HVAC
Furnace not heating, short cycling
CO alarm or gas smell = leave and call 911/utility
Possible cause: Dirty filter
Safe first step: Replace filter
Call a pro: HVAC tech; gas components pro only
DwellingOS repair library · Free to browse
Known symptoms, likely causes and safe first steps—not a diagnosis of your home or a ranking of visitor activity.
Gas smell or a CO alarm: leave immediately and call emergency services or your gas utility from outside. Never work on gas components, wiring or electrical panels yourself.
25 matching problems
HVAC
CO alarm or gas smell = leave and call 911/utility
Possible cause: Dirty filter
Safe first step: Replace filter
Call a pro: HVAC tech; gas components pro only
Plumbing
Sagging wet drywall can collapse — clear the area below
Possible cause: Failed wax ring / toilet seal above
Safe first step: Observe from a safe distance whether the stain grows after showering or flushing; stay clear of sagging drywall.
Call a pro: Plumber, within days; same day if dripping
Plumbing
Gas smell = leave home and call gas utility
Possible cause: Sediment buildup in tank
Safe first step: Check the heater's label and temperature setting; arrange professional service for gas components or tank flushing if unsure.
Call a pro: Plumber; gas units only by licensed tech
Plumbing
Possible cause: T&P relief valve discharging
Safe first step: Dry area and locate the source
Call a pro: Plumber, soon; tank leaks mean replacement
Plumbing
Possible cause: Worn flapper
Safe first step: Food-coloring test in tank
Call a pro: Plumber only if DIY parts fail
Plumbing
Possible cause: Hair/soap clog in trap
Safe first step: Remove and clean stopper/trap
Call a pro: Plumber if multiple fixtures are slow (main line)
Plumbing
Possible cause: Clogged aerator/showerhead
Safe first step: Clean aerators
Call a pro: Plumber if whole-house
Plumbing
Possible cause: Dry P-trap in unused drain
Safe first step: Run water in unused drains
Call a pro: Plumber if smell persists
HVAC
Possible cause: Dirty air filter
Safe first step: Replace filter
Call a pro: HVAC tech; refrigerant and capacitors need a pro
HVAC
Possible cause: Clogged condensate drain line
Safe first step: Flush drain line with vinegar
Call a pro: HVAC tech if pan cracked
HVAC
Possible cause: Closed/blocked vents
Safe first step: Open and clear vents
Call a pro: HVAC duct inspection
Electrical
Possible cause: Tripped GFCI elsewhere on circuit
Safe first step: Reset GFCIs in kitchen/bath/garage/outdoor
Call a pro: Electrician if reset fails
Electrical
Burning smell, scorching or warm outlets = stop, cut power at breaker, call electrician
Possible cause: Overloaded circuit
Safe first step: Unplug devices and reset
Call a pro: Electrician
Electrical
Whole-house flicker can indicate a failing neutral
Possible cause: Loose bulb
Safe first step: With the light off and cool, check the bulb. Wiring and dimmer replacement require an electrician.
Call a pro: Electrician urgently if whole-house
Roof
Possible cause: Failed pipe boot/flashing
Safe first step: Inspect attic with flashlight during rain
Call a pro: Roofer; avoid walking the roof
Moisture
Large mold growth — avoid disturbing it
Possible cause: High humidity / poor ventilation
Safe first step: Run bath fans 20 min after showers
Call a pro: Remediation pro if >10 sq ft
Moisture
Possible cause: High indoor humidity
Safe first step: Use exhaust fans
Call a pro: Window installer for failed seals
Structure
Rapidly widening cracks — get an engineer promptly
Possible cause: Normal settling (hairline)
Safe first step: Mark crack ends and date to monitor
Call a pro: Structural engineer if >1/4 in, widening, or stair-step in masonry
Appliances
Possible cause: Clogged filter
Safe first step: Clean filter
Call a pro: Appliance repair
Appliances
Possible cause: Dirty condenser coils
Safe first step: Vacuum coils
Call a pro: Appliance repair
Appliances
Clogged dryer vents are a fire risk
Possible cause: Clogged lint trap or vent duct
Safe first step: Clean lint trap and full vent run
Call a pro: Dryer vent cleaning service
Exterior
Possible cause: Downspouts discharging near foundation
Safe first step: Extend downspouts 4–6 ft
Call a pro: Drainage contractor
Pests
Possible cause: Rodents entering via gaps
Safe first step: Seal gaps >1/4 in
Call a pro: Licensed pest control; termites need inspection
Safety
EMERGENCY
Possible cause: Gas leak
Safe first step: Leave immediately, no switches or flames
Call a pro: Gas utility / 911 from outside
Safety
EMERGENCY
Possible cause: Combustion appliance venting failure
Safe first step: Get everyone outside to fresh air
Call a pro: 911 / fire department
Eight maintenance checks, ready to print.
Free accounts include two Issue Advisor diagnoses a month. Pro adds unlimited diagnoses and photo analysis.