Updated July 27, 2026: Heat pump startup sequences, protective delays, breaker arrangements, thermostat controls and fault codes vary by manufacturer and system design. Follow the instructions supplied with your equipment and leave internal electrical and refrigeration testing to qualified professionals.
Heat pump won’t turn on? Start by checking the thermostat mode and setpoint, whether the thermostat has power, whether the indoor and outdoor units have power, whether a fault code is displayed and whether a normal compressor restart delay may be active. A dirty filter, blocked condensate drain, electrical problem, sensor fault, fan problem, compressor protection or control failure can also prevent operation.
Before assuming the entire heat pump has failed, identify which part of the system is not running. A blank thermostat, an indoor fan running without the outdoor unit, a completely silent system and an outdoor unit running without indoor airflow all point toward different diagnostic paths.
Do not repeatedly reset a breaker, open electrical compartments, bypass a condensate safety switch or force a contactor to start. If the breaker trips again, there is a burning smell, smoke, damaged wiring or water near electrical components, keep the system off and arrange professional service.
This guide covers central ducted, ductless, multi-zone, full-electric and dual-fuel heat pump systems used in British Columbia.
Why Won’t My Heat Pump Turn On?
A heat pump may fail to start because it is not receiving a valid heating or cooling demand, one part of the system has lost electrical power, a safety control is active or a component has failed.
Common causes include:
- Incorrect thermostat mode
- Setpoint does not require heating or cooling
- Thermostat has lost power
- Normal compressor restart delay
- Tripped breaker
- Outdoor disconnect problem
- Dirty filter or restricted airflow
- Condensate overflow safety switch
- Fault lockout
- Indoor/outdoor communication error
- Sensor fault
- Fan or blower failure
- Control-board problem
- Compressor or inverter fault
- Refrigeration protection
- Installation or setup error
First Check Whether There Is Actually a Call for Operation
If the thermostat is set to Heat at 20°C and the room is already 21°C, the heat pump should not start.
Likewise, a system set to Cool at 24°C may remain off when the room is 23°C.
Confirm the requested mode and temperature before moving deeper into troubleshooting.
Which Part of the Heat Pump Is Not Running?
A heat pump is a system rather than one appliance.
Depending on the installation, it may include:
- Thermostat or wall controller
- Indoor air handler
- Gas furnace
- Ductless indoor units
- Outdoor heat pump
- Auxiliary electric heat
- Condensate pump
- Zoning controls
| What You See | Possible Areas to Check |
|---|---|
| Thermostat screen is blank | Thermostat power, transformer, breaker, safety switch, wiring |
| Thermostat works but nothing starts | Mode, setpoint, controls, power, communication, fault lockout |
| Indoor fan runs but outdoor unit is off | Fan setting, outdoor power, controls, compressor protection, communication |
| Outdoor unit runs but indoor fan does not | Indoor blower, control board, wiring, airflow equipment |
| One ductless head will not run | Remote, mode, local control, sensor, communication, indoor fan |
| All ductless heads are off | Outdoor power, main control, system fault, thermostat or communication |
| Heat pump does not start but furnace works | Heat pump controls, outdoor unit, lockout setting, dual-fuel configuration |
| Heat pump works but furnace will not start | Furnace controls, ignition, gas supply, changeover logic |
Knowing which component responds and which does not can eliminate several unrelated causes before diagnosis begins.
What Should a Homeowner Check First?
Start with checks that do not require removing equipment panels.
- Confirm the thermostat has power.
- Select Heat or Cool rather than Off.
- Set the temperature so there is a clear demand.
- Check the thermostat fan setting.
- Look for Hold, Away, Vacation or schedule settings.
- Record any thermostat or equipment fault code.
- Inspect the air filter.
- Check for water around the indoor unit.
- Look for heavy outdoor ice or snow buildup.
- Check whether the system has recently lost electrical power.
- Allow time for a normal restart delay.
Do Not Change Several Things at Once
Changing the thermostat, resetting breakers and cycling equipment power repeatedly can make diagnosis more difficult.
Record what the system was doing before resetting anything.
Cause 1: Thermostat Mode or Setpoint Is Incorrect
The heat pump will not start without a valid demand from the control system.
