When the machine beeps once every 3 seconds it indicates the HIGH TEMPERATURE SAFETY switch has been triggered.
The HIGH TEMPERATURE SAFETY is activated, when the thermistor which is mounted on the suction line reaches a temperature of 127° F. When this occurs it will shut the unit down, trigger the alarm, and lock it out on a manual reset safety.
Some of the reasons for a High Temperature safety alarm are as follows. You will find these possibilities included on the control board diagnostic label located in the compressor compartment. Follow the instructions provided on the label to reset the alarm and check these areas to locate the problem.
- Check to see if there is a mechanical problem with the hot gas valve sticking open or with the control board relay sticking.
- Check for a temperature differential across the hot gas valve.
- To check for a sticking relay, use a volt meter to check for voltage on pink wire, pin # 2 on the K1 connector.
- Hot water migration can also cause this. This typically happens at night when the only piece of equipment requiring water flow is the ice machine.
- Hot water migration is a tough problem to find and to prove to the customer. The best way to determine that this is happening is to place a temperature recorder on the inlet water line of the ice machine. The recorder will show when migration occurs.
- Usually hot water migration is due to a defective mixing valve in the existing plumbing. A good place to check is the pre-wash area at the dishwasher.
- A stuck head master on a remote air cooled condenser unit operating in a high ambient condition.
- The best way to check for this is to carefully touch the liquid line connection at the rear of the unit. Also, check for heat at the inlet pipe to the receiver tank. If these areas are hot, the head master is likely stuck in the bypass mode.
- Check for a shorted thermistor. If the thermistor reads approximately 500 ohms or less the control board will lock out on this safety.
- A shorted thermistor will signal zero ohms and cause repeated shut down on HIGH TEMPERATURE SAFETY.