Rheem GPH series Installation Instructions Manual page 25

5. After 5 seconds of inter-purge, the
igniter heats for 30 seconds. After 30
seconds, the gas valve opens for 9
seconds. If no flame is sensed, it
closes the gas valve, the igniter de-
energizes, Both the main blower and
the inducer operate for 180 seconds
before the next ignition trial.
6. It repeats this process up to four times.
At the end of the last try, the inducer
stops immediately. The system is in
"soft" lock out for one hour.
7. The above sequence will repeat after a
one hour delay. It will continue
repeating until ignition is successful or
the call for heat is terminated.
8. To reset the lock out, make and
break power either at the
thermostat or at the unit disconnect
switch for 5 to 10 seconds. It then
goes through another set of trials for
ignition.
SETTING BLOWER TIMINGS
The UT Electronic Controls 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.
NOTE: This tap not available on (-)GPJ
or (-)GLJ.
IMPORTANT: Do not connect any
motor speeds to "HEAT" or "COOL" if
you use the "HEAT/COOL" terminal.
5. If heating and continuous speed are
the same, jump across "FAN" and
"HEAT" terminals.
NOTE: This does not apply to (-)GPJ or
(-)GLJ models because the heat tap
functions as the continuous fan tap as
well.
See Figures 19, 20 & 21 for instructions
for setting the blower "OFF" timings.
GAS FURNACE (DIRECT
DRIVE) INSTRUCTIONS FOR
CHANGING BLOWER SPEED
WARNING
!
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
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.
FIGURE 19
UT Electronic Controls 1028-928
BLOWER OFF TIMINGS
ON
NOTE: SWITCH 3 IS USED FOR
TWINNING APPLICATIONS.
I402
OFF TIME SWITCH 1 SWITCH 2
90 SEC. OFF ON
120 SEC. OFF OFF
160 SEC. ON OFF
180 SEC. ON ON
FIGURE 20
UT Electronic Controls 1012-925A
BLOWER OFF TIMINGS
(TIMER IS
RED BLOCK
ON BOARD)
OFF TIME SWITCH 1 SWITCH 2
90 SEC. OFF ON
120 SEC. OFF OFF
160 SEC. ON OFF
180 SEC. ON ON
FIGURE 21
UT Electronic Controls 1012-925B
BLOWER OFF TIMINGS
I335
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