# Temperature Sensor - Quick Reference SSO

**Device Type:** Analog Input - Sensor  
**Signal:** Thermistor (10K) / 0-10VDC / 4-20mA  
**Power:** Unpowered (thermistor) / 24VAC-VDC (transmitter)  
**Version:** 1.0 | **Date:** Dec 2025

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## DEVICE OVERVIEW

**Common Models:**  
- Johnson Controls TE-6000, Honeywell T7350, Siemens QAA, Belimo 22RT, BAPI BA/10K

**Used For:**  
Space temperature, duct air temp, immersion (water/glycol), outdoor air sensing

**Wire Type:** 18AWG minimum, 16AWG recommended, shielded if >50ft  
**Environment:** Space 32-120°F | Duct -40-200°F | Immersion -40-250°F

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## SAFETY - PPE REQUIRED

- ☑ Safety glasses (ANSI Z87.1)
- ☑ Cut-resistant gloves (sheet metal)
- ☑ Hard hat (mechanical rooms/rooftops)
- ☑ Dust mask (drilling ducts)
- ☑ Fall protection (if >6 feet height)

### HAZARDS
- ⚠ Sharp edges - Sheet metal ductwork
- ⚠ Hot/cold surfaces - Ducts near coils, pipes
- ⚠ Falls - Ladder work, rooftop access
- ⚠ Rotating equipment - Air handler fans (LOTO required)

### LOCKOUT/TAGOUT
- [ ] **Required for duct sensors:** Lock out air handler before drilling duct
- [ ] Notify building operator
- [ ] Lock breaker with personal lock
- [ ] Test that fan won't start
- [ ] Remove lock only after work complete

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## INSTALLATION CHECKLIST

### TOOLS NEEDED
- Drill + bits (1/16"-1/2")
- Hole saw (3/4"-1" for duct)
- Wire strippers (18-16 AWG)
- Multimeter (DMM)
- Level, tape measure
- Deburring tool
- Duct sealant (high-temp)
- Label maker

### PRE-INSTALL
- [ ] Location per blueprints verified
- [ ] Space sensor: Away from sun, exterior walls, diffusers (6ft), doors (3ft)
- [ ] Duct sensor: Straight section (3× duct diameter from elbows)
- [ ] Outside sensor: North wall, away from exhaust (10ft)
- [ ] Correct sensor type for controller input (thermistor vs transmitter)

### INSTALL STEPS - SPACE SENSOR
1. **Mount:** 48-60" above floor, interior wall, use level
2. **Route Wire:** Through wall/conduit, 12" service loop
3. **Terminate (Thermistor 2-wire):**
   - Wire 1 (Red): Terminal 1
   - Wire 2 (Black): Terminal 2
   - Polarity doesn't matter for thermistor
4. **Terminate (Transmitter 3-wire):**
   - Red: +24VAC/VDC
   - Black: Common/Ground
   - White/Green: Signal output
5. **Label:** "RM-[#]-TEMP" both ends
6. **Install cover** and verify level

### INSTALL STEPS - DUCT SENSOR
1. **LOCKOUT air handler** before starting
2. **Mark location:** Straight duct, avoid seams/ribs
3. **Drill penetration:** Pilot hole → Hole saw → Deburr edges
4. **Insert probe:** 1/3 duct width (spot) or full width (averaging)
5. **Secure flange:** Sheet metal screws, tight but not distorted
6. **Seal penetration:** High-temp duct sealant, no air leaks
7. **Terminate wiring:** Per sensor type (above)
8. **Restore system:** Remove lockout, verify fan starts

### INSTALL STEPS - IMMERSION SENSOR
1. **Verify thermowell** present in pipe
2. **Apply thermal compound** to probe tip
3. **Insert probe** fully into thermowell
4. **Tighten compression fitting:** Hand tight + 1/4 turn with wrench
5. **Terminate wiring** and support with cable ties

