Carrier Furnace Troubleshooting

No matter how big, powerful or expensive your carrier heater is, they all may face a breakage some day. The causes may be different, but a few simple tips might help the owners troubleshoot their appliance in most of situations. So don’t rush to call your service center or an independent appliance technician if it’s not working properly and take a look at our simple step-by-step repair guide in order to restore your carrier furnace by yourself.

Stage 1
At first, you need to find the thermostat and switch it to the “heat” position. Make sure you set the temperature way above the normal one inside the premise you are in. Try to set in at 70 degrees.
Stage 2
Inspect your power supply as there might simply be no electricity in the house. Find the circuit breaker box and switch the power on in case it is off.
Stage 3
Turn the fan on to check if it works. Clean it if necessary from dust, dirt and damaging particles using a vacuum cleaner.
Stage 4
If the appliance is not producing enough heat, the issue may have to do with SSU switch. It is usually located on one of the furnace’s sides. Find it and switch it on if necessary.
Stage 5
Next, inspect the filter. It must be visually clean and contain no dust, dirt of any other extraneous particles. Visit a local store and to purchase the right model of a filter for your heater if it requires replacement.
Stage 6
Finally, examine the condition of return air grilles. If you see that they are clogged, take a vacuum cleaner and a sponge to remove the dust. The return air grilles shouldn’t be blocked by any big objects or furniture. Finally, make sure supply air registers are open and blow air well.

Carrier 58DX Series Furnace Troubleshooting

Problem Solution
IF YOUR SYSTEM ISN’T RUNNING Check to make sure your control or thermostat is set in the HEAT position. (You’d be surprised; often that’s the problem.) Make sure the temperature is set warmer than the current indoor temperature. If it isn’t, your system won’t know to provide heating.
Ensure your furnace’s power is on. Try turning the fan to ON using the fan switch on the control or thermostat to test for power to the furnace.
Check the circuit breakers in your home’s circuit breaker box (electrical panel) to make sure they’re in the ON position.
Check the furnace power switch to be sure it’s in the ON position (it looks like a light switch on a gray box located at the furnace).
SYSTEM NOT HEATING ENOUGH: Check the filter for buildup. If you have one-inch-thick furnace filters, a once-a-month change is recommended. Two-inch-thick filters – and other high-capacity pleated filters – usually only need to be changed every other month or less, depending on the type. If you don’t change it, the filter will block the proper airflow and strain your furnace.
Check all return air grilles to make sure they are not blocked. Return air grilles are larger and are located on a wall or the ceiling in newer homes. Older homes frequently have return air grilles on the floor.
Check all supply registers to make sure they are open and blowing air.
If you still don’t feel that wonderful rush of warmth throughout your home, it’s time to contact your local Carrier expert for service.
OTHER SIGNS THAT INDICATE A SERVICE CALL MAY BE IN ORDER: You hear your indoor-unit fan coming on, but the air from the registers isn’t warm or the fan is turning on and off more frequently than usual. NOTE: If your system control has a “Constant ON” feature, you will not always feel warmth, even though air may be blowing.
BEFORE YOU REQUEST A SERVICE CALL FOR YOUR VENTILATOR: Check the main power disconnect switch. Verify that the circuit breakers are ON or that fuses have not blown. If you must reset breakers or replace fuses, do so only once. Contact your Carrier expert for assistance if the breakers trip or the fuses blow a second time.
Check for sufficient airflow. Check air filters for accumulations of large particles. Check for blocked exhaust air grilles or ductwork. Keep grilles and ductwork open and unobstructed.

