Cracked furnace heat exchanger and flue backdrafting¶

ຕົວເລກສຸກເສີນແຕກຕ່າງກັນໄປຕາມປະເທດ. ຫນ້ານີ້ໃຊ້ 911, ຕົວເລກສໍາລັບສະຫະລັດແລະການາດາ. ປະເທດອື່ນໆຈໍານວນຫຼາຍໃຊ້ 112, 999, ຫຼືຕົວເລກອື່ນ. ຊອກຫາຕົວເລກສໍາລັບປະເທດຂອງທ່ານ.

Every natural gas, liquid propane, and fuel oil central heating furnace relies on a sealed, thin-walled metal chamber called the heat exchanger to keep toxic combustion exhaust physically separated from the breathable warm air blown through your home's ductwork. Inside the heat exchanger tubes, gas burners generate flame temperatures exceeding 900 to 1,100 degrees Celsius (1,650 to 2,000 degrees Fahrenheit), producing carbon dioxide, water vapor, nitrogen oxides, and, whenever combustion is incomplete or starved of oxygen, lethal concentrations of carbon monoxide (\(CO\)) and pungent aldehydes. Meanwhile, a high-volume squirrel-cage circulating blower fan pushes household room air across the outside of those hot metal tubes and distributes it into every bedroom and living area.

Over 10 to 20 years of relentless thermal expansion and contraction cycles (heating from room temperature to 260 degrees Celsius / 500 degrees Fahrenheit and cooling back down thousands of times each winter), the aluminized or stainless steel walls of the heat exchanger fatigue, rust, and split open. Simultaneously, a blocked chimney flue, a failed draft inducer fan, or extreme negative indoor air pressure caused by powerful kitchen range hoods, clothes dryers, and bathroom exhaust fans can pull deadly flue exhaust backward down the chimney right into your basement (flue backdrafting). Understanding the visual, olfactory, and mechanical warning signs of a cracked heat exchanger or backdrafting water heater / furnace flue prevents mass household carbon monoxide poisoning and basement flame rollout fires.

ເຮັດອັນນີ້ດຽວນີ້¶

If your carbon monoxide alarm sounds, if you smell a sharp, eye-stinging metallic or formaldehyde odor coming from your heating vents, or if you see flames rolling out the front of your furnace cabinet, execute these six steps immediately:

Evacuate all people and pets to fresh outdoor air immediately if CO alarms sound or symptoms appear: If a carbon monoxide alarm is beeping (typically 4 loud chirps, a pause, and 4 chirps), or if household members feel dull frontal headaches, dizziness, nausea, or sudden flu-like lethargy while the heat is running, get everyone outside immediately.
Switch the furnace thermostat to OFF and shut off the emergency furnace power switch: If no one is symptomatic and the CO alarm is not sounding in an IDLH emergency, turn your wall thermostat mode to OFF and flip the red-plate "Emergency Furnace Shutoff" toggle switch (located on the side of the furnace or at the top of the basement stairs) to OFF.
Close the quarter-turn natural gas or propane shutoff valve on the furnace supply pipe: Locate the rigid black iron gas pipe entering the side of the furnace cabinet and turn the manual brass valve handle 90 degrees (one-quarter turn) so the handle sits perpendicular (crosswise) to the pipe.
Call emergency dispatch from outside if anyone has symptoms or if flames rolled out: Call your local ຕົວເລກສຸກເສີນ (911 in the United States and Canada, 112 across the European Union, 999 in the United Kingdom) from outside the building. Firefighters carry parts-per-million electrochemical gas meters and thermal cameras to locate flue leaks and administer high-flow oxygen.
Never reset a tripped manual Flame Rollout Switch yourself: If your furnace stops heating because a manual-reset Flame Rollout Safety Switch tripped above the burner box, do not press the tiny button on the switch to restart the furnace. A rollout switch only trips when 900-degree-Celsius flames are shooting backward out of the heat exchanger tubes due to a severe crack or blocked chimney flue.
Do not run the furnace again until a licensed HVAC technician performs a combustion analysis: Never operate a "red-tagged" or suspect furnace "just overnight to stay warm." Use UL-listed electric space heaters plugged directly into wall outlets while awaiting heat exchanger replacement.

Why carbon monoxide has zero smell, yet incomplete combustion smells like pungent aldehydes

Pure carbon monoxide (\(CO\)) is 100 percent odorless, colorless, and tasteless; you can never smell carbon monoxide itself. However, when a natural gas or propane furnace burns poorly inside a cracked, rusted, or soot-plugged heat exchanger, the starved flame simultaneously produces aldehydes (such as formaldehyde and acetaldehyde). Aldehydes have an unmistakable, sharp, acrid, eye-watering, metallic or "burning radiator / sour exhaust" odor that blows directly out of your floor or ceiling heating registers. If you smell a sharp, stinging chemical or exhaust odor from your heating vents, treat it as an immediate warning that lethal odorless carbon monoxide is also pouring into your rooms.

Tactical decision tree for furnace heat exchanger cracks and flue backdrafting¶

Use this operational decision tree to evaluate furnace flame anomalies, vent odors, rollout trips, and chimney backdrafting.

flowchart TD
    Start["Furnace Anomaly: CO Alarm, Strange Vent Odor, Yellow Flames, or No Heat"] --> AlarmCheck{"1. Is a CO alarm sounding OR does anyone have headache, nausea, or dizziness?"}

    AlarmCheck -->|"Yes: Active CO exposure"| EvacOut["Evacuate All People & Pets Outside Immediately; Leave Doors Open on Way Out"]
    EvacOut --> Call911["Call 911 / 112 / 999 and Gas Utility Emergency Line from Outside"]

    AlarmCheck -->|"No: Physical or mechanical symptom on furnace"| SymptomType{"2. What warning sign did you observe on the furnace or vents?"}

