Programmable Functions Q3 and Qht Controls for Direct Expansion Systems
10 L-2516 ENGLISH
Select C and the fan will run continuously while the system is on. Select I for intermittent operation and the fan will cycle on and
off with the compressor.
8: AC Line Voltage Calibration
The control board assembly has a built-in voltmeter that senses AC line voltage and this feature displays the voltage being read.
The control board automatically responds to sustained low-voltage or high-voltage conditions by shutting down the air
conditioning system to prevent compressor damage. At installation, the control board voltmeter should be calibrated to line
voltage within +/- 1%. To check or re-calibrate AC line voltage:
• Line voltage will be displayed as the last two digits of the voltage. On 115V systems, 95V appears as “95”, 100V as
“00”, and 120V as “20”. On 230V systems, 190V will appear as “90”, 200V as “00”, and 230V as “30”.
• To check accuracy or to calibrate, turn off all on-board AC loads and measure the line voltage with an accurate
voltmeter.
• Press the UP or DOWN buttons to recalibrate the value as required.
9: Temperature Calibration
This feature calibrates the ambient sensor within a range of ±1%. The temperature sensor should be within one or two degrees
of actual room temperature. Note that setting increments are in °F even when the control is set to display °C. Adjust this
parameter to display the correct room-temperature reading.
• The sensed temperature is displayed. Place an accurate thermometer beside the sensor and compare the
temperatures.
• Press the UP or DOWN buttons to recalibrate the value as required.
10: Dehumidification Pre-Circulation Time
(Factory Default: 10 minutes)
The Humidity Control Program (HU) automatically operates the air conditioning system for a programmed time period to help
control humidity in the boat. This dehumidification feature works in three stages:
1. The fan comes on at high speed to circulate air for ten minutes.
2. The fan then drops to low speed, and the compressor cycles on in the Cool Mode to dehumidify.
3. After the dehumidification cycle, the system turns off. The process repeats according to the programmed time period.
The Compressor Time Delay (Programmable Function 1) setting governs when the dehumidification cycle starts. Every one-
second of compressor delay equals a six-minute advance into the dehumidification cycle.
The factory default settings are:
10: Pre-circulation cycle - 10 minutes
11: Dehumidification cycle - 30 minutes
12: Overall time period - 12 hours
The factory settings are adequate for most moderate climates and boats. For very humid climates, shorten the overall time
period and extend the dehumidification time. In dry climates, select a longer overall time period between cycles and a shorter
dehumidification time. Programmable Function 10 governs the pre-circulation cycle time and should not be changed.
11: Dehumidification Time
(Factory Default: 30 minutes)
The dehumidification time determines how long the compressor runs in the Dehumidification Mode (see Programmable
Function 10). The display shows the dehumidification time period in minutes.You can select 10, 20, 30, 40, 50 or 60 minutes.
Select a longer dehumidification time in climates with high humidity and a lower dehumidification time in climates with low
humidity.
12: Dehumidification Overall Time Period
(Factory Default: 12 hours)
This setting determines how often the system performs the dehumidification process. The display shows the overall time period
in hours. You can select intervals of 2, 4, 6, 8, 10, 12, 14 or 16 hours. Choose a shorter overall time period in climates with high
humidity and a longer overall time period in climates with low humidity.
NOTE
If you select intermittent fan operation, you should relocate the thermistor from the return air grill to a cabin wall where
it can best sense the average room temperature. Check with your dealer or call the Dometic Applications Department
for more information.
To Next Page
Loading...
Need help?
General
