6
4.0 INSTALLATION - DISCHARGE PIPE REQUIREMENTS
4.1
The discharge outlet from the Pressure (expansion) Relief Valve and the
Temperature/Pressure relief Valve must be connected to a discharge pipe. It is
recommended that a tundish (not supplied) be installed in the discharge pipe to
give a visible indication that the valves are operating.
4.2
The discharge pipe must fall continuously from the valve outlets and be
unobstructed.
4.3
The pipe from the valves to the tundish should be 15mm o/dia minimum. From the
tundish to the point of discharge the pipe should be 22mm o/dia minimum and have
a resistance to flow equivalent to 9 metres of straight pipe. Long discharge pipe
runs should have an increased internal diameter.
4.4
The pipe material should be capable of conveying water/steam at 100
o
C.
4.5
The final discharge point should be in a safe, visible position.
5.0 COMMISSIONING
5.1
Do not switch on the electrical supply until the unit has been filled with water and
checked for leaks.
5.2
Check that all installation, electrical and discharge pipe requirements have been
met.
5.3
Check that all water and electrical connections are tight.
5.4
Open a hot water tap, turn on mains water supply to the heater.
5.5
Allow unit to fill and leave hot tap running for a short while to purge any air and
flush out the pipework. Close the hot tap and check the system for leaks.
5.6
Manually test the operation of the Temperature/Pressure Relief Valve and, if fitted,
the Pressure (expansion) Relief Valve. Ensure water flows freely from the valve(s)
and through the discharge pipes.
5.7
Switch on the electrical supply. The indicator light will illuminate during heating.
When the set temperature is reached the indicator light will go out.
5.8
The set temperature can be adjusted by rotating the knob located on the Combined
Thermostat and Thermal Cut-out. Access to adjust the temperature is gained by
removing the terminal cover using a flat bladed screwdriver to release the two clips
located towards the front of the terminal cover either side.