    SymptomType -->|"Flames flickering/waving when main blower fan kicks on"| CrackSign["Classic Sign of a Cracked Heat Exchanger (Blower Air Pressurizing Burners)"]
    SymptomType -->|"Yellow/orange lazy burner flames + black soot streaks"| IncompleteComb["Incomplete Combustion: Plugged Secondary Heat Exchanger or Blocked Flue"]
    SymptomType -->|"Manual Flame Rollout Switch tripped OR scorched front door"| Rollout["CRITICAL FIRE & CO HAZARD: Flames Shooting Out Front of Burner Box"]
    SymptomType -->|"Hot exhaust spilling out draft hood or melted plastic rings on water heater"| Backdraft["Chimney Flue Backdrafting into Basement / Utility Room"]

    CrackSign --> ShutDown["Switch Thermostat OFF + Flip Red Furnace Power Switch OFF + Turn Gas Valve 90° OFF"]
    IncompleteComb --> ShutDown
    Rollout --> ShutDown
    Backdraft --> ShutOffExhaust["Turn Off Exhaust Fans/Dryer; Open Window 5 cm (2 in); Shut Off Appliance Gas Valve"]

    ShutDown --> CallHVAC["Do NOT Restart Furnace; Call Licensed HVAC Technician for Combustion & Camera Test"]
    ShutOffExhaust --> CallHVAC

Visual and physical warning signs of a cracked heat exchanger¶

How can you tell if the hidden steel clamshell or tubular heat exchanger inside your furnace has cracked before a carbon monoxide alarm goes off? Look and listen for these five physical indicators:

1. Burner flames suddenly dance, wave, or flutter when the main blower fan turns on¶

When your thermostat calls for heat, a furnace ignites its gas burners first and waits 30 to 60 seconds for the metal heat exchanger to warm up before switching on the large indoor circulating blower fan at the bottom of the cabinet.

Healthy intact heat exchanger: While the burners are running alone, the flames are steady, crisp blue cones roaring smoothly into the heat exchanger tubes. When the big indoor blower fan kicks on 45 seconds later, the burner flames do not move or change shape at all, because the blower air is completely sealed on the outside of the steel tubes.
Cracked or split heat exchanger: The exact second the large indoor circulating blower fan kicks on (with a loud whoosh of air), high-pressure household air from the blower forces its way through the crack into the inside of the combustion tube, or sucks combustion gases out. Looking through the small round glass inspection sight-port on the furnace door, you will see the blue burner flames suddenly waver, dance side-to-side, turn yellow-orange at the tips, or push backward toward the front of the furnace the instant the blower motor engages.

2. Lazy yellow or orange flames instead of crisp blue jets¶

A properly adjusted natural gas or propane atmospheric or induced-draft burner burns with a tight, crisp, roaring blue flame (sometimes with tiny pale-blue inner cones).

Exception: If you are running an ultrasonic cool-mist humidifier in the house using hard tap water, dissolved calcium and sodium minerals in the indoor air will turn gas stove and furnace flames a bright, crisp neon orange (a harmless sodium/calcium spectral emission).
Dangerous yellow flame: If the furnace burner flames look lazy, wavy, candle-like, and bright yellow, the flame is starved of primary oxygen or impinging against a rusted, soot-choked heat exchanger wall. A yellow natural gas flame generates up to 1,000 to 4,000 parts per million (ppm) of carbon monoxide alongside heavy black carbon soot.

3. Black carbon soot streaks ("eyebrows") above the burner ports or flue¶

Inspect the sheet metal directly above the burner manifold and around the draft hood or flue pipe collar:

Clean natural gas combustion leaves zero black soot.
If you see feathery black carbon soot streaks (called "soot eyebrows") above the burner tubes, rust flakes mixed with black powder on the floor of the burner compartment, or white/greenish crusty tracks leaking down from the secondary condensing heat exchanger box, shut the furnace off immediately. Soot buildup rapidly plugs the narrow passages of modern fin-and-tube secondary heat exchangers, causing lethal flame rollout within days.

4. Tripped manual-reset "Flame Rollout Switch"¶

Every modern gas furnace has one or two small, button-sized thermal disc switches mounted on the metal bracket directly above the gas burners, wired in series with the 24-volt gas valve circuit. These are manual-reset Flame Rollout Switches (typically rated to trip open at 120 to 175 degrees Celsius / 250 to 350 degrees Fahrenheit).

Why a rollout switch trips: Under normal operation, the negative suction of the draft inducer fan (or chimney updraft) pulls 100 percent of the 1,000-degree-Celsius flames forward into the heat exchanger tubes. If a heat exchanger tube is plugged with soot/rust, if the steel clamshell has split wide open and blower air is pushing back against the flame, or if the chimney flue is blocked by a bird's nest or collapsed clay tile liner, the flames have nowhere to go. They roll backward out the front of the burner box, scorching the wiring harness and tripping the rollout switch to shut off the gas valve.
Why resetting it can burn down your house: Homeowners who watch DIY videos often take off the furnace door, find the tiny pop-out button between the two wires on the rollout switch, push it back in until it clicks, and walk away. Because the underlying blockage or cracked heat exchanger is still there, the furnace will continue rolling flames out into the cabinet until the wiring catches fire or the house fills with carbon monoxide.

