Seattle HVAC: Fixing a Heat Pump That Won’t Heat or Cool

Estimated Read Time: 9 minutes

Heat pump not heating or cooling the way it should? You are not alone. In Seattle’s damp winters and cottonwood-heavy springs, small issues can knock a system off its game. This guide shows you how to diagnose common problems fast, what you can safely fix, and when to call Cardinal Heating & Air for professional help. Keep reading for practical checks, cost-saving tips, and offers that make maintenance or replacement simple.

How a Heat Pump Moves Heat and Why It Sometimes Struggles

A heat pump transfers heat rather than creating it. In heating mode, it absorbs heat energy from outdoor air and moves it inside. In cooling mode, it takes heat from indoors and releases it outdoors. When performance drops, the cause is usually airflow, controls, power, refrigerant charge, or a stuck component.

Local insight: Puget Sound’s 35 to 45 degree wet winters trigger frequent defrost cycles. That is normal, but long, repeated cycles or thick ice on the outdoor unit can starve your home of heat. Late May to June cottonwood fluff around Seattle, Bellevue, and Kirkland can also blanket outdoor coils and choke airflow.

First Quick Wins Before You Grab Tools

Try these three checks first. They fix many no-heat or no-cool calls in minutes.

1. Set the thermostat correctly.
   • Heat: Set to Heat, 2 to 3 degrees above room temperature.
   • Cool: Set to Cool, 2 to 3 degrees below room temperature.
   • Auto mode can cause short cycling. Test in a single mode first.
2. Replace or wash filters.
   • Central systems: Replace 1 to 2 inch filters every 1 to 3 months, thicker filters every 3 to 6 months.
   • Ductless: Wash indoor head screens monthly, let fully dry before reinstalling.
3. Check supply and return vents.
   • Open all vents. Remove rugs or furniture blocking airflow. Poor airflow makes rooms uneven and forces longer run times.

Thermostat and Controls: Small Settings, Big Impact

A mis-set or failing thermostat can mimic a broken heat pump.

• Confirm the schedule. Temporarily disable smart schedules and home-away modes.
• Fan setting. Use Auto for normal operation. Constant On can reduce dehumidification in cooling.
• Batteries. If your thermostat uses batteries, replace them. Weak power causes erratic calls for heat or cooling.
• Lockouts and balance points. Hybrid Heat dual fuel systems can use either electric or gas. If the lockout temperature is set wrong, you may get poor heat on cold days. Ask us to review your balance point and seven day programmability during a tune-up.

If your screen is blank, check the indoor air handler’s service switch and the breaker. Many thermostats rely on the air handler’s 24 volt transformer.

Power and Breakers: The Silent System Stopper

Your heat pump has two electrical circuits: the outdoor unit and the indoor air handler or furnace.

• Check your main panel. Reset any tripped breakers for the outdoor condenser and indoor air handler.
• Look for outdoor disconnect issues. The pull-out or switch near the outdoor unit must be fully seated and On.
• Breaker trips again? Do not keep resetting. That points to a short, seized motor, or failing capacitor. Call a pro.

Airflow: Filters, Coils, and Ducts

Heat pumps live on airflow. If they cannot move air, they cannot move heat.

• Filters. Dirty filters reduce capacity in both heating and cooling. Replace or wash as noted earlier.
• Indoor coil. A matted indoor coil causes freezing in cooling and weak heat in winter. If the coil looks dirty, schedule a professional cleaning.
• Outdoor coil. Gently hose from inside out with the power off. Do not use high pressure. Remove leaves, cottonwood fluff, and weeds around the unit to maintain at least 18 inches of clearance.
• Duct issues. Closed dampers, crushed flex, or leaking ducts cut delivery to key rooms. If one area is always uncomfortable, ask for a static pressure and duct inspection.

Outdoor Unit Icing and Defrost: What Is Normal

Light frost in winter is normal. The unit should switch into defrost briefly to clear ice, then return to heating.

• Normal defrost signs: outdoor fan stops, a whoosh as refrigerant reverses, then steam as frost melts.
• Not normal: thick ice on the cabinet or coil for hours, loud grinding, or repeated defrosts with no heat recovery.
• Quick homeowner steps:
  1. Set thermostat to Emergency Heat for a few hours to let the outdoor unit thaw, if your system supports that mode.
  2. Shut power at the disconnect and gently remove snow or debris. Never chip ice with tools.

If ice returns fast, causes include low refrigerant, failed defrost sensor, or a stuck reversing valve. That needs professional diagnostics.

