← Field Exercises
S1Point-to-Point Checkout

Basic AHU

A controller wired per submittal. Probe terminals, verify every point, override outputs, and test the safeties. Today everything checks out. Do not expect that in the field.

FAN OFF
Mode:

SAT

72.0°F

MAT

72.0°F

RAT

72.1°F

OAT

44.8°F

DSP

0.00" WC

FDP

0.00" WC

Click a terminal pair to probe. Click WIRED/OPEN to simulate a disconnected wire.

Analog Inputs: Sensors

AI-1Supply Air TempTB1-1,2
SAT-1· 10k thermistor in supply duct, 12" downstream of coils

Controller · TB1-1,2

Device · SAT-1

AI-2Return Air TempTB1-3,4
RAT-1· 10k thermistor in return air plenum

Controller · TB1-3,4

Device · RAT-1

AI-3Mixed Air TempTB1-5,6
MAT-1· 10k thermistor averaging sensor, mixed air section

Controller · TB1-5,6

Device · MAT-1

AI-4Outside Air TempTB1-7,8
OAT-1· 10k thermistor, outside air louver section

Controller · TB1-7,8

Device · OAT-1

AI-5Duct Static PressureTB1-9,10,11
DSP-1· 0–5" WC differential pressure transducer, 0–10V output

Controller · TB1-9,10,11

Device · DSP-1

AI-6Filter Diff PressureTB1-12,13,14
FDP-1· 0–1" WC differential pressure switch/transducer across filters

Controller · TB1-12,13,14

Device · FDP-1

Digital Inputs: Contacts

DI-1Supply Fan StatusTB2-1,2
CS-1· Current switch on supply fan motor lead — N.O., closes when fan is running

Controller · TB2-1,2

Device · CS-1

DI-2Low Limit Freeze StatTB2-3,4
LLFS-1· Freezestat across supply coils — N.C., opens on freeze trip (<35°F)

Controller · TB2-3,4

Device · LLFS-1

DI-3High Duct PressureTB2-5,6
HDPS-1· High-limit duct pressure switch — N.C., opens above 3.0" WC

Controller · TB2-5,6

Device · HDPS-1

Analog Outputs: Control Signals

AO-1Cooling ValveTB3-1,2
CV-1· Chilled water valve actuator — 0–10V, 0–100% open

Controller · TB3-1,2

Device · CV-1

AO-2Heating ValveTB3-3,4
HV-1· Hot water valve actuator — 0–10V, 0–100% open

Controller · TB3-3,4

Device · HV-1

AO-3OA DamperTB3-5,6
OAD-1· Outside air damper actuator — 0–10V, 0–100% open

Controller · TB3-5,6

Device · OAD-1

Digital Outputs: Relays

DO-1Supply Fan CommandTB4-1,2
MCC-1· 24VAC relay to MCC fan starter — energized = fan run

Controller · TB4-1,2

Device · MCC-1

Meter

Place both leads to read

Click RED then BLACK on any terminal pair to take a reading

Reading Log

No readings yet.

Submittal Reference

AI-1TB1-1,2Supply Air Temp✓
AI-2TB1-3,4Return Air Temp✓
AI-3TB1-5,6Mixed Air Temp✓
AI-4TB1-7,8Outside Air Temp✓
AI-5TB1-9,10,11Duct Static Pressure✓
AI-6TB1-12,13,14Filter Diff Pressure✓
DI-1TB2-1,2Supply Fan Status✓
DI-2TB2-3,4Low Limit Freeze Stat✓
DI-3TB2-5,6High Duct Pressure✓
AO-1TB3-1,2Cooling Valve✓
AO-2TB3-3,4Heating Valve✓
AO-3TB3-5,6OA Damper✓
DO-1TB4-1,2Supply Fan Command✓