Takagi T-H1 User manual

W
ARNING
This product must be installed and
serviced by a licensed plumber, a
licensed gas fitter, or a professional
service technician and/or in accordance
with all local code. Improper installation
and/or operation, or installation by an
unqualified person, will void the warranty.
W
ARNING
Operation of this unit creates carbon
monoxide gas and flue gases which can
cause serious injury or death. In addition,
if the information in this manual is not
followed exactly, a fire or explosion may
result causing property damage, personal
injury or death.
T-H1 Instantaneous Appliance
Installation Manual and Owner’s Guide
Flash Appliance
Model T-H1
Suitable for potable water heating and space
heating
FEATURING
•ENDLESS HOT WATER
•ON DEMAND
•COMPACT, SPACE SAVING
•ENERGY CONSERVING
•COMPUTER CONTROLS
•COMPUTERIZED SAFETY
•NO PILOT LIGHT
•HIGH EFFICIENCY
Takagi Industrial Co. USA Inc.
5 Whatney
Irvine, CA 92618
Toll Free [phone] USA
Toll Free [phone] CANADA
www.Takagi.com

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CONTENTS
Specifications …………. 2
Introduction …………..3
For Your Safety …………. 3-4
T-H1 Components …………. 4
Installation …………. 5
•General …………. 5
•Accessories …………. 5
•Outdoor Installation …………. 5-6
•Indoor Installation …………. 6-7
•Venting Instructions …………..7-9
•Gas Supply / Gas Pipe size………..10-11
•Water Connections ………….11-12
•Electrical Connections ………….13
•Initial Operation ………….13
Normal Operation …………..14
•Flow …………..14
•Temperature Settings …………..15
•Freeze Protection Devices………….16
•Maintenance and Service …………..16-17
•Error Codes …………..17
Wiring Diagram …………..18
For your safety …………. 19
Danger …………. 20
Applications ………… 21
•Space Heating …………..21
•Dual-purpose heating …………..22
•Storage Tank …………..23
•Re-Circulation …………..23
Optional Items …………..24
Component Diagram …………25-28
Part List …………29-30
Output temperature Chart …………..31
SPECIFICATIONS
Natural Gas Input Min. 15,000 Btu
Max. 199,000 Btu
Propane (LP) Gas Input Min. 18,000 Btu
Max. 190,000 Btu
Gas Connection ¾” NPT
Water Connection ¾” NPT
Condensate water drain ½” NPT
Water Pressure Min. 15 psi
Max. 150 psi
Natural Gas Pressure Inlet Min. 5” WC
Max. 10.5” WC
LP Gas Pressure Inlet Min. 11” WC
Max. 14” WC
Manifold Pressure Natural 2.6” WC
Propane 2.8” WC
Weight 90 lbs.
Dimensions 29.5”x18.9”x11.8”
Ignition Electronic Ignition
Electrical Supply AC 120 V
*** NOTE ***
•Check the rating plate to ensure this
product matches your specifications;
•This appliance is certified for use at
altitudes from 0ft to 4500ft (1,370m) in
accordance to the latest CAN/CGA 2.17-
High Altitude Installation procedures at
normal manifold pressure 2.6" (Natural
Gas) W.C. Do not alter the orifice jets or
gas supply pressure. At altitudes of 4500ft
to 5,000ft (1524m) lower the manifold
pressure to 2.4 (Natural Gas) " W.C. At
5000ft to 6000ft (1,829m), lower the
manifold pressure to 2.2" (Natural Gas)
W.C. For elevations above 6000ft or for
specific instructions on how to lower the
manifold pressure, please call the Takagi
office
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs
without notice and without incurring obligations.

