3 port valves
A very good heat pump will always allow for hot water priority, meaning when the hot water temperature drops, despite there being a demand for heating, the heat pump will stop heating the building and regenerate hot water.
To do this then the heat pump will need either 2 sets of zone valves (one hot water and one heating) or more commonly a 3 port diverting valve. This will either divert flow on the flow or the return to either the hot water cylinder and the heat distribution of the building.
3 port valves come in all shapes and sizes, some more reliable than others. Commonly they give trouble in the following heat pumps:
A typical heat pump will spend 80-90% of it’s time doing heating and 10-20% of the time doing hot water. This will vary from heat pump to heat pump and varies on installations. If however you find that your heat pump running a lot on hot water and that you may have hot water running hours over 30% then you may have an issue with your 3 port valve.
3 Port Valve