### POST-INSTALL
- [ ] Device mounted securely and level
- [ ] All wires tight (7-9 in-lbs torque)
- [ ] Labels applied both ends
- [ ] Duct penetrations sealed (no leaks)
- [ ] Work area cleaned
- [ ] Photos taken

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## EXPECTED READINGS

### PRE-POWER (Power OFF)

**THERMISTOR (2-wire, unpowered):**
- **Resistance at 70°F:** 9,500 - 10,500 ohms (10K Type II/III)
- **At 60°F:** ~12,500 ohms
- **At 80°F:** ~8,000 ohms
- **If infinity:** Open circuit - failed sensor or broken wire
- **If near zero:** Short circuit

**TRANSMITTER (3-wire):**
- **Continuity:** Each wire <5 ohms end-to-end

**ISOLATION:** >10K ohms to ground (all types)

### POWER-UP

**THERMISTOR:**
- Controller provides excitation (~5VDC)
- Controller converts resistance to temperature

**TRANSMITTER:**
- **Supply Voltage:** 24VAC/VDC ±10% (21.6-26.4V acceptable)
- **Output at 70°F (0-10V, 0-100°F range):** ~7.0V
- **Output at 70°F (4-20mA, 0-100°F range):** ~15.2mA

### ACCEPTABLE RANGE - SPACE TEMP
- ✓ Reading: 68-72°F at room temp (±2°F initially acceptable)
- ✓ Response time: 30-90 seconds to stabilize
- ✓ Controller shows reading (no faults)
- ✓ Graphics display live value

### TYPICAL READINGS - DUCT
- **Supply Air Cooling:** 50-60°F
- **Supply Air Heating:** 90-120°F
- **Return Air:** 68-76°F
- **Outside Air:** Matches local weather (±5°F)

### TYPICAL READINGS - IMMERSION
- **Chilled Water Supply:** 42-48°F
- **Chilled Water Return:** 52-58°F
- **Hot Water Supply:** 140-180°F
- **Condenser Water:** 70-95°F

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## PROOF OUT TESTS

### TEST 1: Response Test
- **Do:** Place hand over space sensor (or heat duct sensor with breath)
- **Expect:** Reading increases 3-8°F within 30-60 seconds
- **Pass If:** Reading changes and returns to baseline when removed

### TEST 2: Accuracy Check
- **Do:** Compare to calibrated reference thermometer (within 6")
- **Expect:** Reading within ±2°F of reference
- **Pass If:** Within tolerance after 5 min stabilization

### TEST 3: Stability Check
- **Do:** Monitor reading for 5 minutes
- **Expect:** Stable reading (±1°F variation max)
- **Pass If:** No erratic jumping or oscillation

### TEST 4: Controller Integration
- [ ] Device appears in controller point list
- [ ] Reading displays correctly (no faults)
- [ ] Graphics show live data updating
- [ ] Control system responds to sensor (heating/cooling calls)

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## TROUBLESHOOTING

### NO POWER / NO READING / FAULT
1. **Thermistor:** Measure resistance at sensor: Should be ~10K at 70°F
   - If infinity: Replace sensor (open circuit)
   - If near zero: Replace sensor (short circuit)
2. **Transmitter:** Check supply voltage at sensor: 24V ±10%
3. Test continuity end-to-end: <5 ohms
4. Check all terminal connections tight
5. Verify polarity correct (transmitters only)
6. **If still dead:** Replace device

### READING TOO HIGH OR LOW (Offset)
1. Compare to calibrated reference thermometer
2. **Space sensor:** Check for influences:
   - Direct sunlight, heat sources, cold surfaces
   - Too close to diffuser (<6ft) or exterior wall
3. **Duct sensor:** Verify insertion depth (1/3 width typical)
4. **Immersion sensor:** Verify probe fully inserted in thermowell
5. Wait 30 min for stabilization
6. **If consistently off by same amount:** Apply controller calibration offset
7. **If off by >5°F:** Relocate or replace sensor

