AH-Passport I/O Control Operations Manual
Programming
L-2232 ENGLISH
9
P-15: Electric Heat Option
Units may have an electric heater added to heat a cabin when the chiller system is in cooling mode. Electric heaters are also
used to supplement the circulated water heating (via the hydronic valve) when necessary. Set to “ELE” for the electric heat
option or set to “nor” to disable.
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For software revision A12 and older:
When this parameter is programmed for electric heat, only the electric-heater
relay located toward the middle of the circuit board is energized during a heating cycle. The electric-heater relay only
exists on circuit boards with revision E or older. (See “Sample Wiring Diagram” on page 16.)
•
For software revision A13 and newer:
When programmed for electric heat, both the electric-heater relay and the
compressor relay are energized. This change supports circuit boards with revision F and newer, without the electric-
heater relay. Therefore, circuit boards that do not have electric-heater relays require a display with software revision
A13 or newer to properly energize the compressor relay. When using this configuration, the electric heater L1
connection must be connected to the COMP L1 terminal on the AH-Passport I/O circuit board (see “Sample Wiring
Diagram” on page 16).
•
Installation Note:
Since both the compressor-relay and electric-heat relay outputs only support a maximum of 30
amps at 115VAC or 20 amps at 230VAC of resistive load, when installing an optional electric heater that exceeds this
load, it is necessary to install an additional contactor that is rated to handle the full load of the electric heater. Please
consult with Dometic Customer Service or with an authorized service technician for assistance.
P-16: Fan Motor Selection
The “SC” (Split Capacitor) default setting is correct for air handlers with high-velocity blowers. Only change the setting to “SP” if
your unit has a Shaded Pole fan motor, recognizable by a blower-motor overhang and “F” in the model number (such as
AT12FZ). The SC motor of a high-velocity unit is inside the blower, and the unit has
“HV” in the model number (such as
AT12HVZ).
If your air handler model has a Shaded Pole fan motor, you must change parameter P-16 to “SP” prior to
operating the equipment.
Save this change as a new default by simultaneously pressing and releasing the Up and Down
buttons prior to exiting the program mode. Make note of new default in the Programmable Parameters table.
P-17: Reset Memorized Defaults
To reset all programming parameters set this parameter to “rSt”. This restores all programmable parameters to the
last saved
default values
. Once new values are entered and memorized the factory defaults are overwritten, and the new parameters
become the default values. To restore the original factory default parameters manually, refer to Table 2, page 10.
P-18: Hydronic Water Valve Forced Open
This parameter opens the water valve to bleed air from the system. “OPn” forces the valve open for 4 hours while the AH-
Passport I/O control is turned off. If you want to utilize the system in its normal operating mode prior to completion of the 4-hour
period, before turning on the AH-Passport I/O you must return the valve to its normal position by changing P-18 back to “nor”
manually.
P-19: Water Temperature Differential
This parameter sets the temperature differential between ambient air temperature and hydronic water temperature that controls
the water valve. For example, selecting 10° F opens the valve when water temperature is ten degrees less than ambient in
cooling mode and 10°F greater than ambient in the heating mode.
Careful selection of the temperature differential can fully utilize the ship’s heating and cooling resources. For example, while in
cooling mode and using a ten degree value, the valve will open to allow some cooling while the hydronic system is coming down
to temperature. See Figure 2 on page 11 for a graphical explanation of this parameter.
P-20: Air Filter Cleaning/Replacement Timer Setting
(Available only in software revision A21 and newer.)
Use this feature for a reminder to clean or replace the unit’s air filter.
The parameter entered represents that number times 10 hours. Select the number of operating hours until the filter reminder
appears. Parameter choices are between 10 (100 hours) and 250 (2500 hours). Dometic recommends that you check the air
filter at least every 500 hours of operation. The default setting is off, designated with “00”.
P-21: Filter Cleaning/Replacement Timer Value & Reset
(Available only in software revision A21 and newer.)
This parameter displays the current elapsed time (in hours times 10)
since the timer was started or reset. For example, if the value of P-21 is “30”, then between 300-399 hours have elapsed since
the timer was started or reset. Once the value of P-21 reaches the value set in P-20 (explained above), “FIL” flashes on the LED
display every 10 seconds until it is cleared. To clear the “FIL” reminder, press either the Up or Down button while viewing the P-
21 parameter. This resets P-21 to 0 and restarts the timer.
P-22: Voltage Calibration
(Available only in software revision A21 and newer.)
This feature displays the voltage being read by the power and logic
circuit board. It displays a live reading of the voltage and can be manipulated by pressing the Up or Down buttons. Use a
reliable voltmeter as a reference when adjusting this parameter.
