AWUF Installation Manual

4
NOTE: The use of a heat shield when brazing is recommended
to avoid burning the serial plate or the finish on the unit.
Heat trap or wet rags should be used to protect heat
sensitive components such as service valves and TXV
valves.
Electrical Connections – Supply Voltage
USE COPPER CONDUCTORS ONLY.
A knockout is provided on the air handler top panel or side
to allow for the entry of the supply voltage conductors. If
the knockouts on the cabinet sides are used for electrical
conduit, an adapter ring must be used in order to meet
UL1995 safety requirements. An NEC or CEC approved strain
relief is to be used at this entry point. The wire is to be
sized in accordance with the “Electrical Wire and MOP” sec-
tion of this manual. Some areas require the supply wire to
be enclosed in conduit. Consult your local codes.
Achieving Less Air Leakage:
Ensure all the gaskets remain intact on surfaces as shipped
with the unit. When these requirements are satisfied, the
unit achieves the following airflow leakage when tested in
accordance with ASHRAE Standard 193:
-Cabinet air leakage less than 2% at 1.0 inch H
2
O
-Cabinet air leakage less than 1.4% at 0.5 inch H
2
O
Fresh Air Openings
All AWUF and AWUT models include 4” fresh air knockouts
on both sides of the cabinet. To utilize, simply remove the
appropriate knockout and connect fresh air inlet venting
directly to cabinet. Ensure the unit mounting system does
not block the fresh air inlet holes. On the AWUF18, AWUF24,
and AWUT24 models, the fresh air will be filtered within
the unit. On all other AWUF models, external filtering for
the fresh air must be provided by the installer. AWUT31,
32 and 37 models are equipped with fresh air filter brack-
ets. These brackets are located on both sides of the cabi-
net at each fresh air intake location.
NOTE: The installing contractor must take into account any
lost capacity due to the the fresh air openings when sizing
the equipment.
Special Instructions
AWUF - FLOWRATOR (PISTON) MODELS
This air handler comes equipped with an evaporator coil
with a check style flowrator assembly, an indoor blower and
all necessary internal electrical wiring. For most installa-
tions with matching applications, no change to the flowrator
orifice is required. However, in mix-matched applications,
a flowrator change may be required. See the piston kit chart
or consult your local distributor for details regarding mix-
matched orifice sizing. If the mix-match application requires
a different piston size, change the piston in the distributor
on the indoor coil before installing the coil and follow the
procedure in this section.
The evaporator coil is shipped from the factory with
approximately 90 PSI tracer gas charge. Use caution
when relieving pressure.
To prevent feeder tube damage, hold the distributor body
with a 3/4" open end wrench when removing or replacing
the 13/16" flare nut.
CAUTION
1. Remove the valve core to allow high pressure tracer
gas to escape. No gas indicates a possible leak.
2. Remove the 13/16" flare nut and tailpiece.
3. Unsweat the access fitting from the suction line.
4. Remove the check piston to verify it is correct and
then replace the piston. See piston kit chart in in-
structions.
5. Unsweat the cap on the tailpiece.
6. Slide the 13/16" flare nut over the tailpiece.
7. Braze tailpiece to the lineset liquid tube.
8. Insert the suction line into the connection, slide the
insulation at least 18" away from the braze joint.
Braze suction line.
9. AFTER THE TAILPIECE HAS COOLED, confirm posi-
tion of the white Teflon® seal and hand tighten
the 13/16" flare nut.
10.Torque the 13/16" flare nut to 10-25 ft-lbs or tighten
1/6th turn.
Excessive torque can cause orifices to stick. Use the proper
torque settings when tightening orifices.
CAUTION
11. Replace suction line insulation.
12. After installation, evacuation and charging of the low
side is complete, check fittings for leaks.
NOTE: With the piston in the distributor, the seal end should
point inside the distributor body and should not be seen
when looking into the end of distributor. Make sure the
piston is free to rotate, and move up and down in the
distributor body.