Willamette Valley rainy season runs November through March, and it’s rough on HVAC equipment. Before the heavy rain sets in, clear the outdoor unit of leaves, check that the pad hasn’t shifted, clean gutters that drain near the condenser, verify crawlspace moisture isn’t finding its way into ductwork, and book a professional fall tune-up. A system that heads into November in good shape handles our wet-and-cold winters cleanly. A system with small problems going in often needs a mid-winter service call when you’d rather not have one.
Why Our Rainy Season Is Hard on HVAC Equipment
I’ve been working on HVAC in Salem, Keizer, and the surrounding Mid-Willamette Valley for 30+ years. Our rainy season isn’t extreme by national standards, but it’s long and relentless.
From November through March, we get:
- Rain on the majority of days
- Humidity near saturation most mornings
- Wet leaves piled against outdoor equipment
- Standing water around poorly-drained pads
- Saturated crawlspaces that push moisture into ductwork
None of these conditions are dangerous on their own. All of them accelerate wear on equipment that isn’t prepared. A little fall prep keeps your system running cleanly through the season.
The Homeowner Checklist for Fall
Before the first heavy rain:
Clear leaves and debris from around the outdoor unit
The outdoor condenser on a heat pump or AC is designed to pull air in from the sides. Leaves, pine needles, and garden debris piled against it restrict airflow, trap moisture against the coils, and accelerate corrosion.
- Rake out a 2-foot radius around the unit
- Cut back shrubs and plants that have grown into the airflow path
- Check that leaves from nearby trees aren’t piling on top (especially important in Silverton, Stayton, and Sublimity where tree cover is heavy)
Do this once in late October and again after any big windstorm.
Check the condenser pad
The concrete or composite pad your outdoor unit sits on can shift over time. Frost heave, saturated ground settling, and tree root pressure all move pads. A unit sitting noticeably off-level can cause:
- Refrigerant line stress
- Condensate drainage issues
- Vibration noise that wasn’t there before
- Premature compressor wear
If the pad has moved, it’s a quick fix — usually just re-leveling. Catch it in fall rather than in February.
Protect the unit (but don’t cover it)
One thing homeowners sometimes do that’s wrong: wrapping the whole condenser in a tarp or slip cover for winter. This traps moisture against the unit, encourages rust, and can provide rodent shelter.
What’s okay:
- A rigid cover that sits on top of the unit only (protects from falling leaves and direct vertical rain)
- A wire mesh guard around the unit (keeps leaves out while allowing airflow)
What’s not okay:
- Sealing the whole unit in a waterproof wrap
- Anything that blocks airflow to all four sides
Heat pumps especially need to breathe — they run year-round, not just in summer.
Clean gutters and check downspout direction
Gutters overflowing because they’re clogged can dump gallons of water near the outdoor unit. Downspouts directed toward the pad make it worse.
- Clean gutters in late October and again after major leaf fall
- Verify downspouts direct water away from the condenser
- Add extension pipes if needed to route water further from the unit
In older homes in West Salem, Independence, and Woodburn, downspout routing near HVAC equipment is often an afterthought. Worth ten minutes to check.
Verify the condensate drain isn’t clogged
High-efficiency furnaces produce condensate during operation. The drain line runs from the furnace to a floor drain, utility sink, or condensate pump. If the line is clogged or the pump has failed:
- Water backs up in the drain pan
- A safety float switch shuts the furnace down
- You find out on a cold night
Before heavy use starts, have the drain inspected. If you’re comfortable, pour a cup of water down the drain opening to make sure it flows freely. If it backs up, call us.
Check the crawlspace
Crawlspaces under older homes in Dallas, Aumsville, and Monmouth often get damp during rainy season. If your ductwork runs through the crawlspace:
- Damp ducts lose heat faster than dry ducts
- Insulation on ducts can mold if moisture is chronic
- Poorly sealed duct connections pull crawlspace air into your return, bringing moisture and mustiness into your home
Quick check: peek into the crawlspace access. If you see standing water, significant dampness, or visible mold, you have a pre-existing issue that worsens during rainy season. Worth addressing separately.
