REFCO LAC Extreme - Manual (Page 3)

HVAC/R
Service Products
REFCO Manufacturing Ltd. Telefon +41 41 919 72 82
Industriestrasse 11 Telefax +41 41 919 72 83
CH-6285 Hitzkirch (Switzerland) [email protected] www.refco.ch
Fitting the Sensor
The HPC sensor is fitted to one of the return bends typically mid-way
through the condenser coil circuit, where it can pick up the temperature
of the condensing gas. Wrap tie around twice for small tubes. Use a heat
sink compound between the sensor and the tune for a good thermal bond.
Insulate using foam tape. Do not over-tighten as damage can be caused
to the sensor bead, which is protected by a thin black insulating sleeve is
damaged. On two-sensor models, each sensor should be fitted to its own
section of the condenser, in the centre of the condensing circuit.
Heat pump Models
Where the head pressure controller is to be used with a heat pump, the con-
denser fan needs to run at full speed during the heating mode, and is only
modulated during the cooling mode. The controller used with heat pumps
therefore have 2 extra terminals which are connected across the reversing
solenoid valve. These then receive a signal feed from either solenoid which
is energised to switch on to heating, and this signal causes the controller to
run the fan at full speed.
Setting Up
The control range of the controller is 30°C to 60°C, and the set point is adjus-
ted by means of the control spindle on the face of the controller. Minimum
speed is factory set for 50Hz operation as standard. Product marked with a
yellow sticker adjacent to the adjuster, indicates that the controller is con-
figured for 60Hz operation. Therefore no further adjustment is necessary.
The minimum fan speed is factory-set to give a motor voltage of 100V for
230V models and 60V for 110V models, which produce a speed of around
30% of maximum, depending in the motor characteristics. Minimum speed
adjustment on low temperature cut-off Models is not advised. To adjust mi-
nimum speed, disconnect sensor and switch on unit, fan automatically runs
at minimum speed after hard start, adjust carefully until the fan is running
just fast enough to prevent stalling in windy conditions. Switch off and re-
connect sensor.