Diagnostic comparison: healthy furnace vs. cracked heat exchanger vs. flue backdraft¶

Diagnostic Feature	Normal Healthy Gas Furnace	Cracked Primary / Secondary Heat Exchanger	Blocked Chimney or Flue Backdrafting
Burner Flame Color & Shape	Crisp, steady blue cones pulled straight into the heat exchanger tubes	Steady blue until main blower starts, then flames wave, flutter, lift off ports, or turn yellow-orange	Flames look lazy and wavering from the very start; may roll out the front of the burner box before blower starts
Odor from Supply Air Vents (Bedrooms / Living Room)	Warm, neutral air (slight dusty smell only on the very first run of autumn)	Sharp, pungent, eye-stinging aldehyde / metallic exhaust smell blowing straight out of floor/wall vents	Exhaust smell strongest in the basement or utility room around the furnace and water heater; spreads upstairs later
Moisture & Window Condensation	Normal low winter indoor humidity (30% to 40% RH)	Sudden heavy water condensation fogging up indoor windows (combustion water vapor leaking into supply ducts)	Condensation and melted plastic rings around the top draft hood of the basement water heater
Flue Draft Hood / Vent Pipe Behavior	Strong upward suction pulling exhaust up the chimney; plastic draft rings intact	Inducer fan runs, but CO in supply ducts exceeds 5 to 50+ ppm or flue CO exceeds 100 to 400 ppm air-free	Hot, humid exhaust gases spill outward into the basement from under the draft hood; smoke match blows into the room
Safety Switch Tripping	None	Flame Rollout Switch or High-Limit Switch trips repeatedly	Spill Switch (on draft hood) or Pressure Switch (on induced-draft furnace) locks out the burner

Chimney flue backdrafting and the "Depressurized House" syndrome¶

Even if your furnace heat exchanger is 100 percent intact without a single crack, your family can still be poisoned by carbon monoxide if your chimney or vent pipe backdrafts (flows backward down the chimney into the house instead of rising up to the roof).

1. Which appliances are most vulnerable to backdrafting?¶

ເຄື່ອງເຮັດຄວາມຮ້ອນແລະເຄື່ອງໃຊ້ນ້ໍາຮ້ອນແບ່ງອອກເປັນສອງປະເພດ:

ເຄື່ອງໃຊ້ທຳມະຊາດໃນບັນຍາກາດ (ຄວາມສ່ຽງສູງທີ່ສຸດ): ເຕົາໄຟທີ່ມີປະສິດທິພາບ 80 ເປີເຊັນ, ໝໍ້ອາຍແກັສມາດຕະຖານ, ແລະເຄື່ອງເຮັດຄວາມຮ້ອນຖັງແກັສທຳມະຊາດຫຼາຍລ້ານເຄື່ອງ** ບໍ່ມີພັດລົມລະບາຍອາກາດ. ແທນທີ່ຈະ, ພວກເຂົາເຈົ້າອີງໃສ່ການ buoyancy ທໍາມະຊາດຂອງອາຍແກັສທີ່ອົບອຸ່ນຂຶ້ນເຖິງທໍ່ B-vent ໂລຫະຫຼື chimney masonry (** ຜົນກະທົບ stack ທໍາມະຊາດ**), decoupled ເທິງຂອງ tank ໂດຍໂກນເປີດເອີ້ນວ່າ ** hood (draft diverter) **. ເນື່ອງຈາກວ່າ buoyancy ທໍາມະຊາດອອກແຮງດັນຂຶ້ນເລັກນ້ອຍພຽງແຕ່ 2 ຫາ 5 Pascals (0.01 ຫາ 0.02 ນິ້ວຂອງຖັນນ້ໍາ), ຄວາມກົດດັນທາງລົບໃດໆພາຍໃນເຮືອນ overwhels chimney ໄດ້ຢ່າງງ່າຍດາຍແລະດູດອາກາດພາຍນອກ * ລົງ * flue ໄດ້.
** ເຕົາເຜົາທີ່ມີປະສິດທິພາບສູງ (90%+ AFUE) ເຕົາເຜົາຜະນຶກເຂົ້າກັນໄດ້ (ຄວາມສ່ຽງຕໍ່າສຸດ): ເຕົາເຜົາທີ່ມີປະສິດທິພາບສູງທີ່ທັນສະໄຫມໃຊ້ສອງທໍ່ພາດສະຕິກ PVC ສີຂາວ (ໜຶ່ງທໍ່ລະບາຍອາກາດແບບແຕ້ມໂດຍກົງຈາກກາງແຈ້ງ, ແລະອີກອັນໜຶ່ງໃຊ້ເຄື່ອງເປົ່າລົມເພື່ອດັນຄວາມເຢັນ 45-degree-1-degree-1. ນອກຜ່ານ sidewall). ຢ່າງໃດກໍຕາມ, ພວກເຂົາເຈົ້າປະເຊີນກັບພາວະສຸກເສີນລະດູຫນາວທີ່ແຕກຕ່າງກັນ: ** ຫິມະລອຍ, ເຂື່ອນນ້ໍາກ້ອນ, ຫຼື hoarfrost ສຽບທໍ່ PVC ພາຍນອກ / goosenecks ໄອເສຍ ** ຢູ່ນອກພື້ນຖານເຮືອນຂອງທ່ານ.

2. ພັດລົມລະບາຍອາກາດ ແລະເຕົາໄຟເຮັດໃຫ້ເກີດຄວາມຕາຍແນວໃດ¶

ຢູ່ໃນເຮືອນທີ່ທັນສະ ໄໝ ຫຼືຖືກປັບປຸງ ໃໝ່ ທີ່ມີສະພາບອາກາດທີ່ເຄັ່ງຄັດ, ເຄື່ອງໃຊ້ລະບາຍອາກາດທີ່ເຮັດວຽກຈະສູບອາກາດພາຍໃນເຮືອນຫຼາຍຮ້ອຍແມັດກ້ອນຕໍ່ນາທີ (CFM) ຢູ່ນອກເຮືອນ:

ເຄື່ອງເປົ່າເສື້ອຜ້າຈະໝົດ 150 ຫາ 200 CFM.
ພັດລົມທໍ່ລະບາຍອາກາດສອງຫ້ອງນ້ຳ 100 ຫາ 200 CFM.
ຝາອັດປາກມົດລູກໃນເຮືອນຄົວມີລະດັບຄວາມແຮງ 300 ຫາ 1,200 CFM.
ເຕົາໄຟ ຫຼືເຕົາໄມ້ທີ່ດັງຢູ່ໃນຫ້ອງຮັບແຂກຈະດຶງ 200 ຫາ 500 CFM ຂຶ້ນທໍ່ຂອງມັນ.