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INTRODUCTION
This manual provides information necessary
for the installation, operation, and maintenance
of the Model T-H1 appliance. This unit includes
a fan enabling sidewall (power) venting, an
advanced electronic ignition system and a
condensate neutralizer.
The model description is listed on the rating
plate which is attached to the front cover of the
appliance. Please read all installation
instructions completely before installing this
product. If you have any problems or
questions regarding this equipment, consult
with Takagi or its local representative.
Experiences have shown that most operating
problems are caused by improper installation.
The T-H1 Appliance is an instantaneous,
tankless appliance designed to supply endless
hot water to your entire household and/or
commercial facility utilizing total efficiency. The
principle behind the T-H1 Appliance is simple.
Once you open a hot water tap, water flows
through the T-H1 Appliance. Once a minimum
of 0.75 GPM is achieved, the flow sensor
automatically commands the computer to turn
on the fan, activate the electronic igniter and
open the gas valves. The computer monitors
water temperature, water flow rate and gas
flow to ensure that you get the right amount of
hot water at the correct hot water temperature.
After the burners are ignited, the “fire on” lamp
is lit. The computer will modulate the gas
supply valve and water flow. 0.75 gallons per
minute is required to turn the burners on; after
the burners are ignited, the flow rate can be
lowered to 0.6 gallons per minute to maintain
the appliance on. It is advisable to open further
the cold tap rather than decreasing the hot tap
to adjust the water temperature. As long as
you have water, gas and electricity, you will get
an endless flow of hot water. Open a hot water
tap to turn on your appliance. Close the tap to
turn off your appliance.
FOR YOUR SAFETY
PLEASE READ THIS MANUAL CAREFULLY
AND FOLLOW ALL DIRECTIONS.
1. Follow all local codes, or in the absence of
local codes, follow the most recent edition
of the National Fuel Gas Code, ANSI
Z223.1/NFPA 54 in the USA or the
CAN/CSA B149.1 Natural Gas and
Propane Installation Code in Canada.
2. Properly ground the unit in accordance with
all local codes or in the absence of local
codes, with the National Electrical Codes,
ANSI/NFPA 70 in the USA or CSA
standard C22.1 Canada Electrical Code
Part 1 in Canada.
3. Carefully plan where you intend to install
your T-H1 Appliance. Ensure that your
appliance will have enough combustible air
and proper ventilation and locate your
appliance where water leakage will not do
damage to surrounding areas. If there is a
possibility of water damage, install a
suitable drain pan under the unit which will
not restrict combustible airflow.
4. Check the rating plate for the correct gas
type, gas pressure, water pressure and
electrical rating. If this unit does not match
your requirements, do not install.
The installer is responsible for the correct
installation of your Flash T-H1 Appliance.
Installation and service must be performed
by a qualified installer (for example, a
licensed plumber or gas fitter) otherwise the
warranty by Takagi will be void.

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5. If any problem should occur, turn off all hot
water taps and turn off the gas. Then call a
trained technician or the Gas Company or
the manufacturer.
6. WARNING: Do not disconnect the
electrical supply if the ambient temperature
will drop below freezing. The Freeze
Prevention Device only works if the unit
has electrical power. The Freeze
Prevention Device is rated for temperatures
down to 0ºF (-18ºC) in a wind free
environment. Refer to the section on
Winterizing and the Freeze Prevention
Device for more information. The Warranty
will not be covered if the heat exchanger is
damaged due to freezing.
7. WARNING: Water temperatures over
125ºF can cause severe burns instantly or
death from scalding. The water
temperature is set at 122ºF (50ºC) from the
factory to minimize any scalding risk.
Before bathing or showering always check
the water temperature.
8. WARNING: Do not use this appliance if
any part has been in contact with or been
immersed water. Immediately call a trained
technician to inspect and/or service the unit
if necessary.
9. WARNING: Do not store or use gasoline or
other flammables, vapors or liquids in the
vicinity of this appliance.
10. WARNING: Do not reverse the water
and/or gas connections as this will damage
the gas valves and can cause severe injury
or death. Following the diagram below
when installing your appliance:
11. WARNING: When the T-H1 is operating,
the surface of the front cover can become
very hot. Please do not touch
T-H1 COMPONENTS
RATING PLATE
H
OT
GAS
COLD