For Heating
Confirm:
- Mode is Heat
- Setpoint is above room temperature
- Emergency Heat is not selected unintentionally
- Schedule is not reducing the temperature
For Cooling
Confirm:
- Mode is Cool
- Setpoint is below room temperature
- Fan-only mode is not selected
Auto Mode
ENERGY STAR recommends using a defined Heat or Cool mode when automatic changeover is unnecessary. This reduces confusion about which operating mode the system is being asked to use.
See the official ENERGY STAR air-source heat pump guidance.
Thermostat Schedule
A programmed schedule may override the temperature you expected.
Check for:
- Sleep schedule
- Away setting
- Vacation mode
- Temporary Hold
- Permanent Hold
Cause 2: Thermostat Has No Power
A blank thermostat can prevent the entire system from receiving operating commands.
Possible Causes Include:
- Low or dead batteries on applicable thermostats
- Loss of low-voltage power
- Failed transformer
- Tripped indoor-equipment breaker
- Open equipment safety switch
- Condensate float switch
- Loose thermostat wiring
Battery Thermostat
If the thermostat uses replaceable batteries, check them according to the manufacturer instructions.
Hard-Wired Thermostat
A blank hard-wired thermostat can indicate a problem elsewhere in the HVAC electrical or control system.
Do not assume the thermostat itself needs replacement.
Thermostat Blank After Water Leak
A condensate safety control may have interrupted the system because water was detected.
Check for water around the indoor equipment before assuming there is an electrical failure.
Cause 3: The Heat Pump Is in a Normal Restart Delay
Heat pumps commonly use compressor-protection delays.
After power interruption, thermostat changes or compressor shutdown, the system may intentionally wait before allowing another compressor start.
Why Is There a Delay?
The delay can help:
- Prevent rapid compressor restarts
- Allow refrigerant pressures to stabilize
- Protect compressor and inverter components
How Long Should You Wait?
There is no universal delay that applies to every manufacturer.
Follow the thermostat and equipment instructions rather than repeatedly switching the system off and on.
When It Is No Longer Just a Delay
Request service when:
- The system never starts
- A fault code appears
- The breaker trips
- The unit repeatedly attempts to start and stops
Cause 4: A Circuit Breaker Has Tripped
A central heat pump can have separate electrical circuits for the outdoor unit, indoor air handler and auxiliary heat.
A ductless system can also have dedicated electrical protection.
One Tripped Circuit Can Produce Confusing Symptoms
For example:
- Indoor blower may operate while outdoor heat pump has no power
- Heat pump may operate while auxiliary heat does not
- Thermostat may lose power while another component remains energized
Should You Reset a Tripped Breaker?
If you know which breaker serves the equipment and there is no smoke, burning smell, water or visible damage, follow the equipment and electrical-panel instructions.
If the breaker trips again, leave it off and request diagnosis.
Do Not Keep Resetting It
A repeated trip may be caused by:
- Compressor electrical fault
- Fan motor problem
- Damaged wiring
- Short circuit
- Failed electrical component
- Circuit problem
ENERGY STAR recommends professional inspection of electrical connections and measurements of voltage and motor current because faulty electrical conditions can make HVAC equipment unsafe and shorten component life.
Cause 5: Outdoor Disconnect or Power Supply Problem
The outdoor unit normally has a local disconnect for service and electrical isolation.
If the outdoor equipment has no power, the indoor system may still respond to thermostat commands.
Possible Symptoms
- Indoor blower runs
- Thermostat shows Heat or Cool
- Outdoor unit remains completely silent
- No outdoor fan or compressor operation
Possible Causes
- Breaker problem
- Disconnect problem
- Electrical wiring fault
- Control failure
Do not open or repair the disconnect yourself.
Recent Service Work
If the system stopped operating immediately after maintenance, installation or electrical work, tell the technician exactly what was done and when the failure began.
Cause 6: Dirty Filter or Airflow Protection
A dirty filter usually reduces performance before it completely prevents a heat pump from operating, but severe airflow problems can trigger protective limits or faults.
Possible Signs
- Weak airflow before shutdown
- Whistling at returns
- Indoor coil icing during cooling
- Fault codes
- System starts and stops instead of running normally
Check the Filter
ENERGY STAR recommends checking filters regularly because dirty filters increase system workload and can contribute to early equipment problems.
