Hot water cylinder return balancing valve?

[Dannyparty92]

Is it a must to fit these valves on all new hot water cylinders? And what's the purpose of these valves just to balance the heat output between the hot water and heating?

[Best]

It is a must if the system is to be properly balanced. The coil in a cylinder means the flow & return are just linked together, with no resistance, so a bypass, short circuit, easy route is created & wastes the pumps performance. A valve fitted will be needed. Also IMO a good idea to have both the return & flow to cylinder fitted with valves so as to isolate if changing cylinder on oil or gas systems.

[Mike Jackson]

Under part L of the building regulations a balancing valve should no longer be fitted. For energy efficiency the coil requires the full output of the boiler for a rapid heat up, The reason for a balancing valve is to share the boiler output between the circuits and make sure that the coil doesn't rob the heating. Under Part L a programmer with independent time control of heating and hot water is required so this is not an issue as the hot water can be set to come on 30 minutes before the heating is required.

[Dannyparty92]

Thank you for your answers. So if the hot water was too hot and hardly no heat in the radiators all you would do is simply close the balanceing valve off slightly so the heat going to the heating as well as heating the contents of the hot water cylinder evenly.

[Best]

I had no idea that part L regs now say a balancing valve should no longer be fitted. Interesting thought as to always heating water separately.
However, if you do have the heating to hot water on at the same time as the radiators - & people will be in the habit of both heating at times, then the system will be badly balanced & would need a valve. Take the example, bad weather, heating on all day, people using a lot of hot water, so cylinder needs reheated.
I wonder if a self adjusting valve, like the way the bypass valves work would make more sense on the cylinder circuit?

[Best]

Thank you for your answers. So if the hot water was too hot and hardly no heat in the radiators all you would do is simply close the balanceing valve off slightly so the heat going to the heating as well as heating the contents of the hot water cylinder evenly.

If the cylinder is supplied with 22mm or larger pipes, the valve will usually need well turned down to slow the flow enough.

[Dannyparty92]

Thanks for your answers guys so the balanceing is fitted on y plans s plans and gravity systems?

[Best]

You don't balance gravity pipes to cylinder as they are not pumped & so are not affecting the balancing of pumped circuits. Only solid fuel can nowadays have gravity pipes.
Also not supposed to restrict gravity pipes & besides, a valve could be turned off by mistake someday, which on a solid fuel boiler wouldn't be a good idea.
Always leave gravity primaries & their vent & feed pipes fully open & without valves.

[Mike Jackson]

I had no idea that part L regs now say a balancing valve should no longer be fitted. Interesting thought as to always heating water separately.
However, if you do have the heating to hot water on at the same time as the radiators - & people will be in the habit of both heating at times, then the system will be badly balanced & would need a valve. Take the example, bad weather, heating on all day, people using a lot of hot water, so cylinder needs reheated.
I wonder if a self adjusting valve, like the way the bypass valves work would make more sense on the cylinder circuit?

I learnt this last time I did my unvented. Also with the rapid recovery times of modern cylinders it's not such an issue.