Balancing Radiators

[Crewood]

Hello All,

I have a radiator problem, one of the replies to a previous post was to balance my radiators. I looked at the FAQ pages and I'm still lost.

The FAQ talks of lock shield valves, can someone please explain in the lowest terms. There are two valves on a radiator, are both LSVs or how can I identify which is the LSV. To get the radiators to balance do I close off one of the valves more the the other valve on the same radiator or equal amounts?

For years my central heating has worked perfectly well, nothing has been changed but recently some of the downstairs rads will not get warm. Also when the pump is not switched on one of the upstairs rads is cold although the others are hot.

Someone suggested there could be sludge in the cold rads, I took these off, there was a small amount of dark liquid but no heavy sludge. I washed them out with a hose, replaced them but I still have the same problem of a cold radiator. As the system was when it worked, all the valves on the radiators were fully open, most of the valves are now difficult to turn, is there anyway I can free these off?

Any help at all would be most welcome.

Regards....Mike

[Steve]

The LSV is the valve with the small plastic cover which is usually placed there to restrict access so it can't be turned.

Just remove the small plastic cover and you will get access to the valve.

I've noticed on my system that all the LSV are wide open and all my rads are hot.

Steve

[Crewood]

Hello Steve,

Both the valves on all my radiators have removable white plastic caps, one with the direction arrows. I'm worried that over a period of time these caps may have been switched so I'm not sure which is the correct valve.

Regards....Mike

[Dave Plowman (News)]

The valves themselves are identical. One should have a cover so it can't be fiddled with, so this is designated the LSD. Normally on the flow, so check which pipe heats up first from cold.

The other becomes the service valve with an adjustable knob - usually left full on, unless it's shut off completely.

[mike ring]

"Crewood" wrote in news:1112958748.049511.260110 @f14g2000cwb.googlegroups.com:

Quick and dirty method.

First designate a lockshield valve on all rads; traditionally the downstream (cooler) side.

Get an infrared thermometer, hopefully on sale somewhere; (not absolutely essential but one of the best toy... tools you can get.

All valves fully open?

Find the hottest rad, and close down the lockshield all the way, and open just a sniff. These valves are only effective as controls for about the first 1½ to 2 turns, so half a turn as a first try is plenty.

After letting this settle, do the same for the next hottest, until you get a rough balance. Try for about a 20 deg F /11deg C across the rad.

If desperate, shut the hottest rads right off, to make sure the presently cooler rads heat up - if they don't there's a problem.

I found in my hovel I got a rough balance very quickly, in fact good enough for jazz; but you also get a "feel" for your system, aaaand with your new I/R thermometer you can tweak it accurately if you feel the need.

HTH

mike

[Crewood]

Hello all,

Thanks for th replies and the help, it seems to have worked. The cold rads downstairs have warmed up for the first time in months.

Only thing I can't understand is why they started running cold in the first place after working so well for years.

Thanks again....MIke

[Dave Plowman (News)]

The pump may have lost some efficiency? Or slight blocking of the rads or pipes? A very small change in flow can make a big difference here.