Filling up
1. Open a hot tap.
2. Open the cold water supply valve
3. when water flows from hot tap, close the tap
4. Allow the system to stabilize for 5 minutes
5. Open each hot water tap in turn to expel air from the system pipe work.
6. Check for leaks.
7. Manually operate Temperature and Pressure Relief Valve (5) to ensure free water flow through
discharge pipe. (Turn knob to left.)
Draining
Switch the electrical power off (important to avoid damage to element). Isolate boiler from OSO unit.
Turn off the cold water supply valve. Open hot water tap close to cylinder. Open drain (13). The unit
will drain.
Safety Cut-out
1. The safety cut-out operates if:
a. Wiring is incorrect.
b. The immersion heater thermostat or cylinder thermostat fails.
c. Thermostat is set too high.
2. Remember before resetting the safety cut-out or altering the thermostat setting, isolate electrical
supply to the unit prior to removal of the electrical box lid.
3. Reduce thermostat setting and press the reset button. After adjustments are completed, ensure
the lid to the electrical box is replaced correctly and the retaining screw is fitted.
4. If still out of operation, contact installer.
Cold or tepid water discharge from tundish
1. Close cold water supply valve
2. Open a hot tap.
3. Repressurise the expansion vessel air charge to its set level.
4. close hot tap
5. Open the cold water supply valve
Hot water discharge from tundish
This indicates a malfunction of a thermal cut-out, operating thermostat or the combined temperature
and pressure relief valve. Turn off the electrical supply to the immersion heater and also isolate an
indirect unit from the boiler. Contact the installer or competent engineer.
-4-
COMMISSIONING
SAFETY AND MAINTENANCE
RECOMMISSIONING INSTRUCTIONS
