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Fix-it and buying guides

Short, practical answers to common home-maintenance problems, and notes on choosing and replacing parts and supplies.

Fix-it guides

• Should a radon vent pipe have a cap?
  When a cap, screen or rain diverter on a radon exhaust pipe is allowed, what state rules say, and how to fit a 3-inch or 4-inch PVC vent cap.
• How to read a radon system U-tube manometer
  What the liquid levels in a radon U-tube manometer mean, what a zero reading tells you, and what to do when the reading changes.
• Radon fan not working: troubleshooting checklist
  A step-by-step checklist for a radon fan that stopped, plus how to choose a replacement fan and what to check after it is back on.
• Radon fan humming, rattling or vibrating: causes and fixes
  Why a radon fan gets noisy, how flexible couplings and pipe supports cut vibration, and when noise means the fan is failing.
• Replacing a radon fan: matching model, pipe size and couplings
  How to pick a replacement radon fan, which couplings fit 3-inch and 4-inch pipe, and what an installation kit includes.
• How to test your home for radon (short-term vs long-term)
  EPA's steps for a DIY radon test: short-term vs long-term kits, closed-house conditions, where to place the kit, and what the result means.
• Septic alarm going off: what to do
  Why a septic or pump-tank alarm sounds, what to do right away, how to silence it safely, and when to call a septic professional.
• Sump pump high-water alarm sounding: causes and checks
  What a sounding sump pit alarm means, the usual causes (power, stuck float, frozen discharge, failed pump), and what to check first.
• Sump pump and power outages: backup options and alarms
  How homeowners protect a basement when the power goes out: battery backup pumps, water-powered backups, generators, and battery-powered high-water alarms.
• Sump and septic float switches: piggyback, tethered and heavy-duty
  How tethered float switches work, what a piggyback plug does, how tether length changes the on/off range, and when to choose a heavy-duty sewage float.
• Where to put water leak sensors and alarms
  The places in a home where leaks start most often and how to place a floor leak sensor or alarm so it catches water early.
• Which way does a furnace filter go? Reading the airflow arrow
  How to install a furnace or AC filter the right way round, where the filter slot usually is, and what happens if it goes in backwards.
• How often should you change your furnace filter?
  Typical replacement intervals for 1-inch and 4-inch furnace filters, what shortens filter life, and how to tell a filter is loaded.
• Can you put a HEPA filter in a furnace?
  Why true HEPA filters are rarely used in standard home furnaces, what whole-house HEPA systems do differently, and the MERV 13 alternative EPA mentions.
• Whole-house humidifier not working: what to check
  A checklist for a furnace-mounted humidifier that is not adding moisture: water supply, solenoid, humidistat, bypass damper and a scaled water panel.
• Fridge water dispenser slow or sputtering after a filter change
  Why water flow is slow or spits after you install a new refrigerator water filter, and how to fix it: flushing air, seating the filter, and checking the part number.
• Refrigerator water filter leaking: causes and fixes
  Why water leaks around a refrigerator water filter: not fully locked, worn or missing O-rings, the wrong part number, or a cracked housing.
• Whole-house water filter housing stuck or leaking: how to change the cartridge
  Step-by-step cartridge change for a whole-house filter: relieving pressure, loosening a stuck housing, and stopping O-ring leaks.
• Smoke alarm still chirping after a battery change
  Why a smoke or CO alarm keeps chirping after you replace the battery: wrong or weak battery, battery door, leftover charge, or end of life.
• Pool cartridge filter pressure high: clean or replace?
  What a rising pool filter pressure gauge means, how to clean a cartridge, and the signs that a cartridge needs replacing.

Buying guides

• How to choose an HVAC air filter MERV rating
  What MERV means, how to read your filter size, and how to balance filtration with airflow when picking a furnace or AC filter.
• How often to replace a refrigerator water filter
  Typical replacement interval for refrigerator water filters, how to find the right part number, and signs it is time to change the filter.
• Which battery does a smoke or CO alarm take?
  How to identify the right replacement battery for a smoke or carbon monoxide alarm, plus testing and replacement reminders.
• Septic effluent filter and alarm basics
  What a septic tank effluent filter does, general maintenance practice, and how high-water alarms help protect a pump tank or drainfield.
• Whole-house humidifier pad replacement
  How to find the right humidifier water panel or pad number and how often to replace it.
• What size furnace filter do I need?
  How to read the nominal size on your furnace or AC filter frame, and which sizes we carry, including MERV options.
• Refrigerator water filter cross-reference
  OEM part-number replacements we carry, including WF3CB, LT700P, 46-9890 and others, grouped from our product listings.
• GE XWF vs XWFE refrigerator water filters
  XWF and XWFE are different GE refrigerator filters. We list XWF replacements and the genuine GE XWFE separately and never treat one as a substitute for the other.
• Mini-split filter finder (Mitsubishi, Fujitsu, Daikin)
  A model-to-filter table for the Mitsubishi, Fujitsu and Daikin mini-split filters in our catalog, taken from the product titles.
• Hayward pool filter cartridge cross-reference
  Hayward housing models and OEM cartridge numbers (including SwimClear C2030 / CX481XRE) as they appear in our product listings.
• Waterdrop RO replacement filters by system
  Replacement sets we carry for Waterdrop systems such as G3P600, G3P800, G6A8 and X12-PRO, grouped from our product titles.
• Sump and septic high-water alarms
  Wi-Fi, 12V and float-switch high-water alarms we sell, grouped from the product names — for sump pits and septic or grinder tanks.