E1: System High Pressure Protection.
E1 TROUBLESHOOTING STEPS:
Safety Note: Before any component is electrically disconnected in the unit, shut off main power. Inverter board DC bus voltage can take up to 15 min to discharge.
IF THE E1 HIGH PRESSURE PROTECTION SWITCH (HPS) HAS OPENED, OR THE DISCHARGE/AMBIENT THERMISTOR HAS SHOWN A VALUE OUTSIDE ACCEPTABLE OPERATION RANGES…
STEP 1: Check that the indoor and outdoor units are clean with adequate airflow through the coils.
TIPS:
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On the indoor unit, check that indoor filters, coils, and blower wheel are clean. Ensure the unit has adequate space for airflow.
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On the outdoor unit, confirm that the condenser has adequate space for airflow and no obstructions or debris.
STEP 2: If new installation, confirm that all service valves are open.
STEP 3: Was the system properly evacuated to 500 microns?
TIPS:
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If not properly evacuated, non-condensables could cause the E1 error.
STEP 4: If a multizone system…
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Confirm that wiring and line sets match the correct ports from the indoor to the outdoor unit.
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Confirm that line sets are sized by the indoor unit and adapted to the smaller size at the outdoor unit.
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Confirm the amount of required additional charge (if any). An overcharge can cause E1.
TIPS:
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Additional charge amounts should be calculated and weighed in, following the piping rules in the installation or submittal documents.
STEP 5: Check if outdoor ambient thermistor is sensing a temperature outside of the operating range or reading an incorrect value. See Thermistor Temperature to Resistance Table.
TIPS:
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Test thermistors with a needle point probe metering device.
STEP 6: Determine if the discharge thermistor is sensing a temperature outside of normal operating range (indicating a high-pressure condition) or reading an incorrect value.
TIPS:
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Some models only contain a discharge thermistor and do not have a high-pressure (HP) switch. If there is no HP switch, the unit may allow multiple HP conditions before a lockout occurs.
STEP 7: Disconnect the Molex Plug for the HP switch at the control board and check ohm across the wires. The resistance reading should be close to zero ohms.
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If the open line (OL) is read and the pressure is not high, then HP switch itself has failed.
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If the resistance is close to zero across the wires, then the HP switch has reset. Shut off power to the unit for 15 minutes. When power is restored, the compressor should run again. In this case, further diagnostics may be required to determine why the HP switch had opened.
TIPS:
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If the high-pressure switch trips, the board will lock the unit off. Turn off power for 15 minutes and then restart.
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The board will only allow the switch to open 1 time and must remain open for 6 seconds, or lockout occurs.
HOW TO RESET E1 ERROR CODE -
Remove the main power from the system and wait 15 minutes before re-applying power to the unit.
TROUBLESHOOTING
STEP 1: If running in HEAT mode, make sure the high side gauge is connected. Make sure pressure is not too high (400psi+). If running in COOLING mode, make sure the low side gauge is connected. Make sure pressure is not too low (below 100 psi). Confirm indoor fans are running both inside and out. If pressures are stable enough, leave the unit on and measure the Delta T on all indoor units.
TIPS:
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High-pressure switch trips at approximately 600PSI.
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In COOLING mode, both refrigerant lines are low side pressure; therefore, high pressure cannot be checked with a gauge.
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Watch the low-pressure gauge: if the pressure continues to fall very low, then the refrigerant must be backing up into the condenser, which can cause a high-pressure trip.
STEP 2: Perform a 4-point temperature check
STEP 3: In COOLING mode, if the Delta T is low and the suction pressure is not low, this is a good indication that the unit is overcharged. In this case, recover and weigh out the charge.
TIPS:
STEP 4: In COOLING mode, if the Delta T is low and the suction pressure is low, this is a good indication that there is a restriction
STEP 5: In HEATING mode, if high pressures are observed or there is an improper Delta, recover and weigh out the charge, perform a triple evacuation and weigh the charge back in. After this, if high pressures or improper Delta T is still observed, perform a 4-point temp check.
TIPS:
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Damaged or loose wiring connections can cause an erratic E1.