ຖ້າປ່ອງຢ້ຽມແລະປະຕູທັງຫມົດຖືກປິດແຫນ້ນໃນລະດູຫນາວແລະບໍ່ມີຊ່ອງລະບາຍອາກາດຂອງເຄື່ອງແຕ່ງຫນ້າ, ເຄື່ອງໃຊ້ເຫຼົ່ານີ້ຈະສ້າງ ** ຄວາມກົດດັນອາກາດທາງລົບ (ສູນຍາກາດ) ຈາກ -5 ຫາ -25 Pascals ** ພາຍໃນເຮືອນ. ເພື່ອທົດແທນອາກາດທີ່ໝົດໄປນັ້ນ, ເຮືອນຂອງເຈົ້າດູດເອົາອາກາດກາງແຈ້ງລົງໄປຕາມເສັ້ນທາງທີ່ມີຄວາມຕ້ານທານໜ້ອຍທີ່ສຸດ: ** ຕັ້ງຊື່ລົງເຕົາໄຟ ແລະ ທໍ່ລະບາຍນ້ຳຂອງເຄື່ອງເຮັດຄວາມຮ້ອນ**. ເມື່ອເຄື່ອງເຮັດນ້ຳອຸ່ນ ຫຼືເຕົາແກ໊ສດັບເພີງຕ້ານກັບຄວາມໜາວເຢັນນັ້ນ, 100 ເປີເຊັນຂອງທາດອາຍຄາບອນໂມໂນໄຊຂອງມັນຈະຮົ່ວໄຫຼອອກມາຈາກໃຕ້ຝາອັດປາກຂຸມຮ່າງໃສ່ຊັ້ນໃຕ້ດິນ ຫຼືຫ້ອງເຄື່ອງໃຊ້ປະໂຫຍດຂອງທ່ານ.

MECHANICS OF CHIMNEY BACKDRAFTING IN A DEPRESSURIZED HOUSE:
   [Roof Chimney Cap]
          ||   <-- Cold outdoor air sucked DOWN chimney (-15 Pascals vacuum)
          ||
          \/
   +--------------+
   | /==========\ | <-- Open Draft Hood on Gas Water Heater / Atmospheric Furnace
   |  (CO Spills) |     Hot combustion exhaust cannot rise against downdraft;
   |  +--------+  |     spills out into basement / utility room
   |  | Tank / |  |
   |  | Burner |  |=========================> [Clothes Dryer + Range Hood + Fireplace]
   +--------------+                            Pumping 600 CFM of air OUT of tight house

3. ວິທີການສັງເກດການແຕ້ມຮູບໃນເຄື່ອງເຮັດຄວາມຮ້ອນນ້ໍາອາຍແກັສຂອງທ່ານໃນ 5 ວິນາທີ¶

ຍ່າງໄປຫາເຄື່ອງເຮັດຄວາມຮ້ອນນ້ໍາອາຍແກັສຂອງເຈົ້າດຽວນີ້ແລະເບິ່ງທໍ່ນ້ໍາເຢັນແລະນ້ໍາຮ້ອນຢູ່ເທິງສຸດຂອງຖັງທີ່ຕິດກັບໂກນໂລຫະແຜ່ນ (ຮູຮ່າງ):

ວົງແຫວນຢາງພລາສຕິກທີ່ລະລາຍ: ເຄື່ອງເຮັດນ້ຳອຸ່ນໃນທີ່ຢູ່ອາໄສເກືອບທັງໝົດມີແຫວນຕັດພລາສຕິກສີ (ສີຟ້າອ້ອມທໍ່ນ້ຳເຢັນ, ສີແດງອ້ອມທໍ່ປ້ຳນ້ຳຮ້ອນ) ນັ່ງຢູ່ຝາດ້ານເທິງຂອງຖັງ. ຖ້າແຫວນປຼາສະຕິກເຫຼົ່ານັ້ນ ຖືກລະລາຍ, ເປື່ອຍ, ມ້ວນ, ຫຼືເປັນສີນ້ຳຕານ, ຫຼື ຫາກໂຟມສນວນສີຂຽວ/ດຳພາຍໃນຮູທໍ່ນັ້ນຖືກເຜົາໄໝ້, ເຄື່ອງເຮັດນ້ຳອຸ່ນຂອງເຈົ້າໄດ້ເອົາແກັສໄອເສຍ 200 ອົງສາ-ເຊລຊຽສ (400 ອົງສາ-ຟາເຣັນຮາຍ) ເຂົ້າໄປໃນເຮືອນຂອງເຈົ້າໂດຍກົງ.
ຂີ້ຕົມ ຫຼື ຝຸ່ນຂີ້ຕົມຢູ່ຝາດ້ານເທິງ: ການເຄືອບບາງໆຂອງຂີ້ເຖົ່າດຳ ຫຼື ເກັດສີຂາວ/ສີເທົາທີ່ເປັນກົດຂົ້ນເປັນເກັດໆທົ່ວກະເປົ໋າໂລຫະດ້ານເທິງຢູ່ອ້ອມຝາຝາຮ່າງການຢືນຢັນການຮົ່ວໄຫຼແບບຊໍາເຮື້ອ.
ສິ່ງທີ່ເຮັດໃຫ້ເກີດການອຸດຕັນທໍ່ທາງກາຍະພາບ:
ກະເບື້ອງດິນເຜົາດິນເຜົາທີ່ຍຸບລົງ: ເມື່ອເຕົາໄຟສະໄໝໃໝ່ຖືກລະບາຍເຂົ້າໄປໃນປ່ຽງດິນຈີ່ເກົ່າທີ່ບໍ່ມີເສັ້ນ (ຫຼືທໍ່ລະບາຍຄວາມຮ້ອນຫຼັງປໍ້ານໍ້າມັນເກົ່າຖືກຖອດອອກ), ອາຍນໍ້າທີ່ເປັນກົດຂົ້ນຢູ່ພາຍໃນປ່ຽງດິນຈີ່ທີ່ເຢັນໃນລະດູຫນາວ, ແຊ່ແຂງ ແລະ thawing ຈົນກ່ວາປູນແລະກະເບື້ອງດິນເຜົາໄດ້ແຕກ, ທໍ່ລະບາຍຄວາມຮ້ອນແລະ pruce. ການເຊື່ອມຕໍ່ (** "ເຄື່ອງເຮັດຄວາມຮ້ອນນ້ໍາກໍາພ້າ" ຫຼືຜົນກະທົບ liner crumbling **).
** ຮັງສັດ, ໃບໄມ້, ຫຼື ຝາຫິມະ/ກ້ອນ**: ກະຮອກ, ກະຕ່າຍ, ກະໂຫຼກ, ແລະໂຕໂຕສ້າງຮັງທີ່ດົກໜາຢູ່ໃນທໍ່ລະບາຍອາກາດທີ່ບໍ່ໄດ້ປົກຄຸມໃນຊ່ວງລະດູຮ້ອນ; ໃນເວລາທີ່ທ່ານເປີດ furnace ໃນເດືອນຕຸລາ, flue ແມ່ນ 90 ເປີເຊັນສຽບ.