Natural Resources Canada also recommends keeping heat pump filters and coils clean and following manufacturer maintenance instructions.
A New Filter Can Still Restrict Airflow
Filter resistance should be compatible with:
- Filter cabinet
- Return ductwork
- Blower capability
- Equipment airflow requirements
Cause 7: Condensate Safety Switch Has Shut the System Down
During cooling, the indoor coil removes moisture from the air.
Some installations have float switches designed to stop cooling if condensate cannot drain safely.
Why Would the Safety Switch Open?
Possible causes include:
- Blocked condensate drain
- Failed condensate pump
- Overflowing drain pan
- Incorrect drain slope
- Standing water
Possible Symptoms
- Thermostat becomes blank
- Cooling suddenly stops
- Water is visible near indoor equipment
- Secondary pan contains water
Do Not Bypass the Switch
The shutdown may be preventing water damage to ceilings, walls or flooring.
ENERGY STAR specifically includes condensate-drain inspection in professional heat pump cooling maintenance.
Cause 8: Outdoor Conditions or Equipment Protection
Heat pumps operate within manufacturer-defined temperature and pressure conditions.
Modern controls may reduce capacity or stop equipment when an operating condition falls outside a safe range.
Possible Conditions Include:
- Extreme outdoor temperature
- Heavy ice or snow blockage
- Outdoor airflow restriction
- Abnormal refrigerant pressure
- Compressor temperature protection
Winter Ice
Natural Resources Canada recommends checking outdoor heat pumps for excessive snow or ice buildup during winter because blocked equipment cannot operate correctly.
See the official Natural Resources Canada air-source heat pump guidance.
Do Not Break Ice With Tools
Sharp tools can damage the coil, fan or refrigerant tubing.
Cause 9: Indoor and Outdoor Units Are Not Communicating
Many modern heat pumps use digital communication between the thermostat, indoor unit and outdoor unit.
A communication problem can prevent startup even when all components have power.
Possible Causes Include:
- Loose control wire
- Damaged communication cable
- Incorrect polarity where applicable
- Control-board fault
- Indoor-unit fault
- Outdoor-unit fault
- Power interruption
Possible Symptoms
- Communication error code
- Indoor unit operates but outdoor unit does not
- System stops after installation or service
- Several ductless indoor units display a related fault
Record the Error Code
Do not clear the fault repeatedly before the service appointment.
The exact code can identify which part of the communication network needs testing.
Cause 10: Temperature or Pressure Sensor Fault
Sensors provide the control system with information needed for safe operation.
They May Monitor:
- Indoor temperature
- Outdoor temperature
- Indoor coil temperature
- Outdoor coil temperature
- Refrigerant piping
- Compressor temperature
- System pressure
A Sensor Problem Can Cause:
- Failure to start
- Immediate shutdown
- Incorrect defrost
- Fan problems
- Compressor lockout
- Fault codes
A Sensor Code Does Not Always Mean the Sensor Itself Failed
The actual cause may be:
- Sensor
- Connector
- Damaged wire
- Control board
- An operating condition outside the expected range
Cause 11: Indoor Blower Will Not Start
A ducted heat pump needs the indoor blower to distribute heating and cooling and to keep the indoor coil within the intended operating range.
Possible Causes Include:
- Blower motor failure
- Control-board problem
- Loose wiring
- Motor protection
- Blower wheel obstruction
- Incorrect control signal
Outdoor Unit Running Without Indoor Airflow
This condition can create:
- Abnormal coil temperatures
- Indoor coil icing during cooling
- Protective shutdown
- Poor heating or cooling
If the outdoor system operates but there is no indoor airflow, turn the system off and arrange inspection rather than allowing the refrigeration system to continue without proper airflow.
Cause 12: Outdoor Fan Will Not Start
The outdoor fan moves air through the outdoor coil during normal heating and cooling operation.
Possible Causes Include:
- Fan motor failure
- Control-board problem
- Electrical connection
- Ice blocking the fan
- Debris
- Motor-control fault
The Fan May Stop During Defrost
During winter defrost, many heat pumps intentionally stop the outdoor fan temporarily.
This is not necessarily a failure.
