3 new radiators all half cold since installation

[gigz]

Close ALL the trv's apart from the problem rad. Make sure this rad has both valves fully open. This should push all the water through the rad, if its still not working there's a problem with one / both valves or the pipework. Has it got a trv ? if it has try swapping the head with one off a rad thats working.

 

[malkie]

Did he undo the rad valves and let the water run into a bowl so he can tell if theres a good flow through the pipework,if its clear both ends,and all the rest are turned off and still not hot then id be looking at weather hes connected the pipework correctly and hasnt took the tees off the one pipe instead of two,can you see were hes teed in

 

[Allyson]

i had the same problem after having my new central heating installed.
i didnt change any rads, as they were quite new and they all had new thermostatic valves on them....just changed the boiler.
the heating worked fine before the change..i just wanted a combi instead of the old back boiler.
with the new boiler, rads only got slightly warm at top, did all the usual...bleeding, balencing etc nothing worked.
one rad wouldnt get hot at all, in the end we uncrewed the tops off the thermo valves, and guess what....heating heating worked a treat.

 

[pinheadplanet]

OK - I've taken off the TRV head so the (return) valve is wide open, the lockshield at the other end (flow) is wide open. Been like this for more than hour and still nothing.

He has definitely tee'd off of two separate pipes as the offending rad is right next to the boiler so you can see.

 

[pinheadplanet]

Should I turn off all the lockshields on all the other rad's as well or is it enough just to turn off the TRV's?

 

[Macgasman]

Is the TRV multi-directional? Some of them are one way and should only go on the flow. Is there an arrow on the side of the valve pointing in both directions?

 

[pinheadplanet]

There is an arrow pointing down and an arrow pointing into the rad

http://www.pegler.co.uk/prod/styles_social.aspx?button=styles&FolderID=98&id=40294

 

[pinheadplanet]

The TRV is Angled NOT Straight and the installer put one of his own straight lockshield valves on instead of the angled one supplied with the TRV.

 

[D_Hailsham]

Balancing procedure:

You will need either two clip on pipe thermometers (£12 each) or an infrared thermometer (about £25 from Maplin). I have used both and prefer the infrared as it has a faster response, is more accurate and can be used for other things, e.g checking the temperature distribution over the surface of a rad.

1. Turn boiler off and allow to cool
2. Make sure HW is turned off
3. Open all LS valves fully; remove all TRV heads and open all manual rad valves fully.
4. Turn the boiler temp to max and bring system up to temperature.
5. Check, by feel, the order in which the rads warm up and make a list.
6. Adjust the bypass (if fitted) as per mfr instructions
7. Measure the temperature differences between the flow and return pipes at the boiler. What it should be will depend on the boiler -refer to the installation manual. If the temperature is not right, you need to adjust you pump speed (higher speed gives smaller difference and vice versa). Set the speed to give as a difference as close to the mfrs recommendation as possible.
8. Turn the boiler off.
9. Close all lockshield valves. Leave TRV heads off.
10. Restart boiler
11. Go to first rad in list made in step 5
12. Attach the pipe thermometers to the rad and open the LS valve a quarter turn.
13. Wait until temperature has stabilised on the two thermometers. If the difference is smaller than that at the boiler, close the LS valve a fraction, or vice versa. Wait until the temp has stabilised and check again.
14. When you are happy with the first rad, move on to the next on the list.
15. Repeat steps 12, 13 and 14 for each rad on the list.
16. When you have reached the last rad, check the boiler temp difference and adjust pump speed if necessary.
17. Go back to the first rad and test it is still giving the correct difference
18. And so on, going round and checking the temperature difference until they are all as near the required drop as you can make them. Don't expect perfection
19. Replace TRV heads and set to required temperature

A very small change in the amount a LS valve is open can have a considerable effect on the temperature difference. Because of the way LS valve are constructed, it is virtually fully open when it is one and a half turns open. So most adjustment will be within one turn from closed.

If you find that the wall thermostat is turning the boiler off before the TRVs in the other rooms work, you should close the wheel valve slightly, so the rad gives out less heat and the room/hall warms up slower. It's a matter of trial and error.

 

[Agile]

Unfortunately an installer who thinks that balancing is not necessary because you have TRVs is NOT very clever! But thats quite common!

Without seeing the pipes he has connected the rad to, its impossible for me to know if its been correctly connected or not!

If water comes out of each valve into a bucket then its connected to something! But possibly each is not connected to the flow and return respectively! Can you follow the connections back to the boiler?

Tony

 

[pinheadplanet]

Yeah the pipes are definitely run from two different pipes right under the boiler.

Any more on the flow direction on the TRV? It has two arrows as detailed in the photo on the previous link: TRV is a pegler terrier angled.

On all the 3 rads he installed he's put the the TRV on the Return and the lockshield on the Flow.

 

[namsag]

Turn the rad off both sides take it off the wall , Then open each valve in turn into a bucket and make sure you have an actuall flow of water out of both sides , it may be a bust valve or carp in pipe further along

 

[D_Hailsham]

Any more on the flow direction on the TRV? It has two arrows as detailed in the photo on the previous link: TRV is a pegler terrier angled.

On all the 3 rads he installed he's put the the TRV on the Return and the lockshield on the Flow.

The two arrows mean that the water can flow through the valve in either direction. Most installers will put the TRV on the flow and the LS on the return; but the other way round is still OK.