My heating balancing

[Stevie1710]

I have a combi boiler and i am trying to balance my heating as it has never been done. I am following instuctions i got from the web.

I have ran in to a problem i hope someone can help me.

One of the first instuctions was to find out what side on the Rad was the flow and what was the return. What side got hot first then this was the flow.

Problm i have is i have 3 Rad's with the thrmostatic valves on the flow side. How can i turn them to reduce the flow of water in to that Rad?

Are the vavles the wrong way around??

Help!!!!!!

Stevie

 

[Agile]

Its normal and in some cases essential to put the TRVs on the flow side.

Its normal to have lockshields on the return ends.

I would recommend you to follow the instructions in the FAQ on this site.

Tony

 

[Hugh Jaleak]

Balancing should be done using the lockshield valves, opposite end of the rad to the thermostatic valves. The TRV's govern room temperature, dont use them to try and balance the system.

Balancing instructions are in the FAQ's, at the top of the plumbing forum index page if you need them!

 

[Stevie1710]

Yes i am using the FAQ's to do the balancing.

So i should put all the TVR's on the return side then???

 

[45yearsagasman]

I'll have a go.......Do not use trv's to balance rads.If your trv's are on the flow..leave them there and only use the lockshield valves to balance.I don't know how else to explain it

 

[Agile]

The FAQs are self explanatory.

If you cannot understand them then at least open the TRVs all fully before balancing.

Tony

 

[Stevie1710]

Ok i dont think i am putting this over right here.

TVR's are fully open.

One Rad had the TVR on the flow side but i have only a 5c difference from one side to the other. This to me says the water is flowing through this too fast. So i need to slow it down but i cant as the TVR is on the flow side.

Now should i change the TVR to the other side of the Rad??

Hope i have explained this better now.

Sorry if i am being dumb.

 

[silverback18]

adjust the locksheild valve to balance the system, most modern TRV valves can be fitted on the flow or return as they are bi-directional, so it does not matter if your TRV is on the flow or return, but it will ALWAYS be the locksheild valve that is adjusted in the balancing of the system, this will increase or decrease the flow through the radiator.

 

[Stevie1710]

ok cheers...... getting late i will try it again tomorrow night.

Thatnks for ur help.

 

[TicklyT]

The way I would put it is the lockshield valves control the maximum heat input to each radiator, and TRVs only control the final room temperature

Balancing is adjusting the heat input to radiators so each rad gets it's fair share of the boiler output.

If the input to a rad. is too high, the radiator cannot absorb the heat, so hot water is returned to the boiler, shutting it down prematurely.

If the input to a rad is set too low, it tales longer to heat a room, and again may cause the boiler to shut down prematurely, as it is producing more heat than the radiators can absorb.

As the LSVs control the input to each rad, they are the ones that should be balanced.

The TRVs only take over control when the room approaches the desired temperature. As they open and shut themselves automatically, they cannot be used to balance a system.

It usually makes no difference which valve is on which pipe, as both are in series, controlling the same flow of water, except for some TRVs, which only work correctly if the flow is in the right direction through the valve body. most valves are either placed for convenience of the user, or to accurately sense room temperatures in the case of TRVs

 

[onlyfitidealboilers]

i often use my temp leads on rads just to set the bypass rad up, when cheaking other radiators even if the radiators only cracked open on the lockshield i end up with 3 or 4 degree temp diff open full an i get no drop at all. granted the bigger the radiator the faster the water will flow, smaller the rad the greater the restriction.

 

[Agile]

There is usually little difference between the resistance INSIDE a rad.

Most of the resistance in in the valves. Thats why balancing is so important.

In fact its almost possible to achieve an adequate balance by following a simple setting of lockshields open 1/2 turn on single rads less that 100 mm long and ONE turn open on larger rads.

Tony

 

[onlyfitidealboilers]

yes but say you carn't have any more then 20 degree temp diff across the boiler an all the trvs switch off your then only have a poxi small bypass rad this will act as a restriction, thats why bypass radiators need to be bigger....