Carrier 58MSA Series Furnace Troubleshooting

Problem Solution
Gas Leak If you suspect a furnace gas leak, deal with this immediately! First, if you smell natural gas in your home or near the furnace, do not light any matches or turn off or on any switches. If the gas odor is strong, immediately evacuate your house, leaving the door open.
Furnace Not Working—No Gas Flame Older gas and combustion-fuel furnaces have pilot lights, whereas some newer ones have electronic ignition
Furnace with a Pilot Light If your older furnace utilizes a pilot light that won’t stay lit, the thermocouple may be loose or faulty, the pilot orifice may be clogged, the pilot’s flame may be set too low, or the safety cutoff valve may be defective.
The thermocouple is a copper rod that the pilot flame heats-up. When it gets hot enough, the thermocouple signals that there is enough heat to burn the gas fuel being released into the appliance—and so it allows the gas to be released to the burners. In some cases where the pilot light won’t stay lit, the thermocouple needs to be adjusted or replaced. This is generally a job for a professional
Electronic Ignition Furnace On an electronic-ignition furnace, turn down the thermostat or turn the power switch off and then on again to reset the ignition control module. Listen for the sound of the spark or watch for the hot surface ignitor to glow
Next check and clean the furnace’s flame sensor. The video below shows you how—note that this guy fixes it in about 5 minutes. We would probably use a little bit of emory paper, but he cleans the sensor with a 5-dollar bill. Another video further down the page under the discussion of “If your furnace keeps shutting off after about 5 minutes” shows the same project with a different brand of furnace.
Heating or Cycling Problems If your furnace runs and provides some heat but not enough
1-Be sure nothing is blocking the flow of warm air.
2-Be sure the thermostat is set properly to “Heat” and the fan is set to “On” or “Auto.” Then try raising the set temperature 5 degrees and waiting a few minutes.
3-Be sure the room heating registers are open.
4-Check the filter. Because a dirty filter can reduce efficiency, replace it with a new air filter if it’s dirty
If your furnace cycles on and off too often The problem is often with the thermostat—especially if you have a combustion furnace. For information on how to solve and repair this problem
If your thermostat has a small lever that moves along a calibrated scale that indicates “longer” (not the heat temperature lever), you can try adjusting this—the heat anticipator. Just set it one calibration mark closer to the “longer” setting if the furnace goes off and on too frequently or one mark away if the furnace allows room temperature to rise too high or drop too low before going on or off. It may take several hours for the thermostat to stabilize at this setting, so wait a while and then adjust it again if necessary.
Furnace Does Not Blow Air If your furnace’s motor runs but the blower doesn’t move air, the belt that connects the two probably has broken. Replacing it is an easy fix. First, turn off all power to the unit and turn off the gas at the gas valve that serves the furnace. Remove the door on the front of the furnace cabinet to give you access to the blower (it might be on a slide-out drawer.) Check the number stamped on the belt and get an exact replacement from a home center or heating supply outlet.
You can usually slip the belt on the motor’s (smaller) pulley first and then start it on the blower pulley. Rotate the blower pulley by hand, holding the belt in place but keeping your fingers from getting caught between the belt and the pulley. The belt should slip right into place. If it seems to be too tight or difficult to set in place, it may be necessary to adjust the motor mount to provide more slack.
Then you can re-tighten the tension once the belt is in place. Check the manufacturer’s specifications for proper tension—in most cases, the belt should deflect about an inch when you press down on it.
Finally, some fan motors and fans need oiling; some have sealed bearings. If recommended by your maintenance manual, oil the bearings according to the manufacturer’s directions.
Blower Runs Continuously Two things can cause a blower to run continuously: the room thermostat or the limit switch located on the furnace just below the plenum (the box that distributes heated air to all the ducts). The limit switch shuts off the furnace if the air in the plenum gets too hot.
Check the thermostat to see if the Fan switch has been turned on. If it has, turn it to Off or to Auto. If it is set to Off or Auto, the furnace’s limit switch must be adjusted.
Call a furnace repair technician to adjust the limit switch, or follow the instructions in your owner’s manual to reset the pointers on the fan side of the limit control. Typically, the lower pointer should be set to about 90 degrees F., and the upper one should be at about 115 degrees F.
Noisy Furnace or Duct Work Many heating ducts are metal, so they conduct noise quite readily from the air-handling unit to your rooms. To break the conduction of sound, you can have a heating contractor insert flexible insulation duct work between the furnace or air conditioner and the duct work runs.
Pinging or Popping Sounds A pinging or popping sound coming from the duct work can come from thermal expansion—the ductwork expanding and contracting as it heats and cools. Or, air blowing past a loose flap of metal can make the sound. Track along the duct runs, listening for the sound. If you locate it, make a small dent in the sheet metal to provide a more rigid surface that’s less likely to move as it heats and cools.
Rattling Noises If the furnace cabinet makes rattling noises when it runs, be sure the cover panels are screwed on tight. Tighten any loose panels.
Squealing Noises Squealing sounds from a forced-air furnace generally occur when the belt that connects the motor to the fan slips. Tighten the fit by adjusting the motor mount. Or, the belt is improperly aligned or worn and needs replacement.
This job involves removing the access panel, loosening a couple of bolts that hold the blower motor at the proper tension, and adjusting its distance or realigning the belt. In many cases, it’s a good idea to remove the belt and buy a replacement at a home center. Last, when reinstalling the belt, be careful not to over-tighten it; this can wear out the motor bearings.
Grinding Sounds If the blower is making a grinding noise, shut off the unit and call a furnace repair technician; the motor’s bearings are probably shot.
Furnace Not Working—Oil Burner First of all, if the oil burner goes on and off too much, clean or replace the filter.
If your oil burner doesn’t work at all, check to see if it is receiving electrical power, if the thermostat is broken or turned off, or if a flame sensor in the burner or heat sensor in the stack has signaled the unit to shut off.
In the event that replacing the filter or checking these issues don’t solve the problem, call a furnace repair technician because oil-burning furnaces are complex to repair.