Fan Striking Ice
Turn the system off.
Continued operation can damage:
- Fan blade
- Motor shaft
- Coil
- Fan guard
- Cabinet
Cause 13: Control Board, Relay or Electrical Component Problem
Heat pumps depend heavily on electronic controls.
Possible Components Include:
- Indoor control board
- Outdoor control board
- Relays
- Contactors
- Transformers
- Inverter electronics
Possible Symptoms
- No response to thermostat demand
- Repeated clicking
- Intermittent startup
- Fault code
- Indoor and outdoor units behave differently
- Burning or electrical smell
Electrical Testing Matters
ENERGY STAR recommends checking HVAC controls, electrical connections, motor voltage and current, and confirming that equipment starts, operates and shuts down correctly during professional maintenance.
Cause 14: Compressor or Inverter Will Not Start
The compressor is central to the refrigeration cycle.
If it cannot start, the indoor fan may still operate without useful heating or cooling.
Possible Symptoms
- Outdoor fan operates but compressor does not
- Unit hums and stops
- Repeated startup attempts
- Breaker trips
- Compressor or inverter fault code
- No heating or cooling
Possible Causes Include:
- Compressor electrical problem
- Inverter fault
- Power supply
- Sensor protection
- Refrigerant pressure problem
- Control-board problem
Do Not Assume the Compressor Is Dead
Several control and electrical failures can prevent a healthy compressor from receiving a valid start command.
A major compressor replacement should follow proper electrical and refrigeration diagnosis.
Cause 15: Refrigeration-System Protection Has Stopped the Heat Pump
A heat pump may shut down when refrigerant temperatures or pressures move outside acceptable limits.
Possible Causes Include:
- Low refrigerant
- Refrigerant leak
- Overcharge
- Restricted airflow
- Dirty coil
- Failed fan
- Refrigerant-flow restriction
Fault Lockout
Some systems stop operation after repeated faults rather than continuing to restart.
This protects equipment from additional damage.
Do Not Add Refrigerant Based on Failure to Start
A heat pump not starting does not prove that refrigerant is low.
The refrigeration system should be tested after airflow, controls, electrical operation and the actual fault condition are considered.
Cause 16: Installation or Commissioning Problem
If a new heat pump has startup problems from the beginning, installation and setup should be reviewed.
Possible Issues Include:
- Thermostat configured incorrectly
- Communication wiring problem
- Outdoor disconnect issue
- Breaker or circuit problem
- Incorrect equipment matching
- Refrigerant commissioning problem
- Indoor airflow not configured
- Dual-fuel controls set incorrectly
A New System Turning On Is Not Enough
Commissioning should confirm that the system:
- Starts correctly
- Operates in heating mode
- Operates in cooling mode
- Provides correct airflow
- Completes normal shutdown
- Operates backup heat correctly
- Communicates without faults
Why Is the Indoor Fan Running but the Outdoor Heat Pump Is Not?
This is one of the most useful symptoms to report.
First Check the Fan Setting
If the thermostat is set to Fan On or Circulate, the indoor blower can run without a compressor demand.
If There Is a Real Heating or Cooling Demand
Possible causes include:
- Outdoor unit has no power
- Outdoor disconnect issue
- Control delay
- Communication fault
- Sensor protection
- Outdoor control-board problem
- Compressor or inverter fault
Do Not Assume It Is the Thermostat
The thermostat may be correctly requesting operation while the outdoor equipment is unable to respond.
Why Is the Outdoor Unit Running but the Indoor Fan Is Not?
This condition needs attention because airflow is necessary for proper heat transfer.
Possible Causes Include:
- Blower motor failure
- Indoor control-board fault
- Loose wiring
- Blower protection
- Thermostat or communication problem
Should You Leave It Running?
No. If the outdoor refrigeration system is operating without indoor airflow, shut the system down and arrange diagnosis.
Continued operation can contribute to coil freezing or other abnormal operating conditions.
Why Does Nothing Turn On?
When the thermostat, indoor unit and outdoor unit all appear inactive, start with the common controls and power sources.
Possible Causes
- Main electrical power problem
- Indoor-unit breaker
- Transformer failure
- Thermostat power loss
- Condensate safety switch
- Control-board failure
Check for Water
If the thermostat became blank during cooling, inspect the indoor-equipment area for condensate overflow.