ປະສິດທິພາບສູງ (90%+) furnaces condensing: plugged ແລກປ່ຽນຄວາມຮ້ອນຮອງແລະ vents PVC frozen¶

ຖ້າ furnace ຂອງທ່ານຜ່ານ ** PVC ສີຂາວຫຼືສີດໍາ ABS / polypropylene ທໍ່ພາດສະຕິກ ** ອອກຈາກຂ້າງຂອງເຮືອນຂອງທ່ານແທນທີ່ຈະເປັນທໍ່ໂລຫະ, ມັນມີ ** ສອງຕົວແລກປ່ຽນຄວາມຮ້ອນ **: ເປັນທໍ່ແລກປ່ຽນຄວາມຮ້ອນຂອງເຫຼັກກ້າຕົ້ນຕໍ, ແລະ ** ເຄື່ອງແລກປ່ຽນຄວາມຮ້ອນຂອງ condensing ທີສອງ ** (ເຊິ່ງຄ້າຍຄື radiator ລົດທີ່ເຮັດດ້ວຍອາລູມິນຽມສະແຕນເລດສະແຕນເລດທີ່ມີຊ່ອງຫວ່າງຢ່າງແຫນ້ນຫນາ) ຫຼືສານສະກັດຈາກ polystylent ຄວາມຮ້ອນ. condensing ໄອນ້ໍາກົດອອກຈາກໄອເສຍ.

** ການແຍກ ແລະ ການສຽບທໍ່ແລກປ່ຽນຄວາມຮ້ອນຂັ້ນສອງທີ່ມີ polypropylene **: ຫຼາຍລ້ານເຕົາ condensing ທີ່ຜະລິດໃນຊຸມປີ 1990 ແລະ 2000 ປະສົບກັບການກັດກ່ອນໄວອັນຄວນທີ່ສານເຄືອບພາດສະຕິກພາຍໃນໄດ້ປອກເປືອກອອກແລະສຽບທໍ່ລະບາຍອາກາດທີ່ແຄບ, ເຮັດໃຫ້ເຕົາເຜົາອຶດຫິວສໍາລັບອົກຊີເຈນແລະສ້າງ ** ກາກບອນທີ່ມີຄວາມເຂັ້ມແຂງຫຼາຍພັນສ່ວນຕໍ່ຫນຶ່ງລ້ານສ່ວນ * ຂອງຄາບອນໄຮໂດຼລິກ *. ມີກິ່ນຫອມ.
** ຈັ່ນຈັບ condensate ທີ່ຖືກບລັອກຫຼືທໍ່ PVC ພາຍນອກທີ່ແຊ່ແຂງ : ເຕົາ condensing ຜະລິດ ** 20 ຫາ 40 ລິດ (5 ຫາ 10 ກາລອນ) ຂອງແຫຼວທີ່ເປັນກົດເລັກນ້ອຍທຸກໆມື້, ເຊິ່ງລະບາຍອອກໂດຍຜ່ານທໍ່ vinyl ຈະແຈ້ງ. ຖ້າຝາອັດປາກມົດລູກອຸດຕັນດ້ວຍຂີ້ຕົມ, ຫຼືຖ້າພາຍຸລະດູໜາວຝັງທໍ່ລະບາຍອາກາດ/ທໍ່ PVC ພາຍນອກໃສ່ໃນຫິມະ (ຫຼືມີກ້ອນຫີນໃຫຍ່ຂຶ້ນເທິງປາກທໍ່), ທໍ່ລະບາຍອາກາດ ຄວາມກົດດັນ ຂອງເຕົາໄຟຈະປິດເຕົາໄຟລົງ. ໃນລະຫວ່າງທີ່ພາຍຸຫິມະຕົກໜັກ, ຮັກສາຫິມະ ແລະນ້ຳກ້ອນເປັນປະຈຳຢ່າງໜ້ອຍ 30 ຊັງຕີແມັດ (12 ນິ້ວ) ຂ້າງລຸ່ມ ທໍ່ລະບາຍອາກາດຈາກເຕົາປຼາສະຕິກພາຍນອກຂອງເຈົ້າໃນຂະນະທີ່ຮັກສາມືຂອງເຈົ້າອອກ ແລະ ຫັນໜ້າອອກຈາກທໍ່ລະບາຍອາກາດ.

