Honeywell TrueSTEAM User manual

Must be installed by a trained, experienced technician
Read these instructions carefully. Failure to follow these instructions
can damage the product or cause a hazardous condition.
TrueSTEAMTM
Operating Manual
69-2035EFS-01

About your new humidifier
TrueSTEAM controls........................................................................................ 1
Maintaining ideal humidity .............................................................................. 2
TrueSTEAM function and operation ............................................................... 3
Setting the controls......................................................................................... 4
Specifications .................................................................................................. 5
Maintenance and operation
LED light indicators.................................................................................................6
Cleaning and maintenance .....................................................................................7
Seasonal or vacation maintenance ........................................................................8
DIP switch setting ...................................................................................................9
Troubleshooting and repair
Parts list.................................................................................................................10
Homeowner troubleshooting ................................................................................11
Professional HVAC technician troubleshooting...................................................12
Limited warranty....................................................................................................16
Read and save these instructions.
Need Help?
For assistance with this product please visit http://yourhome.honeywell.com
or call Honeywell Customer Care toll-free at 1-800-468-1502
Table of contents
® U.S. Registered Trademark.
Patents pending.
Copyright © 2007 Honeywell International Inc. All rights reserved.

TrueSTEAM Direct-Injection Humidifier
1 69-2035EFS—01
About your new thermostat
Congratulations on your new humidifier. Your Honeywell TrueSTEAM direct-injection humidifier
provides the high performance and efficiency of steam humidification with easier maintenance
than traditional humidifiers.
Benefits
• Actually controls your equipment for maintaining desirable humidity levels in your home
year-round.
• Requires less water, reducing usage up to 70% when compared to flow-through
humidifiers.
TrueSTEAM comes with one of the following control packages:
About your new humidifier
VisionPRO IAQ Total Comfort System YTH9421C1002
• Controls both temperature and TrueSTEAM.
• Sensor for displaying outdoor temperature.
• Intuitive user interface for easy 7-day temperature
programming.
• Easy-to-read backlit digital display.
• Maintenance and service reminders.
• Controls other air quality equipment when you’re
ready.
TrueIAQ Digital Control DG115EZIAQ
• Automatic adjustments maintain ideal humidity.
• Sensor for displaying outdoor temperature and
humidity.
• Shows actual humidity and desired setting.
• Maintenance and service reminders.
• Controls other air quality equipment when you’re
ready.
Manual Control H8908ASPST
• Manual control with intuitive comfort settings.
• Integrated humidity chart for accurate control in
changing conditions.

Operating Manual
69-2035EFS—01 2
Maintaining ideal humidity
Optimal Relative Humidity (RH) is defined by industry experts* as between 40-60% RH on an
average annual basis, and 35% during the heating season in dry climates. An environment with
too little humidity leaves the body vulnerable to viruses and bacteria, and can cause woodwork
in the house to shrink and crack. On the other hand, too much humidity creates ideal conditions
for mold and mildew growth.
Proper indoor humidity can also help you save money on energy bills. When maintained proper-
ly, your equipment won’t have to run as much because humidified air feels warmer in the winter.
* American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE)
M24780
0 10 20 30 40 50 60 70 80 90 100
OPTIMUM
ZONE
Bacteria
Viruses
Fungi
Mites
Respiratory
Infections
Allergic Rhinitis
and Asthma
Chemical
Interactions
Ozone
Production
ASHRAE recommeded winter design level

TrueSTEAM Direct-Injection Humidifier
3 69-2035EFS—01
M24784
TrueSTEAM function and operation
Your TrueSTEAM humidifier provides the highest capacity and most efficient steam humidifica-
tion for whole-house residential applications.
The patented Condensate
Collect Dome and beveled nozzle
keep water in the tank, delivering
only true steam into your duct’s
airflow.
Sediment screen
keeps the tank clean
for a longer period of
time, reducing main-
tenance and ensuring
optimum perfor-
mance.
Wiring to your HVAC equipment
allows TrueSTEAM to supply humidity
when you need it by turning on your
equipment automatically.
LED light feedback allows you to
monitor performance, giving you
total control and peace of mind.
True steam provides your home with high-
capacity true humidity, while using up to 70%
less water than flow-through humidifiers.
Snap-lock latch allows
for quick, easy main-
tenance.
Automatically fills with
water and drains when
needed, so you don’t have
to remember to do it.

