Carrier 58MVP 170 Series Troubleshooting Manual Download

Page: 30 / 44

STEP

ACTION

YES

GO TO

Reconnect PL3 to the variable speed furnace control and

connect a DC voltmeter across terminals PL3-3 YELLOW

(+) and PL3-2 GREEN (-). Does the voltage appear to fluc-

tuate more than it did in step 26?

Note: Typical voltmeters will show a fluctuation of .2-vdc to

1-vdc. The amount of fluctuation is not important and you

could see even more fluctuation depending on the voltmeter

you use.

Check the blower motor serial output signal. To do this dis-

connect PL3 from the furnace control and connect a DC

voltmeter across terminals PL3-4 (+) and PL3-2 (-) on the

variable speed furnace control. The voltage should be near

0-vdc but it will fluctuate briefly several times a second. If

you have an analog voltmeter the needle will briefly go high

several times a second. If you have a digital voltmeter with

a bar graph it will show a large change in magnitude on the

bar graph several times a second. If you have a plain digital

voltmeter it will show a brief fluctuation in voltage and the

magnitude may vary depending on the volt meter used.

Note: Some voltmeters will not sense this fluctuation at all.

Test your voltmeter on a known good furnace prior to ser-

vicing this product.

Note: You can also make a simple blinky light with a 1 KW
resistor and an LED (RED works best). These parts can be

purchased at a nearby Radio Shack. The schematic is

shown in Figure 1:

When using the blinky light the LED will flash briefly several

times a second when the blower motor serial output signal

is working properly. LED’s are directional and the lead clos-

est to the flat side goes to PL3-2.

Does the voltage fluctuate as described in step 28?

Reconnect PL3 to the variable speed furnace control and

connect a DC voltmeter across terminals PL3-4 BLUE (+)

and PL3-2 GREEN (-). Does the voltage fluctuate as de-

scribed in step 28?

Disconnect PL13 from the blower motor and connect a DC

voltmeter across terminals PL13-10 BLUE (+) and PL13-1

GREEN (-). Does the voltage fluctuate as described in step

28?

You have an open wire or bad terminal on the BLUE wire

between connectors PL3 and PL13. Repair it or replace

harness.

Disconnect PL13 from the blower motor and connect a DC

voltmeter across terminals PL13-10 BLUE (+) and PL13-1

GREEN (-). Does the voltage fluctuate as described in step

28?

You have short to ground on the BLUE wire between con-

nectors PL3 and PL13. Repair it or replace harness.

The blower motor and furnace control are communicating

but the RPM must be below 250.

Wait at least 5 minutes after disconnecting line voltage from
equipment before opening blower motor to prevent electric
shock which can cause personal injury or death.

Fig. 1—Blinky Light Schematic

A03094

PL3-4

Ω

PL3-2

Summary of Contents for 58MVP 170 Series

Page 1: ...and servicing heating equipment can be hazardous due to gas and electrical components Only trained and qualified person nel should install repair or service heating equipment Untrained personnel can perform basic maintenance functions such as cleaning and replacing air filters All other operations must be performed by trained service personnel When working on heating equipment observe precautions ...

Page 2: ...listed in the Index You should ALWAYS begin in the START HERE section see Index for page number which will guide you to the appropriate section where a minimal number of steps will be used to correct the problem Once in a section read the ACTION An ACTION may have a number in the GO TO column Do whatever the ACTION says then proceed to the step indicated in the GO TO column 2 ...

Page 3: ...ed After the 90 second period the furnace will respond to the thermostat normally The blower access panel must be installed for power to be conducted through the blower door interlock switch ILK to the furnace control CPU transformer TRAN inducer motor IDM blower motor BLWM hot surface igniter HSI and gas valve GV Step 1 Single Stage Thermostat and Two Stage Heating Adaptive Mode NOTE The low heat...

Page 4: ...turned ON at high heat airflow Simultaneously the humidifier terminal HUM and electronic air cleaner terminal EAC 1 are energized and remain ener gized throughout the heating cycle 7 Switching from Low to High Heat If the furnace control CPU switches from low heat to high heat the furnace control CPU will de energize the high heat pressure switch relay HPSR to close the NC contact and slowly incre...

