12
°
OUTDOOR TEMP
° F ° C
115 46
45 7
55 13
65 18
75 24
95 35
105 41
85 29
C00019
Fig. 18 -- Cooling Charging Chart, 50ZP042 Units
°
OUTDOOR TEMP
° F ° C
115 46
125 52
45 7
55 13
65 18
75 24
95 35
105 41
85 29
C00020
Fig. 19 -- Cooling Charging Chart, 50ZP060 Units
Step 5 — Un it Con trols
All compressors have the following internal-- protection controls.
HIGH--PRESSURE RELIEF VALVE — This valve opens when
the pressure dif ferential between the low and high side becomes
excessive.
COMPRESSOR OVERLOAD — This overload interrupts power
to the compressor when either the current or internal temperature
become excessive, and automatically resets when the internal
temperature drops to a safe level. This overload may require up to
60 minutes (or longer) to reset; therefore, if the internal overload is
suspected of being open, disconnect the electrical power to the unit
and check the circuit through the overload with an ohmmeter or
continuity tester.
Step 6 — Sequence of Operation
FAN OPERATION — The FAN switch on the thermostat controls
indoor fan operation. When the FAN switch is placed in the ON
position, the IFR (indoor-- fan relay) is energized through the G
terminal on the thermostat. The normally--open contacts close,
which then provide power to the indoor (evaporator) fan motor
(IFM). The IFM will run continuously when the FAN switch is set
to ON.
When the FAN switch is set to AUTO, the thermostat deenergizes
the IFR (provided there is not a call for cooling). The contacts open
and the IFM is deenergized. The IFM will be ener gized only when
there is a call for cooling.
NOTE: 50ZP030 and 060 units are equipped with a time--delay
relay. On these units, the indoor fan remains on for 30 seconds
after G or Y is deenergized.
COOLING — On a call for cooling, the compressor contactor (C)
and the IFR are energized through the Y and G terminals of the
thermostat. On units with a compressor time--delay relay, there is a
5-- minute (±45 sec) delay between compressor starts. Energizing
the compressor contactor supplies power to the compressor and the
outdoor (condenser) fan motor (OFM). Energizing the IFR
provides power to the IFM.
When the need for cooling has been satisfied, the OFM,
compressor , and IFM (FAN on AUTO) are deenergized. If the unit
is equipped with a 30--second delay, the indoor fan will remain
energized for 30 seconds after the compressor is deenergized (030
and 060 units only).
MAINTENANCE
To ensure continuing high performance, and to reduce the
possibility of premature equipment failure, periodic maintenance
must be performed on this equipment. This cooling unit should be
inspected at least once each year by a qualified service person. To
troubleshoot cooling of units, refer to Troubleshooting chart in
back of book.
NOTE: TO EQUIPMENT OWNER: Consult your local dealer
about the availability of a maintenance contract.
PERSONAL INJURY AND UNIT DAMAGE
HAZARD
Failure to follow this warning could result in personal
injury or death and possible unit component damage.
The ability to properly perform maintenance on this
equipment requires certain expertise, mechanical skills,
tools and equipment. If you do not possess these, do not
attempt to perform any maintenance on this equipment,
other than those procedures recommended in the Owner ’s
Manual.
!
WARNING
The minimum maintenance requirements for this equipment are as
follows:
1. Inspect air filter(s) each month. Clean or replace when
necessary.
2. Inspect indoor coil, outdoor coil, drain pan, and condensate
drain each cooling season for cleanliness. Clean when
necessary.
3. Inspect blower motor and wheel for cleanliness each
cooling season. Clean when necessary .
4. Check electrical connections for tightness and controls for
proper operation each cooling season. Service when
necessary.
5. Check the drain channel in the top cover periodically for
blockage (leaves, insects). Clean as needed.
50ZP
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