Aprilaire 800 Series User manual

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Troubleshooting Guide for Installers and Call Center
Single PCB model 800
Required Tools:
1. Clip on Ammeter/voltmeter
2. #2 Phillips screw driver
3. Needle nose pliers
4. Slip joint pliers
5. 2.25” c-clamp (or equivalent device to override canister door switch)
6. ½” and 7/16” open end wrenches
7. 2” 18 gage wire stripped at both ends
8. 1/8” by 2 ½” flat head screw driver
9. 5/16” nut driver
10. Model 80 steam humidifier replacement canister
Note: Identify the symptom to be analyzed prior to shutting down the humidifier for troubleshooting.
Turning off or disconnecting power will reset all lights and may impede the troubleshooting effort.
Identify the Problem:
1. Humidifier doesn’t turn on. See sections System Setup Verification, and Using Lights to
Troubleshoot # 1
2. No or low humidity with no abnormal lights. See sections System Setup Verification and Verify
Operation.
3. Solid red service light. See sections System setup Verification and Using Lights to
Troubleshoot # 5.
4. Flashing red service light. See sections System setup Verification and Using Lights to
Troubleshoot # 4.
5. Solid yellow steam light. See sections System setup Verification and Using Lights to
Troubleshoot # 2.
6. Solid red fill light. See sections System setup Verification and Using Lights to Troubleshoot #
3.
7. Moisture in or outside of the duct. See Moisture in the Duct section
Control Panel Light Explanation
1. On/Off –Solid Green, indicates humidifier is turned On. See Using Lights to Troubleshoot
section 1.
2. On/Off –Flashing Green, indicates power is restored to humidifier originally in the On state.
Flashes for one minute then remains solid green.
3. Fill –Solid Green, indicates fill valve is open.
4. Fill –Solid Red, humidifier is shut down for fill fault. See Using Lights to Troubleshoot section
3.

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5. Steam –Solid Green, humidifier is operating with a call for humidity.
6. Steam –Solid Yellow, humidifier has been operating for 168 hours but has not reached full
capacity. See Using Lights to Troubleshoot section 2.
7. Drain –Solid Green, Humidifier is in a drain cycle or humidifier drained for end of season due to
no humidity call for 72 hours, light will stay on for 24 hours. Humidifier will resume normal
operation with a humidity call. Drain Valve is energized for 30 minute.
8. Drain –Flashing Green, Flashes for 15 seconds before humidifier goes into a 4 minute drain
cycle humidifier is filling with cold water during this time to cool the water in the canister.
9. Service –Flashing Red, Sensed amperage is 75% of the maximum amperage recorded. See
Using Lights to Troubleshoot section 4.
10. Service –Solid Red, humidifier is shut down for overcurrent fault. See Using Lights to
Troubleshoot section 5.
System Setup Verification:
1. Verify Humidifier is installed according to all relevant local codes.
2. Verify electrical power is supplied to the Humidifier from 120, 208 or 240VAC on a dedicated
breaker per local codes.
3. Verify water supply tubing is properly attached to a cold water pipe, not leaking, and saddle valve
has pierced the pipe and is open.
4. Verify humidifier control is installed and wired properly.
5. Verify Model 62 humidifier control is not in the Test Reset position or the OFF position.
NOTE: If a control other than the supplied Aprilaire Model 62 ADHC is used, verify it uses
a dry contact On/Off signal. Do not apply 24 volts to the humidistat terminals of the
Model 800.
6. Verify the canister is properly seated with the O-ring in its groove (no leaking or scale buildup at
the drain valve/canister junction).
7. Verify the steam hose slopes down and away from the duct toward the humidifier or a tee and
drain trap with no low spot or sags in the hose. A minimum slope of 2” per foot is recommended.
8. If drain tees and water traps are installed, verify water traps have proper air gap and are full of
clean water.
9. Verify hose clamps on steam hose at the canister and dispersion tube are tight by pulling lightly
on the steam hose.
10. Verify drain hose is properly attached with no kinks or obstructions.
11. If condensate pump is installed:
a. Verify discharge line installed per manufacturer’s directions.
b. Verify condensate pump is rated for at least 140°F water.
c. Verify sump is clean and free of debris or hard water build up.