Page 5: ...he Y Y2 terminal and switch the outdoor unit to high cooling The furnace control CPU can start up the cooling unit in either low or high cooling If starting up in low cooling the furnace control CPU determines the low cooling on time from 0 to 20 minutes which is permitted before switching to high cooling If the power is interrupted the stored history is erased and the furnace control CPU will sel...

Page 6: ... is de creased from 90 seconds to 5 seconds Step 5 Super Dehumidify Mode Super Dehumidify mode can only be entered if the furnace control is in the Thermidistat mode and there is a demand for dehumidi fication The cooling operation described in item 3 above also applies to operation with a Thermidistat The exceptions are listed below 1 When the R to Y1 circuit is closed R to G circuit is open and ...

Page 7: ...ansition the blower motor BLWM to low cooling airflow If both the Y1 and Y Y2 signals disappear at the same time the blower motor BLWM will remain on at low heat airflow for the selected blower OFF delay period At the end of the blower OFF delay the blower motor BLWM will shut OFF unless G is still energized in which case the blower motor BLWM will operate at continuous blower airflow Step 8 Compo...

Page 8: ...EN Check for Obstructed pressure tubing Pressure switch stuck closed 24 SECONDARY VOLTAGE FUSE IS OPEN Check for Short circuit in secondary voltage 24 VAC wiring 25 MODEL SELECTION OR SETUP ERROR Either Indicates the model plug PL4 is missing or incorrect or setup switch SW1 1 or SW1 6 is positioned improperly If code flashes only 4 times on power up control is defaulting to model selection stored...

Page 9: ... Water in vent piping possible sagging pipe Stuck open low heat pressure switch Disconnected or obstructed pressure tubing 45 CONTROL CIRCUITRY LOCKOUT Auto reset after 1 hour lockout due to Flame sense circuit failure Gas valve relay stuck open Software check error Reset power to clear lockout Replace control if status code repeats COMPONENT TEST To initiate the component test sequence shut OFF t...

Page 10: ...sed by putting setup switch SW1 1 in the ON position and jumpering R W W1 and Y Y2 simultaneously until status code 11 is flashed 9 10 9 Go to page number indicated in the Index for the section covering the first previous status code INDEX 10 Does the problem appear to be low cooling airflow 11 12 11 Go to page number indicated in Index for the section cover ing IMPROPER COOLING AIRFLOW INDEX 12 S...

Page 11: ...connects to the prob lem unit correctly set 11 10 10 Fix problem 5 11 Are the Auxiliary Limit switches properly set 12 10 12 Do you have 115 vac across L1 and NEUTRAL L2 in the problem unit 13 15 13 Do you have 24 vac across SEC 1 and SEC 2 in the prob lem unit 6 14 14 Replace the transformer 5 15 Turn power off to both units Check continuity of power leads and door switch in the problem unit If n...

Page 12: ...flow when the G thermostat lead is disconnected and a call to dehumidify is active 12 13 12 Replace the variable speed furnace control 7 13 Reconnect the G thermostat lead or jumper and observe operation of furnace in cooling mode for 10 minutes 14 14 Does the furnace operate properly in cooling mode 15 16 15 Check outdoor unit for correct suction pressure and verify charge Check filter s and duct...

Page 13: ... 8 You have an open wire or bad terminal on the BROWN wire from the high heat pressure switch HPS to the gas valve GV Repair it or replace the harness 9 9 Go to the page number indicated in Index for the CLEANUP AND STARTUP INSTRUCTIONS INDEX 10 Replace the gas valve 9 11 Is the high heat rate within 2of that specified on the rating plate 13 12 12 Ensure the gas inlet pressure and burner orifice a...

Page 14: ...replace the variable speed furnace control 4 Status Code 12 BLOWER ON AFTER POWER UP Blower will run for 90 seconds when furnace power is interrupted and later restored during a call for heat R W W1 closed or if the call for heat is interrupted R W W1 opens during the blower on delay period If this status code repeats every couple of minutes it is probably caused by a direct short in the pressure ...

Page 15: ... STARTUP INSTRUCTIONS INDEX Status Code 13 LIMIT CIRCUIT LOCKOUT Lockout occurs if the limit or flame rollout switch is open longer than 3 minutes or 10 successive limit trips occurred during high heat The variable speed furnace control will auto reset in 3 hours Flame roll out switch FRS requires manual reset STEP ACTION YES NO GO TO 1 Remove the blower access panel Make sure the thermo stat is N...

