Q3 & Qht Controls for Direct Expansion Systems Condensate Drains
L-2516 ENGLISH 21
MAINTENANCE OF SYSTEM COMPONENTS
CONDENSATE DRAINS
At least once every three months, check the condensate drains for obstructions by pouring a quart of water rapidly into the
condensate pan. If it does not drain completely within 30 seconds, check the drain outlets for clogging. Remember that many air
conditioning units have two drains and hoses, one at each end of the drain pan.
RETURN-AIR FILTER
Check the return-air filter about once a month and replace or clean as necessary. To clean the filter, remove it from the unit,
rinse with water, air dry and reinstall.
SEAWATER CONNECTIONS
Verify that all seawater connections are tight, and check for water flow from each unit’s overboard discharge.
SEAWATER PUMP
If the seawater pump has a plastic pump head, then the impeller is made of either plastic or rubber and should be inspected
after 300 hours of operation. Replace the impeller if it is worn. If the seawater pump head is made of bronze, then the impeller is
too, and regular maintenance is not needed as often; inspect the pump if there are signs of reduced seawater flow.
"Ar / FL" is flashing.
(Filter Reminder)
Filter needs to be cleaned or replaced.
Clean or replace filter. Reset and stop flashing by
pressing the FAN, UP, and DOWN buttons simultaneously.
"HI / - -" is flashing. 1. High-pressure switch is open (in cooling) due to improper seawater flow.
Strainer or intake may be plugged, seacock may be closed. Check seawater hose for
kinks or collapses. Verify pump operation; check pump circuit breaker if applicable.
2. High-pressure switch open (in heating) due to improper airflow. Remove
obstructions in return air stream. Clean air filter and grille. Check for crushed or
restricted ducting. Ducting must be as straight, smooth and taut as possible.
If problem persists, reprogram Low Fan Speed Limit for maximum value. Set
Programmable Function 5 to 57.
"LO / - -" is flashing. 1. Low-pressure switch is open due to low seawater and/or low return air
temperatures. Try restarting the air conditioning unit, the optional low pressure
switch has a ten minute shutdown time delay that may be in effect.
2. Low pressure switch is open due to loss of refrigerant. Check air conditioning unit
for refrigerant oil leakage, call service technician.
"HI / PS" is flashing.
(High Pressure)
1. Head pressure above 425 PSI for R-22 or R-417A systems or above 575 PSI for
R-410A systems.
"LO / PS" is flashing.
(Low Pressure)
1. Head pressure below 30 PSI for R-22 or R-417A systems or below 60 PSI for R-
410A systems.
"LO / AC" is flashing.
(Low AC Voltage)
1. Supply voltage is too low. Verify power to unit with multimeter.
2. Voltage is improperly calibrated. Verify that Programmable Function 8 matches
voltage reading to unit with a multimeter. Adjust Programmable Function 8 if
necessary.
"- -" is flashing. Display connected to SMXII unit instead of a Q-Logic or U-Board.
Replace with Q-
Logic or
U-Board.
Table 7: Digital-Controls Troubleshooting (continued)
PROBLEM POSSIBLE REASON/SOLUTION
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