•
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,
corresponding to the current firing rate.
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,
corresponding to the current firing rate.
90%
IGNITION
(80%)
70%
60%
50%
2 MINS.
MIN.
Operation with Conventional 2-Stage Thermostat
(DIP switch selects 2-stage heat)
10 MINS.
8 MINS.
10 MINS.
8 MINS.
Call for 2nd-Stage Heat - Thermostat contacts close R to W1
and W2.
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 80%.
•
Thereafter, the IFC will increase 10%, at a rate of 1%
per second, every 10 minutes for the remainder of
the call for heat.
•
The circulator is adjusted to the appropriate CFM,
corresponding to the current firing rate.
100%
IGNITION
(80%)
78%
50%
2 MINS.
MIN.
Call for 2nd-Stage Heat with 1st-Stage call for heat call in
progress, with conventional 2-Stage Thermostat.
•
The IFC increases the firing rate to 100% at a rate of
1% per second for the remainder of the W2 call.
•
The circulator is adjusted to the appropriate CFM,
corresponding to the current firing rate.
Call for 2nd-Stage Heat satisfied; Call for 1st-Stage Heat re-
mains.
•
The IFC remains at the current firing rate until the
1st-Stage call for heat is satisfied.
H
O
EATING
PERATION WITH
(C
)
OMMUNICATING
•
When the Thermostat Heat Setup DIP switch is set
to 2-Stage heat, the IFC operation will be compatible
with a CTK01AA communicating thermostat.
•
When a call for heat is sent, the furnace will go through
the Light Off Sequence, at which time the Heat Current
Demand Status will still show 0%. After the successful
Light Off Sequence and expiration of the Ignition
Stabilization Period:
•
The IFC adjusts to the low firing rate.
•
After 2 minutes, the IFC accepts the specific Heat
Requested Demand.
36
UNIT CALL FOR HEAT ENDS
CALL FOR
2ND STAGE HEAT
CTK01AA T
HERMOSTAT