A heat pump requires a hot water cylinder that is Heat Pump compatible. Usually this means a high surface area coil. The reason for this is that as a heat pump works at a high flow rate with low temperature difference of 5 degrees, you need a high surface area to transfer the heat into the water, otherwise the heat pump won’t be able to do it’s job correctly.
If you have a relatively new hot water cylinder and cannot see the economic viability of replacing in order to install a heat pump. You can opt for a retrofit solution in the form of a plate heat exchanger. See diagram below (please note this is a simplified diagram to show the concept)
- Plate heat exchanger rated for heat pump.
- Insulation Jacket / Shell for the Plate Heat exchanger.
- Hot Water Recirculator pump
- Isolation valves & non-return valves as necessary.
- 2 port or 3 port according to plumbing arrangement ie 2 x 2 port for S plan, or 3 port if using Y plan or W plan in the case of PDHW
Electrical Installation Instructions
Once the plumbing components are connected as shown in the diagram, with optional isolation valves omitted, you simply have to connect the live from the the hot water demand signal either by direct means to the hot water recirculation pump and heat pump switch live (or dry contact depending on interface) or indirectly via the 2 port relay switch which will activate the hot water recirculation pump and provide switch live signal to the heat pump (or dry contact depending on interface).
Priority Demand Hot Water
Please note if you have PDHW setup then you would wire accordingly.