Operating Manual
69-2035EFS—01 4
With automatic controls like TrueIAQ and VisionPRO
IAQ, you need only calibrate this setting once. The
automatic feature will adjust by itself as outdoor condi-
tions change, based on your initial settings. After set-
ting your auto control to the desired RH% level, check
for condensation or frost forming on windows on the
first cold day. If present, adjust your frost settings on
the control (see control owner’s manual if needed).
The Window Frost Protection feature protects your
home by limiting humidity output based on outdoor
conditions (for example, on colder days, your home can hold less humidity).
Frost Settings should be lowered by one value each morning that you see frost or condensa-
tion on windows. Allow 24 hours for the adjustment to take affect. Once you have this set to a
comfortable level without condensation forming, you will not need to adjust this again. You can
adjust your humidity settings without worrying about condensation.
With Manual Humidity Controls—such as the H8908—you
will need to adjust your RH% settings each time the outdoor
conditions change (more humidity with warmer outdoor con-
ditions, lower humidity with colder conditions). These con-
trols provide accurate operation, but require more hands on
adjustment. These controls are a good choice for homeown-
ers who desire continuous interaction with humidity settings.
Setting the controls
The colder it is outside, the less humidity can be retained by the air. Initially setting your humidi-
stat to ideal comfort levels will help your TrueSTEAM deliver optimal humidification. The table
below provides suggested control settings based on outdoor conditions.
M24830
123456789
LESS HUMIDITY
LOOSE HOME/SINGLE-PANE WINDOWS
MORE HUMIDIT
Y
TIGHT HOME/TRIPLE-PANE WINDOWS
You may experience that your home needs
humidity levels to be slightly higher or lower
than the suggested levels given in the table, in
order to prevent window condensation or dry-
ness. This is because your home is unique in
size, shape, building tightness, and age. These
variables play an active role in how your indoor
humidity fluctuates. Use the table as a start-
ing point, but adjust according to your comfort
and observations of condensation.
Outdoor
Temperature
Recommended RH %
Setting
-20°F (-29°C) 15%
-10°F (-23°C) 20%
0°F (-18°C) 25%
10°F (-12°C) 30%
20°F (-7°C) 35%
>20°F (-1°C) 40%

TrueSTEAM Direct-Injection Humidifier
5 69-2035EFS—01
Install TrueSTEAM according to National Electric Codes.
Capacity:
HM512: 12 gallons per day (gpd) (45 liters per day [lpd])
HM509: 9 gpd (34 lpd)
HM506: 6 gpd (23 lpd)
Humidified Area:
House Description Air Changes Per Hour HM512 HM509 HM506
Loose Two 2000 sq. ft. 1300 sq. ft. 1000 sq. ft.
Average One 2500 sq. ft. 1800 sq. ft. 1500 sq. ft.
Tight One-half 3000+ sq. ft. 2500 sq. ft. 2000 sq. ft.
Weight:
Model Empty Filled with Water
HM512 9 lbs. 15 lbs.
HM509 9 lbs. 14.5 lbs.
HM506 8 lbs. 12 lbs.
Dimensions: 11-1/4 in. W x 19 in. H x 9 in. D
Humidifier Operating Temperature Range: 34ºF–104ºF (1.1ºC–40ºC)
Remote Hose/Nozzle Operating Temperature Range: -50ºF–250ºF (-46ºC–121ºC). Meet this spec-
ification if purchasing hose off-the-shelf.
Operating Humidity Range: 0–95% RH, non-condensing
Drain Hose Operating Temperature Range: 34ºF–212ºF (1.1ºC–100ºC)
Electrical Ratings and Tolerances
Specifications
Input Ratings
• Power Supply: 120VAC +10/ -15%, 60Hz
- HM512: 1440W at 120VAC at full load
- HM509: 1200W at 120VAC at full load
- HM506: 840W at 120VAC at full load
• HM512: 12A, 120VAC
• HM509: 10A, 120VAC
• HM506: 7A, 120VAC
• 15A, 120VAC interlock switch
• Thermostat/HVAC power monitor (R to
C): 10mA resistive at 24VAC
• Field wiring terminals: 18–22 ga. solid
• HVAC power/airflow monitor: 10 mA
resistive at 24 VAC
Output Ratings
• Relay output contacts:
- Fan: 1.5A full load, 7.5A locked rotor
at 24VAC
- Heat and Backup: 15A resistive at
120VAC
• Fill Solenoid: 0.1A at 120VAC, 0.5 PF
• Drain Solenoid: 0.1A at 120VAC, 0.5PF
• Humidistat output contacts: 10mA
resistive at 24VAC
• Humidistat power supply: 100mA at
24VAC
Standards & Approval Body Requirements
Underwriters Laboratories: UL998, File no. E185662.
Federal Communications Commission: Class B compliance, File no. YU555.
Tested to ARI standard 610 and ASHRAE 62.2 for performance rating of central system humidi-
fier for residential applications. Intended to be used in accordance with the National Electrical
Code (NEC), ANSI/NFPA 70, and the rules of the Canadian Electrical Code (CEC), Part 1, C22.1.

