New radiator in loft causing problems

[Stevemarch1969]

Apologies, reposted in central heating forum.

 

[Stevemarch1969]

Hi


i have a conventional boiler situated on the ground floor of my house and the 2 header tanks,hot water cylinder, pump and 3 port motorised valve in the loft. The header tanks are at the highest point in the apex of the loft on stilts.


The 3 port valve was replaced by a plumber 12 months ago as the old one was stuck open giving us hot radiators when the hot water was on.




We are using the loft to store some items and wanted a radiator up there to keep it from getting too cold.i got a plumber to do this.


He teed into the flow pipe a short distance from the 3 port valve ch side. The flow pipe is 22mm the new radiator pipe 15mm.


There is a 15mm return pipe from the bottom of the hot water cylinder which he teed into for the return again with 15mm.


This gave us problems as when hot water only was on, hot water was somehow travelling up the return pipe of the new radiator and entering ch system causing other radiators to be red hot.


The plumber came back and to combat the above fitted a one way valve on the return side of the new radiator pipe to prevent any water from the return pipe entering the new radiator.


We still have hot radiators with hot water only and the new radiator now does not get hot at all when the ch is on.it seems that when the new radiator is switched off all the problems stop?


It has been suggested that the 3 port valve may be to blame again but the ch pipe next to this only gets Luke warm when hot water only is on but the return is red hot.I have trawled the forums and see reverse circulation is mentioned and also that the return from the cylinder should be last near the boiler( which may be the case but this rad return in it prob not helping)


Sorry to waffle on and hope the above makes sense?


thanks in advance


Steve

 

[Mike Jackson]

The only correct way of sorting it out is to run the return from the rad back to the heating circuit. An easy solution would be to take the connection from the rad before the 3 port so that it is on whenever the heating or hot water is on and fit a TRV. Alternatively run it from the hot water circuit so it comes on with the hot water.

Not the best solution but the least disruptive.

 

[SafeGasInstall]

welcome to the forum

You can do few things to overcome problem :
1. have the radiator piped to hot water flow and return and in the sumer you just turn it of manually
2. convert to a pressurised ch system and convert to S plan with 2 x two port valves

 

[Stevemarch1969]

Hi

Many thanks for your quick reply.

Option 1 sounds interesting.

If I do this I assume radiator will be on ( if thermostatic valve allows) with hot water only, central heating only or both. I think that's how I understand it.

Thanks again.

Steve

 

[SafeGasInstall]

radiator will be on when there is demand for hot water and also be on when there is demand for hot water and heating at the same time . If there is thermostatic valve rad will be on only depend on settings on the rad valve


hope it makes sense

 

[lame plumber]

out of interest is your loft insulation on the sloping part of the roof or all over the "floor"

 

[village idiot]

I don't know why you are bothering yourself about all this problems you have been left with?
Get the plumber back and let him resolve the problem.
You paid him to do a job. He hasn't done the job, so give him a chance to put it right.
My only worry is, he might create more excuses and get you to spend even more money

 

[Dotty]

Thread's merged. can't delete OP as it kills the whole thread........

 

[Stevemarch1969]

The only correct way of sorting it out is to run the return from the rad back to the heating circuit. An easy solution would be to take the connection from the rad before the 3 port so that it is on whenever the heating or hot water is on and fit a TRV. Alternatively run it from the hot water circuit so it comes on with the hot water.

Not the best solution but the least disruptive.

Thanks Mike for your reply.

Taking into account what others have said does it make a difference if the connection is before the 3 port valve or on the hot water side?Am I correct in assuming 3 port valve is either water only or both CH and HW?

Cheers

Steve

 

[SafeGasInstall]

3 position mid position 3 port valve is :
hw only
ch only
hw and ch at the same time

2 position diverter 3 port valve is :
hw only
ch and hot water at the same time

 

[Stevemarch1969]

3 position mid position 3 port valve is :
hw only
ch only
hw and ch at the same time

2 position diverter 3 port valve is :
hw only
ch and hot water at the same time

My valve is a Plumb Center 3 port valve product code 340080.

