Furnace
The Blinking Light on Your Furnace Is Talking: How to Read Error Codes
The LED behind your furnace's panel window blinks a code. Count the flashes, check the door legend, and learn what common codes mean and which are DIY.
Formerly Adam & Sam Brothers RepairNorth Seattle · Furnace service
North Seattle furnace repair for post-war basements
Between Northgate, Lake City and Greenwood, we meet post-war basements holding gas furnaces, electric furnaces and air handlers. We repair both kinds and, when one is worn out, price a heat pump beside it. Northgate is 13–17 minutes from our shop.
- Gas and power
- PSE supplies gas; Seattle City Light supplies electricity
- Peat ground
- Greenwood peat areas listed environmentally critical in 2008
- Drive time
- 13–17 min to Northgate; 16–20 to Lake City
- $85 diagnosticBecomes part of the repair price when you say yes. If you pass on the repair, that visit is all you pay.
- Up to $18 offAny repair requested through the online form. The diagnostic itself is never reduced.
- No-charge site visitInstalls are quoted in writing, equipment and installation work in one number.
Most of north Seattle was built after World War II. Lake City incorporated as a township in 1949 and was annexed by Seattle in 1954, when the city limits moved from 85th Street up to 145th; Greenwood north of 85th came in the same year. The houses in Northgate, Lake City, Greenwood, Broadview, Haller Lake and Maple Leaf are largely 1940s to 1960s homes with basements or crawlspaces, and many still push heat through the ducts laid when they were built. Citywide, about 61% of homes heat with electricity, a census figure that lumps baseboards, electric furnaces and heat pumps together, while PSE gas heats roughly a third; in north-end basements we see plenty of both kinds of furnace.
In practice, a north Seattle furnace call lands in one of three buckets. A gas furnace that will not light, short-cycles or howls at startup gets repaired, usually with an igniter, sensor, inducer, valve or board from the van. An electric furnace or air handler that is losing heat gets its elements and relays tested. A furnace of either kind that is past twenty years and failing again is where the conversation widens: we come back to measure the house and write prices for a new furnace and for a heat pump. Whichever bucket you are in, you get a diagnosis and one written number before any work starts.
North Seattle furnace symptoms
Crawlspace furnace near Thornton Creek shows rust on the burners
- Likely cause
- Damp air corroding burners, the rollout switch or the cabinet
- What we do
- Clean and inspect the burners, test the rollout switch and clear the condensate path
Basement gas furnace fires, runs a few minutes and cuts out
- Likely cause
- Coated flame sensor, a loaded filter or a tired high limit
- What we do
- Polish or swap the sensor, restore airflow and test the limit at temperature
High squeal from the furnace a moment before ignition
- Likely cause
- Inducer bearings drying out
- What we do
- Fit a new inducer and watch the pressure switch close on a healthy draft
Duplex or apartment electric furnace barely warms the unit
- Likely cause
- A burned element or dead sequencer
- What we do
- Check each stage under load and replace whatever has opened
Greenwood house: fresh wall cracks, sticking doors, a vent pipe sitting crooked
- Likely cause
- Settlement pulling flue and duct joints apart
- What we do
- Refasten and reseal vent and duct connections before the furnace runs hard
Gas odor anywhere indoors
- Likely cause
- Possible leak
- What we do
- Head outside first; from the yard, ring 911 or PSE's gas line at 1-888-225-5773
Lake City, Northgate, Greenwood and the heat pump question
When a gas or electric furnace in a Lake City or Northgate basement wears out, the replacement usually comes down to three candidates. A new gas furnace can often sit where the old one did if PSE already serves the house. A plain electric furnace needs no gas and no flue but costs more to run, which matters in the many north-end homes that are all-electric. A heat pump, alone or with a compact electric furnace as backup, heats for less and doubles as summer cooling. Houses warmed only by baseboards, with no ducts at all, are better served by ductless heads planned room by room. Seattle City Light is the electric utility across the city, and we look into which City Light or city programs fit your address before writing a heat pump quote.
Greenwood sits on old peat bog, and settling houses are a known problem there; the city listed its peat bogs as Environmentally Critical Areas in 2008. On furnace visits in that neighborhood we take a closer look at flue joints, duct seams and condensate lines, because a house that shifts can open them. Around Northgate, where Link light rail arrived in 2021 and new apartment buildings followed, a growing share of homes heat with electric furnaces, air handlers or heat pumps, and the repairs there are elements, sequencers and blower motors rather than burners. Thornton Creek runs through both Northgate and Lake City, and low lots near it can keep crawlspaces damp.
We reach Northgate in 13 to 17 minutes off-peak, Lake City in 16 to 20 and Greenwood in 17 to 21, usually via I-5 or SR 522. During the June 2021 heat dome, Sea-Tac hit an all-time record of 108°F, and as of 2019 fewer than half of Seattle-area homes had air conditioning. That is one more reason many north Seattle owners choose a heat pump when an old furnace finally gets replaced. Northgate Mall, opened in 1950 and often called the first covered mall in the country, sits at the center of the neighborhoods we reach first; Lake City Way and Aurora Ave N carry us to the rest.