Page 16: ...s code 34 If the inducer motor is running at full speed during lockout this indicates that flame sense was lost 3 times within 60 minutes of cumulative gas valve operating time after the gas valve was already ON for 70 seconds It is usually caused by flame rollout that causes loss of flame sense before the flame rollout switch can trip Status Code 15 BLOWER MOTOR LOCKOUT This status code indicates...

Page 17: ...n Index for CLEANUP AND START UP INSTRUCTIONS INDEX Status Code 23 PRESSURE SWITCH DID NOT OPEN This status code indicates the low or high heat pressure switch LPS or HPS is made when a call for heat is initiated The variable speed furnace control will flash status code 23 until the switch opens then cycle begins STEP ACTION YES NO GO TO 1 Turn power off remove blower access panel and discon nect ...

Page 18: ...ece of tape to hold switch closed 7 7 Does status code 24 flash 8 12 8 Turn power off and disconnect PL1 from variable speed fur nace control 9 9 Do you have continuity between either RED wire connected to the limit circuit and chassis ground 10 3 10 You have a short circuit in the limit switch circuit This in cludes limit switch LS and flame roll out switch FRS 11 11 Fix problem 4 12 Disconnect t...

Page 19: ... W W1 and W2 thermostat terminals 41 41 Does status code 24 begin flashing when the high heat pressure switch HPS is energized 42 33 42 Turn power off and disconnect PL1 from variable speed fur nace control 43 43 Do you have continuity between the BROWN wire and chassis ground 44 3 44 The BROWN wire to high heat pressure switch HPS and gas valve GV is shorting to ground Replace or repair it 11 45 ...

Page 20: ... the setting in memory 5 5 Go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS INDEX 6 Is setup switch SW1 1 in the ON position 7 8 7 Put setup switch SW1 1 in the OFF position 5 8 Is setup switch SW1 6 in the ON position 9 10 9 Put setup switch SW1 6 in the OFF position 5 10 Is this a new service replacement control 11 13 11 You need to remove the model plug PL4 from the ol...

Page 21: ...switch HPS remakes the variable speed stops flashing status code 31 and continues heating cycle If high heat pressure switch HPS does not remake within 45 sec after opening the variable speed shuts the unit down and continues flashing status code 31 After the blower off delay is completed the variable speed will stop displaying status code 31 and if there is a call for heat begin a new heating cyc...

Page 22: ...es or until status code starts flashing 35 35 Does status code 31 flash 37 36 36 Does a different status code flash 7 43 37 Turn power off and disconnect jumper wire across R W W1 and W2 thermostat terminals 38 38 Connect 1 side of slope manometer with a tee to collector box pressure tap Connect other side with a tee to gas valve pressure fitting Refer to pressure check diagram in Appendix C 39 39...

Page 23: ...de INDEX 8 Return setup switch SW1 2 to its original setting and go to page number indicated in Index for CLEANUP AND START UP INSTRUCTIONS INDEX 9 Is 24 vac across YELLOW wire to the low heat pressure switch LPS and COM 24V on variable speed furnace con trol 12 10 10 Is 24 vac across connector terminal PL1 2 and COM 24V on variable speed furnace control 11 13 11 You have an open wire or bad termi...

Page 24: ... C 40 40 Turn power on and jumper R and W W1 thermostat termi nals 41 41 Monitor slope manometer Does the pressure reading ap pear to be stable when fault occurs 43 42 42 Check for a sag in vent pipe or partially clogged drain trap or line Also check for improperly plumbed drainage tubing within furnace Install combustion air disk if not used or add additional restriction to combustion air inlet 8...

Page 25: ...uate combustion air supply This may be caused by Reversed vent and combustion air pipes Poor burner manifold or orifice alignment Blocked heat exchanger Leak in secondary heat exchanger Leak somewhere between primary and secondary heat exchangers 26 26 Fix problem 10 27 While the unit is operating in low heat jumper R and W2 28 28 Observe furnace operation for another 10 minutes or until status co...