ການທົດສອບການເຜົາໃຫມ້ HVAC ມືອາຊີບ ແລະການຈັດວາງສັນຍານເຕືອນຄາບອນໂມໂນໄຊ¶

ເຈົ້າຂອງເຮືອນຫຼືຜູ້ກວດກາເຮືອນສາມາດ ** ບໍ່ເຄີຍຢືນຢັນວ່າເຄື່ອງແລກປ່ຽນຄວາມຮ້ອນແມ່ນປອດໄພໂດຍການກວດກາສາຍຕາດ້ວຍໄຟສາຍຢ່າງດຽວ **, ເພາະວ່າ 80 ເປີເຊັນຂອງພື້ນຜິວແລກປ່ຽນຄວາມຮ້ອນແມ່ນເຊື່ອງໄວ້ຢູ່ຫລັງແຜ່ນໂລຫະແລະເຮືອນເຄື່ອງເປົ່າ.

1. ສິ່ງທີ່ນັກວິຊາການ HVAC ທີ່ມີໃບອະນຸຍາດຕ້ອງວັດແທກ¶

ເມື່ອທ່ານໂທຫາຊ່າງເຮັດຄວາມຮ້ອນທີ່ໄດ້ຮັບການຮັບຮອງ (ເຊັ່ນ: NATE-certified in the US, TSSA-certified in Canada, or Gas Safe Registered in the UK) ເພື່ອກວດສອບເຕົາໄຟທີ່ສົງໃສ, ໃຫ້ແນ່ໃຈວ່າພວກເຂົາເຮັດການທົດສອບຈຸດປະສົງສາມຢ່າງ:

ການວິເຄາະການເຜົາໃຫມ້ອາຍແກັສ Digital Flue: ການໃສ່ເຄື່ອງກວດວິເຄາະອາຍແກັສ flue electrochemical ທີ່ໄດ້ປັບເຂົ້າໃສ່ພອດທົດສອບໄອເສຍກ່ອນ ແລະຫຼັງຈາກພັດລົມພັດລົມຫຼັກເປີດ. ໃນເຕົາແກ໊ສທໍາມະຊາດທີ່ມີສຸຂະພາບດີ, ** ຄາບອນໂມໂນໄຊທີ່ບໍ່ໄດ້ເຈືອຈາງ (ບໍ່ມີອາກາດ) ໃນທໍ່ລະບາຍອາກາດຈະຕ້ອງມີລະດັບຕໍ່າກວ່າ 50 ຫາ 100 ppm** (ປົກກະຕິ 10 ຫາ 35 ppm), ແລະ ** CO ລ້ອມຮອບໃນທໍ່ລະບາຍອາກາດຕ້ອງມີຄວາມເຂັ້ມງວດ 0 ppm**. ຖ້າອົກຊີເຈນ (\(O_2\)) ຢູ່ໃນທໍ່ໄຟກະໂດດຂຶ້ນ ຫຼື \(CO\) ເພີ່ມຂຶ້ນເມື່ອເຄື່ອງເປົ່າລົມເປີດຢູ່ໃນເຮືອນ, ເຄື່ອງແລກປ່ຽນຄວາມຮ້ອນຈະລະເມີດ.
ການກວດກາກ້ອງ Borescope/Endoscope: ການກວດກາກ້ອງວິດີໂອເສັ້ນໄຍ-optic ທີ່ມີຄວາມຄົມຊັດສູງຜ່ານຮູສະວິດທີ່ມີຂີດຈຳກັດສູງ ຫຼືພອດເຕົາເຜົາ ເພື່ອກວດກາເບິ່ງຈຸດເກີດຄວາມຄຽດ, ການເຊື່ອມຕາຂອງຕາ, ແລະເສັ້ນໂຄ້ງທຳອິດຂອງທຸກໆຫ້ອງແລກປ່ຽນຄວາມຮ້ອນ.
Worst-Case Depressurization Draft Test (CAZ Testing): ເປີດພັດລົມລະບາຍອາກາດໃນຄົວເຮືອນທັງໝົດ, ເຄື່ອງເປົ່າເສື້ອຜ້າ, ແລະ ຝາອັດປາກມົດລູກດ້ວຍປະຕູພາຍໃນປິດ, ຈາກນັ້ນວັດແທກຄວາມດັນຂອງທໍ່ລະບາຍຄວາມຮ້ອນໃນ Pascals ດ້ວຍເຄື່ອງວັດແທກດິຈິຕອນເພື່ອກວດສອບເຄື່ອງເຮັດນ້ຳອຸ່ນ ແລະເຕົາໄຟຍັງສ້າງຮ່າງຂຶ້ນບວກພາຍໃນ 60 ວິນາທີ.

2. ການຕິດຕັ້ງຈໍພາບຄາບອນໂມໂນໄຊດິຈິຕອນລະດັບຕ່ໍາ¶

ມາດຕະຖານ UL 2034 / EN 50291 ສັນຍານເຕືອນໄພຄາບອນໂມໂນໄຊທີ່ຢູ່ອາໃສຖືກອອກແບບໂດຍເຈດຕະນາເພື່ອປ້ອງກັນການເດີນທາງທີ່ລົບກວນ: ພວກມັນ ** ຈະບໍ່ສົ່ງສຽງເຕືອນຕ່ໍາກວ່າ 30 ppm ເປັນເວລາ 30 ມື້ , ແລະຢູ່ທີ່ ** 70 ppm ພວກເຂົາລໍຖ້າ 60 ຫາ 240 ນາທີ ** ກ່ອນທີ່ຈະມີສຽງດັງ. ເພື່ອຈັບເຄື່ອງແລກປ່ຽນຄວາມຮ້ອນທີ່ຮົ່ວໄຫຼໄວ, ແລະເພື່ອປົກປ້ອງແມ່ຍິງຖືພາ, ເດັກນ້ອຍ, ຜູ້ສູງອາຍຸ, ແລະຄົນເຈັບຫົວໃຈ, ໃຫ້ຕິດຕັ້ງຈໍສະແດງຜົນດິຈິຕອລຄາບອນໂມໂນໄຊລະດັບຕໍ່າຢ່າງໜ້ອຍໜຶ່ງອັນ (ເຊິ່ງສະແດງການອ່ານແບບດິຈິຕອລແບບສົດໆ ເລີ່ມແຕ່ 5 ຫາ 10 ppm ແລະ ມີສຽງເຕືອນຢູ່ທີ່ 15 ຫາ 25 ppm) ຢູ່ໃນທຸກລະດັບການນອນຂອງເຮືອນຂອງທ່ານ.

