Reading Gas Pressure; Typical Heat/Cool Speed Tap Connections; Filter Performance - Pressure Drop Inches W.c. And (Kpa) - Unitary products group GY8S*UH Installation Manual

166753-UIM-C-0706
MANIFOLD PRESSURE "U" TUBE CONNECTION
OUTLET
PRESSURE TAP
GAS VALVE
FLAME
SENSOR
GAS
BURNERS
FIGURE 29: Reading Gas Pressure
ADJUSTMENT OF TEMPERATURE RISE ADJUSTMENT OF TEMPERATURE RISE
ADJUSTMENT OF TEMPERATURE RISE ADJUSTMENT OF TEMPERATURE RISE
The temperature rise, or temperature difference between the return
air and the supply (heated) air from the furnace, must be within the
range shown on the furnace rating plate and within the application
limitations shown in Table 7 "RATINGS & PHYICAL / ELECTRICAL
DATA".
The supply air temperature cannot exceed the "Maximum Supply
Air Temperature" specified in these instructions and on the fur-
nace rating plate. Under NO circumstances can the furnace be
allowed to operate above the Maximum Supply Air Temperature.
Operating the furnace above the Maximum Supply Air Temperature
will cause premature heat exchanger failure, high levels of Carbon
Monoxide, a fire hazard, personal injury, property damage, and/or
death.
The temperature rise, or temperature difference between the return air
and the heated supply air from the furnace, must be within the range
shown on the furnace rating plate and within the application limitations
as shown in Table 7.
After about 20 minutes of operation, determine the furnace temperature
rise. Take readings of both the return air and the heated air in the ducts,
about six feet (1.83 m) from the furnace where they will not be affected
by radiant heat. Increase the blower speed to decrease the temperature
rise; decrease the blower speed to increase the rise.
TABLE 15: Filter Performance - Pressure Drop Inches W.C. and (kPa)
Airflow Range
CFM Cm/m
0 - 750 0 - 21.24
751 - 1000 21.27 - 28.32
1001 - 1250 28.35 - 35.40
1251 - 1500 35.42 - 42.47
1501 - 1750 42.50 - 49.55
1751 - 2000 49.58 - 56.63
2001 & Above 56.66 & Above 463 0.0076 658 0.0108 0.19 0.0473 0.11 0.0274 0.18 0.0448 0.1 0.0249 0.3 0.0747 0.17 0.0423
24
1/4" TUBING
MAINIFOLD
PIPE
3.5 IN
WATER
COLUMN
GAS
PRESSURE
U-TUBE
SHOWN
MANOMETER
Minimum Opening Size
1 Opening 2 Openings 1 Opening
In³ m³ In³ m³ inwc
230 0.0038 0.01 0.0025
330 0.0054 0.05 0.0125
330 0.0054 0.1 0.0249
330 0.0054 0.1 0.0249
380 0.0062 658 0.0108 0.15 0.0374 0.09 0.0224 0.14 0.0349 0.08 0.0199 0.3 0.0747 0.17 0.0423
380 0.0062 658 0.0108 0.19 0.0473 0.11 0.0274 0.18 0.0448 0.1 0.0249 0.3 0.0747 0.17 0.0423
All direct-drive blowers have multi-speed motors. The blower motor
speed taps are located in the control box in the blower compartment.
Refer to Figure 31, and the unit-wiring label to change the blower
speed. To use the same speed tap for heating and cooling, the heat ter-
minal and cool terminal must be connected using a jumper wire and
connected to the desired motor lead. Place all unused motor leads on
Park terminals. Two are provided.
Do not energize more than one motor speed at a time or damage to
the motor will result.
ADJUSTMENT OF FAN CONTROL SETTINGS ADJUSTMENT OF FAN CONTROL SETTINGS
ADJUSTMENT OF FAN CONTROL SETTINGS ADJUSTMENT OF FAN CONTROL SETTINGS
This furnace is equipped with a time-on/time-off heating fan control. The
fan on delay is fixed at 30 seconds. The fan off delay has 4 settings (60,
90, 120 and 180 seconds). The fan off delay is factory set to 120 sec-
onds. The fan-off setting must be long enough to adequately cool the
furnace, but not so long that cold air is blown into the heated space. The
fan-off timing may be adjusted by positioning the jumper on two of the
four pins as shown in Figure 31.
FAN OFF
ADJUSTMENT
JUMPER
FIGURE 30: Typical Heat/Cool Speed Tap Connections
FILTER PERFORMANCE FILTER PERFORMANCE FILTER PERFORMANCE FILTER PERFORMANCE
The airflow capacity data published in Tables 17 & 18 represents blower
performance WITHOUT filters. To determine the approximate blower
performance of the system, apply the filter drop value for the filter being
used or select an appropriate value from the Table 15.
The filter pressure drop values in Table 15 are typical values for the
type of filter listed and should only be used as a guideline. Actual pres-
sure drop ratings for each filter type vary between filter manufacturers.
Filter Type
Disposable Washable Fiber
2 Openings 1 Opening
kPa inwc kPa inwc kPa
0.01 0.0025
0.05 0.0125
0.1 0.0249
0.1 0.0249
RED - LOW SPEED
YELLOW - MED. LOW SPEED
BLACK - HIGH SPEED
BLUE -MED. HIGH SPEED
NEUTRALS
Y/Y2 W
R G C
Pleated
2 Openings 1 Opening
inwc kPa inwc kPa
0.15 0.0374
0.2 0.0498
0.2 0.0498
0.25 0.0623
Unitary Products Group
2 Openings
inwc kPa