47
Step 14 — Check Belt Tension
Measure the belt span length as shown in Fig. 54. Calculate the
required deflection by multiplying the belt span length by
1
/
64
.
For example, if the belt span length is 32 inches: 32 x
1
/
64
=
1
/
2
inch deflection.
BELT FORCE — DEFLECTION METHOD
Check the belt tension with a spring-force belt force deflection
gauge (available from drive belt manufacturer).
1. Place a straightedge along the belt between the two pul-
leys. Measure the distance between the motor shaft and
the blower shaft.
2. Set the tension gauge to the desired tension (see Table 1 in
Fig. 54). Place the large O-ring at that point.
3. Press the tension checker downward on the belt until the
large O-ring is at the bottom of the straightedge.
4. Adjust the belt tension as needed.
Adjust belt tension by loosing the motor mounting plate front
bolts and rear bolt (see Fig. 55) and slide the plate towards the
fan (to reduce tension) or away from the fan (to increase ten-
sion). Ensure the blower shaft and motor shaft are parallel to
each other (pulleys aligned). Tighten all bolts securely when
finished.
BELT TENSION METHOD
Requires belt tension gauge that measures tension in belt in
units of lbs force.
Fig. 54 — V-Belt Force Label
Fig. 55 — Belt Drive Motor Mounting
Pre-Start and Start-Up
This completes the mechanical installation of the unit. Refer to
the unit’s Service Manual for detailed Pre-Start and Start-Up
instructions. Download the latest versions from HVAC Part-
ners (www.hvacpartners.com).
Typical Unit Piping
Each heat pump refrigeration system includes a compressor, ac-
cumulator, reversing valve, dual-function outdoor coil with va-
por header check valve, cooling liquid line with a filter drier and
a check valve, dual-function indoor coil with a vapor header
check valve, and heating liquid line with a check valve and a
strainer. See Fig. 56 and Tables 21-23 for typical unit piping
schematic. Dual-function outdoor and indoor coils are designed
to provide parallel coil circuits during evaporator-function oper-
ation and converging coil circuits during the condenser-function
operation.
Table 1
Table 2
BELT
CROSS
SECTION
SMALLEST
SHEAVE
DIAMETER
BELT DEFLECTION FORCE (LBS)
UNNOTCHED
BELTS
NOTCHED BELTS
USED
NEW
USED
NEW
A, AX
3.0-3.6
3.7
5.5
4.1
6.1
3.8-4.8
4.5
6.8
5.0
7.4
5.0-7.0
5.4
8.0
5.7
8.4
B, BX
3.4-4.2
—
—
4.9
7.2
4.4-5.6
5.3
7.9
7.1
10.5
5.8-8.6
6.3
9.4
8.5
12.6
BELT CONDITION
TENSION FORCE IN BELT (LBS)
New
100
Used
80
BLOWER PULLEY
V-BELT
MOTOR
PULLEY
MOTOR
MOTOR MOUNTING
PLATE
MOUNTING
BOLTS (4)
Summary of Contents for 50HCQD07
Page 4: ...4 Fig 2 Unit Dimensional Drawing 07 08 Size Units ...
Page 5: ...5 Fig 2 Unit Dimensional Drawing 07 08 Size Units cont ...
Page 6: ...6 Fig 3 Unit Dimensional Drawing 09 Size Units ...
Page 7: ...7 Fig 3 Unit Dimensional Drawing 09 Size Units cont ...
Page 24: ...24 Fig 37 Electro Mechanical Control Wiring 50HCQ A07 D07 208 230v 460v 575v ...
Page 25: ...25 Fig 38 Electro Mechanical Control Wiring 50HCQ D07 Tier 2 1 Compressor 208 230v 460v 575v ...
Page 26: ...26 Fig 39 Electro Mechanical Control Wiring 50HCQ 08 09 208 230v 460v 575v ...
Page 27: ...27 Fig 40 Electro Mechanical Power Wiring 50HCQ A07 D07 208 230v 460v 575v ...
Page 28: ...28 Fig 41 Electro Mechanical Power Wiring 50HCQ D07 Tier 2 1 Compressor 208 230v 460v 575v ...
Page 29: ...29 Fig 42 Electro Mechanical Power Wiring 50HCQ 08 09 208 230v 460v 575v ...
Page 30: ...30 Fig 43 PremierLink Wiring Schematic 50HCQ07 09 208 230v 460v 575v ...
Page 31: ...31 Fig 44 RTU Open System Control Wiring ...
Page 49: ......