Operating Manual
69-2035EFS—01 6
LED light indicators
The LED light panel on the TrueSTEAM lets you know that the humidifier is operating correctly,
when maintenance is needed, and when it is safe to remove the tank for cleaning. The push but-
tons allow the tank to be drained for cleaning, and quickly return to operation when the tank is
reattached to the humidifier.
Power indicates the TrueSTEAM is plugged in and that the humidifier is
ready for operation.
Humidifying indicates that steam is being delivered to the home.
Clean Tank: This LED blinks to indicate the TrueSTEAM is draining when
you press the EMPTY button. When the light is on solid (not blinking), the
tank is empty and safe to remove for cleaning.
Call Service is a fault indicator. Call your HVAC technician to service the
humidifier. HVAC technicians: Refer to page 12 for fault identification and
troubleshooting.
Press Reset will blink when power is applied or reapplied (upon initial
installation or after cleaning). This is a stand-by mode to ensure water
lines are hooked up properly before unit resumes operation. This will blink
for 5 minutes before going to system ready. The 5-minute default can be
overriden by the installer by pressing the RESET button.
Press Empty will blink to indicate that the water tank needs cleaning. Push
the EMPTY button to drain the tank for safe removal and cleaning.
Reset Button If the Press Reset light is blinking, press the RESET button to
override the 5-minute delay at startup. If the Call Service LED is on (fault is
present), press/release the RESET button to blink a diagnostic code on the
Call Service LED. Press/Hold the button for 5 seconds to clear all faults and
reset “Clean Tank” timers. If the Press Empty LED is blinking, press/hold the
RESET button for 5 seconds to turn off the Press Empty LED and restart the
Clean tank timer.
Empty Button will drain the tank of water when pushed. Do this before
servicing the tank and internal parts.
POWER
HUMIDIFYING
CLEAN TANK
CALL SERVICE
PRESS RESET
PRESS EMPTY
RESET
EMPTY
SEE LABEL BELOW !
M24763

TrueSTEAM Direct-Injection Humidifier
7 69-2035EFS—01
About your new thermostatCleaning and maintenance
Warning: Scalding hazard.
Do not attempt to remove the humidifier from the mounting bracket during operation, or
the humidifier’s water tank when full of water. The heating element could be hot when
tank is removed. Failure to comply could result in severe scalding or death.
To clean TrueSTEAM:
1. Press the EMPTY button. Wait for the CLEAN TANK light to be on solid (not blinking).
2. Turn the manual shut-
off valve at the bottom
of the tank to the
“Unlock” position.
Maintenance is made simple with the TrueSTEAM—just remove the water tank for cleaning.
EMPTY
M24774
CLEAN TANK
(BLINKING LIGHT)
M24775
M24777
M24778
M24779
4. Firmly grip the tank
bottom. Push down the
cover's safety button and
pull the latch forward to
release the tank.
Note: Latch does not come
off humidifier with tank.
3. Grip the white water
valve arm and slide it
back within the bracket
to disengage from the
tank.
M24776
CLEAN TANK
(ON SOLID)
Wait Go to Step 2