### ERRATIC / JUMPING READINGS
1. Check all terminal connections tight (wiggle test)
2. Inspect wiring for damage, pinching
3. **Check for EMI/RFI interference:**
   - Wire running parallel to power cables?
   - Near motors, VFDs, transformers?
4. Verify shielded cable used if required (>50ft runs)
5. Test at sensor AND at controller (same reading?)
6. Look for moisture in connections
7. **If wiring OK:** Replace sensor

### SLOW RESPONSE
1. Normal: 30-90 seconds for most sensors
2. **Duct sensor:** May be outside airstream - check depth
3. Check for buildup on sensor element
4. **If >2 minutes consistently:** Clean or replace

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## ESCALATION - COMPLETE BEFORE CALLING

### PRE-ESCALATION CHECKLIST
- [ ] Verified supply voltage at sensor (transmitters: 24V ±10%)
- [ ] Tested sensor resistance (thermistors: ~10K at 70°F)
- [ ] Verified all wire connections tight and correct
- [ ] Tested continuity end-to-end (<5 ohms)
- [ ] Compared to calibrated reference thermometer
- [ ] Checked for environmental influences
- [ ] Verified sensor type matches controller input config
- [ ] Documented all readings with multimeter
- [ ] Taken photos of installation and wiring
- [ ] Reviewed sensor installation manual

### PROVIDE THIS INFO
- **Device:** [Mfg / Model / Location]
- **Sensor Type:** Thermistor / 0-10V / 4-20mA
- **Measured Resistance:** _____ ohms (thermistors)
- **Supply Voltage:** _____ V (transmitters)
- **Output Signal:** _____ V or mA
- **Controller Reading:** _____ °F
- **Reference Reading:** _____ °F
- **Error:** _____ °F (sensor - reference)
- **Environment:** Temp ____ / Humidity ____ / Airflow ____
- **Steps Taken:** [List troubleshooting completed]
- **Photos:** Attached to Service Fusion ticket

### CONTACTS
- **Field Specialist:** [Phone]
- **Programmer:** [Phone] (if calibration offset needed)
- **Project Manager:** [Phone] (if design/location issue)
- **Dispatch:** [Phone] (parts/resources)

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## CALIBRATION

**When Required:** All sensors verified during commissioning, annually for critical apps

**Quick Steps:**
1. **Stabilize:** Wait 15-30 min (space), 30 min (duct with system running)
2. **Position reference:** Within 6" of sensor, same height/location
3. **Wait:** 2-3 min for reference to stabilize
4. **Compare:** 
   - Sensor reading: ______°F
   - Reference reading: ______°F
   - Error: ______ °F
5. **Acceptable:** ±2°F for most BAS, ±1°F for tight tolerance apps

**If Outside Tolerance:**
- **Option A (Preferred):** Apply controller calibration offset
  - Access controller config for this input
  - Enter offset value (+ if sensor reads low, - if reads high)
  - Verify reading now matches reference
  - Document offset in Service Fusion

- **Option B:** Adjust sensor (if has calibration pot)
  - Remove cover, locate adjustment screw
  - Adjust while monitoring reading
  - Re-verify with reference

- **If Cannot Calibrate:** Replace sensor

**Document:** Tech name, date, reference ID & cal date, before/after readings

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## COMMON ISSUES & TIPS

✓ **Space sensors reading high:** Check if in direct sun or near heat source  
✓ **Duct sensors inaccurate:** Verify insertion depth (1/3 width for spot sensing)  
✓ **Outdoor sensors erratic:** Ensure north-facing, away from exhaust/relief dampers  
✓ **Immersion sensors slow:** Normal - thermal mass requires 15-20 min to respond  
✓ **All sensors offset same amount:** Apply controller calibration offset, don't replace  
✓ **Shielded cable:** Ground shield at controller end ONLY (not both ends)  
✓ **10K Type II vs Type III:** Most controllers auto-detect, but verify in config

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**Document ID:** SSO-TEMP-001  
**Revision:** 1.0  
**Next Review:** Dec 2026