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INSTALLATION
GENERAL
All gas appliances require careful and correct
installation to ensure safe and efficient
operation. This manual must be followed
exactly. Read the “For Your Safety” section at
the beginning of this manual.
1. The gas regulator is preset at the factory; it
is computer controlled and should not need
adjustment;
2. Maintain proper space for servicing. Install
the unit so that it can be connected or
removed easily;
3. The electrical connection requires a means
for switching off the power supply;
4. If you will be installing the unit in a
contaminated area with a high level of dust,
sand, flour, aerosols or other contaminants,
they can become airborne and enter and
buildup within the fan and burner causing
damage to the unit. In those environments,
please purchase the optional TK-TV07
direct vent conversion kit and convert the
T-H1 to a sealed combustion unit. The
warranty will not cover damage caused to
the unit due to installation in a
contaminated environment that has not be
converted using the TK-TV07.
5. Particles from these objects may clog the
air vent or reduce the functions of the
rotating fan and cause improper burning of
the gas. Regular maintenance is
recommended for these types of
environment.
6. Do not install the unit where the exhaust
vent is pointing into any opening in a
building or where the noise may disturb
your neighbors. Make sure the vent
termination is 4 feet from a doorway or
opening to prevent exhaust from entering.
7. A condensation drain must be connected to
the neutralizer drain plug.
8. Some chemicals used in a beauty salon
may affect the flame sensor. Appliance
may not work properly. Please consult with
Takagi, when the appliance is installed in a
beauty salon.
9. Water hardness may affect the appliance.
Appliance may be damaged. The warranty
will not cover damage caused by water
quality.
ACCESSORIES
Check that the installation manual, the
extension cable and the warranty card were
included with the unit.
OUTDOOR INSTALLATION
Follow all local codes, or in the absence of
local codes, follow the most recent edition of
the National Fuel Gas Code ANSI
Z223.1/NFPZ 54 in the USA or the CAN/CSA
B149.1 Natural gas and Propane installation
Code in Canada.
Ensure that the unit is set for outdoor
installation. The ‘OUT’ dipswitch on the
computer board should be switched to its ‘ON’
(up) position:
Outdoor dip switch setting
When installed outdoors, the T-H1 appliance
shall be wall mounted only. Locate the
appliance in an open, unroofed area and
maintain the following minimum clearances:
Outdoor Installation Service Clearances
Piping side (Bottom) 12”
Front (Maintenance space) 24”
Back of appliance 1”
Sides of appliance 2”
Top of appliance 36”

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The diagram below details the required
clearances around the unit:
WARNING: Do not install this appliance under
an overhang less than 3 feet from its top or
eaves. The area under an overhang must be
open to three sides
WARNING: Do not have the vent terminal
pointing toward any opening into a building. Do
not locate your appliance in a pit or location
where gas and water can accumulate.
WARNING: Do not install the appliance where
water, debris or flammable vapors may get into
the flue terminal. This may cause damage to
the appliance and void the warranty.
WARNING: Do not install the appliance vent
terminator within 4 feet in the USA of any air
intake or building opening, and with in 3 feet in
Canada of any air intake or building opening.
(Refer to Page.9)
INDOOR INSTALLATION
When installed indoors, the T-H1 appliance
shall be located in an area to maintain the
following minimum clearances around the unit:
Indoor Installation Service Clearances
Piping side (Bottom) 12”
Front (Maintenance space) 24”
Back of appliance 1”
Sides of appliance 2”
Top of appliance 12"
Combustion Air Supply
The appliance location must provide enough
air for proper combustion and ventilation of the
surrounding area. See the latest edition of
ANSI Standard Z223.1 or any applicable local
codes. In general, these requirements specify
that if the unit is installed in a confined space,
there must be a permanent air supply opening.
Air Supply from Outside Building
When combustion air is supplied from outside
the building, an opening communicating
directly with the outside should have a
minimum free area of one square inch per
15,000 BTU/H input of the total input rating of
appliance in the enclosed area.
Air Supply from Inside Building
When combustion air is supplied from inside
the building, an opening communicating with
the rest of the dwelling should have a minimum
free area of one square inch per 1000 BTU/H
input of the total input rating of appliance in the
enclosed area. These openings should never
be less than 100 sq. in.
Minimum recommended air supply opening size
for appliance:
Appliance
size
When drawing
make-up air
from outside
the building
When drawing make-up
air from inside the
building (from other
rooms within)
Max. 199,000
BTU/H
13.5 square
inches
199 square inches

