Testing Sensors:
Warning:
No wires connected to control box
during testing
Outdoor Air Temperature Sensor (OATS):
• First measure the ambient air temperature next to
the OATS sensor.
• Disconnect all field wiring from the OATS sensor.
• Measure (ohms) resistance directly at the OATS
sensor location, convert ohms reading to
temperature (Table 4).
• Compare ambient air temperature to the measured
sensor resistance. Both temperatures should be
close +/- 10% (Table 4).
Supply & Return Sensors:
• Disconnect sensor wiring from control box.
• Measure the resistance (ohms) of the Supply then
the Return sensor (Wires have no polarity).
See Table 4.
• Compare fluid temperature to Resistance/
Temperature Chart (Table 4). Both temperatures
should be close +/- 10%.
Possible reasons for short circuit:
• Water in OATS sensor case
• Nail or staple in field wiring
Possible reasons for open circuit:
• Sensor wire jacket has been compromised
• Sensor is disconnected
• Sensor insulation is interfering with sensor at the
pipe location
• Faulty sensor
Page 16
•
Call For Heat and Pump Performance Reduced LEDs
are flashing (Fig. 14):
–
There is a short or open circuit to Boiler Return
Sensor
–
Boiler protection is disabled
Figure 14
- Control Lights (PPR & CFH)
Call for Heat
% Of Pump Perf.
Power On
Pump Perf. Reduced
Boiler