Change your furnace filter
Going into heating season is always the right time to start with a fresh filter. See our article on filter changes for the full schedule.
The Professional Fall Tune-Up
A fall tune-up does what homeowner prep can’t. A typical visit includes:
- Clean the burners and flame sensor (gas furnaces)
- Check and clean the heat exchanger; look for cracks or corrosion
- Test the ignition system and flame characteristics
- Verify gas pressure under load
- Measure carbon monoxide levels during operation
- Test the blower motor, amperage, and airflow
- Calibrate the thermostat
- Inspect electrical connections for tightness and corrosion
- Replace the filter
- Flush and test the condensate drain
- Check all safety controls and limits
This typically runs 60 to 90 minutes. It catches the small issues before they become big ones.
Why October or early November matters
October is the single busiest HVAC month of the year in our industry. Everyone who didn’t prep calls after the first cold night. By mid-November we’re booking a week or two out. In September or early October, we can usually get you on the schedule within a few days.
Heat Pump-Specific Fall Prep
Heat pumps run year-round — they’re cooling in summer, heating in winter. Some fall prep specific to them:
Check the defrost cycle
Heat pumps cycle through defrost mode periodically during cold, damp weather to clear ice off the outdoor coil. If you’ve noticed steam or water dripping from the outdoor unit occasionally, that’s normal defrost. If you see heavy ice buildup that doesn’t clear, the defrost cycle isn’t working properly. Call us.
Elevate if you can
In areas that see occasional snow or heavy frost, having the outdoor unit elevated 6 to 12 inches off the ground (on a taller pad or bracket) helps with drainage during defrost and keeps snow accumulation from blocking airflow. Most Willamette Valley installs don’t need this — but foothill homes east of Silverton or Stayton sometimes do.
Listen for new noises
Compressors getting ready to fail often develop new sounds during heavy shoulder-season runtime. Catch them in fall, schedule the fix, and you don’t find yourself waiting in December.
Ductless Mini-Split-Specific Prep
If you have a ductless heat pump:
- Clean each indoor head filter (they slide out for washing — instructions in your owner’s manual)
- Check the outdoor unit same as a conventional heat pump
- Verify the condensate drain from each indoor head isn’t backed up
- Listen for unusual fan noise from any head
What Signals a Bigger Problem
During fall prep, a few things indicate the system needs more than a tune-up:
- System won’t fire or cycles erratically during the first cold night
- Heating bills already higher than prior years despite similar weather
- New musty or burning smells when the system runs
- Weak airflow at supply registers
- Rooms that never warm up to setpoint
Any of these is worth a service call before heavy use starts.
Replacing Before Winter Arrives
If your system is over 15 years old and your fall tune-up turns up multiple issues, we’ll have a straight conversation about whether replacement now — before the heating season hits full force — makes more sense than repairs plus the risk of a mid-winter failure.
October and early November are actually good times to replace. Our schedule is more open, and you’d rather choose your replacement on your timeline than scramble after a cold-weather breakdown.
How We Do It at CHS
Fall tune-ups that actually cover the full inspection list. Honest assessment of whether what we find is a tune-up issue, a repair issue, or a replacement conversation. Salaried technicians, not commissioned. Family-owned in Salem since 2001. Licensed and insured under CCB# 147550.
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Ready to Talk to Stan?
No pressure, no surprises — just honest advice from a team that’s been keeping Salem homes comfortable since 2001.
Call or text: (503) 581-6999
Email: chssatt@gmail.com
Service area: Salem, Keizer, Dallas, Monmouth, Independence, Silverton, Stayton, Aumsville, Sublimity, Albany, Woodburn, Scio, and surrounding Mid-Willamette Valley communities.
Licensed & insured: CCB# 147550
Call or text to book a fall tune-up or a free estimate. The earlier you call before the rainy season really settles in, the easier it is to get you on the schedule.