Automatic bypass valve required or not?

[stu550]

Hi All

I have what I think is a Y plan system - the hot water goes into a valve which either goes to the radiators or the hot water cylinder.

There is a gate valve used as a bypass currently. I was looking at switching this for an auto bypass but not sure if anything is actually required.

The question is, do I actually need any bypass on this system? If the pump is still pumping, I presume it sends it to the HW cylinder rather than hitting a block wall? Am I right in thinking the current valve either sends the water left or right? It can't just stop it?

Many thanks

Stuart

 

[45yearsagasman]

If you have thermostatic rad valves on all rads then the bypass is required. If say at least 2 rads have no trv's then you can get away with no bypass. The flow rate through the boiler should be maintained to the boiler specs. Automatic bypasses are now recommended.

 

[D_Hailsham]

When the boiler is running the motorized valve on a Y plan system can be open in any one of three positions: HW only; HW and CH (mid-position); CH only. When the boiler goes out the valve will be in either HW or CH position, depending on which finished last.

 

[stu550]

Thanks - there's one towel rail without a thermostat and another large radiator in a large room that never gets up to temperature (another story) so sounds like it will be okay closing this valve down.

 

[stu550]

Oh, and it's a worcester greenstar camray 18/25. The manual says:

An automatic bypass valve must be connected between the heating flow and return where TRVs are used on all radiators, fitted to give at least a 3 metre circuit when activated.

 

[Nige F]

another large radiator in a large room that never gets up to temperature (another story) so sounds like it will be okay closing this valve down.

you might find that rad gets up to temperature then.

 

[stu550]

The rads get hot, they're just undersized for the size of the room... big old stone house, no insulation, high ceilings in the that room...