Any plumbers out there

[badapple]

Need some advise from a experienced master plumber please.

Cold weather has arrived so fired up the central heating and the double radiator in the master bedroom is just getting luke warm from the top, bottom is cold.
The boiler, rads, valves & piping is all new & only one year old. The whole system is new & was working fine when installed. Yes, power flush was done & 2 bottles of Fernox inhibitor installed.
Not needed heating but used boiler for hot water and no problem. The Worcester boiler itself is working fine.

I have 11 rads in total & all seem to work fine except the double rad in my bedroom, which just stays luke warm.
The incoming water pipe into the rad is hot but the rad remains cold or just luke warm.
I have blead the rad several times and no air is trapped.
I have removed the cover from the rad TVR & the pin is not stuck, it seem to be fine. The valves are open and rad is full of water.
I have put into the system 3 bottles of Fernox F3 system cleaner for over 2 weeks to clean the whole system. Still no luck.
Today, I drained the whole system, removed the double rad & flushed it with a hose pipe for a long time.(only a little bit of black sludge came out)

Put rad back & re-filled the system, blead all the rads and the same results.
All the rads warm up properly, except the one in my bedroom.

The water pipe that supplies the rad with water is hot but rad is cold/luke warm. What does that mean & what could be the problem???

Any ideas what could be the problem & what I should try doing next???

Thanks

[cactikid]

i presume you bleed it when system was not running,if you turned other rads off does this get hotter?

[badapple]

Yes, boiler was off when bleeding rads.
yes, rad gets hot after a while when all other rads are off.

[super jumbe]

First you need to check your boiler gauge needle presher at 2bar before bleading the rads.

[ifred]

1.Normally you would assume sludge in the radiator! 2. However double check the TRV pin isnt bent(jamming) 3, one person had this problem (Sorry I didn't get back quicker. I wanted to be sure it was cured, then I got distracted!
When BG came the guy said the system had air-locked. He turned all the other TRV's to off and the cold rad one to max, turned the master stat up for 10 mins and let it run. This has cured it!) unusual but worth a try he had tried all the other reasons ?

[Johnner]

Your rad circuit is unbalanced mate....yer gonna have to run around them all checking the temps of each

You'll have to adjust the lockshield(return valve) on each of them.....nearest rads to the boiler will probably need to be turned down a good bit,and furthest away turned up more

My old man used to use a multimeter with temp thingy plugged into it...think he measured the temp between the inlet and outlet valves

You'll only need to get it right once(unless you change rads)

Best of luck

[badapple]

Your rad circuit is unbalanced mate....yer gonna have to run around them all checking the temps of each

You'll have to adjust the lockshield(return valve) on each of them.....nearest rads to the boiler will probably need to be turned down a good bit,and furthest away turned up more

My old man used to use a multimeter with temp thingy plugged into it...think he measured the temp between the inlet and outlet valves

You'll only need to get it right once(unless you change rads)

Best of luck

I think this is the best idea.
After cleaning & flushing the system & getting no joy, I was quite sure that the system needed balancing.
And yes, the nearest rad is the most hottest in the house. I did make sure the boiler pressure was at 2 bar before bleeding rads.

To balance the system, should I FULLY OPEN all the rads first & then turn them down one by one or FULLY CLOSE all first & then open one by one to the desired temperature?
or don't it matter which way.

[rideon]

Agree...

https://en.wikipedia.org/wiki/Hydronic_balancing

Temperature difference between input and output is used to 'tune' the system
Quick and dirty is to start with all rads cold, start heating and adjust the one that heats first...(turn down a little)

[Meat-Head]

Long time ago "Penis Peterson" a local plumber, with #hepititus
said what johnner said, about tweaking them down.

he said run from cold for 10 mins, then quick grope, then set as requured
so next cold start all even

[badapple]

Sorted. as per advise above.
All working as should.
Thanks guys.

[cunny]

Sounded more like an outlet issue than needed balancing. Tthe opening of all valves would have cleared any air lock on the outlet.

Just top up pressure and bleed all rads again. Keep en eye on your pressure. 1.5 - 2 bar will be sufficient