A whole-house humidifier needs one service visit a year. The humidifier pad gets replaced, the water path gets cleaned, and the control gets checked and reset. Air Comfort Service has serviced St. Louis homes since 1969 and services every brand of whole-home humidifier, including the Carrier bypass and fan-powered models we install.
What a humidifier service visit includes
Humidifier service includes:
- New humidifier pad. The pad is the part that does the work. Warm air from the furnace passes through it and picks up moisture. Carrier calls for a new pad every heating season (twice a season on Water Saver models). A pad crusted with minerals moves less air and less water.
- Distribution tray and scale control insert cleaned. Minerals collect where water enters the humidifier. Some buildup is normal. Enough of it blocks the openings and starves the pad.
- Feed tube, strainer, and orifice inspected. The in-line strainer catches debris before the valve. The orifice meters the water flow. Both clog, and both are small enough to miss.
- Drain line flushed. A bypass humidifier is designed to send a small, steady stream of water to the drain while it runs. That stream carries minerals away. A flattened or clogged drain line defeats the design.
- Control checked and reset. We confirm the solenoid valve opens and closes on command, run the Test cycle, reset the pad-change indicator on HumidiTrac controls, and return the dial to your setting.
- Bypass damper set for the season. Open for heating (the WINTER position), closed (the SUMMER position) for cooling.
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Why the humidifier pad matters more than anything else.
On a Carrier bypass humidifier, water flows by gravity from the distribution tray down over the pad. The furnace blower pushes dry, heated air through the wet pad. The air picks up moisture as vapor and carries it through your ductwork into every room. The pad and the scale control insert also trap the mineral deposits that would otherwise leave white dust around the house.
When the pad is worn, three things happen at once: less water evaporates, more water goes straight to the drain, and the humidity in the house drops even though the control is calling for more. Homeowners read that as "the humidifier stopped working." Most of the time it's a pad that was due last year.
What you can check yourself.
The owner's manual gives homeowners a short list of safe checks. Anything beyond this list involves 120-volt power and a water line; shut both off first. That's the point to call us.
- Is the furnace blower running? The humidifier only runs when the blower runs. If the thermostat isn't calling for heat, the humidifier sits idle.
- Is the control set? Carrier's starting point for the HumidiTrac dial is 5. Condensation or moisture on the inside of your windows means the setting is one notch too high. Dry air, static, and cracking wood trim mean one notch too low.
- Does Test mode run water? With the blower running, turn the HumidiTrac dial to Test. Water should flow for one minute and stop. Turn the dial back to your setting afterward. The humidifier will not run if the dial is left on Test.
- Is the bypass damper open? If it's still in the SUMMER position from last cooling season, no air reaches the pad.
If the humidifier runs in Test but the house stays dry, or it won't shut off when the dial is at Off, call us.
When the pad is worn, three things happen at once: less water evaporates, more water goes straight to the drain, and the humidity in the house drops even though the control is calling for more. Homeowners read that as "the humidifier stopped working." Most of the time it's a pad that was due last year.
If you have an Aprilaire 600M or 700M
Most of the whole-house humidifiers we service in St. Louis are one of two Aprilaire models, and both work the way this page describes: water runs down a panel, warm air passes through it, and the minerals go down the drain. The difference is how the air gets there.
The Aprilaire 600M is a bypass unit. Your furnace blower pushes air through a short duct to the humidifier, and a handle on the side switches that duct between WINTER and SUMMER. The Aprilaire 700M has a fan of its own and a power cord, so there is no bypass duct and no handle to turn.
Both use a manual dial you set by the outdoor temperature, and both take the same Water Panel, part 35, once a year. The service visit above covers either one. The model pages walk through the dial, the two-click check, and what we replace.
Once a year, at the start of the heating season. Carrier's manual calls for a new pad at least annually, and twice per heating season on Water Saver models.