Carrier 58MVC Furnace Troubleshooting

Error code Cause Solution
11 No previous code – Stored status codes are erased automatically after 72 hours or as specified above.
12 Blower on after power up – (115 VAC or 24 VAC) – Blower runs for 90 seconds, if unit is powered up during a call for heat (R-W/W1 closed) or (R-W/W1 opens) during the blower on delay period.
13 Limit circuit lockout – Lockout occures if the limit, or flame rollout switch is open longer than 3 minutes or 10 successive limit trips occurred during high-heat. Control will auto reset after 3 hours.
14 Ignition lockout – Control will auto-reset after 3 hours.
15 Blower motor lockout – Indicates the blower failed to reach 250 RPM or the blower failed to communicate within 30 seconds after being turned ON in two successive heating cycles.
Control will auto reset after 3 hours.
21 Gas heating lockout – Control will NOT auto reset. Check for: – Mis-wired gas valve. -Defective control (valve relay)
22 Abnormal flame-proving signal – Flame is proved while gas valve is de-energized. Inducer will run until fault is cleared. Check for: – Leaky gas valve. – Stuck-open gas valve.
23 Pressure switch did not open – 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 in memory. Check the following: – Thermostat call with “SW1-1” ON. – Thermostat call with “SW1-6” ON. – “SW1-1” and “SW1-6” both ON together. – Two different furnace models twinned. – Wiring diagram for model plug number and resistance values if code flashes continuously. – Board does not recognize new model plugs HK70EZ017 – 021. New board software version V12 or later required.
31 Medium-heat pressure switch or hpsr relay did not close or reopened – Indicates the medium-heat pressure switch input failed to close on a call for medium- or high-heat, or opened during medium- or high-heat. HPSR relay may be defective.
32 Low-heat pressure switch did not close or reopened – Indicates the low-heat pressure switch input failed to close on a call for low-heat, or opened during low-heat. If opens during 5 minutes after ignition the next heating cycle will be restricted to high-heat. Check for: – Proper vent sizing. – Plugged condensate drain. – Excessive wind. – Low inlet gas pressure (if LGPS used). – Improper pressure switch wiring. – Restricted combustion air supply. – Disconnected or obstructed pressure tubing. – Water in vent piping, possible sagging pipe. – Failed or “Out-of-Calibration” pressure switches.

Carrier 58MCA series Furnace Troubleshooting

Problem Solution
Furnace Produces No Heat If the furnace is producing no heat, it’s not likely there’s an issue with the heating element so much as there is a problem with its supplementary systems. Tempstar furnaces are typically gas-powered models, though they rely on electronic regulators to make sure they work properly. These regulators are usually at fault. First, check to make sure that the furnace is receiving electricity and that the circuit breakers have not been tripped. In older houses, you may have to check the fuse box and replace a blown fuse. Make sure that the valve feeding the furnace with propane or natural gas is open and ensure that the pilot light has not gone out. If all these things are working properly, the thermostat is to blame. Make sure it’s in “heat” mode and set it to a temperature above the room’s current temperature. If the furnace doesn’t turn on, the thermostat is broken and needs to be repaired by a Tempstar furnace product support representative
Furnace Makes Odd Noises There are three noises that are not normal for a Tempstar furnace. A high-pitched squeal may be the result of poorly oiled bearings or the blower motor’s fan belt slipping. The fan belt should be tightened and lightweight oil poured into the Tempstar furnace’s oil induction ports. Should the furnace make a rumbling sound when the gas burners are turned on, it means the burner is dirty from carbon deposits and should be removed and cleaned. If the furnace makes a rumbling noise when the burners are turned off, it means the pilot light is burning too hot. The amount of fuel reaching the pilot light should be reduced until the rumbling goes away.
Furnace Turns On and Off Frequently If the furnace is coming on and off too often, it’s because it has to work too hard to maintain the home’s temperature. This may be because the furnace air filter is dirty, preventing adequate hot air from passing through and heating the home. Look at the filter. If it’s discolored in any way, it needs to be replaced. The hot air from the furnace might not be getting to the rest of the house because of the blower motor. It’s essentially a large fan set into the top of the furnace and receives the energy to turn from a fan belt. The fan should be oiled first; there will be oil induction ports on the exterior of the furnace. The fan belt should be inspected; make sure it’s not frayed, it has good tension, and it has not jumped its rods. If any such problem exists, the belt should be replaced immediately.

Carrier 59MN7A Furnace Troubleshooting

Problem Solution
FOR INSUFFICIENT AIRFLOW: • Check for dirty air filter(s).
• Check for blocked return-air or supply-air grilles throughout your home. Ensure they are open and unobstructed.
If problem still exists, call your dealer for service.
IF FURNACE FAILS TO OPERATE: Follow this checklist step by step, advancing to the next step only if furnace fails to start.
• Check thermostat for proper temperature. Is thermostat set above room temperature?
• Is thermostat set on HEAT?
• Check fuses and circuit breakers. Is electrical supply on?
• Is manual shutoff valve in gas supply pipe in open position? (Follow start-up procedures if you open gas valve.)
NOTE: Turn off electrical supply before continuing with checklist.
• Is control switch on gas valve in ON position? (Follow startup procedures if you must reset switch to ON position.)
• Check manual reset flame rollout switch located on the burner box. If furnace has experienced high temperature conditions, this switch will shut off the furnace.
Reset it by pushing the button on the switch.
If it trips again, shut down the furnace and call for service.
• Check for obstructions around the vent termination.
If the furnace still fails to operate, call your service representative.