When the R to G and Y1 circuit open, the furnace blower
continues operating on FAN speed for an additional 90 sec.
To set the cooling off-delay to 3 sec instead of 90, connect
a jumper between the Y1 and DHUM thermostat connects
on the furnace control.
c. Two-Speed Outdoor Unit with Thermidistat-See Figure 11
and 13.
The dehumidification output, DHUM, on the Thermidistat
should be connected to the furnace control thermostat
terminal DHUM. When there is a dehumidify demand, the
DHUM input is activated, which means 24 vac signal is
removed from the DHUM input terminal. In other words,
the DHUM input logic is reversed. The DHUM input is
turned ON when no dehumidify demand exists and is
turned OFF when demand exists. Once 24 vac is detected
by the furnace control on the DHUM input, the control
operates in Thermidistat mode.
The thermostat closes the R to G and Y1 circuits for low
cooling and the R to G, Y1 and Y/Y2 circuits for high
cooling. The R to Y1 circuit starts the outdoor unit on low
cooling and the R to G and Y1 circuits start the furnace
blower on FAN speed. The R to Y1 and Y2 circuits start the
outdoor unit on high cooling and the R to G, Y1 and Y2
circuits start the furnace blower in COOL speed. If the R to
Y2 circuit opens with the R to G and Y1 circuits still
closed, the outdoor unit will drop to low cooling and the
furnace control will drop the blower speed to FAN. When
the thermostat is satisfied, the R to G and Y1 circuits are
opened. The outdoor unit stops. When there is a dehu-
midify demand, the cooling blower off-delay is decreased
from 90 to 3 sec.
In Two-Speed Cooling with only the R to G and Y1 circuits
closed and there is a demand for dehumidification, the
furnace control blower will remain at FAN speed. In high
cooling with a demand for dehumidification, the furnace
control will drop the blower speed from COOL to HEAT
for a maximum of 10 minutes before reverting back to
COOL speed. If there is still a demand for dehumidification
after 20 minutes, the control will drop the blower speed
back to HEAT speed. This alternating 10-minute cycle will
continue as long as there is a call for cooling. If the DHUM
input is low for more than 48 hours, the control reverts back
to non-Thermidistat operation.
3. Continuous blower mode
NOTE:
EAC-1 terminal is energized with 115v whenever blower
operates.
When the R-G circuit is made, the blower motor operates on
FAN speed. During a call for heat, the blower stops, allowing
the furnace heat exchangers to heat up more quickly, then
restarts at the end of the 45-sec blower on delay period at
HEAT speed. If jumper is across PL7-6 AND PL7-9, the
blower on delay is 66 sec.
The blower reverts back to FAN speed after the heating
blower OFF delay is completed.
When the thermostat "calls for cooling," the blower operates
on COOL speed. When the thermostat is satisfied, the blower
operates an additional 90 sec before reverting back to con-
tinuous operation on FAN speed.
4. Continuous blower speed selection from thermostat
To select different continuous blower speeds from the room
thermostat, momemtarily turn off the FAN switch or pushbut-
ton on the room thermostat for 1-3 sec after the blower is
operating. The control will shift the blower speed from factory
setting of FAN to HEAT speed. Momentarily turning off the
FAN switch again at the thermostat will shift the continuous
blower speed selection from HEAT to COOL. Repeating the
procedure will cause the control to shift from COOL to FAN
speed. The selection can be changed as many times as desired
and is stored in the memory to be automatically used follow-
ing a power interruption.
5. Heat pump mode
When installed with a heat pump, the furnace control auto-
matically changes the timing sequence to avoid long blower
off time during demand defrost cycles. When the W-Y1,
W-Y/Y2, W-Y1-G, or W-Y/Y2-G thermostat inputs are re-
ceived at the same time, the control changes the blower to
HEAT speed or starts the blower if it was off, and begins a
heating cycle. The blower remains on until the end of the
prepurge period, then shuts off until the end of the ignition
warm-up and trial for ignition periods (a total of 24 sec). The
blower then comes back on at HEAT speed.
When the W input signal disappears, the control begins the
normal inducer post-purge period and the blower changes to
COOL speed after a 1-sec delay. If the W-Y/Y2-G or W-Y1-G
signals disappear at the same time, the blower remains on for
the selected heating blower off delay period and the inducer
goes through its normal post-purge period. If the W-Y1 or
W-Y/Y2 inputs should disappear, leaving the G signal input,
the blower remains on at HEAT speed for the selected blower
off-delay period and the inducer remains on for the normal
post-purge period. After the blower off-delay is completed the
control switches the blower to FAN speed.
Anytime the control senses false flame, the control locks out
of the heating mode. This occurs because the control cannot
sense the W input due to the false flame signal, and as a result,
sees only the Y/Y2 and/or Y1 input and goes into cooling
mode, blower off delay. All other control functions remain in
standard format.
NOTE:
EAC-1 terminal is energized whenever blower operates.
HUM terminal is only energized when gas valve is energized
START-UP PROCEDURES
1. Purge gas lines—After all connections have been made, purge
the lines and check for leaks.
Never purge a line into a combustion chamber. Never use
matches, candles, flame, or other sources of ignition for the
purpose of checking leakage. Use a soap-and-water solution
to check for leakage. Failure to follow this warning can cause
fire, explosion, personal injury, or death.
2. Component test—The furnace control board allows all com-
ponents, except gas valve, to be run for a short period of time.
This feature helps diagnose a system problem in case of a
component failure. To initiate component test procedure, short
(jumper) the TEST 3/16-in. quick connect terminal on control
(behind the Y/Y2 terminal) and the C
OM
-24V terminal on
furnace thermostat connection block for approximately 2 sec.
(See Fig. 15.)
NOTE:
Component test feature will not operate if any thermostat
signal is present at control board.
Component test sequence is as follows.
a. Momentarily jumper TEST and C
OM
-24V terminals until
LED goes off.
b. LED will display previous status code 4 times.
15
Summary of Contents for WEATHERMAKER 8000 58WAV
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