METER TIME IN MINUTES AND SECONDS FOR NORMAL
INPUT RATING OF FURNACES EQUIPPED FOR NATURAL
OR LP GAS
INPUT
BTU/HR
METER
SIZE
CU. FT.
HEATING VALUE OF GAS BTU PER CU. FT.
900 1000 1040 1100 2500
MIN. SEC. MIN. SEC. MIN. SEC. MIN. SEC. MIN. SEC.
ONE 1 12 1 20 1 23 1 28 3 20
45,000
TEN 12 0 13 20 13 50 14 40 33 20
ONE 1 5 1 12 1 15 1 18 3 20
50,000
TEN 10 50 12 00 12 30 13 12 30 00
ONE 0 48 0 53 0 55 0 59 2 13
67,500
TEN 8 0 8 53 9 15 9 50 22 13
ONE 0 44 0 48 0 50 0 53 2 0
75,000
TEN 7 12 8 0 8 19 8 48 20 0
ONE 0 33 0 36 0 38 0 40 1 30
100,000
TEN 5 24 6 0 6 15 6 36 15 0
ONE 0 26 0 29 0 30 0 32 1 12
125,000
TEN 4 19 4 48 5 0 5 17 12 0
ONE 0 31 0 24 0 25 0 26 1 0
150,000
TEN 3 36 4 0 4 10 4 20 10 0
Heating Value of Gas (BTU/Ft
3
) x 3600
Input BTU/HR =
Time in Seconds (for 1 cu.ft.) of Gas
TABLE 4
FIGURE 25
UTEC - 925
BLOWER OFF TIMINGS
OFF TIME SWITCH 1 SWITCH 2
90 SEC. OFF ON
120 SEC. OFF OFF
160 SEC. ON OFF
180 SEC. ON ON
(TIMER IS
RED BLOCK
ON BOARD)
I335
27
SETTING BLOWER TIMINGS
The Honeywell and UTEC control
boards have four quick connect
terminals for connecting the motor
speed leads. These are:
1. FAN SPEED — motor runs on this
speed when the thermostat is in the
“FAN” position.
2. COOL — connect desired cooling
speed.
3. HEAT — connect desired heating
speed.
4. HEAT/COOL — connect desired
speed when heating and cooling
speed are the same.
IMPORTANT: Do not connect any
motor speeds to “HEAT” and “COOL” if
you use the “HEAT/COOL” terminal.
5. If heating and continuous speed are
the same, jump across “FAN” and
“HEAT” terminals.
See Figures 23, 24 and 25 for instructions
for setting the blower “OFF” timings.
GAS FURNACE (DIRECT
DRIVE) INSTRUCTIONS FOR
CHANGING BLOWER SPEED
DISCONNECT THE ELECTRICAL
SUPPLY TO THE FURNACE BEFORE
ATTEMPTING TO CHANGE THE
BLOWER SPEED. FAILURE TO DO
SO CAN CAUSE ELECTRICAL
SHOCK RESULTING IN SEVERE
PERSONAL INJURY OR DEATH.
The blower motor is wired for blower
speeds required for normal operation
as shown.
If additional blower speed taps are
available (leads connected to “M1” and
“M2” on the electronic control), speeds
may be changed if necessary to fit
requirements of the particular
installation. Reconnect the unused
FIGURE 23
UTEC -920 OR WHITE RODGERS
50A62-101 BLOWER OFF
TIMINGS
FIGURE 24
HONEYWELL E2001
BLOWER OFF TIMINGS
OFF TIME SWITCH 1 SWITCH 2
90 SEC. OFF ON
120 SEC. OFF OFF
160 SEC. ON OFF
180 SEC. ON ON
OFF TIME SWITCH 1 SWITCH 2
90 SEC. ON OFF
120 SEC. OFF OFF
160 SEC. OFF ON
180 SEC. ON ON
TWIN
2nd
SINGLE
1st
NOTE: SWITCHES 3 & 4 ARE USED
FOR TWINNING APPLICATIONS.
ON
(TIMER IS
RED BLOCK
ON BOARD)
I402
I335
WARNING
!
motor leads to “M1” or “M2.” Check
motor lead color for speed designation.
Heating speeds should not be reduced
where it could cause the furnace air
temperature to rise to exceed the
maximum outlet air temperature
specified for the unit.
IMPORTANT: Always check air
temperature rise after changing the
heating speed for any reason.
ADJUSTING OR CHECKING
FURNACE INPUT
The maximum gas supply pressure to
the furnace should be 7( W.C. for
natural gas. The minimum gas supply
pressure for purposes of input
adjustment to the furnace should be 5(
W.C.
A properly calibrated manometer or
gauge is required for accurate gas
pressure readings.
The manifold pressure should be set at
3.5( W.C. for natural gas. Only small
variations in the gas flow should be
made by means of the pressure
regulator adjustment. In no case
should the final manifold pressure vary
more than plus or minus 0.3( W.C.
from the above specified pressures.
To adjust the pressure regulator:
1. Remove the regulator cap.
2. Turn the adjustment screw
clockwise to increase pressure or
counterclockwise to decrease
pressure.
3. Replace the regulator cap securely.
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