Reversing Valve and Mode Problems

If your system cools well but will not heat, or heats but will not cool, the reversing valve may be stuck or the control board may not be energizing the right solenoid.

• Signs: outdoor unit runs, indoor blower runs, but air is not the right temperature for the mode selected.
• Homeowner options are limited. Try a full system power reset at the breakers for 5 minutes, then restore power. If symptoms remain, schedule service.

Refrigerant Charge: Why You Should Not Top Off Yourself

Low charge equals low capacity. In cooling, you may see coil icing and warm supply air after a thaw. In heating, supply air feels lukewarm and run times are long.

• Causes: small leaks at flare fittings, line set rub points, or indoor coil.
• Safe action: turn system Off to prevent compressor damage if the coil is icing.
• Next step: a licensed technician should perform leak checks, weigh in the factory charge, and verify superheat or subcooling to manufacturer specs.

Remember, EPA rules require certification to handle refrigerants. DIY top offs risk equipment damage and fines.

Auxiliary Heat and Heat Strips: When They Should Turn On

Many heat pumps use electric heat strips or a gas furnace for backup. On very cold Puget Sound mornings, auxiliary heat may run to maintain setpoint.

• Normal: brief Aux Heat during recovery from a setback or when outdoor temps are very low.
• Not normal: Aux Heat runs constantly above 40 degrees or your bill spikes. That can mean low charge, failed outdoor sensor, or a control setting that needs correction.

Ductless Mini Splits: Room by Room Checks

Ductless systems are simple to maintain.

• Clean the indoor head filters monthly during heavy use.
• Verify each head’s mode matches your goal. A unit set to Dry can fight a neighbor set to Cool.
• Clear the outdoor unit of leaves and fluff. Maintain free airflow under and behind wall brackets.

If one head never matches its setpoint, a board, sensor, or refrigerant issue may be present.

Uneven Rooms and Short Cycling

Short cycles reduce comfort and wear parts.

• Causes: oversizing, clogged filters, mis-set thermostats, dirty coils, or low airflow from closed vents.
• Fixes you can try:
  1. Open all vents and doors to promote circulation.
  2. Increase the setpoint difference slightly to prevent rapid on off calls.
  3. Replace filters and inspect coils as noted.

If short cycling continues, a professional load review or airflow measurement can reveal sizing and duct issues.

Maintenance That Prevents Most Breakdowns

Consistent maintenance keeps capacity high and bills low.

• Annual tune-up tasks a pro should do:
  1. Clean indoor and outdoor coils.
  2. Test capacitors, contactors, sensors, and safeties.
  3. Verify refrigerant charge with manufacturer targets.
  4. Flush drain lines and check pan heaters where installed.
  5. Calibrate thermostat and review Hybrid Heat balance point.

With Cardinal’s planned maintenance, you get regular inspections and a reduced rate for 24,7 emergency service. Our tune-up comes with a No-Breakdown Guarantee. If your system breaks down within 6 months of service, we will come out at no cost to diagnose the problem, give you priority scheduling, and credit your original maintenance charge toward the repair. An additional dispatch fee may apply, and conditions exist.

When to Call a Professional

Call right away if you notice any of the following.

• Repeated breaker trips or burning odors
• Thick outdoor ice that returns quickly
• Hissing at the indoor coil, oil stains on refrigerant lines, or coil freeze ups
• Loud grinding or metal on metal sounds
• Supply air that never rises above 85 in heat or never falls below 55 in cool after basic checks

Cardinal Heating & Air offers 24,7 emergency service, same day appointments, and fully stocked vans to complete most repairs on the first visit.

Considering Repair vs. Replacement

Some situations point toward replacement.

• Age over 12 to 15 years with rising repair costs
• R-22 legacy equipment or mismatched components
• Comfort gaps, high bills, or major parts like compressors failing

We specialize in HVAC system replacements and can design electric heat pumps, ductless, or Hybrid Heat setups that match your home. If you want top tier efficiency, our ClimateMaster geothermal systems can reduce energy usage by up to 80 percent compared to traditional HVAC systems. We also offer financing with payments as low as $209 per month on qualifying heat pump installations, with a free proposal and same day service available.

Local Tips for Puget Sound Homes

• Cottonwood season. Check and rinse your outdoor coil in late spring. A 10 minute rinse can restore lost capacity.
• Salt air and rain. Keep at least 18 inches of clearance around the outdoor unit. Trim shrubs in Bellevue, Redmond, and Kirkland yards that trap moisture.
• Smart ventilation. High humidity days make homes feel warmer. Use timed bath fans and kitchen hoods to help your heat pump dehumidify while cooling.