Operating Manual
69-2035EFS—01 8
About your new thermostat
Seasonal or vacation maintenance
TrueSTEAM has the built-in intelligence to shut down when humidity is not needed for an
extended period. After 48 hours of inactivity, TrueSTEAM will drain its tank and remain empty
until it is needed again. This prevents water from stagnating within the tank. There are a few
house-cleaning steps to follow to keep your TrueSTEAM at peak efficiency:
1. Follow steps 1–6 in the Cleaning section on pages 7–8 at least once per year, or when the
Press Empty light is blinking.
2. Clear ventilation holes in the humidifier’s cover.
3. Clear the water drain tube.
4. Make sure the water tank gasket seal is not cracked or split before reattaching the
humidifier water tank.
5. Check that the humidifier is still level.
Extended Vacation
When you leave on extended vacations, it is recommended you turn off the humidifier’s water
supply and turn off the humidity control. When you return, turn on the humidifier water supply and
reset your humidity control to a comfortable position.
5. Use tap water to flush loose minerals
from the tank. Sediment screen at
tank's bottom is removable. For a more
thorough cleaning, soak tank in warm,
soapy water, then rinse clean. Tank is
also dishwasher-safe.
Cleaning and maintenance
M24856
M24857
6. Carefully rub minerals off of the heating
element and reservoir walls. Scouring
pads suitable for non-stick pots or pans
are suitable for cleaning the TrueSTEAM
reservoir walls and components within the
tank.
Sediment screen
Once clean, reattach tank by securing the latch. Engage the water valve to the cam shaft, and
“Lock” the shut-off valve. The “Press Reset” light will blink at start-up. Push the RESET button
to ready the humidifier.

TrueSTEAM Direct-Injection Humidifier
9 69-2035EFS—01
Between the transformer and LED displays on the circuit board are two sets of DIP switches.
DIP 1 and 2 can be configured to adjust cleaning cycles. DIP 4 and 5 can simplify wiring. DIP 3
and 6 are not used at this time. Refer to the chart for details.
Run time (hrs) End-of-Season
timer (hrs)
Clean tank indicator
10 hrs of
humidifying
before system
auto-flushes
debris from
tank.
48 hrs before sys-
tem auto-drains
and remains empty
until next call for
humidity.
1 year of total time
(operational and inactive)
before the Press Empty
light will blink, indicat-
ing it is time to manually
clean the water tank.
20 hrs of
humidifying
before system
auto-flushes
debris from
tank.
48 hrs before sys-
tem auto-drains
and remains empty
until next call for
humidity.
1 year of total time
(operational and inactive)
before the Press Empty
light will blink, indicat-
ing it is time to manually
clean the water tank.
30 hrs of
humidifying
before system
auto-flushes
debris from
tank.
48 hrs before sys-
tem auto-drains
and remains empty
until next call for
humidity.
1 year of total time
(operational and inactive)
before the Press Empty
light will blink, indicat-
ing it is time to manually
clean the water tank.
DIP 4 OFF, DIP 5 ON: If TrueSTEAM determines that no air-
flow* is present two minutes after the blower fan call, it will shut
down steam output and activate a service light.
*Requires installation of air flow switch. See 'Wiring' section for details.
DIP 4 ON, DIP 5 either setting: TrueSTEAM will allow humid-
ity without HVAC power present and without airflow.
DIP 4 OFF, DIP 5 OFF: TrueSTEAM will not be allowed to
humidify without HVAC power being present.
M24899
OFF
ON
OFF
ON
OFF
ON
DIP 1 DIP 2 DIP 3
DIP 4 DIP 5 DIP 6
DIP 1 DIP 2 DIP 3
DIP 4 DIP 5 DIP 6
DIP 1 DIP 2 DIP 3
DIP 4 DIP 5 DIP 6
DIP
3
DIP
3
DIP
3
D
IP
6
D
IP
6
D
IP
6
M24900
DIP 1 DIP 2 DIP 3
DIP 4 DIP 5 DIP 6
OFF
ON
DIP 1 DIP 2 DIP 3
DIP 4 DIP 5 DIP 6
OFF
ON
DIP 1 DIP 2 DIP 3
DIP 4 DIP 5 DIP 6
OFF
ON
DIP
3
DIP
3
DIP
3
D
IP
6
D
IP
6
DIP
6
DIP switch setting—For professional HVAC technician only

