Traulsen Door Open Alarm

What does Traulsen Door Open Alarm mean?

The door open alarm warns that a cabinet door has been open longer than five minutes, or that the control reads a door as open. On H1 and MIT 1 control versions the alarm is tied to the five-minute door-open timer. It protects against temperature loss from doors left ajar, but it can also be triggered by a faulty door switch or door/light relay.

Symptoms

• Alarm LED illuminated and horn sounding on the control
• Door appears open to the control even when closed
• Cabinet temperature climbing from lost cold air
• Water visible inside the door switch

Common causes

• Door(s) actually open longer than five minutes
• Failed door/light relay
• Water inside the door switch
• Mis-wired door switch

Diagnostic steps

1. 01

   Close the doors

   Confirm whether a door has been open longer than five minutes and close any open doors.

2. 02

   Check the door/light relay

   Check for a failed door/light relay per the manual procedure; replace the relay if it is not OK.

3. 03

   Inspect the door switch for water

   Check whether there is water in the door switch; if so, replace the door switch.

4. 04

   Check switch wiring

   Check for a mis-wired door switch and replace the switch if the wiring is not correct.

5. 05

   Verify switch operation

   With the switch removed, use a meter to confirm COM-to-NO reads open with the door closed; replace if not.

When to call a professional

Call a technician if the alarm persists with all doors closed, which points to a failed relay or door switch rather than operator behavior. Note that equipment with the MIT II controller version does not include a door/light relay. Removing doors and hinges, metering switch contacts, and replacing the relay are service tasks that should be done by qualified personnel.