Page 26: ...grilles for blockage Add turning vanes more supply openings or more return air openings Use Appendix D to evaluate external static pressure 26 57 While the unit is operating in low heat jumper R and W2 47 58 With blower access panel in place record temperature rise across return air duct before and after the bypass 59 59 Is temperature rise from bypass greater than 15 deg F 60 61 60 The bypass is ...

Page 27: ...l Repeat the COMPO NENT TEST by turning setup switch SW1 6 OFF and then back ON Is 115 vac across PL2 3 and NEUTRAL L2 dur ing the 15 second warm up period 14 13 13 Replace the variable speed furnace control 8 14 Check continuity in harness and igniter Replace failed com ponent 15 15 Fix problem 8 16 Put setup switch SW1 6 in the OFF position and jumper the R and W W1 thermostat terminals 17 17 Is...

Page 28: ... and alignment Inadequate flame carryover Add restriction to combustion air pipe or lengthen a few feet if possible 8 38 While the unit is operating in low heat jumper R and W2 39 39 Do you have burner pulsation s in high heat 37 8 40 Turn off the power and disconnect the jumper across the R and W W1 thermostat terminals 41 41 Turn power on and jumper R W W1 and W2 thermostat terminals 42 42 Do th...

Page 29: ...nals 17 17 Are all pins and wire leads intact on connectors between the variable speed furnace control and the blower motor 18 12 18 Turn the power on and depress the door switch Use a piece of tape to hold it closed 19 19 Do you have 115 vac across the BLACK blower motor wire connected to L1 and the WHITE blower motor wire con nected to NEUTRAL L2 21 20 20 Replace the variable speed furnace contr...

Page 30: ...an LED RED works best These parts can be purchased at a nearby Radio Shack The schematic is shown in Figure 1 When using the blinky light the LED will flash briefly several times a second when the blower motor serial output signal is working properly LED s are directional and the lead clos est to the flat side goes to PL3 2 29 29 Does the voltage fluctuate as described in step 28 30 20 30 Reconnec...

Page 31: ...including blower control mod ule Inspect blower control module for water damage If present find source of water and fix Check A coil and or humidifier 8 Status Code 42 INDUCER MOTOR FAULT This status code indicates the inducer has not started within 20 seconds after a call for heat the inducer RPM is outside its valid range of operation or the inducer RPM signal was lost for 5 seconds during opera...

Page 32: ...assembly 40 34 Disconnect jumper across R and W W1 thermostat termi nals 35 35 Check the RPM feedback line To do this connect a DC voltmeter across terminals PL11 2 BROWN and PL11 1 ORANGE then put setup switch SW1 6 for COMPO NENT TEST in ON position Does the voltage across the BROWN and ORANGE wires change between states as shown below State 1 OFF 11 5 12 5 vdc State 2 MED 9 5 10 5 vdc 36 25 36 ...

Page 33: ...heat pressure switch HPS makes Note Check for 24 vac between the N O Normally Open contact on high heat pressure switch HPS and Com on the variable speed furnace control to know when the high heat pressure switch HPS makes 45 49 Status Code 43 LOW HEAT PRESSURE SWITCH OPEN WHILE HIGH HEAT PRESSURE SWITCH IS CLOSED This status code can occur as a result of the low heat pressure switch LPS not makin...

Page 34: ...ach ORANGE wire interconnecting the low heat pressure switch LPS and the variable speed furnace control Repair open wire or replace harness 8 18 Replace the variable speed furnace control 8 19 Replace the low heat pressure switch or the pressure switch assembly 8 Status Code 45 CONTROL CIRCUITRY LOCKOUT This status code indicates the variable speed furnace control detected one of the following 1 F...

Page 35: ...ATION CONNECTOR AIR CONDITIONING A C AIRFLOW SETUP SWITCHES MODEL PLUG CONNECTOR SW1 SETUP SWITCHES AND BLOWER OFF DELAY STATUS AND COMM LED LIGHTS 3 AMP FUSE TRANSFORMER 24 VAC CONNECTIONS PL3 ECM BLOWER HARNESS CONNECTOR PL1 LOW VOLTAGE MAIN HARNESS CONNECTOR EAC 1 TERMINAL 115 VAC 1 0 AMP MAX 115 VAC L1 LINE VOLTAGE CONNECTIONS 115 VAC L2 NEUTRAL CONNECTIONS PL2 HOT SURFACE IGNITER INDUCER MOTO...

