This device monitors compressor safety switch trips to prevent short cycling, protecting the compressor.
After a fourth safety switch trip, a manual reset is required within 6 hours.
LED Indicator
- Lockout is indicated by a solid (non-flashing) Red LED.
- LED will be flashing to indicate that a Safety Input has opened while a Y Call is present.
Safety Device Trip
- A Safety Device Trip occurs when the Y signal is applied to the control, but the SI is sensed as open when the Compressor Contactor Output is energized. If the Compressor Contactor Output is not energized while a Y signal is applied and the SI is sensed as open, this will not count as a fault but will not allow the Compressor Contactor to energize.
Anti-Short Cycle
- If the Y signal is applied to the control, then if either the Y signal or SI signal is removed from the board for at least 33 milliseconds, the output to the Compressor Contactor will be held off for a fixed time of 3 minutes.
- If a device safety trip is sensed at the moment the Anti-Short Cycle Timer expires (even if the Compressor Contactor Output was not energized), the control will increment the Safety Device Trips Counter and go into either another Anti-Short Cycle or a Lockout (depending on the new Safety Device Trips Count).
Compressor Lockout
- If the unit experiences four safety device trips within 6 hours (the Unit reads open on the SI while a Y call is present), it locks out and requires a manual reset (power cycled on R input). Lockout is indicated by a solid (non-flashing) red LED.
LSD Device Additional Info
- If the R + Y + SI has 24 volts at power-up, the CC output will energize immediately.
- If the R + Y + SI have 24 volts, removing and reinstalling C does not count as a trip, and there is no 3-minute delay for the CC output to re-energize. (for example, it will cycle on the frostat opening and closing all day long)
- If there is an R + Y at power-up with the SI open, and after 3 minutes, you apply 24 volts to SI, the CC output will come on immediately.
- The SI open time counts towards the 3-minute delay. For example, if the SI input opens for 2 minutes and then closes, 1 minute later, the CC output will energize.
Problem:
Compressor contactor will not pull in with 24 vac present at R, Y and SI on the LSD.
Fault LED Indicator on the Lockout Safety Device is not Flashing or Steady On.
This is a representation of the current Factory LSD wiring.
Below is a typical wiring diagram for the safety circuit and LSD1 & LSD2
Change the LSD circuit wiring to this configuration and the contactor pulls in strong, even with high resistance in the field wiring between the unit the thermostat.
Procedure
- Circuit 1 - Unplug 140B & D Black wire from the DTL1 Black wire and cap off with a wire nut.
- Circuit 2 - Unplug 141F & G Red wire from the DTL2 Red wire and cap off with a wire nut.
LSD Circuit(s) after wiring change.
3. Now locate the LTB and add a new wire from the LTB-1 R and run it to the DTL1 and DTL2 switches. Connect it to the Black wire from DTL1 and the RED wire from DTL2.
WARNING:
Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.