Recent Electrical Outage
A power interruption can leave the system in a restart delay or reveal an existing electrical component problem.
Why Won’t My Heat Pump Start After a Power Outage?
After power returns, the system may not start immediately.
Possible Reasons Include:
- Compressor protection delay
- Thermostat restarting
- Control boards rebooting
- Breaker trip
- Electrical surge damage
- Communication fault
What Should You Do?
- Check that the thermostat has restarted normally.
- Confirm Heat or Cool mode.
- Check for a fault code.
- Allow the normal restart sequence to complete.
If equipment does not return to normal operation or a breaker has tripped repeatedly, request professional service.
Do Not Rapidly Cycle Power
Repeated manual power cycling can restart delays without resolving the actual problem.
Why Did the Heat Pump Stop Working After a New Thermostat Was Installed?
Heat pumps require thermostat configuration that matches the installed system.
Important Settings Can Include:
- Heat pump equipment type
- Reversing-valve logic
- Number of compressor stages
- Auxiliary electric heat
- Dual-fuel furnace
- Fan control
- Outdoor sensor
Possible Symptoms of Incorrect Setup
- No heating
- No cooling
- Indoor fan works but outdoor unit does not
- Backup heat never operates
- Furnace and heat pump sequence incorrectly
Smart Thermostat Compatibility
A thermostat should be compatible with the heat pump and its control architecture.
Some communicating systems require manufacturer-specific controls rather than a conventional thermostat.
Why Does the Heat Pump Work in Heating but Not Cooling?
If heating operates normally, several shared components are already proven to work.
Cooling-specific problems may involve:
- Thermostat cooling command
- Reversing-valve operation
- Cooling-mode controls
- Sensor problem
- Refrigeration conditions
Check Cool Mode First
Confirm the thermostat is actually requesting cooling.
Reversing Valve
A heat pump changes refrigerant direction between heating and cooling. A valve or control problem can affect one mode while the other still works.
Why Does Cooling Work but Heating Will Not Start?
The system may have a heating-specific control or operating problem.
Possible Causes Include:
- Thermostat heating configuration
- Reversing-valve control
- Defrost-related fault
- Outdoor-temperature control
- Heating lockout setting
- Backup heating issue
Dual-Fuel Systems
A poorly configured changeover strategy can also affect whether the heat pump or furnace is allowed to operate at a given outdoor temperature.
Ductless Heat Pump Won’t Turn On
A ductless system has several additional homeowner checks.
Check the Controller
Confirm:
- Remote has power
- Correct mode is selected
- Setpoint requires operation
- Timer or schedule is not active
- No fault code is displayed
Remote-Control Batteries
Weak remote batteries can prevent commands from reaching some indoor units.
Multi-Zone Mode Conflict
Many conventional multi-zone heat pumps require connected indoor heads to use compatible operating modes.
A zone may appear inactive when another zone is requesting a conflicting mode.
One Indoor Unit Does Not Start
If other heads on the same outdoor unit work normally, possible local causes include:
- Indoor control board
- Fan motor
- Temperature sensor
- Communication
- Remote or wall controller
No Indoor Units Start
Outdoor-unit power, central controls and system-wide faults become more likely.
Dual-Fuel Heat Pump Won’t Turn On
A dual-fuel system adds another layer of controls because the heat pump and gas furnace share the heating responsibility.
The Heat Pump May Be Intentionally Locked Out
Controls can stop heat-pump operation below a selected outdoor temperature and use the furnace instead.
Natural Resources Canada describes heat pump control strategies that coordinate heat-pump and supplementary heating operation according to outdoor conditions and system design.
Review the official NRCan heat pump operating guide.
Possible Problems Include:
- Incorrect changeover temperature
- Outdoor sensor error
- Thermostat configuration
- Heat pump fault
- Furnace fault
- Communication problem
If the Furnace Also Will Not Start
Shared thermostat, power or blower problems may need to be considered along with furnace-specific issues.
Should You Use Emergency Heat if the Heat Pump Will Not Start?
Emergency Heat is available on some central heat pump systems as a temporary backup mode.