3. ເປັນຫຍັງການສຽບການກັ່ນຕອງອາກາດກັບຄືນໄປບ່ອນເຮັດໃຫ້ການແລກປ່ຽນຄວາມຮ້ອນແຕກໃນສະຖານທີ່ທໍາອິດ¶

ສາເຫດທາງກົນຈັກອັນດຽວທີ່ພົບເລື້ອຍທີ່ສຸດຂອງເຄື່ອງແລກປ່ຽນຄວາມຮ້ອນໃນເຕົາອົບທີ່ເກີດມີຮອຍແຕກແມ່ນ ການຈຳກັດການໄຫຼວຽນຂອງອາກາດຊຳເຮື້ອຈາກເຄື່ອງກອງອາກາດເປື້ອນ ຫຼືທໍ່ລະບາຍອາກາດທີ່ຖືກບລັອກ:

ການໝູນວຽນຄວາມກົດດັນຄວາມຮ້ອນສູງກວ່າ 260 ອົງສາເຊນຊຽດ (500 ອົງສາຟາເຣນຮາຍ): ເຄື່ອງແລກປ່ຽນຄວາມຮ້ອນໃນເຕົາໄຟຂອງເຈົ້າແມ່ນຂຶ້ນກັບກະແສລົມທີ່ມີປະລິມານສູງຢ່າງຕໍ່ເນື່ອງຂອງອາກາດທີ່ເຢັນພາຍໃນເຮືອນ (ໂດຍປົກກະຕິ 1,000 ຫາ 1,600 ລູກບາດຟຸດຕໍ່ນາທີ) ທີ່ໄຫຼຜ່ານທໍ່ເຫຼັກເພື່ອເອົາຄວາມຮ້ອນທີ່ຮຸນແຮງຂອງເຕົາແກ໊ດອອກໄປ.
ການຂີ່ຈັກຍານສັ້ນໃນສະວິດທີ່ມີຂອບເຂດຈຳກັດສູງ: ເມື່ອເຈົ້າຂອງເຮືອນລືມປ່ຽນຕົວກອງເຕົາເຜົາທີ່ຖິ້ມໄວ້ເປັນເວລາ 6 ເດືອນ, ຫຼືຕິດຕັ້ງຕົວກອງກອງ MERV ທີ່ມີຂໍ້ຈຳກັດຫຼາຍເກີນໄປ ແລະປິດການສະໜອງຫ້ອງນອນ, ກະແສລົມຫຼຸດລົງ 40 ເປີເຊັນ. ເຄື່ອງແລກປ່ຽນຄວາມຮ້ອນຂອງເຫລໍກຈະຮ້ອນເກີນ 95 ອົງສາເຊນຊຽດ (200 ອົງສາຟາເຣນຮາຍ) ອຸນຫະພູມອາກາດ, ເຊິ່ງເຮັດໃຫ້ເຄື່ອງອັດໂນມັດ ສະວິດຄວາມປອດໄພສູງຂີດຈຳກັດ ປິດເຕົາແກ໊ສອອກ ໃນຂະນະທີ່ເຄື່ອງເປົ່າລົມສືບຕໍ່ແລ່ນເພື່ອເຮັດໃຫ້ໂລຫະເຢັນລົງ. ສາມນາທີຕໍ່ມາ, ເຕົາໄຟຈະລຸກຂຶ້ນ, ຄວາມຮ້ອນຂອງໂລຫະອີກເທື່ອຫນຶ່ງ, ແລະປິດອີກເທື່ອຫນຶ່ງ ("ວົງຈອນສັ້ນຈໍາກັດ"). ຫລາຍພັນແຫ່ງຂອງຄວາມດັນການຂະຫຍາຍ-ການຫົດຕົວຂອງຄວາມຮ້ອນທີ່ຮຸນແຮງເຫຼົ່ານີ້ເຮັດໃຫ້ການເຊື່ອມໂລຫະເຫລໍກທີ່ເມື່ອຍລ້າ ໃນທີ່ສຸດກໍມີຮອຍແຕກເປັນຮອຍແຕກໂດຍກົງຜ່ານຝາຜະໜັງແລກປ່ຽນຄວາມຮ້ອນ. ສະເຫມີປ່ຽນເຄື່ອງກອງເຕົາໄຟມາດຕະຖານ 25 ມິນລິແມັດ (1 ນິ້ວ) ທຸກໆ ** 30 ຫາ 90 ມື້** ໃນຊ່ວງລະດູຄວາມຮ້ອນ ແລະຮັກສາຢ່າງໜ້ອຍ 80 ເປີເຊັນຂອງພື້ນເຮືອນ ແລະ ຝາລະບາຍອາກາດໃຫ້ເປີດອອກ.

ການໄດ້ຮັບການຊ່ວຍເຫຼືອຄັ້ງທໍາອິດແລະຫຼັກສູດ CPR ຈາກອົງການກາແດງ, St John Ambulance, ຫຼືຜູ້ໃຫ້ບໍລິການທີ່ໄດ້ຮັບການຮັບຮອງໃນທ້ອງຖິ່ນໃຫ້ແນ່ໃຈວ່າທ່ານສາມາດຮັບຮູ້ການເປັນພິດຂອງຄາບອນໂມໂນໄຊທີ່ຮຸນແຮງແລະສະຫນອງການສະຫນັບສະຫນູນຊີວິດໃນຂະນະທີ່ລໍຖ້າແພດຫມໍ.