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Combustible Air Supplied by Mechanical
fan or Make up air device.
The T-H1 appliance is equipped with a
combustible air sensor that will shut off the unit
when inadequate combustible air supply to unit
is detected.
If a mechanical fan or make up air device is
used to supply air to the appliance or utility
room, the installer should make sure it does
not create drafts which could cause nuisance
shutdowns. If a blower is necessary to provide
adequate combustion air to the appliance, a
switch or equivalent device must be wired
(interlocked) with the appliance control circuit
or other proper devices to prevent the
appliance from firing unless the blower is
operating.
Direct intake vent system
This T-H1 appliance may be converted to a
direct vent (sealed combustion) appliance by
installing an adapter (part No TK-TV07) which
will bring all required combustible air from
outside the building. The T-H1 must be
installed in a location where the proper amount
of combustible air will be available to it at all
times without obstructions. If used as a direct
vent appliance, the T-H1 requires a 3”
combustible air supply pipe. The intake pipe
must be sealed airtight with aluminum tape and
can be made of ABS, galvanized steel,
corrugated aluminum, corrugated stainless
steel or Category III stainless steel.
Ensure that the unit is set for direct vent and
indoor installation. The ‘DIRE’ dipswitch on the
computer board should be switched to its ‘ON’
(up) position and the ‘OUT’ dipswitch should
be switched to its ‘OFF’ (down) position:
Direct vent dip switch settings
VENTING INSTRUCTIONS
General
WARNING: Improper venting of this appliance
can result in excessive levels of carbon
monoxide which can result in severe personal
injury or death.
This appliance must be vented in accordance
with the section “Venting of Equipment" of the
latest edition of the Natural Fuel Gas Code,
ANSI Z223.1 and all applicable local building
codes. In Canada, follow section 7 of the
CAN/CSA B149.1 Natural Gas and Propane
Installation Code.
Exhaust Vent
This is a Category III appliance and must be
vented accordingly. The vent system must be
sealed air tight. All seams and joints must be
sealed with high heat resistant silicone sealant
or UL listed aluminum adhesive tape having a
minimum temperature rating of 350ºF. For best
results, a vent system should be as short and
straight as possible.
This unit requires 4”, Category III approved,
single wall stainless steel vent pipe or any
other Category III approved, non-combustible,
corrosion-resistant material. The following are
UL listed manufacturers: ProTech Systems Inc.
(FasNSeal), Flex-L Inc., Z-Flex Inc. (Z-Vent III)
and Heat-Fab Inc. (Saf-T Vent). Follow the
vent pipe manufacturer’s instructions when
installing the vent pipe. Do not common vent
this appliance with any other vented appliance.
The maximum length of exhaust vent piping
must not exceed 50 ft. deducting 5 ft. for each
elbow used in the venting system. Do not use
more than 5 elbows.
Pipe
Diam
eter
Max. #
of
Elbows
Maximum Vertical or
Horizontal Vent Length
4” 5 50 ft
For each elbow added, deduct 5 ft. from
maximum vent length:
# of Elbows Max. Vertical or
Horizontal Length
0 50 ft.
1 45 ft.
2 40 ft.
5 25 ft.
4” exhaust3” intake

