circuit instead of just one!
As you have said, the return to the cylinder is where he went wrong. That shouldn't be joined into for the rad unless you also joined the flow to the hot water flow & at least the rad would work when hot water only on & not effect the other rads.
What is happening at moment when only hot water on, is the flow is going through cylinder coil & then out through the return pipe the plumber has wrongly connected - then through the rad & into the flow he connected to the main rad circuit.
Simple! And it really just is the usual mistake - 2 connections to the main return circuit instead of just one!
S
Stevemarch1969
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S
Stevemarch1969
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S
Stevemarch1969
Thanks for reply.
that makes perfect sense the only weird thing is the flow pipe to the loft rad does not get hot when water on, return does but is prevented from entering rad due to NRV fitted. Something is happening though cause if Trv switched off on loft rad, other rads do not get warm when HW only on. Trv on, other rads get hot.
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J
jase158
that pipe to right of pump, did plumber fit it? the one with white handle on it!!
S
Stevemarch1969
No that's always been there.
he only teed into ch flow and HW cylinder return.
he only teed into ch flow and HW cylinder return.
Think it is below the pump if the picture was right way up. Don't think that should be joined in there, if it is before the 3port. I am confused!
Lock shield as a bypass from the look of it......an attempt at one atleast
J
jase158
yeah it shouldn't, 3 port valves automatically close to h. water. Heating should have bypass or 1 rad with no trv on it. please close it by turning clockwise. then try it. make sure 1 rad either doesn't have trv or TRV head is taken off if they all have trvs!!
S
Stevemarch1969
pump is at top so pic needs rotating one turn quarter clockwise to be right way up.
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Kind of says it all! Joining to CH flow & then cylinder return won't work IMO.
Get a heating engineer to repipe the rad.
Either just use the cylinder circuit, so new rad will only work when hot water on sadly,
Or have the new radiators return pipe joined into the returns of the rad circuit somewhere if this is feasible, but NOT into the main circuit!
S
Stevemarch1969
Towel radiator in bathroom has no Trv all other rads have TRV.
So are you staying tighten the white lock shield in the pic?
So are you staying tighten the white lock shield in the pic?
J
jase158
Its a lot easier to connect into the hw return though as that's the only returns in loft, saves breaking walls etc. non return should of solved this though!! The issue is the bypass, bet it was blocked before and he moved it by cutting and soldering new fitting and caused back flow. Need to shut valve and replace with automatic bypass valve!!
None of what you have shown or have described looks or sounds right....i don't think the installer in the first place had a great deal of an idea about what they were doing tbh!!
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