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d. Check condensate pump function by engaging the float.
12. If Humidifier is OFF:
a. Remove the canister door and override the interlock switch with a small c-clamp.
b. Verify internal wiring per Appendix A.
c. Turn ON; ensure the On/Off green LED is lit. Humidifier will not produce steam unless
there is a call for humidity.
Using Lights to Troubleshoot
1. On/Off Green Light not on, humidifier is Off and/or power is not supplied. If humidifier will not
power up when On/Off button is depressed:
a. Check reset switch on transformer. If it is tripped, reset it (75 VA transformer only).
b. Check the breaker at the power supply to the humidifier.
c. Verify humidifier is properly wired to line voltage.
d. Check LED (D8) on circuit board (4” from the bottom of the board) is glowing green, if
not illuminated and power is supplied to the humidifier check for 24V at the transformer
terminals by removing the connector at P4 and inserting a volt meter into the connector
on the transformer.
i. If 24V is present but LED does not light, replace circuit board (Part Number
5530). If there is voltage other than 24V, remove power to the humidifier at the
circuit breaker and move the jumper wire to the correct terminal on the PCB.
ii. If 24V is not present then check input power to the transformer by checking
voltage between L1 and L2/N on connector P5.
If input power is correct, replace transformer, if no input power to the transformer,
check line power wiring.
iii. Transformer Part Numbers:
1) Model 800 and Model 801 (40VA): 5529.
2) Model 865 and Model 866 (75VA): 5306.
e. If control board LED is on, but On/Off Light will not energize when On/Off switch is
depressed. Replace Membrane switch (Part Number 5532).
2. Yellow Steam Light: humidifier has been operating for 168 hours but has not reached full
capacity. The humidifier is making steam and is working to get to full capacity, boiling action
concentrates minerals in the canister (the more minerals in solution, the higher the amperage and
therefore output). To help speed this up:
a. Set the furnace to constant fan or use the blower activation feature on the Model 62
control. This allow the humidifier to run as needed to provide humidity.
b. Increase the humidity setting on the control (do not over humidify the home as damage
can occur from condensation).
c. If available, plumb to softened water. Sodium does not precipitate out of solution easily,
this allows the water conductivity to rise quickly compared to Calcium in hard water.
Expect to see more drain cycles as a result.
d. Wire humidifier to 240VAC.
NOTE: Canisters should be changed every season. If the canister has not been changed,
capacity will be significantly reduced or inoperable.

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3. Solid Red Fill Light: indicates humidifier had a fill fault, humidifier is shut down. The humidifier will
try to fill for 50 minutes, if the high water pin has not been tripped or the humidifier has not
reached nominal amperage, the humidifier will shut off. 30 minutes into the fill fault (prior to
shutting off) the humidifier will rapidly cycle the fill and drain valves to try to dislodge any
sediment blocking the valves.
a. Verify saddle valve pierced the pipe header and is open.
b. Ensure yellow high water pin sensor wire is firmly installed on canister post and both
black electrode wires are installed and fully seated.
c. If all wires are attached, check operation of the fill valve. See the Verify Operation
section below.
d. Verify the steam hose does not have sags or low spots, water will condense and pool in
these areas causing backpressure which will cause the humidifier to fill due to low level in
the canister.
4. Flashing Red Service Light: indicates sensed amperage is 75% of the maximum amperage
recorded. The humidifier must operate for 168 hours (1 week) and have had its amperage drop to
75% of the maximum amperage recorded.
a. Verify amperage with a clamp on ammeter through multiple fill cycles. See Verify
Operation section below.
i. For 11.5 amp operation, humidifier will fluctuate between 10.3 and 12.7 amps.
ii. For 16.0 amp operation, humidifier will fluctuate between 14.4 and 17.6 amps.
b. If amperage is within the correct operating band, depress the On/Off button to shut the
humidifier down which will reset the PCB memory.
c. If amperage is below the correct operating band, depress the On/Off button to shut the
humidifier down allowing the humidifier to fully drain, and then replace the canister (Part
Number 80).
5. Solid Red Service Light, humidifier is shut down for overcurrent fault. This typically happens when
the canister or drain valve is plugged with minerals; the humidifier cannot maintain the proper
conductivity through drain operations.
a. Remove and rinse canister.
b. Clean sediment out of the drain valve.
c. Reinstall canister and start humidifier (see the Verify Operation section).
d. If red service light persists replace the canister (Part Number 80).
e. If humidifier cannot drain after cleaning drain valve, replace the drain valve (part number
4983).
6. Erratic light behavior (i.e. no lights while humidifier is on or multiple lights coming on at one time)
or humidifier shuts down for no reason; replace the membrane switch (Part Number 5532).
a. Verify steam hose fit on canister.
b. Check for evidence of leaks.
Verify operation:
1. Turn the humidifier off and allow it to fully drain before moving on, this will take about 5 minutes.
2. Remove canister door and electrical access panel.
3. Clip the ammeter on one electrode wire.
4. Remove the humidistat line and jumper across the two HUMIDISTAT terminals with an 18AWG
wire. Do not apply 24 volts to the humidistat terminals of the Model 800.
5. Use the small c-clamp to override the canister door safety switch.