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When installing the vent system, all applicable
national and local codes must be followed. If
you install thimbles, fire stops or other
protective devices and they penetrate any
combustible or noncombustible construction,
be sure to follow all applicable national and
local codes.
When the horizontal vent run exceeds 5 ft., the
following criteria must be observed:
•Support the vent run at 3 ft intervals with
overhead hangers.
•Slope the vent run downwards toward the
vent terminal at a rate of ¼” per foot.
Vent Termination
A sidewall vent terminator must be used when
the appliance is vented through a sidewall.
Takagi recommends the use of its part No.TK-
TV01 or the TK-TV05 with the TK-TV07 when
using the direct vent option. The vent
terminator provides a means of installing vent
pipe through the building wall and must be
located in accordance with ANSI Z223.1/NFPA
54, or in Canada with CAN/CSA-B149.1 and
local applicable codes.
Locate the vent terminator so that it cannot be
blocked by snow. Most codes require that the
terminator be at least 12 inches above grade,
but the installer may determine if it should be
higher depending on the job site condition and
applicable codes.
WARNING: Improper installation can cause
nausea or asphyxiation, severe injury or death
from carbon monoxide and flue gases
poisoning. Improper installation will void
product warranty. For high altitude installation
above 4,500 feet, contact Takagi on how to
handle this situation.
General rules for venting the T-H1 appliance
are:
1. Place the appliance as close as possible
to the vent terminator;
2. The vent collar of the appliance must be
fastened directly to an unobstructed vent
pipe.
3. Do not weld the vent pipe to the appliance
collar.
4. The weight of the vent stack must not rest
on the appliance.
5. The vent must be easily removable from
the top of the appliance for normal service
and inspection of the unit.
6. The appliance vent must not be connected
to any other gas appliance or vent stack.
7. Avoid locating the appliance vent
terminator near any air intake devices or
air-conditioning units. These fans can pick
up the exhaust flue products from the
appliance and return them to the building.
This can create a health hazard.
8. Avoid using an oversized vent pipe or
using extremely long runs of the pipe.
Rain ca
p
Roof
Flashing
Condensation drain
(Install according to
local code)
TK-TV03 (Back flow
prevention)
zRegarding the clearance from the
terminator to the air inlet or opening,
refer to the next page.
zInstall a condensation drain in the
venting.
zFollow the vent system to vent
manufacture’s instruction and local
code.
zDo not common vent or connect any
vent of appliance to the vent.
zUse the 4” category III Vent pipe
approved, single wall stainless steel
vent pipe.
The exhaust
goes to the roof

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Canada U.S.A
Direct vent and
other than Direct Vent Direct vent Other than Direct Vent
A Clearance above grade, veranda, porch,
deck, or balcony. 1 foot 1 foot 1 foot
B Clearance to window or door that may be
opened. 3 feet 1 foot
4 feet from below or
side opening. 1 foot
from above opening.
C Clearance to permanently closed window * * *
D
Vertical clearance to ventilated soffit located
above the vent terminator within a horizontal
distance of 2 feet (61cm) from the center
line of the terminator.
* * *
E Clearance to unventilated soffit * * *
F Clearance to outside corner * * *
G Clearance to inside corner * * *
H Clearance to each side of center line
extended above meter/regulator assembly 3 feet * *
I Clearance to service regulator vent outlet. 3 feet * *
J
Clearance to non-mechanical air supply inlet
to building or the combustion air inlet to any
other application.
3 feet 1 foot
4 feet from below or
side opening. 1 foot
from above opening.
K Clearance to mechanical air supply inlet. 6 feet 3 feet 3 feet
L Clearance above paved sidewalk or paved
driveway located on public property. 7 feet * 7 feet
M Clearance under veranda, porch deck, or
balcony. 1 foot * *
*For clearances not specified in ANSI Z223.1 / NFPA 54 or CAN/CSA-B149.1, please use clearances in
accordance with local installation codes and the requirement of the gas supplier.