DIY Troubleshooting Checklist You Can Save

1. Thermostat in the correct mode, schedule disabled for testing
2. New batteries if applicable
3. Filters replaced or washed
4. All supply and return vents open and clear
5. Breakers on, outdoor disconnect seated
6. Outdoor coil rinsed, debris cleared
7. Observe defrost behavior in winter
8. If problems persist, call Cardinal for diagnostics and options

Special Offers for Heat Pump Service

• Special Offer: Up to $500 off a new qualifying heat pump or air conditioning unit. Call for conditions and restrictions. Expires 2025-09-30.
• Special Offer: Heat pump installation financing for as low as $209 per month with a free proposal and same day service. Call for conditions and restrictions.
• Special Offer: Heat pump tune-up with a No-Breakdown Guarantee and priority scheduling if failure occurs within 6 months. Additional dispatch fee may apply. Call for conditions and restrictions.

Call (425) 827-9997 or book at http://cardinalheating.com/ and mention the offer you prefer when scheduling.

What Homeowners Are Saying

"I just had a heat pump system installed by Cardinal Heating and Air. Dan and his team did an excellent job of installing the heat pump, reconfiguring my furnace and making sure everything was working perfectly. After all of that work, their clean-up was top notch. I would highly recommend this company and their products."
–Nancy S., Heat Pump Install

"Kenneth came first thing in the morning to service the furnace and heat pump. He was professional, courteous, and very knowledgeable. He performed the work in an efficient timeframe and did an entire overview of what might be needed in the future. He gave me information on other offerings Cardinal heating has without the major sales pitch, which I appreciated and may take advantage of in the future. 100% satisfied today. Great work Kenneth."
–Tim K., Maintenance Service

"Great experience swapping our oil furnace out for an electric heat pump!"
–Jonathan F., System Replacement

"Turned out to be a complicated project to add heat pump. Our electric service was just adequate for the installation. The Cardinal team was great all around from Jonas and Dylan getting things set up to Luis, Luis, Terry and Drew on the install and fine tuning. Would highly recommend."
–Charlie H., Heat Pump Install

Frequently Asked Questions

Why is my heat pump running but not heating?

Check thermostat mode, replace dirty filters, and confirm outdoor defrost is working. If supply air stays lukewarm, you may have low refrigerant, a sensor issue, or a stuck reversing valve.

Is it normal for steam to come from my heat pump in winter?

Yes. During defrost, the unit reverses briefly to melt frost. The outdoor fan stops and steam rises. It should end within minutes. Hours of ice buildup is not normal.

How often should I replace my heat pump filter?

For 1 to 2 inch filters, every 1 to 3 months. For 4 to 5 inch media, every 3 to 6 months. Ductless screens should be washed monthly during heavy use.

When should I use Emergency Heat?

Use Emergency Heat if the outdoor unit is iced over or failed. This runs backup electric or gas heat. Return to normal Heat after a technician resolves the issue.

What maintenance prevents most breakdowns?

Annual professional tune-ups to clean coils, check charge, test capacitors and sensors, and verify drain lines and thermostat calibration prevent many failures.

In Summary

If your heat pump is not heating or cooling effectively, start with thermostat settings, clean filters, clear airflow, and basic power checks. Watch winter defrost behavior and call if ice returns quickly. For Seattle and the greater Puget Sound, Cardinal Heating & Air brings fast diagnostics, honest options, and energy efficient upgrades, including geothermal and Hybrid Heat.

Ready to Get Comfortable Again?

Call Cardinal Heating & Air at (425) 827-9997 or schedule at http://cardinalheating.com/. Ask about Up to $500 off a new heat pump or installation financing from $209 per month. If you prefer a tune-up, book our No-Breakdown Guarantee service and get priority if an issue occurs within 6 months. Serving Seattle, Bellevue, Redmond, Kirkland, Bothell, Everett, Renton, Kent, Marysville, and Bremerton.

About Cardinal Heating & Air

For over 30 years, Cardinal Heating & Air has served Puget Sound with honest advice and precision workmanship. Our NATE-certified, background-checked technicians handle heat pumps, geothermal, hybrid heat, ductless, and full HVAC design-build. We offer 24/7 emergency service, same-day appointments, and free in-home estimates. We partner with leading brands like Trane, Mitsubishi Electric, Carrier, Honeywell, and ClimateMaster. Expect clean jobsites, fully stocked vans, and clear communication, backed by our No-Breakdown Guarantee on tune-ups and flexible financing for replacements.