Carrier 48LJE004 Installation, Start-Up And Service Instructions Manual page 29

Table 21 — Economizer Service Analysis
PROBLEM
CAUSE
REMEDY
Damper does not
open.
Evaporator fan not on.
Check wiring between G on connection board and indoor fan
contactor
No power to economizer motor.
' 1. Check that SW3 is making proper contact with the damper blade.
2, Check continuity across R1 coil. If not connected, replace relay
R1.
3. Check diode D1. If diode is not functioning properly, replace D1.
4 Check wiring in economizer relay pack (See unit label
diagram.)
Economizer motor failure If there is 24 vac power at the motor terminals, but motor is not oper¬
ating, replace motor
Economizer opera¬
tion limited to mini¬
mum position.
OAT or EC set too high. 1 Set at correct temperature (3 F below indoor space temperature).
2. Check OAT or EC by setting set point above outdoor temperature
or humidity level. If switch does not close, replace OAT or EC.
Check wiring of economizer relay packs
1 Check continuity across relay R2 coil. If not connected, replace R2
relay.
2. Check continuity across relay R3 coil If not connected, replace R3
relay.
Check SAT
If supply-air temperature is over 57 F, switch T2 should be closed. If
not, replace SAT.
Damper does not
close.
Incorrect wiring or wiring defects. 1. Check switch 2 and 4. If non-operational, replace.
2. Check diode D2. If diode D2 is not functioning properly, replace.
3. Check wiring on economizer and on economizer relay pack (see
unit label diagram).
Check SAT
If supply air thermostat is below 52 F, switch T1 should be closed If
not, replace SAT.
Economizer motor failure. If there is 24 vac power at motor terminals, but motor is not operating,
replace motor.
LEGEND
EC
— Enthalpy Control
OAT
— Outdoor-Air Thermostat
SAT
— Supply-Air Thermostat
Legend for Fig. 39 — Typical Component Arrangement
and Fig. 40 — Typical Wiring Schematic
IMPORTANT: Refer to unit wiring label for actual unit wiring.
AHA
C
CAP
CC
CH
COMP
D
EC
ECON
EPS
EQUIP
ER
FPT
GND
HPS
HS
I
IDM
IFC
IFM
IGC
LED
LPS
LS
MGV
MTR
OAT
OFM
P
PL
QT
R
— Adjustable Heat Anticipator
— Contactor, Compressor
— Capacitor
— Cooling Compensator
— Crankcase Heater
— Compressor Motor
— Diode
— Enthalpy Control
— Economizer
— Emergency Power Supply
— Equipment
— Economizer Relay
— Freeze-Up Protection Thermostat
— Ground
— High-Pressure Switch
— Hall Effect Sensor
~ Ignitor
— Induced-Draft Motor
— Indoor-Fan Contactor
— Indoor-Fan Motor
— Integrated Gas Unit Controller
— Light-Emitting Diode
— Low-Pressure Switch
— Limit Switch
— Main Gas Valve
— Motor
— Outdoor-Air Thermostat
— Outdoor-Fan Motor
— Plug
— Plug Assembly
— Quadruple Terminal
— Relay
RS
— Rollout Switch
SAT
— Supply-Air Thermostat
SEN
— Sensor
SW1
— Switch Fully Open
SW2
— Switch Fully Closed
SW3
— Switch Min. Vent Position
SW4
— Switch Max Vent Position
TC
— Thermostat-Cooling
TH
— Thermostat-Heating
TRAN
— Transformer
Field Splice
x )> Marked Wire
<X> Terminal (Marked)
O Terminal (Unmarked)
| x | Terminal Block
# Splice
<CZy* Splice (Marked)
- Factory Wiring
-Field Control Wiring
———— Field Power Wiring
-Accessory or Optional Wiring
To indicate common potential only;
not to represent wiring
NOTES:
1 If any of the original wire furnished must be replaced, it must be re¬
placed with Type 90 C wire or its equivalent
2. Number(s) indicates the line location of contacts A bracket over 2
numbers signifies single-pole, double-throw contacts. An underlined
number signifies a normally closed contact. Plain numbers (no lines)
signifies a normally open contact
3 Three-phase motors are protected under primary single phasing con¬
ditions
4 Thermostat: HH07AT170, 172, 174 and P272-2783
Subbase: HH93AZ176, 178 and P272-1882, 1883
5 Set heat anticipator at 14 amp For units with 2 stages of heating, set
stage 2 anticipator at 14 amp.
6. Use copper conductors only.
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