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2.6 Low temperature kit (ceiling mounting)
Hinge back the fan plate and remove the inner draintray,
Lay the heater element on the coil block and fix using clips
supplied. Ensure that the heater is secure. Refit the inner
drain tray over the heater.
For models TEC1 to TEC6, the heater is wired back to the
terminal box using the additional electrical block provided
in the kit. On models TEC7 and TEC8 the heater should
be wired to the additional terminal box provided in the kit
which should be fixed to the back plate, adjacent to the
motor terminal box. Ensure all wiring is secure and clear
of the fan.
Low temperature kit (wall mounting)
This defrost kit must be used in conjunction with the wall
mounting kit. If a ceiling mount defrost kit is fitted, this
must be removed. Hinge back the fan plate and feed coil
face heater wires through holes in coil end plates, and se-
cure elements with wire clips provided. Sandwich the drain
pan elements between the backing plate (supplied) and
heater retaining plate (supplied) and secured to studs us-
ing washers and wing-nuts provided. Thread heater wires
through the knock-outs back to the existing terminal box.
(On models TEC7 and TEC8 an additional terminal box is
provided for heater connection, which should be fitted to
the back plate adjacent to the motor terminal box.) Fix the
guard across the front of the drain pan using the screws
and inserts provided.
If the initiation of defrost periods is by a timing device then
it is recommended that it be initially set to four defrost
periods per 24 hours until operating experience is gained.
System 'pump down' (fans running) is recommended
(essential on very low temperature applications) prior to
defrost so that the resulting defrost is neither prolonged
nor uneven.
Drain line heater cables or tapes should be permanently
energized and cover the drain pan connection.
Fitting A Defrost Termination Thermostat'
If a defrost termination device is fitted then it can be
located inside the electrical end closing plate and installed
in accordance with the manufacturer's instructions.
The phial should initially be positioned near vertical
between the coil fins on the air on side. Once the system
is in operation it may be necessary to relocate the phial to
the area of the coil where ice remains the longest during
defrost (possibly on air face). It is secured into position bt
wrapping the fins around it.
Initial Defrost Termination Settings
Time/Time defrost system
Electric defrost: 20 minutes
Time/Temperature termination system
Electric defrost minimum setting: 4.5°C
Time/Pressure termination system
Reverse cycle/hot gas defrost
Pressure equivalent to 25°C SST of the system
refrigerant.
Time: 10 min
Drain Down Time
A 'drain down' time, with fans off and no cooling, of five
minutes duration should be given immediately following a
defrost termination.
Fan Delay Setting
a)
With Thermostat: -7°C
b)
With Pressure Switch: Refrigerant pressure at a
saturation temperature of -12°C
3. Inital Starting
Before running the unit for the first time, check that all
guards, motor mountings and electrical covers are secure,
all unnecessary terminal block links are removed, internal
wiring is clear of fans and that the fans rotate freely. After
allowing the unit to operate at conditions close to design,
the TEV must be adjusted to provide the correct level of
superheat. This is between 0.6 and 0.75 x cooler TD, to a
maximum of 8K. Similarly review all defrost settings.
4. MAINTENANCE (Routine)
WARNING!
UNIT MUST BE ELECTRICALLY ISOLATED BEFORE MAINTENANCE
WORK IS UNDERTAKEN.
The following routine maintenance is required:
Periodically inspect units for ice build up where the
bient temperature is below 5°C.
Every 12 months check
Check security of fixings especially fan motor mountings.
Check motor(s) rotate freely.
Check electrical connections for security of attachment.
When necessary
Clean the fins, guard, drain pan and drain lines and gen-
eral casework. Care must be taken when cleaning fins to
prevent damage. A soft brush and mild detergent solution
is recommended.
5. Component Replacemen
Access to all electrical components is achieved by lowering
the fanplate/drainpan.
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