If fitting a secondary return on a cylinder that has a secondary return connection. I understand you just need to fit a pump pointing back to the cylinder? No check valve is needed like when you tee it in to the cold connection? Someone implied to me you needed one when going in to the secondary connection on the cylinder. Can't see why.
Secondary return hot water
- Thread starter Matt887
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Not clear what you're asking. Can you post a sketch?
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We have a return flow as you described.
The check valve ensures water only flows from the supply connection - which is higher and has hotter water.
When our check valve failed (stuck) water was fed from both connections to the bathroom, taking much longer to warm up.
That's only significant if, like us, you switch the return flow on shortly before you use water. If the pump is on 24/7 it doesn't matter if you have a check valve, though you'll find the waste of heat expensive.
The check valve ensures water only flows from the supply connection - which is higher and has hotter water.
When our check valve failed (stuck) water was fed from both connections to the bathroom, taking much longer to warm up.
That's only significant if, like us, you switch the return flow on shortly before you use water. If the pump is on 24/7 it doesn't matter if you have a check valve, though you'll find the waste of heat expensive.
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Easier to show you -
(edit) - Just to add, the ISO's are there to allow easy servicing of the pump and check valve
(edit) - Just to add, the ISO's are there to allow easy servicing of the pump and check valve
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Our pump is on a timer. It comes on just before get up for 30 minutes and again just before we go to bed. We have a manual override zo turn it on before we use the bath.
Outcome? It's great to get almost instant hot water and bath top ups are hot, too, even in winter.
I turned it completely off for a couple of days out of curiousity and the electrical energy saved was barely noticeable.
On the other hand, we have no way of knowing how much heat was lost from the water. Gas consumption normally varies daily by a larger amount than any saving I could find using daily meter readings.
Outcome? It's great to get almost instant hot water and bath top ups are hot, too, even in winter.
I turned it completely off for a couple of days out of curiousity and the electrical energy saved was barely noticeable.
On the other hand, we have no way of knowing how much heat was lost from the water. Gas consumption normally varies daily by a larger amount than any saving I could find using daily meter readings.
Do you mean if it was fitted somewhere else, or not fitted?
I suppose when the pump is not running, draw-off would be some from the cylinder top connection, and some slightly cooler from the lower connection (backwards through the pump). I'd be surprised if you'd notice the difference in practice.
Secondary circuit must be run in copper, you shouldn’t use plastic pipes
Check valve is there to avoid reverse circulation
Not necessarily we use tectite metal (aluminium layer in it) with tectite classic fittings and correct insert)
Other makes are available.
Reverse circulation, as in when the pump is off if on a timer. The secondary pipework could draw water out of the cylinder, if no check valve?
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