Operating Manual
69-2035EFS—01 10
About your new thermostatParts list
Part Part Number Fig. Reference
10-foot Remote Hose and Nozzle Kit 50024917-001 1
20-foot Remote Hose and Nozzle Kit 50024917-002 1
Cover 50028004-001 2
Duct Injection Nozzle for Humidifier 50028003-001 3
Remote Humidifier Nozzle 50028001-001 4
Remote Duct Nozzle 50028002-001 5
Mounting Bracket 50020012-001 6
Solenoid Valve 50027997-001 7
In-Line Water Filter 50028044-001 8
Sediment Screen for Tank 50024895-001 9
HM512/HM509 Water Tank 50020017-001 10
HM506 Water Tank 50025892-001 11
Water Level Sensor Assembly 50027998-001 12
Wire Channel Harness 50022641-001 13
Latch 50024921-001 14
Saddle Valve 32001616-001 15
M24787
1
2
34
5
6
7
8
9
10
11
12
13
15
14

TrueSTEAM Direct-Injection Humidifier
11 69-2035EFS—01
Homeowner troubleshooting
If you have difficulty with TrueSTEAM, please try the following suggestions.
Most problems can be corrected quickly and easily.
Problem Look For What to Do
Low humidity Humidifier heater is
not operating
• Confirm that power light is on.
• Set the humidistat higher.
• Check that the furnace power is on.
• Reset your circuit breaker or check for blown fuse.
• If fault persists, turn humidistat off, unplug unit,
reset circuit breaker and call a professional HVAC
contractor.
Rapid air changes.
Drafts (cold air
is dry and is an
added load for the
humidifier)
• Keep doors and windows closed.
• Close fireplace damper when not in use.
• Keep exhaust fan running time to a minimum.
• Seal around doors and windows.
High Humidity Condensation on
walls
• Turn off the humidity control until condensation is
completely evaporated. Lower humidistat setting to
prevent reoccurance of condensation (see pages 2–4
for controlling humidity levels).
Heavy
condensation on
windows
• Turn humidity control down low enough to eliminate
condensation caused by moisture from bathing,
mopping, cooking, etc. If moisture persists, more
ventilation is needed.
Call for
Service LED
is blinking
TrueSTEAM has
detected one of 15
system faults.
• Press Reset button.
• If fault persists, turn off power supply to the
humidifier, and turn back on.
• If fault persists, call a professional HVAC contractor.

Operating Manual
69-2035EFS—01 12
About your new thermostat
TrueSTEAM has internal system diagnostics that monitor system operation and maintenance
schedules as well as system faults. If a system fault is detected, the system will attempt to
recover itself up to five times in a 24 hour period. If unable to recover in that time, the red Call
Service light will activate.
NOTE TO HOMEOWNERS: If the Call Service light is active, unplug and plug the TrueSTEAM
back in to clear the fault codes. If the Call Service light turns back on within one day, contact
your professional HVAC installer to troubleshoot the device.
HVAC INSTALLING TECHNICIANS: If the TrueSTEAM Call Service light is red, a system fault
has occurred from which the humidifier can not recover by itself. The table below shows the
possible faults, along with steps to fix TrueSTEAM.
To see which of these faults has occurred, pressing the Reset button when the red Call Service
light is on will identify the fault through a series of red light blinks. Pressing and holding the
Empty button will clear the service fault lights.
Some of these faults will cause TrueSTEAM to shut down and enter Service mode, and some
can be recovered if the fault condition no longer exists after 1 hour (as indicated in column 3).
After 5 retries within 24 hours of any individual shutdown fault, the unit will enter Service mode
and will not try to recover until the power has been cycled. The retry counter will reset every 24
hours on time if it has not reached the maximum of 5 retries. The control will return to Ready
mode after all the faults have been recovered.
No. of
Red
Light
Blinks
Fault Description Auto-
Recoverable?
Steps to Fix
To be Performed by Professional HVAC
Technician Only
1 Water/Heater tempera-
ture sensor failed.
Yes, system
will return to
“Ready” if
fault no longer
exists in 1
hour.
• Unplug TrueSTEAM and remove cover.
• Check water sensor connection to
electronic board.
• Reattach cover and plug TrueSTEAM in.
• If fault reappears, press EMPTY button and
follow tank cleaning steps on pages 7–8.
• Reassemble tank and press the RESET
button.
• If fault returns, replace with applicable
wattage heating element.
2 Water sensors failed. Yes, system
will return to
“Ready” if
fault no lon-
ger exists in
1 hour. Will
attempt to
reset itself 5
times in 24
hours.
• Unplug TrueSTEAM and remove cover.
• Disconnect water level sensor wiring,
remove screen and lift snap-hinge clamp.
Remove water sensor assembly.
• Clean water sensor probes using warm
soapy water so that the metal is exposed.
• Reassemble the sensor assembly in the
unit, reattach and secure cover.
• Plug unit back in and press the RESET
button.
• If fault reappears, replace water sensor
assembly.
Professional HVAC technician troubleshooting
M24901
A
B