Which one of the above is this please?


many thanks


Steve

 

[SafeGasInstall]

can you select CH ONLY from programmer and run it independently without the need for HW to be on too ?

 

[Stevemarch1969]

can you select CH ONLY from programmer and run it independently without the need for HW to be on too ?

Yes. Programmer is Acl Lp522 and has HW one side and ch other

Steve

 

[SafeGasInstall]

i did not ask my Q correctly
If you select CH only does boiler works and you get CH , or do you have to have hot water selected at the same time to have Ch running ?

 

[Stevemarch1969]

i did not ask my Q correctly
If you select CH only does boiler works and you get CH , or do you have to have hot water selected at the same time to have Ch running ?

I can select either hot water or central heating separately or both together on the programmer.

Steve

 

[SafeGasInstall]

so you have a 3 position 3 port valve

 

[Stevemarch1969]

so you have a 3 position 3 port valve

Great, thanks for that.

So best option is to take flow for rad before 3 port valve as if I do it HW side it will only work when HW on.

It is currently connected to ch side of the 3 port and does not work when ch selected though so maybe this option will not change anything?

I assume also the return from the hot water cylinder is separate from the rad return system (although they may join further down the pipe)

Steve

 

[SafeGasInstall]

i think piping it to after the 3 port on the Hw side will be your best option or
have it piped as a bypass radiator and it will be on at all the time and then secondary control will be your thermostatic radiator valve

 

[Stevemarch1969]

i think piping it to after the 3 port on the Hw side will be your best option or
have it piped as a bypass radiator and it will be on at all the time and then secondary control will be your thermostatic radiator valve

Bypass radiator sounds good as HW side would mean only on while demand for hot water on.

How is a bypass radiator piped and how does it work please?

Cheers

Steve

 

[SafeGasInstall]

as mention before by MJ ,
flow from before 3 port valve and return back to return pipe

 

[Stevemarch1969]

as mention before by MJ ,
flow from before 3 port valve and return back to return pipe

Brill thanks.
Only thing I'm not sure about is the fact that at the moment the radiator doesn't work when ch only selected since the one way valve has been fitted on the return.( It must have worked before this was fitted by being filled from the return?)The return pipe however is red hot. It's as if the water in the return is preventing the rad from flowing correctly if that makes sense.

Steve

 

[SafeGasInstall]

I think your plumber has messed things up , as there is no way return pipe to be hotter then flow pipe unless pipes are been crossed over or secondary circulation has been present before work started , pls post some pictures as it gets complicated or list location for a trusted plumber to visit and sort it out for you

 

[TBServices]

Daft question, is there a chance he's used a directional TRV and put it on the wrong side of the rad?

 

[Stevemarch1969]

Daft question, is there a chance he's used a directional TRV and put it on the wrong side of the rad?

Thanks for reply.

Trv is fitted to return side and is ecocal.

it does get some heat in it when on HW only.

Steve

 

[SafeGasInstall]

or nrv wrong way around ?

 

[SafeGasInstall]

or NRV is faced wrong way

 

[Stevemarch1969]

or NRV is faced wrong way

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

 

[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.

 

[mfgs]

Sounds like it is definitely piped wrong, lots of possibilities as to what he has done. Best thing is to get him to do it again from scratch, there will be no need for any non return valves when pipes correctly.

 

[SafeGasInstall]

You have let the air out have you ?

 

[Stevemarch1969]

You have let the air out have you ?

Loft rad rad has water coming out when I bleed it if that's what you mean?

 

[Stevemarch1969]

Sounds like it is definitely piped wrong, lots of possibilities as to what he has done. Best thing is to get him to do it again from scratch, there will be no need for any non return valves when pipes correctly.

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

 

[SafeGasInstall]

Post photos

 

[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.