Reznor MAPS - A,B,C Users Manual - Manual (Page 34)

Form O-MAPSIII&IV Cabinets A/B/C, Page 34
7.3 Troubleshooting the Heat Section
7.3.1 General Troubleshooting - Electric Heat Section - RECB, RECC, REDB, & REDC
PROBLEM PROBABLE CAUSE REMEDY
Unit does not
operate
1. No power to unit 1. Turn on power; check supply fuses or main circuit breaker.
2. Blown fuses 2. Check and replace if necessary.
3. Defective or incorrect wiring. 3. Check wiring and connections. Refer to wiring diagram provided with unit.
4. Defective or burned out control transformer 4. Check secondary voltage with voltmeter. Replace if necessary.
Fan operates
but element
does not heat
1. Dirty filters 1. Check filters and clean or replace if necessary.
2. Defective air proving switch 2. Check and replace if necessary.
3. Blown element fuses 3. Check and replace element fuses if necessary.
Insufficient
heat
1. Burned out element 1. Turn off power and check element resistance with ohmmeter. Replace if open.
2. Blown fuses 2. Check and replace if necessary.
3. Cycling on limit control 3.
a) Check air throughput (temperature rise).
b) Check motor rpm against nameplate rating. Replace motor if speed is too slow.
c) Defective limit control. Check wiring and connections. Check continuity through
control and replace if necessary.
4. Defective or incorrect wiring. 4. Check wiring and connections. Refer to wiring diagram provided with unit.
Red 3 Flashes Compressor Protector
Trip (demand signal
>1.44VDC & no
compressor current)
Possible causes - internal overload, fuse or breaker,
compressor wiring. After 2-minute anti-short cycle timer
the controller will attempt to restart the compressor as
long as demand is above 1.44VDC. No lockout feature.
Red 4 Flashes Locked Rotor Alert Locked rotor sensed by controller on four consecutive
start-ups. Lockout occurs and can only be reset by
cycling 24VAC power off and on.
Red 5 Flashes Demand Signal Loss
(below .5VDC)
When demand signal input rises above 0.5VDC, alarm
code will reset. When demand reaches above 1.44VDC
and anti-short cycle timer has timed out, modulating
capacity compressor will restart.
Red 6 Flashes Discharge Thermistor
Fault (no signal being
received)
Modulating compressor capacity limited to 50%.
Re-connect or replace thermistor.
Red 7 Flashes Unloader Solenoid Valve
Fault
Red 8 Flashes Compressor Contactor
Fault (compressor
running on less than
1.44VDC demand signal)
Modulating compressor will run unloaded. Alarm will be
reset when current is no longer detected while system
demand signal is below 1.44VDC.
Red 9 Flashes Low 24VAC supply
to controller (below
18.5VAC)
Alarm will reset when supply voltage to controller rises
above 19.5VAC.
All Solid Digital compressor
controller failure
The installed digital compressor controller can be tested
to verify that it is working properly. In each test, 24VAC
must be supplied to 24VAC and 24COM. For output
test, 24-250VAC must be supplied to L1 and L2.
Input Tests - 1) Thermistor Input - Disconnect thermistor
(T1 & T2); LED should display Code 6.; and 2) Demand
Input - Disconnect unit controller (C1 & C2); LED
should display Code 5 unless a previous alert code was
present.
Output Tests - 1) Contactor Output - while the controller
is powered off (no supply voltage to 24VAC and
24COM), disconnect signal wire from C1 & C2; add
jumper wires from P3 to C2 and from P1 to C1; re-apply
power to 24VAC and 24COM. If functioning normally,
same voltage should be read across M1 and M2 as
across L1 and L2, unless an LED ALERT code is
present.; and 2) Unloader Output - while controller is
modulating the unloader solenoid (whenever the yellow
LED is lit), voltage across U1 and U2 should be the
same as L1 and L2.
All Flashing 24VAC Supply too low for
operation
Compressor Digital Controller LED’s (cont'd) 7.2 Compressor
Digital
Controller
Troubleshooting
- all MAPS ® IV
Models (cont'd)