TrueSTEAM Direct-Injection Humidifier
13 69-2035EFS—01
About your new thermostat
No. of
Red
Light
Blinks
Fault Description Auto-
Recoverable?
Steps to Fix
To be Performed by Professional HVAC
Technician Only
3 Failure to fill tank with
water.
Yes, system
will return to
“Ready” if
fault no longer
exists in 1
hour.
• Ensure inlet water is on.
• Check for leaks around the tank seal and
solenoid.
• Turn off water supply and replace in-line
water filter.
• Press/hold RESET button until the red Call
Service light turns off.
• If tank still fails to fill, press the EMPTY
button (if unit fails to drain, unplug unit and
make sure water in tank is cool).
• Follow tank cleaning instructions on page
7. Ensure you have a firm grip of the tank
prior to releasing the tank, especially if
water is present.
• Clear any excess debris from the tank’s
bottom orifice to the solenoid.
• Reassemble tank and plug unit back in.
Press the RESET button.
• If water still fails to flush into the tank,
replace the solenoid valve.
4 Heating element
overheated.
No • Press EMPTY button.
• Follow tank cleaning steps (pages 7–8).
• Reassemble tank and press the RESET
button.
• If fault returns, replace with applicable unit.
5 Input voltage
insufficient.
Yes, system
will return to
“Ready” if
fault no longer
exists in 1
hour.
• Unplug and replug the unit in to see if the
fault returns.
• If fault returns, unplug unit and remove
cover.
• Ensure wiring connections are secure and
attached.
• If fault returns, replace the TrueSTEAM
with a new one (field service is not
recommended in the event line voltage is
lost).
HVAC technician troubleshooting

Operating Manual
69-2035EFS—01 14
No. of
Red
Light
Blinks
Fault Description Auto-
Recoverable?
Steps to Fix
To be Performed by Professional HVAC
Technician Only
6 Water overflow sensed. Yes, system
will return to
“Ready” if
fault no longer
exists in 1
hour.
• Ensure drain hose is not kinked or
submerged in water at the drain. Check
functionality of condensate pump if used.
• Check for water coming out of drain/
overflow line. If continuous water flow
is present, follow the cleaning steps on
pages 7–8.
• Press EMPTY button to drain tank.
• Set humidistat RH setpoint to Test mode.
• If fault returns, unplug TrueSTEAM.
• Loosen cover screw and remove cover.
• Disconnect water level sensor wiring and
lift snap-hinge clamp to remove water
sensor assembly. See image on page 12.
• Clean probes using warm soapy water so
that the metal is exposed.
• Reassemble the sensor assembly in the
unit, reattach and secure cover.
• Plug unit in, and press RESET button.
• If fault reappears, replace water sensor
assembly and/or solenoid valve.
7 HVAC power not pres-
ent (monitor this fault
only when DIP 4 and 5
are OFF).
Yes, system
will return to
“Ready” if
fault no longer
exists in 1
hour.
• Unplug and replug the unit in to see if
power returns.
• If not, ensure HVAC equipment has power.
Check circuit breaker and replace fuse if
circuit is tripped.
• Unplug TrueSTEAM and remove cover.
• Ensure DIP 4 is ON and reattach cover.
• Plug unit in.
• If fault reappears, ensure the circuit being
used has the rating to support the unit.
Unplug any additional equipment plugged
into this circuit. If fault disappears, the
circuit capacity is not properly sized to
your unit.
• If fault returns, replace unit.
8–11 The backup weld moni-
tor input is active when
the backup heater
relay is off.
No • Replace the unit.
HVAC technician troubleshooting

