Thermo Scientific Unity Lab Services 3307 User manual

Model 3307 and 3310 Stericult
Incubator Troubleshooting-
Resetting Overtemp Protection
(OTP)
This troubleshooting document provides basic instructions for resetting the manually
resettable overtemperature protection device to restore heating functionality.
The device description, location, and instructions for resetting are outlined.
Model 3307_3310 Stericult Troubleshooting-
Resetting Overtemperature Protection (OTP)
Revision Date: March 27, 2017

3307_3310 Troubleshooting- Resetting OTP
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Description of OTP Device:
The unit is fitted with a manually resettable overtemperature protection device (OTP).
This device is designed to open and interrupt the heating circuit in the event of an
overtemperature condition.
The device will open at a temperature of 160C +/-5.6C (320F +/-10F).
Potential Causes of a Tripped OTP:
Unit temperature sensor is not fully seated in plenum.
Heater TRIAC on micro board is shorted (constant heating).
Device tripped during the 140C sterilization cycle.
Location of OTP:
The OTP device is located on the rear of the unit just below the access port opening.
The device opening is covered with a 1” black plastic plug (see Figure 3 below).

3307_3310 Troubleshooting- Resetting OTP
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Resetting the OTP:
Turn unit power off.
Remove 1” black, plastic hole plug from OTP opening. Pry off using a flat-tipped tool.
Press button in center of OTP with a narrow, non-conductive tool (i.e. pencil) until reset.
Reinstall plastic hole plug.
Press button in
center of OTP to
reset.

3307_3310 Troubleshooting- Resetting OTP
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Photo of OTP Location on Exterior Rear Wall of Chamber During Assembly:
Part Number for OTP Device: 400150 –T-Stat Snap-action 160C