Cold Radiators

[terryplumb]

Turn off the mains electricity supply to boiler by either switching off at the wall isolation switch ,or if your boiler supply cable has a standard plug on the end ,switch off and take the plug out the socket ( like you unplug a toaster ,kettle etc)

 

[morpheus83uk]

Ah right and then just use the filling valve to push the water around the system?

Thanks

James

 

[terryplumb]

Yes ,effectively connecting mains water pressure into the system ,to see what the resulting flow is exiting each valve on the problem rad ( obviously with rad removed ). Depending on what this result is , will determine how you proceed.

 

[morpheus83uk]

Brilliant thanks. I think it's on the lock shield side since it doesn't get hot and the TRV does but as you say it could be that it's not getting round.

 

[jackthom]

Brilliant thanks. I think it's on the lock shield side since it doesn't get hot and the TRV does but as you say it could be that it's not getting round.

The TRV side gets hot because there's a trickle of hot water entering the radiator from that end. Wherever the restriction is (very likely to be the TRV stuck) the lockshield end is bound to remain at least considerably cooler.

 

[morpheus83uk]

Thanks. When I compare to the other radiators both sides are hot. The TRV is new as of a few months old and I have taken this off and the pin moves freely up and down.

 

[wig]

I want to ask what is the best way after removing the rad, to connect a hose pipe to the valve ends on the system i.e. not to the rad?

There will be screw fittings, so am wondering if there is a way of using hope pipe fittings that screw the hose onto the screw fittings?

Also my boiler's pressure display is digital so electrically isolating the boiler will cause the pressure to be unreadable....any work arounds for this?

OP, How did you add the cleaning agent to the system? You asked three times, no-one gave you the answer, and then you said you had done it.

 

[morpheus83uk]

Hi Wig,

I got a kit from Screwfix as well as the inhibitor and the cleaner:

Cleaner: https://www.screwfix.com/p/sentinel-x400-system-restorer-1ltr/89458
Inhibitor: https://www.screwfix.com/p/sentinel-x100-central-heating-scale-inhibitor-1ltr/79683
Filling Kit: https://www.screwfix.com/p/flomasta-universal-filling-kit-5-pcs/8145k

I drained the radiator first by turning off the TRV and attaching a hose to the bit of pipe sticking out under the TRV and then undone the valve which releases the water from that one radiator (you may need to open up the bleed valve to allow the water to flow)./ I then attached the filling kit to the radiator from the top of the radiator through a valve on the opposite side of the bleed valve (you have to take this out first) and then just waited for the cleaner to go in. I hope this makes some sense.

Thanks

James

 

[wig]

Yeah makes sense and what I thought, just wanted to know.

Found this link on the screwfix product specifications

http://www.free-instruction-manuals.com/pdf/pa_1385742.pdf

 

[terryplumb]

The threads on radiator valves are predominantly either 1/2 inch BSP or 3/4 inch BSP ,and male. There are various ways to connect these to a hose pipe ,this is one....
Buy flexible tap connector hoses ,such as screwfix codes 6768G ( 1/2 inch) ,9989G ( 3/4). They are about two quid each ,or less. One end screws onto the rad valve ,the other end is 15 mm compression fitting ,into which you fit a short piece of 15 mm copper tube.you then push hose onto the copper pipe and retain with a jubilee clip. Note your hose diameter needs to be big enough to accommodate the copper 15 mm.

 

[dilalio]

The rad in question has a blocked return.
If you’re lucky it might be right at the lockeshield... have a container handy and poke about in it with a small screwdriver/brawdl with valve open.
I’ve usually managed to free these up with Kalchem over a period of time and with ebb and flow methods.
Next stop... powerflush.

 

[morpheus83uk]

Thanks so its not the water coming in its the return which would be the lock shield end I presume?

Would giving it a hoover out with a wet and dry vac help? Also wouldn't the cleaner in the system I have put in clear this out since its been in for two weeks now?

Also just to clear up one thing would it be the return since the radiator is unable to get any more hot water through the return so its just backing up the the pipework before hand and that's why only the top is getting hot and the bottom not because the warm / cool water isn't being passed back to the boiler?

Thanks

James

 

[dilalio]

It’s usually the return, especially on drops. If the rad is clear (think you mentioned it’s been flushed or is new), then it’s most likely the pipework.
Hard to give you an exact diagnosis without being there and looking with plumber vision!

 

[morpheus83uk]

Yes thanks its a new radiator.

I added the cleaner to hopefully clear any blockage. So could I use my wet and dry vac on it to remove anything from the pipe as I will be draining the system soon and flushing it out to remove the cleaner I currently have in there.

Thanks

James

 

[dilalio]

It can’t hurt to try a wet vac but it might be a blockage that has formed a plug and needs to go the other way! I’d take the lockshield off and try it on the pipe - also, try hose to push the other way... as advised by others on this thread... it’s what I meant by ebb and flow!