ຄຳຖາມທີ່ມັກຖາມເລື້ອຍໆ¶

Can you smell a cracked heat exchanger or carbon monoxide coming from your heating vents?

Pure carbon monoxide gas is completely odorless and colorless, so you can never smell CO itself. However, when a furnace has a cracked or soot-plugged heat exchanger, incomplete combustion of natural gas or propane simultaneously produces aldehydes, which are chemicals that have a sharp, pungent, metallic, eye-stinging or sour exhaust smell blowing out of your heating vents. If you smell an acrid exhaust or chemical odor from your vents, shut the furnace off and evacuate immediately.

What does it mean if my furnace burner flames waver or turn yellow when the blower fan kicks on?

If your furnace burner flames burn steady and blue during the first 45 seconds after ignition, but suddenly wave, dance, flutter, or turn yellow at the exact instant the large indoor circulating blower fan switches on, that is the classic signature of a cracked heat exchanger. High-pressure household air from the blower is forcing its way through a split in the steel heat exchanger wall directly into the burner chamber.

Why did the little button on my furnace's Flame Rollout Switch pop out, and can I push it back in?

A manual-reset Flame Rollout Switch only trips when 1,000-degree-Celsius burner flames shoot backward out the front of the furnace instead of going up the heat exchanger, caused by a severely cracked heat exchanger, a soot-plugged secondary coil, or a blocked chimney flue. You must never push the reset button back in to restart the furnace yourself, as doing so can ignite a basement fire or fill your home with lethal carbon monoxide.

How can I tell if my gas water heater or furnace chimney is backdrafting into my basement?

Look at the cold and hot water pipes on the top of your gas water heater right next to the metal exhaust hood cone. If the blue and red plastic trim rings around those pipes are melted, warped, or scorched brown, hot combustion exhaust has been spilling backward out of the chimney hood into your home instead of rising up the flue.

Can running a kitchen range hood, clothes dryer, or fireplace cause carbon monoxide poisoning?

Yes. In a tightly sealed house with all windows closed, running a powerful kitchen range hood, a clothes dryer, bathroom fans, or a wood-burning fireplace pumps hundreds of cubic feet of air outdoors every minute, creating a negative vacuum inside the house. That vacuum easily overpowers the weak natural updraft of an atmospheric gas water heater or 80-percent furnace chimney, sucking deadly carbon monoxide exhaust backward down the chimney into your living space.

If an HVAC technician says my heat exchanger is cracked, can they weld it or seal it with furnace cement?

No, it is illegal and extremely dangerous to weld, braze, or apply high-temperature furnace cement to a cracked residential furnace heat exchanger. Because the thin aluminized steel expands and contracts continuously under extreme thermal stress, any patch or weld will immediately crack open again along the brittle heat-affected zone; you must either replace the entire heat exchanger assembly with a factory part or replace the furnace.

ກວດສອບແຫຼ່ງທີ່ມາ¶

ຄະນະກໍາມະການຄວາມປອດໄພຂອງຜູ້ບໍລິໂພກຂອງສະຫະລັດ (CPSC, ສະຫະລັດ): * ສານພິດຄາບອນໂມໂນໄຊຈາກລະບົບຄວາມຮ້ອນທີ່ຢູ່ອາໄສ, ເຄື່ອງແລກປ່ຽນຄວາມຮ້ອນທີ່ມີຮອຍແຕກ, ແລະການສືບສວນການຮົ່ວໄຫຼຂອງອາຍແກັສ *.
ສະມາຄົມປ້ອງກັນໄຟໄຫມ້ແຫ່ງຊາດ (NFPA, ສະຫະລັດ) ແລະສະມາຄົມອາຍແກັສອາເມລິກາ (AGA): * NFPA 54 / ANSI Z223.1 ລະຫັດອາຍແກັສນໍ້າມັນເຊື້ອໄຟແຫ່ງຊາດ (ປະເພດ I ຫາ IV ການລະບາຍອາກາດ, ການຮົ່ວໄຫຼຂອງຝາອັດປາກມົດລູກ, ແລະຄວາມຕ້ອງການອາກາດເຜົາໃຫມ້)*.
ຜູ້ບໍລິຫານດ້ານສຸຂະພາບ ແລະຄວາມປອດໄພ (HSE, ສະຫະລາດຊະອານາຈັກ) ແລະການລົງທະບຽນປອດໄພຂອງອາຍແກັສ (ສະຫະລາດຊະອານາຈັກ): ຂັ້ນຕອນສະຖານະການບໍ່ປອດໄພ (GIUSP) ສໍາລັບເຄື່ອງໃຊ້ອາຍແກັສທີ່ບໍ່ມີດອກໄຟ ແລະໄຟເປີດ, ການທົດສອບການຮົ່ວໄຫຼ, ແລະຄວາມສົມບູນຂອງເຄື່ອງແລກປ່ຽນຄວາມຮ້ອນ.
ມາດຕະຖານເຕັກນິກ ແລະອົງການຄວາມປອດໄພ (TSSA, ການາດາ) ແລະ CSA Group (ການາດາ): CSA B149.1 ອາຍແກັສທໍາມະຊາດ ແລະລະຫັດການຕິດຕັ້ງ Propane ແລະຂ່າວຄວາມປອດໄພຄາບອນໂມໂນໄຊກ່ຽວກັບ delaminating ເຄື່ອງແລກປ່ຽນຄວາມຮ້ອນຂັ້ນສອງ.
ສະຖາບັນປະສິດທິພາບການກໍ່ສ້າງ (BPI, ສະຫະລັດ): ເຂດອຸປະກອນການເຜົາໃຫມ້ (CAZ) ການທົດສອບການຊຶມເສົ້າຂອງກໍລະນີຮ້າຍແຮງທີ່ສຸດ ແລະຂອບເຂດການປະຕິບັດຂອງອາຍແກັສ flue CO2.