HVAC Tools · PQCA1

Low Ambient
Controller.

Supplies the condenser an alternate temperature value so it continues operating at lower ambient temperatures. Two auxiliary low-voltage dry contacts signal additional equipment to protect the compressor — heat, airflow, or whatever the site needs.

Download cut-sheet Talk to sales
Fidure PQCA1 Low Ambient Controller in its enclosure

Prominent features

  • Separate set-points for the ODU thermistor and the dry contacts
  • Heartbeat LED
  • Powered from the 12V "thermostat" header on the ODU board
  • Uses the popular 10K-2 thermistor for ambient sensing
  • 1-year limited warranty

Specifications

Power supply
3.3–12 V DC
Compatibility
Condensers using a 10K-2 temperature sensor
Ambient sensor
10K-2 thermistor (external)
Temperature set-points
-36 °C (-33 °F) to 3 °C (37.5 °F), in 3 °C steps
Set-point selection
4-position DIP, plus always-on / always-off
Dimensions
1.25" H × 2" W × 2.75" D
Warranty
1-year limited

How it works

Function 1

Ambient override

The PQCA1 sits between the ODU thermistor and the ODU control board. SW2 sets the temperature the board sees. On SW1, position 2 ON and position 1 OFF reads the external thermistor; reversing them disables it and always reports 16 °C.

Function 2

Auxiliary dry contacts

SW4 (AUX1) and SW3 (AUX2) each carry their own set-point, closing a low-voltage dry contact to signal auxiliary equipment such as heat or airflow — independently of the ambient override.

PQCA1 board with the lid removed, showing the SEN, ODU and PWR terminals and the SW1–SW4 DIP switches
Angled view of the PQCA1 board and its pluggable screw terminals
PQCA1 Manual & Cut-sheet PDF · set-point tables & wiring