7.8.9 Thermostatic Control of Hot Water Temperature The unit is fitted with a Mixcall III Thermostatic Blending Valve, to control the hot water temperature, and prevent scalding.   Control Knob Position Min 1 2 3 4 5 6 7 Max Outlet Temp. (°C) 27 32 38 44 49 53 58 63 67 The Valve is adjustable from 27°C to 67°C, and has a lockable head, as shown. Typically the valve should be set to obtain a supply temperature of 65°C, to protect against Legionella.  Check the setting of the Thermostatic Blending Valve by opening a hot water outlet to a low flow rate (approximately 10 litres per minute) and measuring the output temperature. The head of the Blending Valve may be locked in position if required. The graph shows the pressure drop across the valve for various hot water flow rates.

7.9 Set the Room Thermostat as required.

7.10 Should the incoming mains flow rate exceed the maximum transfer rate for the domestic heat exchanger, the hot outlet temperature will drop. This can be corrected by adjustment of the stop cock on the incoming mains to achieve a flow rate off approximately 26 litres/minute.

7.11 Check that a copy of both the Installation / Users Instructions is left with the Heat Bank Thermal Store, or occupier, as required.