Aprilaire 500M Humidifier Instruction Manual

Name: Aprilaire 500M Humidifier Instruction Manual
Brand: Manualverse
Availability: InStock
Rating: 5 (1 reviews)

Aprilaire 500M Humidifier Instruction Manual

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📖 Manual 📋 Specifications 📝 Summary 💬 FAQs

Aprilaire 500M Humidifier

User Manual

20 pages

Installation Guide

2 pages

Aprilaire 500M Humidifier Instructions

Here we offer the Aprilaire 500M Humidifier manual completely free and in English. We have cataloged this manual in the Humidifiers section on Manualverse, and it has been rated by 1 users with an average rating of 5. If you have any specific questions about Aprilaire 500M Humidifier, we suggest checking the Frequently Asked Questions (FAQs) section of this manual.

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Aprilaire 500M Humidifier Specifications

Feature	Specification
Model	Aprilaire 500M Small Bypass Humidifier
Humidifier Type	Evaporative, bypass, flow-through with drain
Humidifier Control	Manual Humidifier Control (included)
Width (including solenoid valve)	15 5/8 in.
Height (including drain spud)	13 in.
Depth	10 1/4 in.
Plenum Opening	9 1/2 in. W x 9 1/2 in. H
Bypass Duct Opening	6 in. diameter
Water Feed Rate	3 gph
Electrical Data	24 VAC, 60 Hz, 0.5 A
Transformer	24 VAC transformer included; must not be wired into the furnace blower circuit
Accessory Terminal Transformer Rating	10 VA minimum
Replacement Water Panel	Aprilaire Water Panel 10
Water Panel Replacement Interval	At least once a year
Supply Water Types	Hot, cold, hard or mechanically softened
Maximum Hot Water Temperature	140°F (60°C)
Maximum Water Pressure	125 psi
Maximum Plenum Pressure Differential	0.4 in. wg between supply and return plenums
Water Supply Line	1/4 in. copper tubing (not included)
Drain Line	1/2 in. I.D. hose (not included)
Mounting Location	Supply or return plenum; upflow or horizontal systems
Bypass Connection	Left side by default, can be switched to the right
Bypass Damper	Built-in, WINTER/SUMMER positions
In-Line Strainer Part Number	4004
Orifice Part Numbers	4231 (yellow) or 4232 (blue), depending on model
Housing Materials	Parts that touch water are non-metal and do not rust or corrode
Warranty	5 years limited, from date of purchase
Technical Support	800.334.6011

Aprilaire 500M Humidifier Details

The Aprilaire 500M is an evaporative bypass humidifier. It uses heat from the HVAC system to turn water into vapor. When the control calls for humidity and the system fan is running, water flows into a distribution tray. The tray spreads the water evenly over the Water Panel, and warm, dry air from the supply duct passes through the wet panel and returns to the return duct carrying moisture.

The unit uses a flow-through drain design. A small, steady stream of water runs to the drain, which flushes away most of the minerals that cause problems and prevents stagnant water. An orifice supplied with the humidifier keeps the water flow correct. The saddle valve should only ever be fully open or fully closed and must never be used to adjust the flow.

The included Manual Humidifier Control can be mounted in the cold air return duct or on an inside wall. For duct mounting, place it at least 6 in. upstream of the humidifier or bypass connection. For wall mounting, pick a spot away from drafts and heat sources. To estimate the indoor RH, turn the knob slowly back and forth and listen for two clicks. The current humidity is within that range.

Because the control does not adjust itself, the owner should lower the set point before outdoor temperatures drop to avoid condensation. Recommended settings are 45% RH at +40°F, 35% at +20°F, 25% at 0°F and 15% at -20°F. Fog or frost on the inside of windows usually means the humidity is too high.

The humidifier is designed for one-person servicing. Release the top and bottom tabs to remove the front cover, pull the feed tube out of the tray, and tip out the evaporative assembly. Unsnap the distribution tray, then gently scrape or brush mineral deposits from it without stretching the fabric liner. Vinegar or a lime-removing agent helps loosen stubborn scale.

Slide the new Water Panel 10 into the scale control insert with the colored spot facing up. Fit the assembly's drain into the round receptacle at the base and press it in until it snaps into place. Check the feed tube for cracks, flush the drain line under pressure, and make sure the drain line slopes steadily downward.

Once a year, also clean the in-line strainer, check that the orifice opening is clear, and check the solenoid valve connections. Use two wrenches when tightening any compression nut. At the end of the heating season, turn the bypass damper handle from WINTER to SUMMER and set the control knob to OFF.

The installation must be done by a qualified HVAC contractor, or the warranty is void. Do not mount the humidifier on the furnace jacket, in a space where it could freeze, or where the blanked-off ends of a cooling coil block airflow. On heat pump systems, use hot water to make up for the lower supply air temperature.

The warranty does not cover consumables such as Water Panels, labor charges, improper installation, or normal wear. Register the product at aprilaire.com/warranty to make any future claim easier.

Frequently Asked Questions (FAQs)

Can't find the answer you need? Here are some frequently asked questions about the Aprilaire 500M Humidifier, and we answer them below.

Which Water Panel does the Aprilaire 500M use?

The 500M uses the genuine Aprilaire Water Panel 10. Replace it at least once a year for the best performance.

Can I use cold or softened water with the 500M?

Yes. It works with hot, cold, hard or mechanically softened water. Hot water up to 140°F (60°C) gives the most evaporation and is required for heat pump installations.

How do I check the current indoor humidity with the manual control?

Turn the knob slowly clockwise and counterclockwise and listen for two clicks. The indoor RH is within the range between those two clicks.

What humidity setting should I use?

Follow the outdoor temperature: 45% at +40°F, 40% at +30°F, 35% at +20°F, 30% at +10°F, 25% at 0°F, 20% at -10°F and 15% at -20°F. Lower the setting before cold weather arrives.

How do I test that the humidifier works?

Make a heat or fan call at the thermostat so the HVAC fan runs. Open the saddle valve, make sure the unit has power, and turn the knob to the highest setting. Then turn it back to the setting you want.

What should I do in summer?

Turn the built-in bypass damper handle from WINTER to SUMMER and set the Manual Humidifier Control knob to OFF.

Can I use the saddle valve to adjust the water flow?

No. The saddle valve is meant to be either fully open or fully closed. The factory orifice controls the water flow.

Why does water keep running to the drain?

This is normal. The flow-through design sends a small, steady stream of water to the drain to flush away minerals and prevent stagnant water.

What are the electrical requirements?

The unit runs on 24 VAC, 60 Hz, 0.5 A, supplied by the included transformer. Power the transformer from a 120 VAC source that is not on the furnace blower motor circuit.

How large are the duct openings?

The plenum opening is 9 1/2 in. x 9 1/2 in., and the bypass duct is 6 in. in diameter.

Can the bypass be connected on the right side?

Yes. The bypass connection comes on the left. To move it to the right, twist out the drain spud and cap and swap their positions.

What is the maximum water pressure?

Do not install the humidifier where water pressure is above 125 psi, or the humidifier may be damaged.

How long is the warranty?

The limited warranty covers defects in materials or workmanship for 5 years from the date of purchase. Water Panels and labor are not covered.

Which parts need cleaning or replacing during maintenance?

Clean the distribution tray and scale control insert, flush the in-line strainer (Part No. 4004), check the orifice (Part No. 4231 or 4232), and check the feed tube and drain line.