Quartz 4

SSO Temp Sensor

7 min read

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

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

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

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

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

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)

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

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)

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

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

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

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