It May Be Appropriate When:
- The outdoor heat pump cannot operate
- The home needs temporary heat while repair is arranged
- The manufacturer or technician instructs you to use it
Emergency Heat Is Not a Repair
It does not solve the reason the compressor heat pump failed to start.
Operating Cost
Where Emergency Heat uses electric resistance heating, it typically requires more electricity to deliver the same amount of heat than normal heat-pump operation.
Dual-Fuel Systems
A gas furnace may provide the backup instead, depending on the installed controls.
When Should You Leave the Heat Pump Off?
Keep It Off and Request Service When:
- The breaker trips repeatedly
- There is a burning smell
- Smoke is present
- Electrical arcing or severe buzzing occurs
- Water is reaching electrical equipment
- Visible wiring is damaged
- The compressor repeatedly attempts to start
- A fan is striking ice or metal
- Severe grinding or mechanical noise occurs
Do Not Keep Testing a Fault by Repeatedly Restarting It
A protection control may be preventing additional equipment damage. Repeated resets can make diagnosis more difficult and may worsen an electrical or mechanical fault.
What Should a Technician Test When a Heat Pump Will Not Turn On?
A useful diagnosis should identify whether the failure is caused by the thermostat, power supply, safety controls, airflow, communication, fans, compressor controls or the refrigeration system.
Depending on the system, a technician may inspect:
- Thermostat mode, setpoint and configuration
- Thermostat power and low-voltage controls
- Indoor and outdoor electrical supply
- Breakers and disconnects
- Fault-code history
- Condensate safety switches
- Filters and airflow
- Indoor blower operation
- Outdoor fan operation
- Indoor and outdoor communication
- Temperature and pressure sensors
- Control boards, relays and contactors
- Motor voltage and current
- Compressor and inverter operation
- Refrigerant pressures and temperatures where appropriate
- Defrost and outdoor operating protections
- Dual-fuel changeover controls where installed
The Cause Should Be Confirmed Before Parts Are Replaced
A heat pump that will not start can have several different causes with similar symptoms. The technician should verify the failed condition rather than replacing parts based only on a blank thermostat, clicking sound or non-running outdoor unit.
Does a Heat Pump That Will Not Start Need Repair or Replacement?
A no-start condition does not automatically mean the heat pump needs replacement.
Minor Correction May Be Enough When:
- Thermostat settings are incorrect
- A filter is severely restricted
- A condensate safety has opened because of drainage
- A loose control connection is found
- Thermostat configuration needs correction
Repair May Be Appropriate When:
- A fan or blower motor has failed
- A sensor is faulty
- A relay, contactor or control board has failed
- A condensate pump or safety control needs service
- A repairable electrical or refrigerant problem is present
Replacement May Be Considered When:
- The compressor has major failure
- The equipment is old and has repeated major problems
- Parts are obsolete or unavailable
- Several expensive components are deteriorating
- The original installation has major design or equipment-matching problems
A replacement recommendation should explain why repair is not practical and how the new system will correct the current problem.
Heat Pump No-Start Diagnosis in Metro Vancouver and Fraser Valley
Bernoulli Heating and Cooling provides diagnostic and repair service for ducted, ductless, multi-zone, full-electric and dual-fuel heat pump systems.
If your heat pump will not turn on, diagnosis can include thermostat controls, electrical power, fault codes, indoor and outdoor communication, airflow, condensate safeties, fan motors, sensors, control boards, compressor operation and refrigeration-system protection.
The current diagnostic appointment charge for an existing heat pump is $135. Required repair labour, refrigerant, replacement components and additional materials are quoted separately.
New heat pump installation estimates are free.
Call 604-518-4438 or email heatingbernoulli@gmail.com to arrange service.
Explore local installation information:
For general operating and maintenance information, review the official ENERGY STAR HVAC maintenance checklist and Natural Resources Canada heat pump guide.
Heat Pump Won’t Turn On: Frequently Asked Questions
Why won’t my heat pump turn on?
Possible causes include thermostat settings, power loss, a tripped breaker, control delay, condensate safety switch, communication fault, sensor problem, electrical failure, compressor fault or protective lockout.
What should I check first when my heat pump will not start?
Check thermostat power, mode, setpoint, fault codes, filter condition, visible water problems and whether the system recently lost power.
