6
4.0 INSTALLATION -
DISCHARGE PIPE REQUIREMENTS
4.1
The discharge outlet from the Pressure (expansion) Relief Valve and the Tem-
perature/Pressure relief Valve must be connected to a discharge pipe. It is recom-
mended that the tundish 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 unob-
structed.
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 in the terminal
cover. It is possible to lock the thermostat knob in either the mid-range or a “hot”
position by following the procedures in 5.9 or 5.10 below. Always switch off the
electrical supply before removing the terminal cover.
5.9 Setting the “mid-range” position:
Rotate the thermosatat knob to the mid postion. Remove the terminal cover by
using a large flat bladed screwdriver to depress the three snap lugs located in the
three top rectangular depressions. Holding the thermostat knob in position turn
the terminal cover over and remove the backing disc from the underside of the
