NOAA figures for the station named Columbia
NOAA's engineering weather data lists a station named Columbia. NOAA counts about 610 hours there in an average year with the wet-bulb temperature above 73°F, and about 1,692 hours above 67°F. The same data lists a 50-year basic wind speed of 90 mph (3-second gust at 33 feet), a 100-year rainfall rate of 3.3 inches per hour and about 56 freeze-thaw cycles in an average year.
Reading this checklist
The list moves through the year in four seasons, with a short monthly round that applies in all of them. Each season splits into things you can do yourself, things to book a technician for, and things to note down. For safety, set the thermostat to off and switch off power at the furnace or air handler switch and the outdoor disconnect before you open a panel or reach into the outdoor unit.
The monthly round
A short walk through the house once a month can catch small problems early:
- Check the filter. If it looks gray and matted, change it, and mark the date on its edge with a marker.
- Glance at each supply register and return grille. Furniture, rugs and stored boxes can creep over them.
- Look at the floor around the indoor unit for water, and at the cabinet for rust trails.
- Listen to a full start and stop. Write down any new rattle, squeal or hum along with the date.
Spring changeover
Do it yourself
- Clear the outdoor unit of winter leaves, twigs and anything stacked against it, and cut back shrubs to the clearance in the owner's manual.
- With the disconnect off, rinse the coil fins gently with a garden hose at low pressure, never a pressure washer.
- Check that the unit still sits level on its pad and that the insulation on the larger copper line is whole.
- Find the end of the condensate drain line and confirm it is open. Pour a little water in at the indoor end, or into the pump reservoir, and watch it leave.
- Run cooling on a mild afternoon before you need it, and stand by the outdoor unit for a few minutes.
Book a technician for
- A cooling tune-up with refrigerant readings written on the ticket, a look at the capacitor and contactor, and a check of the indoor coil and drain pan.
Note down
- The date cooling first ran and anything that sounded or smelled unusual.
Peak cooling
Do it yourself
- Check the filter more often while the system runs for long stretches.
- Look into the drain pan under the indoor coil with a flashlight. Standing water there may point to a slow drain.
- Keep grass clippings, dryer lint and leaves off the outdoor coil.
- Leave interior doors open where you can, so supply air has a way back to the returns.
Shut it down and call if
- frost or ice shows on the copper lines or the indoor coil (switch to fan only and wait for service);
- water is spreading near the air handler or furnace;
- the outdoor fan hums but does not turn.
Note down
- Rooms that stay warm late in the day, with the time and thermostat setting.
Fall changeover
Do it yourself
- Switch to heat on a cool morning before the first cold night. A brief dusty smell can be normal; a hot plastic or electrical smell is a reason to shut it off and call.
- Test every smoke and carbon monoxide alarm, and change batteries where they take them.
- Clear leaves from around a heat pump and from any plastic intake and exhaust pipes on an outside wall.
- If the furnace carries a humidifier, replace its pad and reopen its water valve.
- Set the heating schedule and change the thermostat batteries if it uses them.
Book a technician for
- On a gas furnace: burners, flame sensor, ignitor, heat exchanger inspection, gas pressure and a combustion reading.
- On a heat pump: defrost operation, the reversing valve and the backup heat.
The cold months
Do it yourself
- After snow or ice, clear the furnace's intake and exhaust pipes and the area around a heat pump by hand.
- Let a heat pump finish its defrost cycles without interfering, and keep roof drip off the unit.
- Watch the thermostat for auxiliary or emergency heat and jot down when it appears.
- If windows fog or frost on the inside, lower the humidifier setting.
Leave and call if
- a carbon monoxide alarm goes off. Get everyone outside, then call from there.
After wind, heavy rain or an outage
- Once power returns, wait a little while before restarting, and check that the thermostat kept its settings.
- Walk around the outdoor unit for branches, bent fins, a shifted pad or debris inside the cabinet.
- If water reached the furnace, air handler or the base of the outdoor unit, leave the system off until a technician has looked at it.
- Photograph any damage before cleaning up, in case your insurer asks for pictures.
Warning signs worth a call any time
- A breaker that trips again after a reset.
- Short on-and-off cycles, every few minutes.
- A burning smell. For a gas smell, leave the house and call the gas utility from outside.
- Soot or scorch marks near the furnace or its vent.
- A jump in the energy bill without a change in how you use the house.
When replacement comes up
If a repair estimate runs high, ask the same company for a replacement price too, and ask:
- Is the size backed by a room-by-room load calculation, and do I get the report?
- What is the AHRI reference for the exact indoor and outdoor match?
- Is duct sealing included, or priced separately?
- What state license or registration, if any, covers this work, and what is the number?
- Does the city need a permit for this, and who applies?
- Will you send proof of liability coverage and workers' compensation?
A notebook for the system
Keep one notebook, or one phone note, for the heating and cooling equipment. Write in the filter size and each change, every service visit with the date, the technician's name and what was measured, refrigerant added, parts replaced, and the model and serial numbers of the indoor and outdoor units. The next technician gets a head start, and a warranty claim has dates to point to.