We need to install a HW recirculation pump and circuit in our Village Hall. There is a very long draw off from the HWC in the loft to the furthest tap in the Doctors Consulting room handbasin. As a result the water does not reach 55 degrees C within 1 minute which is the requirement for our legionella risk assessment. (I don't wish to get into discussion about need for Legionella risk assessment only that it is required by NHS and the two surveys we have had done have both highlighted HW temperature as a problem).
I need to get a plumber to install a recirculating pump in the loft near the HWC and run pipework to the furthest point we can reach where it will be connected to HW supply pipe. Our aim is to install a pipe thermostat on the newly installed return pipe which will control the pump so that when the HW flow reaches temperature it will turn off the pump. In addition control of the electrical supply to the pump will be taken from the two port valve so that the pump only runs when the cylinder is calling for heat from the boiler. I don't know how much load the pump would put on the controller and wiring but aim to use a seperate 13amp spur with a relay so that the pump load is not added to the existing boiler controls.
After reading other discussions on this forum about not being able to use standard PolyPipe or similar we aim to use pre-lagged 16mm Uponor MLC pipe which is rated for continuous HW temperatures.
The return from the pump to the HW cylinder will be via the existing "Shower"boss 2/3 of the way up the cylinder. This will hopefully avoid too much mixing of the colder water at the bottom of the cylinder and reduce energy wastage.
My question is where should we locate the pipe thermostat to ensure the pump doesn't cycle too much. I was thinking about asking the plumber to install a short length of copper pipe approximately 1M from the pump inlet onto which the pipe thermostat can be clamped. The reason being that the MLC between the copper and pump inlet should prevent any heat conduction from the pump body as it warms up.
I need to write up a spec for plumbers to quote against to ensure they follow what is required. Any observations or advice on the above setup would be appreciated.
I need to get a plumber to install a recirculating pump in the loft near the HWC and run pipework to the furthest point we can reach where it will be connected to HW supply pipe. Our aim is to install a pipe thermostat on the newly installed return pipe which will control the pump so that when the HW flow reaches temperature it will turn off the pump. In addition control of the electrical supply to the pump will be taken from the two port valve so that the pump only runs when the cylinder is calling for heat from the boiler. I don't know how much load the pump would put on the controller and wiring but aim to use a seperate 13amp spur with a relay so that the pump load is not added to the existing boiler controls.
After reading other discussions on this forum about not being able to use standard PolyPipe or similar we aim to use pre-lagged 16mm Uponor MLC pipe which is rated for continuous HW temperatures.
The return from the pump to the HW cylinder will be via the existing "Shower"boss 2/3 of the way up the cylinder. This will hopefully avoid too much mixing of the colder water at the bottom of the cylinder and reduce energy wastage.
My question is where should we locate the pipe thermostat to ensure the pump doesn't cycle too much. I was thinking about asking the plumber to install a short length of copper pipe approximately 1M from the pump inlet onto which the pipe thermostat can be clamped. The reason being that the MLC between the copper and pump inlet should prevent any heat conduction from the pump body as it warms up.
I need to write up a spec for plumbers to quote against to ensure they follow what is required. Any observations or advice on the above setup would be appreciated.