Why is my thermostat on but the heat pump is not running?
The thermostat may not have an active demand, the outdoor unit may have lost power, a protection delay may be active or the system may have a control, communication or equipment fault.
Why is my thermostat completely blank?
Possible causes include thermostat batteries, loss of low-voltage power, a transformer problem, indoor-equipment breaker, condensate safety switch or wiring issue.
Can a condensate drain problem stop my heat pump?
Yes. Some systems use float switches that stop cooling when water backs up to reduce the risk of overflow and property damage.
Should I bypass the condensate safety switch?
No. The switch may be preventing water damage.
Can a dirty filter stop my heat pump?
A severely restricted filter can contribute to abnormal airflow and protective faults. It should be checked before deeper troubleshooting.
Why does my heat pump have a delay before starting?
Heat pumps often use compressor-protection delays after shutdown, thermostat changes or power interruptions to prevent rapid restart.
How long should a heat pump startup delay last?
The delay varies by manufacturer and control system. Follow the equipment instructions rather than using one fixed time for every heat pump.
Why does my heat pump click but not start?
Possible causes include control relays, electrical components, low-voltage problems, motor faults, compressor protection or failed equipment startup.
Why does my heat pump hum but not start?
A motor or compressor may be receiving power without starting correctly, or another electrical component may be involved. Do not repeatedly cycle the equipment.
Why does my breaker trip when the heat pump starts?
Possible causes include compressor, fan motor, wiring, electrical-component or circuit faults. Repeated breaker trips require professional diagnosis.
Can I reset the heat pump breaker?
Follow the equipment and electrical-panel instructions. If the breaker trips again, leave it off and request service rather than continuing to reset it.
Why did my heat pump stop after a power outage?
The system may be in a restart delay, a breaker may have tripped or electrical or communication components may have been affected.
Should I keep turning the heat pump off and on after a power outage?
No. Allow the system to complete its normal restart sequence. Repeated power cycling can restart protective delays and make troubleshooting harder.
Why will my heat pump not turn on after changing the thermostat?
The new thermostat may be configured incorrectly for the heat pump, reversing valve, compressor stages, auxiliary heat or dual-fuel system.
Can a smart thermostat prevent a heat pump from starting?
Yes, if it is incompatible, wired incorrectly, configured incorrectly or unable to communicate with the installed equipment.
Why does heating work but cooling will not start?
The problem may involve the cooling thermostat command, reversing valve, cooling controls, refrigeration conditions or a cooling-specific sensor fault.
Why does cooling work but heat will not start?
Possible causes include heating controls, reversing-valve logic, outdoor-temperature lockouts, defrost-related faults or backup-heating configuration.
Why will my ductless mini-split not turn on?
Check the remote or wall controller, mode, setpoint, timers, filters and fault codes. Indoor controls, fan motor, communication or outdoor-unit problems may require service.
Why does only one mini-split head not turn on?
The problem may be local to that indoor unit, such as its remote, sensor, fan motor, control board or communication circuit.
Why do none of my mini-split heads work?
A system-wide outdoor power, control or communication fault becomes more likely when all connected indoor units stop together.
Can different mini-split zones prevent each other from running?
Some multi-zone systems require connected indoor units to operate in compatible modes. Conflicting heating and cooling requests can affect operation.
Why is the indoor fan running but the outdoor unit is off?
The fan may be set to On or Circulate, or the outdoor unit may have lost power, entered a delay or developed a control, communication or compressor fault.
Why is the outdoor unit running but the indoor fan is not?
Possible causes include blower motor, indoor control board, wiring or communication problems. Turn the system off because normal indoor airflow is required for proper operation.
Can Emergency Heat be used if the heat pump will not start?
On systems designed for it, Emergency Heat may provide temporary backup heating while service is arranged. It does not repair the heat pump fault.
Does a heat pump that will not start need replacement?
Usually not. Thermostat, control, sensor, fan, drainage and many electrical problems can be repaired. Replacement becomes more relevant when an older system has major compressor damage or several expensive failures.
How much is a Bernoulli heat pump diagnostic appointment?
Bernoulli Heating and Cooling currently charges $135 for a diagnostic appointment on an existing heat pump system. Repair labour, refrigerant, replacement parts and additional materials are separate.