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6. Turn the furnace blower to constant fan.
7. Turn the steam humidifier On. If humidifier fails to turn On, verify power at the input power
terminal block
8. The canister will fill to the high water pin and begin to heat water to make steam.
9. If the humidifier does not begin to fill within 15 seconds:
a. Ensure the two electrode wires and high water pin (yellow wire) on the top of the canister
are attached and fully seated.
b. Remove the high water pin wire from the high water pin on the canister
i. If the humidifier begins filling, reinstall the high water pin, turn the humidifier Off
to allow it to fully drain, and then replace the canister (Part Number 80).
ii. If the humidifier does not begin to fill in five seconds, shut the humidifier Off and
remove the humidistat jumper installed in step 4:
1) Verify that the saddle valve is open.
2) Remove the yellow high water pin wire from the top of the canister. Place
one of the electrical access panel door screws into the red connector at
the end of the high water pin wire. WARNING –care should be taken
when performing this step as the screw is has live electricity.
3) Turn the humidifier on.
4) Touch the screw to the copper ground lug on the electrical panel for 5
seconds, the Service light should illuminate red.
5) If the Service light does not turn on remove power at the circuit breaker
and replace the current sensing board (Part Number 5530).
c. Verify fill valve operation by removing the yellow fill valve leads at the bottom of the PCB
and energizing the fill valve coil with 24VAC. If valve does not audibly click open, replace
fill valve.
10. Monitor amperage during filling and operation.
a. Amperage will increase as water level increases and as temperature in the canister rises.
When water starts to touch the electrodes, the amperage should increase slowly from 0
to approximately 5 amps. As the water in the canister heats, amperage should continue
to increase though less rapidly.
b. If canister is used, and there is no increase in amperage as the canister fills, drain the
humidifier and replace the canister.
11. Check for water outside of the canister.
a. Drain valve/canister joint –Replace drain valve O-ring (Part Number 5258).
b. Fill lines - Verify spring clamps and fill valve compression fittings are tight.
12. Check for steam leaks at the canister/steam hose joint.

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Moisture in the duct
1. Verify absorption distance for voltage and amperage setting. Many factors contribute to
absorption distance. See table 2 in the Installation & Maintenance Instructions.
a. Verify plenum temperature, air velocity and humidity level
b. Ensure control is properly mounted
c. Install a high humidity switch in series with the humidifier and humidistat to prevent over
humidification in the duct.
2. If the steam dispersion tube is mounted on a horizontal run, verify the dispersion tube is low in the
duct, at least 4” from the top of the duct. On vertical runs center the dispersion tube on the duct.
3. Verify the steam hose slopes down and away from the duct toward the humidifier or a tee and
drain trap. A minimum slope of 2” per foot is recommended.
4. Verify the steam dispersion tube is mounted with the “TubeletsTM” facing up.
Water Chemistry
1. The minerals contained in the supply water dictate how the humidifier operates and plays a large
role in the life of the canister. Water quality and mineral content varies dramatically across the
country, following the guidelines below will help determine what water type to use.
a. Softened water, whether with sodium chloride or potassium chloride will allow the
humidifier to come to full capacity faster, and the canister will last longer. There will be
more frequent drain cycles and a higher potential for foaming both resulting in more water
usage.
b. Hard water minerals, calcium and Magnesium, combine with bicarbonate and carbonate
ions and drop out of the water when heated, this reduces the ions in the water causing a
slower start up and scale formation in the canister reducing canister life. Using hard water
will drain less than soft water; this uses less water and energy and gives a more constant
steam output.
2. Check with the local water utility to see if orthophosphates or polyphosphates are used. These
chemicals are used to control corrosion and sequester lead in piping systems. Phosphates will
insulate the electrodes in the canister causing the canister life to be significantly degraded. Do not
install the humidifier is phosphate levels are above 1ppm (or 1mg/L).

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Figure 1 Electrical panel
Ground and input power (P5)
Jumper wire
Humidistat terminals
Fan Pack terminals
Membrane switch
Drain valve connection
Canister door safety switch
Electrode wires
High water pin wire
Relay
D8 LED power indication
Transformer secondary
connection (24VAC)
Fill valve connection
Transformer
Fill valve assembly

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Appendix A - Wiring Diagram

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Appendix B –Parts List

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