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Service Facts
STAND ALONE OPERATION
(CONTINGENCY MODE)
The Contingency Mode allows the installer to set the
equipment to operate in an ON/ OFF Duty Cycle
mode. This mode will be activated using the User
Interface. Contingency Mode is NOT available in
24VAC mode. The user will select the desired level
of capacity required, Stage 1 (40%) or 2 (100%). The
user will select the desired ON/ OFF Duty Cycle,
10% minimum to 50% maximum, (10% increments,
10% = 2 minutes On, 18 minutes Off; 50% = 10
minutes on, 10 minutes off).
CONTINGENCY MODE
Note:
Stage 1 = 40% (low) heat, Stage 2 = 100% (high) heat
Note:
If a communicating comfort control is detected to be
present and the contingency mode is selected,
NOT AVAILABLE will be displayed on the User
Interface.
•
Stand alone operation can only be entered at the
user interface.
•
Stand alone operation can be set up to operate the
furnace in Heating Only.
•
The contingency mode is used when the communi-
cating comfort Control is not communicating with
the furnace or when setting gas manifold pres-
sures.
•
Before attempting to enter contingency mode,
disconnect the Data wire "D" from the Furnace
IFC terminal block.
•
The contingency mode will function only when the
Furnace IFC is not flashing a fault code at its
Fault LED.
•
To enter the contingency mode of operation, turn
115 VAC power off. When the Green LED on the
variable speed inducer drive goes out, turn 115
VAC power back on.
•
Scroll down using the down arrow 6 at the User
Interface until you see CNTNGNCY Mode, then
press the Enter button.
•
CNTNGNCY MODE and 3 STAGE 4 will now
be displayed. Press the Enter button.
•
STAGE and 3OFF [OFF] will now be displayed.
First or Second heat stage must be selected. Use
3or4
the
arrows
of heat wanted and then push the Enter button
and then the 6 button.
•
DUTY CYCLE and 10% [10%] will now be dis-
played. A duty cycle must now be selected from 10
to 50%. A 10% duty cycle will run the furnace for
2 minutes and then off for 18 minutes. A 50%
duty cycle will run the furnace for 10 minutes and
then be off for
10 minutes. These duty cycles
will be repeated 3 times per hour. Use the 3or4
arrows to select a duty cycle and then push the
Enter button and then
14
to
select
the
stage
the 6 button.
•
Start and NO [NO] will now be displayed. With
a NO/NO question being asked, use the 3or4
arrows to select the YES and then press the
ENTER button.
•
Are you Sure and NO [NO] will now be dis-
played. With a NO/ NO question being asked,
use the 3or4 arrows to select the YES and then
press the ENTER button.
•
Turn 115VAC power off. When the Green LED on
the variable speed inducer drive goes out, turn
115 VAC power back on.
•
When the furnace is operating in the contingency
mode (stand alone operating cycle), the user
interface will display the following information.
The top line will say CNTNGNCY MODE. The
bottom line will show the duty cycle stage num-
ber STG (1 or 2) selected, and the percent num-
ber 10-50 % selected.
•
All furnace operating controls, pressure switches
and communications between the IFC and the
variable speed inducer drive and the variable
speed indoor blower will be functional during
contingency mode operation of the furnace.
•
The 3456 and ENTER buttons do not func-
tion in the contingency mode of operation.
•
To exit the contingency mode of operation turn
off the 115 VAC power to the furnace.
•
The contingency mode will stop for any of the
following reasons:
(1) If the furnace IFC receives a signal from
the communicating comfort control. This will
only happen if the data wire "D" from the comfort
control has been reconnected to the furnace IFC
terminal board terminal "D".
(2) Power is removed from the furnace and
then turned back on.
(3) The Furnace IFC enters a RESET mode
of operation.
(4) A fault is detected by the furnace IFC.
Fault LED will be flashing an Alert Code.
24V CONTINGENCY MODE
An alternative method for the contingency mode can
be used by changing the mode of operation in the
Use Interface to 24V mode and installing a
conventional 24V comfort control.
To set this mode of operation:
Remove all wiring from the *CONT900 comfort
control and install a 24V comfort control. If the
comfort control requires a 24V common; connect
R and B to respective terminals. Connect a third
wire to "W". At the control board, connect the
same three wires to the corresponding terminals.
Jumper W1 to W2 at the control board.
stage delay between W1 and W2 can be set by
scrolling thru the User Interface. It is factory set
to zero minutes but can be adjusted to 5, 10, or
15 minutes.
The
UHM-DHM-SF-1H
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