TrueSTEAM Direct-Injection Humidifier
15 69-2035EFS—01
No. of
Red
Light
Blinks
Fault Description Auto-
Recoverable?
Steps to Fix
To be Performed by Professional HVAC
Technician Only
12 Temperature of the
electronic circuit board
is too high.
Yes, system
will return to
“Ready” if
fault no longer
exists in 1
hour.
• Ensure ventilation holes in the cover are
clear of obstruction, and that 1 foot of
clearance is maintained around the cover’s
vent holes.
• Ensure the TrueSTEAM is installed in a
location with conditioned air 32°F (0°C) to
104°F (40°C).
• Turn humidistat off and allow time for
electronic board to cool.
• Turn humidistat on and press RESET
button.
• Confirm humidity call starts by
HUMIDIFYING light turning on.
• Allow unit to run and check for steam leaks
around tank and ventilation holes.
• If steam is present, replace TrueSTEAM.
13 Tank failed to drain. No • Press the EMPTY button.
• If unit fails to drain, wait for water in tank
to cool. Ensure tank water is cool before
proceeding.
• Once cool, follow tank cleaning steps
(pages 7–8).
• Reassemble tank and press the RESET
button.
• If fault persists, replace the solenoid valve.
14 Heater failed to boil
water.
Yes, system
will return to
“Ready” if
fault no longer
exists in 1
hour.
• Press EMPTY button, and follow tank
cleaning steps (pages 7–8).
• Reassemble tank and press the RESET
button.
• If fault returns, replace the heating element
with the applicable wattage replacement
part.
15 No Airflow Yes • Ensure Airflow Switch is wired correctly.
The TrueSTEAM installation guide
(69-2036) contains diagrams for proper
wiring.
• Ensure DIP switches are set correctly.
• If fault persists, replace AFS and/or unit.
HVAC technician troubleshooting

Operating Manual
69-2035EFS—01 16
About your new thermostat5-year limited warranty
Honeywell warrants this product to be free from defects in the workmanship or materials, under normal use and service, for a
period of five (5) years from the date of purchase by the consumer. If at any time during the warranty period the product is deter-
mined to be defective or malfunctions, Honeywell shall repair or replace it (at Honeywell’s option).
If the product is defective,
(i) return it, with a bill of sale or other dated proof of purchase, to the place from which you purchased it; or
(ii) call Honeywell Customer Care at 1-800-468-1502. Customer Care will make the determination whether the product should be
returned to the following address: Honeywell Return Goods, Dock 4 MN10-3860, 1885 Douglas Dr. N., Golden Valley, MN 55422,
or whether a replacement product can be sent to you.
This warranty does not cover removal or reinstallation costs. This warranty shall not apply if it is shown by Honeywell that the
defect or malfunction was caused by damage which occurred while the product was in the possession of a consumer.
Honeywell’s sole responsibility shall be to repair or replace the product within the terms stated above. HONEYWELL SHALL
NOT BE LIABLE FOR ANY LOSS OR DAMAGE OF ANY KIND, INCLUDING ANY INCIDENTAL OR CONSEQUENTIAL DAMAGES
RESULTING, DIRECTLY OR INDIRECTLY, FROM ANY BREACH OF ANY WARRANTY, EXPRESS OR IMPLIED, OR ANY OTHER
FAILURE OF THIS PRODUCT. Some states do not allow the exclusion or limitation of incidental or consequential damages, so
this limitation may not apply to you.
THIS WARRANTY IS THE ONLY EXPRESS WARRANTY HONEYWELL MAKES ON THIS PRODUCT. THE DURATION OF ANY
IMPLIED WARRANTIES, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE,
IS HEREBY LIMITED TO THE FIVE-YEAR DURATION OF THIS WARRANTY. Some states do not allow limitations on how long an
implied warranty lasts, so the above limitation may not apply to you.
This warranty gives you specific legal rights, and you may have other rights which vary from state to state.
If you have any questions concerning this warranty, please write Honeywell Customer Relations, 1985 Douglas Dr, Golden
Valley, MN 55422 or call 1-800-468-1502. In Canada, write Retail Products ON15-02H, Honeywell Limited/Honeywell Limitée, 35
Dynamic Drive, Toronto, Ontario M1V4Z9.

Honeywell International Inc.
1985 Douglas Drive North
Golden Valley, MN 55422
http://yourhome.honeywell.com
Honeywell Limited-Honeywell Limitée
35 Dynamic Drive
Toronto, Ontario M1V 4Z9
® U.S. Registered Trademark.
© 2007 Honeywell International Inc.
Patents pending.
69-2035EFS—01 M.S. 08-07
Automation and Control Solutions
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