Balancing rads after having 1 cold radiator (lockshields hardly open?)

[SMH78]

Hi Everyone!

I just need a bit of advice on balancing radiators after managing to get 1 cold rad working, i'm just a general DIY'er hence the need for professional feedback.

Initially i had 1 cold rad in Utility room toward rear of house, no matter what i did i could not get this to work, also some of other downstairs rads weren't as hot as they could have been. So to start with i turned down all/closed the lockshields (apart from cold rad) to force the flow there. Good news it got hot so i then decided to go upstairs and release the lockshields 1/4 turn and see what happened. Again, good news everything stayed hot as i imagine i forced flow downstairs.

I then backed off the rads lockshields downstairs 1/4 turn and assessed. Again good news, all stayed hot, however obviously i wanted to increase flow in some of rads furthest from boiler so i started to increase some of these a little to 3/4 to 1 full turn individually, however this is when i noticed some of the further rads from boiler started to cool down a little.

It seemed anything more than 1/4 to 1/3 turn in any of the rads further from boiler caused them to lose some heat and only be betweeen warm and hot.

Firstly, by having all lockshields upstairs open 1/4 turn and the majority downstairs also 1/4 turn, am i keeping too much pressure in system and maybe also not giving enough return flow?

Should i leave as is or assess if i can increase flow in any of the rads to increase return flow and reduce pressure a little?

No idea whether keeping the flow to a minimum out of all rads is a bad thing?

Just to note, boiler is in garage and pipework comes into house under the floors upstairs which is why i imagine the upstairs was easier to get hot.

Thanks in advance,

Steve.

 

[doitmyself]

1/4 to 1/2 turn open sounds about right.

What is the pump speed setting - if it's adjustable?

 

[SMH78]

1/4 to 1/2 turn open sounds about right.

What is the pump speed setting - if it's adjustable?

Thanks for the reply!
I have no idea on that one, i will have to take a look, and to see if adjustable.

So a quarter turn throughout house will not overstress anything and provide adequate return flow to boiler?

 

[Chuck]

I find 'quarter turns' to be a bit coarse for accurate balancing. I use 'hours' , i.e. 1/12th turns. Smart (i.e. constant pressure, or PP) pumps make balancing a lot easier than it used to be but these days one wants to a bit more careful about the temperature drops. It's no longer hot vs cold but getting delta-T in the appropriate range.

 

[Rob Foster]

Thanks for the reply!
I have no idea on that one, i will have to take a look, and to see if adjustable.

So a quarter turn throughout house will not overstress anything and provide adequate return flow to boiler?

basically you cannot do any harm...is like all the trv closing down cause house is hot enough, pump,speed is a good try . you should have one bypass rad with no trv and bith valves open ...a little if required BUT not closed
centralheatking

 

[doitmyself]

I use 'hours' , i.e. 1/12th turns.

The hexagonal nut round the valve spindle is a useful guide as point to mid-flat is 1/12th of a turn.