North Seattle furnace repair and replacement prices
Gas and electric furnace repair in north Seattle starts at $285. Flame sensors and igniters are the common jobs in Greenwood and Lake City basements, and a control board sits toward the upper end. Pairing a furnace or air handler with a heat pump outdoor unit starts at $5,250, equipment and installation included; a full switch away from a gas furnace or baseboards can bring extra items such as a new circuit, a panel change or capped venting, each shown on its own line of the quote. Think of these as the floor of local pricing, not a quote. After the diagnosis you get the exact figure in writing, and measuring the house for a replacement costs nothing.
- Flame sensor cleaning or replacementfrom $285
- Furnace igniterfrom $285
- Limit switchfrom $285
- Pressure switchfrom $285
- Sequencer or heat relayfrom $285
- Electric heat strip / elementfrom $285
- Furnace or air handler control boardfrom $425
- Gas valvefrom $425
- Blower motor (standard PSC)from $475
- Inducer motorfrom $550
- Blower motor (ECM / variable speed)from $850
- Diagnostic visit$85, included in the repair
Starting prices for the north Seattle area, 2026. The $85 diagnostic is included in any repair you approve, and the exact price is in the written estimate before work starts.
System, installed
- Gas furnace, 80% AFUEfrom $4,750
- Gas furnace, 95%+ AFUEfrom $6,500
- Electric furnacefrom $4,500
- Heat pump outdoor unit onlyfrom $5,250
Install prices start here, equipment and installation included, before any utility program. Multi-zone systems are priced after a visit. We do not charge for the site visit or the written quote.
Repair, replace, or add a heat pump
For a gas or electric furnace in a north Seattle bungalow, the deciding factors are age, the state of the heat exchanger and what the repair costs. Ten or twelve years old with a bad igniter or limit: repair it. Past twenty with a failed inducer or gas valve: we write the replacement price beside the repair price so the comparison sits in front of you. An electric furnace ages differently, since elements and sequencers can be swapped for years, but its running cost is why many owners trade it for a heat pump instead. Either way, our advice is to choose the replacement while the old system still runs, rather than in the middle of a cold snap when options shrink. Since the 2021 heat dome, many neighbors have picked heat pumps because they also bring cooling. Post-war ducts can be too small for one, so we size them first; where they fall short, a ductless head for part of the house can make up the difference.
Common questions
Do you repair electric furnaces as well as gas?
Yes, our furnace work covers both. On an electric furnace or air handler we test each heating element, the sequencers or relays, the limits and the blower, and replace whatever has failed, often from stock on the van. In north Seattle duplexes and apartments with electric heat, that is much of our winter work. If the unit is very old, we also price a heat pump so you can compare.
How much of Seattle do you cover?
The north end: Northgate, Lake City, Greenwood, Broadview, Bitter Lake, Haller Lake, Pinehurst, Maple Leaf and Wedgwood. Off-peak, Northgate takes us 13 to 17 minutes, Lake City 16 to 20 and Greenwood 17 to 21. The price is the same at every one of those addresses, with nothing added for the drive.
Can a heat pump heat a 1950s Seattle house?
In most cases, once the ducts check out. A heat pump pushes more air at a gentler temperature than a gas or electric furnace, so cramped or leaky ductwork can hold it back, and we measure before recommending one. Refrigerant work is done by our own technicians under EPA Section 608 rules, and we look into Seattle City Light and city programs for you.
My Greenwood house has settled. Should I worry about the furnace?
It is worth a look. Movement can loosen flue connections, open duct joints and kink condensate lines. If you have noticed new cracks or doors that stick, mention it when you book. During the visit we inspect the venting and duct connections and repair anything that has pulled apart, then confirm the furnace drafts properly.
There is a gas smell near the furnace. What now?
Step outside before doing anything else, and leave the lights and thermostat alone. From the sidewalk, ring 911 or PSE's gas line at 1-888-225-5773, and stay out until PSE says the line is safe. Then we can examine the furnace and its gas fittings and price whatever needs repair.
Talk to Adam & Sam
North Seattle homeowners can ring (425) 570-9520, or reserve online and trim up to $18 from the repair. Once you approve the work, the $85 diagnostic is part of the repair price, and the visit to measure for a replacement or heat pump costs nothing.
From Sam’s repair notes
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Schedule a repair
Request a visit from Adam & Sam
Send the basics and we call you back with an arrival window, most days the same morning.
- $85 diagnostic Becomes part of the repair price when you say yes. If you pass on the repair, that visit is all you pay.
- Up to $18 off Any repair requested through the online form. The diagnostic itself is never reduced.
- $10 off A second appliance’s diagnostic when we check it during the same trip.