Page 36: ... C onnector PL3 4 Circuit EC M BLW M C onnector PL4 4 Circuit M odel Plug Connector PL7 4 Circuit C om munication Connector PL9 2 Circuit OAT Connector PL10 2 Circuit HSI Connector PL11 IDM C onnector 12 C ircuit PL12 1 Circuit Inductor Splice Connector PL13 16 Circuit EC M Blower Ctrl Connector PL14 5 Circuit EC M Blower Power Connector SW 1 1 Manual Sw itch Status C ode Recall SPST N O SW 1 2 Ma...

Page 37: ...rial commands received from the variable speed furnace control The ECM blower motor is configured via the variable speed furnace control to react to changes in system static pressures to maintain constant airflow CFM The ECM blower motor delivers requested airflow CFM up to about 1 0 in w c of static pressure for most airflow settings The variable speed furnace control is pre programmed and contai...

Page 38: ... 40 000 1 81 in wc max 1 63 in wc 0 05 0 75 in wc max 0 60 in wc 0 05 60 000 1 81 in wc max 1 63 in wc 0 05 0 95 in wc max 0 80 in wc 0 05 80 000 100 000 120 000 Fig 5 Pressure Check A95050 0 4 IN SLOPE GAGE Fig 6 Upflow Total Static Pressure A03091 COMBUSTION AIR PIPE A C COIL OUTDOOR UNIT VENT PIPE HUMIDIFIER GAS FIRED WATER HEATER ELECTRONIC AIR CLEANER AIRFLOW SUPPLY STATIC INCLINE MANOMETER R...

Page 39: ... A03092 ELECTRONIC AIR CLEANER HUMIDIFIER A C COIL VENT COMBUSTION AIR OUTDOOR UNIT AIRFLOW SUPPLY STATIC INCLINE MANOMETER RETURN STATIC INCLINE MANOMETER Fig 8 Horizontal Total Static Pressure A03093 SUPPLY STATIC INCLINE MANOMETER RETURN STATIC INCLINE MANOMETER VENT PIPE ELECTRONIC AIR CLEANER FURNACE CONDENSATE DRAIN REFRIGERATION PIPING AIR CONDITIONING COIL AIRFLOW COMBUSTION AIR PIPE 39 ...

Page 40: ...ging algorithm will provide 16 minutes of low heat provided setup switch SW1 2 is off If call for heat still exists after operating for 16 minutes in low heat furnace switches to high heat until the thermostat is satisfied During subsequent calls for heat Low heat run time is calculated based on previous heating cycle High heat run time is not calculated High heat is energized in 1 of 3 ways and r...

Page 41: ... heat run time is 0 min EXAMPLE 3 Furnace ran for 13 minutes in low heat and 5 minutes in high heat during previous call for heat This can happen if the furnace staging algorithm calculated 13 minutes based on previous call for heat LH 13 HH 5 Calculate 228 x 13 350 x 5 4714 3648 4714 5600 Calculate low heat run time for next cycle LHrun time 5600 4714 122 7 26 Next cycle furnace will run for 7 mi...

Page 42: ...minute for a period of time as calculated by the following LH run time 5600 HL 122 Unit will initiate the next cycle in Low Heat for a maximum of 16 minutes before initiating High Heat if the call for heat still exists Unit will initiate the next cycle in High Heat until the thermostat is satisfied The next cycle will be initiated with the calculated Low Fire run time before initiating High Heat i...

Page 43: ...roduct theory and skills programs is available using popular video based formats and materials All include video and or slides plus companion book Classroom ServiceTraining plus hands on the products in our labs can mean increased confidence that really pays dividends in faster troubleshooting fewer callbacks Course descriptions and schedules are in our catalog CALL FOR FREE CATALOG 1 800 644 5544...

Page 44: ...46231 58mvp10sm Manufacturer reserves the right to discontinue or change at any time specifications or designs without notice and without incurring obligations Book 1 4 Tab 6a 8a PC 101 Catalog No 535 80083 Printed in U S A Form 58MVP 10SM Pg 44 6 03 Replaces New ...

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