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Section 4. Commissioning the Heater - All Types
Before starting to commission a heater read this section through and fully understand its contents.
Only competent engineers should carry out the work.
Commissioning of the cooling equipment must be carried out in accordance with the cooling equipment
manufacturers instructions and relevant codes of practice.
4.1
Pre Commission Checks
Checks before lighting the unit heater
Ensure that the heater and all controls are suitable for the gas, pressure and electrical supply that
they are being connected to.
4.1.1
Electrical Checks
A preliminary electrical check should be carried out by a qualified engineer, after completion of the
installation and before commissioning the heater as follows:-
Check that all site wiring is connected in accordance with the appropriate wiring diagram of Section 5.
Check the correct 10A fuses are fitted and that they are connected in the live conductors (see Polarity
Test below).
Earth Continuity Test
The appliance earthing must be tested using a suitable method according to local regulations. The
resistance of the earth circuit from the heater to the earth connection must be 0.1 ohm or less.
Polarity Test
Connect one lead of a suitable voltmeter to earth and connect the other lead to the each of the phase
supply terminals in turn at the heater.
Turn on power to heater. A reading of approximately 230 volts 50 Hz AC should be found for each
phase. The same result should be obtained by connecting the test leads from live to neutral.
A test between any two phases must indicate 400volts.
Note: should the fan rotate in the wrong direction, interchange any two incoming supply phases to
correct.
Connecting the voltmeter between Neutral 'N' and Earth should give a reading of 0 volts. If these
tests do not conform to the above there is a fault which must be rectified before progressing further
with the commission. An electrician should be consulted to carry out this work.
Note: For Automatic Ignition models the burner control box will not operate with a neutral to earth
voltage above 15v and may be unreliable at any reading other than 0.
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