Evacuation
To avoid potential moisture related problems, it is neces-
sary to evacuate the complete system to a minimum of
1 torr (1.3mbar). All parts of the system must be above
freezing and ideally higher than +10°C during evacua-
tion.
Electrical
All motors are single phase with automatic internal over-
load protection, and can be operated in conjunction
with a high quality ‘triac’ type speed controller.
Generally ‘cage clamp’ type terminals are used. These
are opened by inserting a correctly sized screwdriver
into the square aperture adjacent to the conductor en-
try.
Low temperature models
Defrost
The electric defrost option is supplied in kit form. The
kit consists of a heater element, securing clip(s) (except
JG1) and a terminal block for electrical connection. To fit
the heater element, first remove the fan plate and inner
drain tray. The elements should be located as shown
using the clips provided, (Diag 1) and the inner drain
tray refitted.
The terminal blocks provided with the defrost kit should
be clipped onto the DIN rail inside the junction box. En-
sure that the cable is routed via the cable tie used for the
earth lead and that all cables are secured clear of the
fan(s) when the fan plate is repositioned.
If the initiation of defrost periods is by a timing device
then it is recommended that it be initially set to four de-
frost 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
energised and cover the drain pan connection.
Initial Defrost Termination Settings
Time/Time defrost system
Electric defrost: 30 minutes
Time/Temperature termination system
Electric defrost minimum setting: 4.4°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.
INITIAL STARTING
Before running the unit for the first time, check that all
guards, motor mountings and electrical covers are se-
cure, 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 UNDER-
TAKEN.
The following routine maintenance is required:
Periodically inspect units for ice build up where the
ambient temperature is below 5°C.
Every 12 months check
Security of fixings especially fan motor mountings.
Refrigerant pipeline for damage and leaks.
Motor(s) rotate freely.
Electrical connections for security of attachment.
Defrost, if used, is operating effectively.
When necessary
Clean the fins, guard, drain pan and drain lines and
general casework. Care must be taken when clean-
ing the fins to prevent damage. A soft brush and mild
detergent solution is recommended.
5.
INVALIDATION OF GUARANTEE
Failure to install, set up or put to work any part of the
equipment in the manner specified in the Installation
and Maintenance Instructions could invalidate the
guarantees set out in the Standard Terms and
Conditions of Sale.
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