6
Thermann Installer’s Manual
25L & 50L Electric Storage Water Heaters
FILLING AND DRAINING
Filling the Water Heater:
The water heater must be filled with
water before turning on the electrical
supply.
1. Open all hot water taps.
2. Open the isolating valve at the cold
water inlet slowly and allow the
water heater to fill until water flows
through the system.
3. Close each hot water tap after the
air is expelled from its line.
4. Open the Pressure & Temperature
Relief Valve for approximately 10
seconds by lifting the easing lever
on the valve. Confirm water is
relieved to waste through the relief
valve drain pipe.
5. Lower the lever gently and check it
closes correctly.
Draining the Water Heater:
1. Turn off the electricity supply to the
water heater.
2. Turn off the cold water supply to the
water heater at the isolating valve.
3. Gently operate the easing lever on
the Pressure & Temperature Relief
(PTR) Valve to release the pressure
in the water heater.
4. Disconnect the cold water inlet
union and attach a drain hose to the
water heater.
5. Gently operate the easing lever
on the PTR Valve to let air into the
water heater and allow water to
escape through the hose.
Note: a combined isolating valve/non-return valve/line strainer may be used.
The expansion control valve is only required where local regulations demand,
although it is recommended in areas where the water saturation index is greater
than 0.40.
Cold Water Connection Diagram:
Summary of Contents for 25THMS124P
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