hot return

[Fallout]

Hey when adding a hot return to a hot water cylinder is a check valve required after the bronze circulating pump. So it would go bronze circulating pump then check valve the hot return cylinder connection?

 

[neiltheplumber]

Not required!

 

[Agile]

That's probably a matter of opinion!

It depends very much on whether the pump is left running all the time ( which is very wasteful ) like many I see. In that case it could be argued that its not really necessary.

But if the pump is thermostatically controlled and only run for a couple of minutes every 10-15 min then I would say that it is needed to ensure the hot water comes from the top of the cylinder to the outlets.

Tony

 

[Fallout]

If the pump is to have a timer on it so it only runs say between 7am and 5pm every day is it then required?

 

[neiltheplumber]

To be fair I've never come across one on a timer but as you say if it's on a timer it would make sense to fit a check valve.

 

[Fallout]

and is it best fit after the bronze pump and cylinder connection?

 

[Fallout]

Is it common to tee the hot return pipe in to the hot pipework at the furthest hot water draw off point?

 

[neiltheplumber]

Yes you need the furthest point but think of it as a loop. If there are sections that tee off to another part of the building then again these will return at the furthest point and and can tee into the return back to the cylinder.

What type of cylinder is it?

You can tee the return into the cold feed so long as there is a check valve on the cold which you would have anyway on an unvented system. Some cylinders have a connection at the bottom solely for the return.

 

[Fallout]

Yes you need the furthest point but think of it as a loop. If there are sections that tee off to another part of the building then again these will return at the furthest point and and can tee into the return back to the cylinder.

What type of cylinder is it?

You can tee the return into the cold feed so long as there is a check valve on the cold which you would have anyway on an unvented system. Some cylinders have a connection at the bottom solely for the return.

Thanks yes there are sections of the hot that tee off to a different area can I tee the hot return in at more than one place?

 

[Boilerman2]

Fit a Non-return valve, it will prevent reverse flow when pump is not running, and will also prevent Gravity circulation (both are wasteful and to be avoided!)

 

[neiltheplumber]

Yes you can. If it's a large property then you may need to balance the return with lock shields (gate valve type) or oventrop valves.

 

[Steelmasons]

Whether circulator is running or not a NRV is required.

 

[Agile]

It is not very ideal to return the loop to the cold inlet of the cylinder as that will effectively lengthen the reheat time before you get some useful hot water. It can provide some benefits if hot water usage is not very high compared with the store volume.

I see little point in timing the loop pump between 7am to 5pm.

Many advantages in having it on a thermostat though. Then in addition perhaps inhibited overnight.

A non return valve does no harm and in many configurations is beneficial ( or essential ).

Tony

 

[Fallout]

Untitled

• Fallout
• 30 Sep 2013
• 1

Would a hot return loop that tees off both ways to connect to the hot pipework work ok as shown in the picture?

 

[neiltheplumber]

It is not very ideal to return the loop to the cold inlet of the cylinder as that will effectively lengthen the reheat time before you get some useful hot water. It can provide some benefits if hot water usage is not very high compared with the store volume.

I see little point in timing the loop pump between 7am to 5pm.

Many advantages in having it on a thermostat though. Then in addition perhaps inhibited overnight.

A non return valve does no harm and in many configurations is beneficial ( or essential ).

Tony

Why would it effect reheat time? If there's no demand then the cold will not flow and therefore not effect anything.either way the cold enters the cylinder and will be always cold wherever it enters, so the return mixing with the cold when it enters can't be any different to the cold hitting a hot tank?!