balancing radiators

[UpAroundTheBend]

Ive been reading up about balancing radiators and was gonna have a go at doing mine. I only have 3 big double rads in my house downstairs and no heating upstairs, its a 70s ex council house with original rads. Thing is though I dont have TRVs on my rads so im not sure how to tell which side is the TRV side and which is the lockshield side.

So without having to turn on a cold system and feel which side of the rads warm up first, how can I tell which side is the TRV side and which is the lockshield side? They both look similar.

And after reading a few different pages on the process, am I right in saying that the TRV valves should all be wide open, and the lockshield/balancing sides should be closed and opened up a qtr turn and then more to find a balance?

And even more precisely is to have the input pipe no more than 12° hotter than the output pipe on each rad?

 

[D_Hailsham]

how can I tell which side is the TRV side and which is the lockshield side? They both look similar.

Feel the pipes on each rad and find out which is the cooler of the two. That is the return pipe, so that will have the LS valve.

LS valves normally have a plain cover (see pic), so they can't be fiddled with . Take an existing handle to a diy store or plumbers merchant and you should be able to get some LS covers.

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All valves on the hotter (flow) pipes should be fully open when balancing the system. Start with the LS valves about a third of a turn open.

And even more precisely is to have the input pipe no more than 12° hotter than the output pipe on each rad?

All input (flow) pipes will be about the same temperature. It's the drop to the output (return) which you are adjusting when you balance. The actual drop is not so important as having the same drop across each rad. Modern condensing boilers are designed for a 20C drop, so a 15-20C drop across the rad would be more appropriate if you have a condensing boiler.

 

[UpAroundTheBend]

What I cant figure out is....if the lockshield/adjuster valve is on the output/return side of the rad, how does adjusting the valve change the way the rads heat up, ie, how does changing the flow of water coming out of a rad change the way it heats up? Or am I missing something?

 

[Terry lambert]

Water can only come in if water is going out.

If you close down the return, less water flows through the rad and circulates to the next

 

[UpAroundTheBend]

Just for reference, what temp do you have the radiator water heat set too on your boilers at this time of year?....december in the uk!

if the rad water temp is set to 70° on my boiler (thats the flow temp?) Will the heat be maintained through the pipework so that the input temp at the rads will be 70°, so that means the temp at the outlet pipe/lockshield side of the rads wants to be roughly 12°-20° less than that ie 50°-58°?

 

[Terry lambert]

On a standard efficiency boiler you should be aiming for a 10 degree drop across the system

On a condensing boiler 20

 

[JasonW]

I just did mine to try to get a cold one working. With all the other rads shut off (locksh closed fully) the cold one stayed cold and the boiler stopped immediately on fire up. Just wondered if Mr Bodger who fitted the rad for me has connected both sides to flow!? Trv side is hot and top of rad lukewarm but never gets hot like tothers. New rad not sludge. New Trv pin comes in/out ok with cap off. Wife moanin ... Happy xmas ...

 

[Terry lambert]

Was he replacing an existing rad or piped in a new one ?

If the rad has a nut at the top that you can remove. Shut both valves,remove nut, tray under rad) you will get a little water out.

Attach a 1/2 inch male iron to compression with a little bit of copper., then attach a small hose.

Get the mrrs to hold the hose in bucket.

Open one valve to see flow, shut, then the other

If it's a blockage this may shift it.

 

[UpAroundTheBend]

Sorry to be a pain!....... on closer inspection of my 3 rads,1 has a lockshield as pictured above which has been fitted since the rads were originally installed on one side and a turnable plastic knob which sits secured on a square valve pin by way of a little screw through the top, so on that i can gather that the knob side is inlet and the lockshield is outlet...correct?

now the thing is that the other 2 rads have the turnable plastic knob sitting on a square valve screw/pin on BOTH sides of the rad. Is this normal/acceptable? How can I tell which is inlet/outlet? And can the balancing still be done if theres no lockshield? Thanks

 

[JasonW]

Will try it - ta. Was new but feeds for two old rads available in ceiling so he uncapped and joined there. But four cap ends only one visibly coming off flow to my eyes so return was a 2 in 3 bet I reckon!

 

[Terry lambert]

Yes, just pick a side to balance the rad with, restricting either side will have the same effect

The reason we have a lockshield side is so that the customer can't tamper with the balancing of the system and undo all of our hard work, so it has q non turnable cap

The other side being a wheel head allows the customer to turn the rad on and off.

 

[Terry lambert]

If you want to be sure, wait until the system cools, then fire it up and see which end gets hot.

To save you messing around with a spanner when balancing, take one wheel head cap off and use that to turn the lock shields when balancing and then re fit it when you have finished

 

[UpAroundTheBend]

Thanks for the answers, all making good sense.

now ive just checked the inlet and outlet of the rads as they came on with the timer and on the 1 rad thats had a lockshield fitted...the lockshield is the inlet and the plastic knob is the outlet! Again, is this ok, and can I still do the balancing? Thanks again


by the way, the one with lockshield inlet is the kitchen one, which is the reason why I started googling today cos the kitchen always feels hotter than the front room. The plastic outlet knob on this was turned fully anti clockwise/open, havent touched the lockshield/inlet side.

 

[Terry lambert]

I obviously cant see what valves you have, but often an engineer will fit the same valves both sides and it is just the cap that is different, so you can swap the caps over if you like.

 

[UpAroundTheBend]

On the rad with the later fitted lockshield which is on the inlet side I have 2 different valves.

Theres the lockshield on the inlet side, just like the picture posted above..white plastic cap
sat on top of a narrow rectangular metal adjuster.

The outlet side has a bigger plastic cap which sits on top and attaches to a square valve adjuster by way of a little screw through the top of the plastic cap into the square valve adjuster.

can I still balance by opening the inlet/lockshield side fully anticlockwise, then closing the outlet/squarehead valve adjuster and turning back open a quarter turn or more?

its thrown me because everything ive read today on this topic always has the lockshield as the outlet and the big plastic knob/wheel/TRV on the inlet, then when I look at mine theyre on the other way round???