Hi
I'm considering putting a secondary return loop and pump to help reduce the time it takes for the hot water to reach the taps since we installed an unvented cylinder in the garage.
Currently the hot water pipe from the cylinder goes straight into the loft and across to central point where the old vented hw cylinder was installed previously to redistribute throughout the house. it takes approx 1 minute to get the hot water flowing from the taps. The size of the main pipes are 22mm and from the garage to the furtherest point ~16m + ~5m from garage to loft = 21m.
My questions
- What size should the return pipe be? I was under the impression 15mm should be enough to reduce the amount of hot water in the pipes and reduce the amount of water to criculate.
- I was looking at Grundfos UP 15-14BA PM GB bronze pump and the Wilo Star-Z Nova T. Both these only have 1m delivery head and I wanted to check if this is sufficient for the flow required for the secondary return? It's a pressurised system so it may be good enough but wasn't sure if a larger pump would be required.
- Any preferences on either pump? Does the autoadapt on the Grundfos work well?
- We have an ASHP so the water temp in the cyclinder is not as high as with gas boiler - (50c I think or it may be 45c).
Many thanks for your responses.
I'm considering putting a secondary return loop and pump to help reduce the time it takes for the hot water to reach the taps since we installed an unvented cylinder in the garage.
Currently the hot water pipe from the cylinder goes straight into the loft and across to central point where the old vented hw cylinder was installed previously to redistribute throughout the house. it takes approx 1 minute to get the hot water flowing from the taps. The size of the main pipes are 22mm and from the garage to the furtherest point ~16m + ~5m from garage to loft = 21m.
My questions
- What size should the return pipe be? I was under the impression 15mm should be enough to reduce the amount of hot water in the pipes and reduce the amount of water to criculate.
- I was looking at Grundfos UP 15-14BA PM GB bronze pump and the Wilo Star-Z Nova T. Both these only have 1m delivery head and I wanted to check if this is sufficient for the flow required for the secondary return? It's a pressurised system so it may be good enough but wasn't sure if a larger pump would be required.
- Any preferences on either pump? Does the autoadapt on the Grundfos work well?
- We have an ASHP so the water temp in the cyclinder is not as high as with gas boiler - (50c I think or it may be 45c).
Many thanks for your responses.
