Cold radiator

chris_n

Check to see if one of the valves is completely closed first keeping  a check on how far you move them. If they aren't completely closed then open both of the valves by the same amount (maybe 1 turn) to see if you can establish a flow.

Vortigern

janbeno said:

Hi born_again, both pipes were cold on the hall rad when I turned on the heating. I did try to bleed the hall rad, but when I usually bleed it starts hissing then water splutters out , but with the hall one water just runs quite quickly.

If one of those valves is open and the other is closed, you'll still get water coming out of the bleed valve, but there'll be no circulation and thus no heat.  On that rad with 2 manual valves, one valve should be fully open, the other should only be open by about a quarter turn.

There are videos on youtube showing how to balance radiators.  Most start with all the lockshield valves open by a quarter turn. Then tweak to balance the system by slightly opening the lockshield on the cold rads.

janbeno

Thanks, we'll give your suggestions a try. Hopefully they'll work

janbeno

If one of those valves is open and the other is closed, you'll still get water coming out of the bleed valve, but there'll be no circulation and thus no heat.  On that rad with 2 manual valves, one valve should be fully open, the other should only be open by about a quarter turn.

I am presuming where the TRV's are on the other rads is the inlet, should this be the side that's a 1/4 open or fully?

chris_n

janbeno said:

If one of those valves is open and the other is closed, you'll still get water coming out of the bleed valve, but there'll be no circulation and thus no heat.  On that rad with 2 manual valves, one valve should be fully open, the other should only be open by about a quarter turn.

I am presuming where the TRV's are on the other rads is the inlet, should this be the side that's a 1/4 open or fully?

It doesn't matter, what matters first is that you get flow through the radiator. Until you establish what the current position of the valves is and whether opening them creates flow (noting how far you have moved them) everyone here is guessing. 

janbeno

chris_n said:

janbeno said:

If one of those valves is open and the other is closed, you'll still get water coming out of the bleed valve, but there'll be no circulation and thus no heat.  On that rad with 2 manual valves, one valve should be fully open, the other should only be open by about a quarter turn.

I am presuming where the TRV's are on the other rads is the inlet, should this be the side that's a 1/4 open or fully?

It doesn't matter, what matters first is that you get flow through the radiator. Until you establish what the current position of the valves is and whether opening them creates flow (noting how far you have moved them) everyone here is guessing. 

Thanks, I'll give it a go tomorrow, your input is really helpful.

ThisIsWeird

Hi Janbeno.
With the rads that have TRVs fitted (and lockshields on their other ends), it isn't actually important to ID which end is the Flow and which the Return. The rads should operate regardless, TRVs these days being 'bi'.
Ditto with the hall rad - it doesn't matter which end is l/s and which the control. At some point, tho', you'll likely want to get a white cap that actually sits on the spindle to provide adjustable heat control.
Meanwhile, to help with understanding what the issue could be, I think the thing to try would be; pull off both caps. Cut two wee paper flags and tape them to the spindle, pointing, say, towards the wall. Now place a spanner or plier on a spindle's 'flat', and turn it clockwise to close it off. Note down the number of turns and part turns this takes. Repeat for the other end. If the spindle won't turn clock, then try  it anti, just in case it's already fully closed!
Let us know what you've found.
Then open both ends a full turn, which should be enough to get the rad working - check that it is. If it doesn't heat up, open both a further full turn. Also note down which valve heats up first - for the sake of convention only, we'll make that one the 'control'. 
Once you've got it working, we can then look at balancing it, tho' only very crudely...

Have you bled every rad?! Really worth doing, because there was a load of air in at least that one rad - the one you managed to get working - and that air was displaced from that rad, but had to go somewhere else! Possibly the boiler has removed most of it, but I'd expect some to have ended up in other rads. Really important for all to be fully bled, as it can affect how well they work.
Always 'bleed' with the boiler turned off.

Make and model of boiler?

janbeno

Thanks for the comprehensive explanation, it does help. I am going to do it later today. I did check that all the rads were hot all over, a couple that weren't I bled them.The make is Worcester Bosch and it's a Greenstar 30CDi.

Thanks again

ThisIsWeird

janbeno said:

Thanks for the comprehensive explanation, it does help. I am going to do it later today. I did check that all the rads were hot all over, a couple that weren't I bled them.The make is Worcester Bosch and it's a Greenstar 30CDi.

Thanks again

You're welcome.

That model will have a built-in auto air vent, so any air that gets as far as the boiler should have been removed. Of course, air could have made its way into other rads too, and this would tend to show itself by a cool rad top. If a rad heats up pretty evenly hot, right up to the very top, it's usually fine.

janbeno

ThisIsWeird said:

janbeno said:

Thanks for the comprehensive explanation, it does help. I am going to do it later today. I did check that all the rads were hot all over, a couple that weren't I bled them.The make is Worcester Bosch and it's a Greenstar 30CDi.

Thanks again

You're welcome.

That model will have a built-in auto air vent, so any air that gets as far as the boiler should have been removed. Of course, air could have made its way into other rads too, and this would tend to show itself by a cool rad top. If a rad heats up pretty evenly hot, right up to the very top, it's usually fine.

Just had a go, the left spindle moved 3 1/4 turns , but the right one with the drain spout was locked absolutely solid. I sprayed with WD40 and left it for a while, still no joy, it won't budge either way. The rad was working before the service and drain . Realistically the locked side must have been like that before and as I said it was working fine?

All the other rads heated up fully. I'm really at a loss now.