Goodman GMVM Service Instructions Manual page 47

OPERATION
H I
ORIZONTAL NSTALLATIONS
Filters must be installed in either the central return register or in
the return air duct work.
Startup Procedure & Adjustment
Furnace must have a 115 VAC power supply properly connected
and grounded. Proper polarity must be maintained for correct
operation. In addition to the following start-up and adjustment
items, refer to further information in Operational Checks section.
100%
IGNITION
(80%)
78%
57%
2 MINS.
MIN.
Operation with Conventional 1-Stage Thermostat
(DIP switch selections 1-Stage heat)
Call for heat, thermostat energizes W1 on IFC (W2 input is
ignored).
After a successful Light Off Sequence and expiration of the
Ignition Stabilization Period:
• After 2 minutes, the IFC increases to 57% at a rate of
1% per second
• After 10 total minutes, the IFC increases to 78% at a
rate of 1% per second.
• After 20 total minutes, the IFC increases to 100% at a
rate of 1% per second for the remainder of the call for
heat.
• The circulator is adjusted to the appropriate CFM, cor-
responding to the current firing rate.
UNIT CALL FOR HEAT ENDS
10 MINS.
8 MINS.
IGNITION
(80%)
70%
60%
50%
2 MINS.
MIN.
Operation with Conventional 2-Stage Thermostat
(DIP switch selects 2-stage heat)
Call for 1st-Stage Heat - Thermostat contacts close R to W1.
After a successful Light Off Sequence and expiration of the
Ignition Stabilization Period:
• The IFC adjusts to the low firing rate.
• After 2 minutes, the IFC increases to 50% fort he next
8 minutes.
• Thereafter, the IFC will increase 10%, at a rate of 1%
per second, every 10 minutes for the remainder of the
call for heat (See above figure).
• The circulator is adjusted to the appropriate CFM, cor-
responding to the current firing rate.
10 MINS.
8 MINS.
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