cold rad

[067256]

10mm microbore drops down to the rad in question. Microbore behind 'dot and dab' plasterboard.
Could i force mains water up the return pipe via the bleed valve and 'hope' the blockage shifts?

 

[PaulRB]

067256
At the start of my troubles I took off the rad and attached a hose to the flow valve, connected to the outside tap ( but any mains tap will do ). Then I opened the valve and opened the outside tap. The mains pressure should force water into the pipework and hopefully shift the blockage.
I then repeated the process for the return valve.
BUT only run the mains for 5-10 seconds or it will back-fill the F + E tank ( you will know this because water will start coming out of the overflow!!! )
Also, it can be fiddly trying to attach a hose to the valves but worth persevering.
It might clear the blockage.
Good luck.

 

[fuzzy]

Pump switched off.
Closed both valves on rad and removed the rad in question. Opened flow valve and get a good flow of water.
Open lockshield valve and only a trickle, there is nothing wrong with the valve as i have actually tried it on another rad when i fitted a TRV.
I'm just convinced now that it is a blockage.

sounds like it mate, maybe force mains pressure back up

 

[PlumbingBud]

Microbore is well known for being soft and getting squashed easily. It is also prone to blockage being of narrow bore.
I wonder if there is a squashed bit behind the dot and dab?

Its like a garden hose being kinked. Water may well flow through, but will be unable to reach top flow rate.

 

[fuzzy]

if its worked before and no works been done its unliekly to have become kinked

 

[067256]

Ok, so today i have traced as much of the pipework as possible by taking up floorboards etc....
i cannot find any kinks. squashed bits. It goes 22mm down to 15mm down again to 10mm for about the last 2 metres.
I have taken off the rad in question and connected a washing machine hose between the flow and return...opened both valves, turned on heating briefly to check and now i have a good flow and the washing machine pipe is getting hot!!!
Why dont i get this when i connect the rad back up???????????????????????????????????????????????

 

[PlumbBobBob]

maybe a restriction in the radiator? take it outside and put your garden hose on it and flush it out

 

[fuzzy]

Ok, so today i have traced as much of the pipework as possible by taking up floorboards etc....
i cannot find any kinks. squashed bits. It goes 22mm down to 15mm down again to 10mm for about the last 2 metres.
I have taken off the rad in question and connected a washing machine hose between the flow and return...opened both valves, turned on heating briefly to check and now i have a good flow and the washing machine pipe is getting hot!!!
Why dont i get this when i connect the rad back up???????????????????????????????????????????????

take rad outside and flush it out

 

[067256]

Its a new rad...flushed out still and all ok.

 

[fuzzy]

must be greater resistance, the system needs balancing

when rad off did you open both valves for split second to check they both run well?

 

[Halesowen1]

Again as the previous one, i reckon biggest problem here is the need to balance the system correctly. I bet less than 10% of fitters balance a system correctly or even know how to.

 

[fuzzy]

its often not needed with powerful pumps and well designed systems, but when something like this happeneds its required

 

[067256]

Stupid question.
Shall i open the valves and check for flow with the heating switched off?
Should i get a good flow of water from the flow and return??

 

[067256]

Ok, so i now have taken off the washing machine hose and both valves are closed. HEATING TURNED OFF.
Open wheelshield(flow) lots of water coming out and good flow, no air spluttering. Close wheelshield.
Open Lockshield(return) bleed valve closed.........a trickle of water coming out.....constant but trickling, no air spluttering.
Opened bleed valve aswell...the same result
WHY IS THIS HAPPENING ON THE RETURN??????????

 

[PaulRB]

3 days, still going strong!!
Fingers still crossed.

 

[067256]

Why have i only got a trickle of water coming out of the return pipework?

 

[Gray0689]

You have an airlock or a blockage

 

[PaulRB]

Glad I haven't got microbore!!

 

[fuzzy]

Ok, so i now have taken off the washing machine hose and both valves are closed. HEATING TURNED OFF.
Open wheelshield(flow) lots of water coming out and good flow, no air spluttering. Close wheelshield.
Open Lockshield(return) bleed valve closed.........a trickle of water coming out.....constant but trickling, no air spluttering.
Opened bleed valve aswell...the same result
WHY IS THIS HAPPENING ON THE RETURN??????????

have you tried valve open on return with rad off?

 

[tony diggs 69]

agree with Fuzzy . try changing TRV

 

[067256]

Valve open on return...water trickling out. There is no TRV, just a lockshield on return and wheel valve on flow.

 

[fuzzy]

then there is obviously a problem in the return pipe, can you get the mains on it

 

[CES]

Either mains pressure water to unblock it as Fuzzy says, or attach a footpump and give it a couple of jabs. Thats what usually works for me.

 

[PaulRB]

Day 4 and still working!
Beginning to relax.
Another couple of days and I'll believe we've cracked it!!!

 

[PaulRB]

Hi guys.
1 week and rads still working!
I think we've cracked it.
Thanks to everyone for their help, especially Fuzzy and Halesowen1, who have stuck with this from the start.
Great site and great help.
Once again, THANKS