Installations Instructions

39
F
ILT
ER
AIR FLOW
CENTRAL
RETURN
GRILLE
RETURN
DUCT
F
ILT
E
R
FILTER
SUPPORT
BRACKET
(Field Supplied)
FILTER
ACCESS
DOOR
Possible Upright Counterflow Filter Locations
Figure 44
HORIZONTAL INSTALLATIONS
Filters must be installed in either the central return register
or in the return air duct work.
S TART UP P ROCEDURE & A DJUST MENT
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 adjust-
ment items, refer to further information in Operat ional Checks
section.
MIN.
57%
78%
(80%)
100%
IGNITION
UNIT CALL FOR HEAT ENDS
10 MINS.
8 MINS.
2 MINS.
Operation with Conventional 1-Stage Thermostat
(DIP switch selects 1-Stage heat)
Figure 45
Call for heat, thermostat energizes W1 on the furnace con-
trol board (W2 input is ignored).
Af t er a successf ul Light Of f Sequence and expi r at ion of t he
Igni t ion St abil izat ion Per iod:
• The furnace control board adjusts the firing rate to
35% (low fire rate).
• After 2 minutes, the furnace control board increases
the firing rate to 57% at a rate of 1% per second.
• After 10 total minutes, the furnace control board
increases the firing rate to 78% at a rate of 1%
per second.
• After 20 total minutes, the furnace control board
increases to 100% at a rate of 1% per second for
the remainder of the call for heat.
• The circulator fan is adjusted to the appropriate
CFM, corresponding to the current firing rate.
MIN.
50%
60%
(80%)
70%
IGNITION
10 MINS.
8 MINS.
2 MINS.
Operation with Conventional 2-Stage Thermostat
(DIP switch selects 2-stage heat)
Figure 46
Call for 1st-Stage Heat - Thermostat contacts close R to W1.
Af t er a successf ul Light Of f Sequence and expi r at ion of
t he Igni t ion St abil izat i on Per iod:
• The furnace control board adjusts to the low firing
rate.
• After 2 minutes, the furnace control board
increases the firing rate to 50% for the next 8
minutes.
• Thereafter, the furnace control board will increase
the firing rate 10%, at a rate of 1% per second,
every 10 minutes for the remainder of the call for
heat (See above figure).
• The circulator fan is adjusted to the appropriate
CFM, corresponding to the current firing rate.
MIN.
50%
60%
(80%)
70%
IGNITION
10 MINS.
8 MINS.
2 MINS.
90%
Operation with Conventional 2-Stage Thermostat
(DIP switch selects 2-stage heat)
Figure 47