Service Manual

PRODUCT DESIGN
15
LINE VOLTAGE W IRING
Power supply to the unit must be N.E.C. Class 1, and must comply
wit h all applicable codes. The unit must be electrically grounded
in accordance wit h the local codes or, in their absence, with the
latest edition of the Nat ional Electrical Code, ANSI/ NFPA No. 70,
or in Canada, Canadian Electrical Code, C22.1, Part 1. A fused
disconnect ed must be provided and sized in accordance with the
unit minimum circuit ampacit y.
The best protection for the wiring is the smallest fuse or breaker
which will hold the equipment on line during normal operat ion
wit hout nuisance t rips. Such a device will provide maximum cir-
cuit protect ion.
WARNING
DO NOT EXCEED THE MAXIMUM OVERCURRENT
DEVICE SIZE SHOWN ON THE UNIT DATA PLATE.
All line volt age connections must be made through weat her proof
fit tings. All exterior power supply and ground wiring must be in
approved weat her proof conduit. Low voltage wiring from the
unit control panel t o the thermost at requires coded cable.
The unit transformer is connected for 230V operat ion. If the
unit is to operat e on 208V, reconnect the transformer primary
lead as shown on the unit wiring diagram.
If it is necessary for the inst aller to supply additional line volt age
wiring t o the inside of t he package unit, t he wiring must comply
wit h all local codes. This wiring must have a minimum tempera-
ture rating of 105°C. All line voltage splices must be made inside
the unit or heat kit control box.
Expansion Valve (TXV) System
SINGLE SPEED APPLICATION (APH1624-42)
1. Purge gauge lines. Connect service gauge manifold to ac-
cess fittings. Run syst em at least 10 minut es to allow pres-
sure t o stabilize.
2. Temporarily inst all thermomet er on liquid (small) line near
liquid line access fitting with adequat e contact and insu-
late for best possible reading.
3. Check subcooling and superheat. Systems with TXV applica-
tion should have a subcooling and superheat within t he
range list ed on the chart .
a. If subcooling and superheat are low, adjust TXV then check
subcooling.
b. If subcooling is low and superheat is high, add charge to
raise subcooling then check superheat.
c. If subcooling and superheat are high, adjust TXV valve then
check subcooling.
d. If subcooling is high and superheat is low, adjust TXV valve
superheat and remove charge to lower the subcooling.
The TXV should NOT be adjusted at light load conditions
55º to 60º F, under such condit ions only the subcooling can
be evaluated. This is because suction pressure is dependent
on indoor air flow, and wet bulb temperature.
NOTE: Do NOT adjust charge based on suction pressure unless
there is a gross undercharge.
4. Disconnect manifold set. Installation is complet e.
TWO SPEED APPLICATION (APH1642-60 / APC1560)
Run t he unit on low st age cooling for 10 minutes until
refrigerant pressures st abilize. Follow the guidelines and
met hods below to check unit operat ion and ensure that the
refrigerant charge is within limits. Charge the unit on low
stage.
1. Purge gauge lines. Connect service gauge manifold to ac-
cess fittings. Run syst em at least 10 minut es to allow pres-
sure t o stabilize.
2. Temporarily inst all thermomet er on liquid (small) line near
liquid line access fitting with adequat e contact and insu-
late for best possible reading.
3. Check subcooling and superheat. Two st age systems run-
ning on high stage with TXV applicat ion should have a
subcooling and superheat within t he range listed on the
chart.
a. If subcooling and superheat are low, adjust TXV then check
subcooling.
NOTE: To adjust superheat , turn the valve st em clockwise
to increase and counter clockwise to decrease.
b. If subcooling is low and superheat is high, add charge to
raise subcooling then check superheat.
c. If subcooling and superheat are high, adjust TXV valve su-
perheat , t hen check subcooling.
d. If subcooling is high and superheat is low, adjust TXV valve
superheat and remove charge to lower the subcooling.
NOTE: Do NOT adjust the charge based on suct ion pressure
unless there is a gross undercharge.