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GAS S SIZING
Check that the type of gas matches the rating
plate located on the cover of your appliance.
The minimum and maximum inlet gas pressures
are:
Natural Gas Min. 5” WC - Max. 10.5” WC
Propane Gas Min. 11” WC - Max. 14” WC
Gas pressure below this specified range for the
T-H1 and/or insufficient gas volume will adversely
affect performance. Inlet gas pressure must not
exceed the above maximum values; gas pressure
above the specified range will cause dangerous
operating conditions and damage to the unit. Until
testing of the main gas line supply pressure is
completed, ensure the gas line to the T-H1 is
disconnected to avoid any damage to the
appliance.
Size the gas pipe appropriately to supply the
necessary volume of gas required for the T-H1
(NG 199,000 BTU/H; LPG 190,000 BTU/H) using
ANSI233.1/NAPA 54 in the USA or CAN/CSA
B149.1 in Canada or local codes. Install a manual
gas shut-off valve between the T-H1 and the gas
supply line. When the gas connections are
completed, it is necessary to perform a gas leak
test either by applying soapy water to all gas
fittings and observing for bubbles or by using a
gas leak detection device. Always purge the gas
line of any debris before connecting to the
appliance gas inlet.
Pipe Sizing Example: This table below is for
Natural gas piping supply straight to the
appliance without any tabs to other gas
appliances
Recommended Gas Pipe Size for
T-H1 Appliance (Example for NG)
Distance from Gas Meter Pipe Size (inches)
0' - 20' 3/4"
30' - 80' 1"
90' – 200’ 1-1/4"
1. Turn off all electric power to the
appliance if service is to be
performed.
2. Turn the manual gas valve located
on the outside of the unit clockwise
3to the off position.
A. This appliance does not have a
pilot. It is equipped with an
electronic ignition device that
automatically lights the burner. Do
not try to light the burner manually;
B. BEFORE OPERATING, check all
around the appliance area for gas
leaks. Be sure to check next to the
floor as some gases are heavier
than air and will settle on the floor;
C. Use only your hand to turn the gas
valve knob. Never use tools. If the
knob will not turn by hand, do not
attempt to repair it. Call a qualified
service technician. Force or
attempted repair may result in a fire
or explosion.
D. WARNING: Conversion of this unit
from natural gas to propane or
propane to natural gas cannot be
done in the field. Contact your local
distributor to get the correct unit for
your gas type. Conversion done by
anyone other than the
manufacturer will void all warranty.
TO TURN OFF GAS TO
APPLIANCE
FOR YOUR SAFETY, READ
BEFORE OPERATING:

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Natural Gas Supply Piping
Maximum Capacity of Natural Gas Based on a 0.60 specific gravity at a 0.5” WC pressure drop
Pipe Size kBTU of Natural Gas
Length 10’ 20’ 30’ 40’ 50’ 60’ 70’ 80’ 90’ 100’ 125’ 150’ 200’
¾” 372 255 205 175 156 142 130 121 114 107 95 86 74
1” 702 482 387 331 293 266 245 228 213 202 179 162 139
1 ¼” 1441 990 795 680 603 546 503 468 439 415 367 332 285
1 ½” 2158 1483 1191 1019 903 819 753 701 658 621 550 499 427
2” 4155 2856 2293 1963 1740 1576 1450 1349 1266 1195 1060 960 822
Propane (LP) Gas Supply Piping
Maximum Capacity of Propane (LP) Gas Based on 11” WC supply pressure at a 1.0” WC pressure drop
Pipe Size kBTU of Propane
Length 10’ 20’ 30’ 40’ 50’ 60’ 70’ 80’ 90’ 100’ 125’ 150’ 200’
¾” 567 393 315 267 237 217 196 185 173 162 146 132 112
1” 1071 732 590 504 448 409 378 346 322 307 275 252 213
1 ¼” 2205 1496 1212 1039 913 834 771 724 677 630 567 511 440
1 ½” 3307 2299 1858 1559 1417 1275 1181 1086 1023 976 866 787 675
2” 6221 4331 3465 2992 2646 2394 2205 2047 1921 1811 1606 1496 1260
WATER CONNECTIONS
All pipes, pipe fittings, valves and other
components, including soldering materials,
must be suitable for potable water systems. A
manual shut off valve must be installed on the
cold water inlet to the appliance between the
main water supply line and the T-H1. In
addition, a manual shut off valve is also
recommended on the hot water outlet of the
unit. If the T-H1 is installed within, or subjected
to, a closed loop water system, such as one
having an anti-backflow device in the cold
water supply line, a thermal expansion tank
must be installed. Contact the water supplier or
local plumbing inspector on how to control this
situation.
After installation of the appliance is complete,
purge the water line to remove all the debris
and air from the line. Failure to do so may
cause damage to the appliance. There is a
wire mesh filter within the cold inlet to trap
debris from entering your appliance. This will
need to be cleaned periodically to maintain
optimum flow.
Unit Draining & Filter Cleaning Procedures
To drain your unit, please follow these
instructions carefully:
1. Turn off the power supply to the T-H1
Appliance.
2. Close the manual gas shut off valve
located on the gas supply line.
3. Close the manual water shut off valve
located on the water supply line.
4. Open all hot water taps in the house.
(Bathroom, kitchen, laundry room, etc.).
When the residual water flow has ceased,
close all hot water taps.
5. Have a bucket or pan to catch the water
from the unit’s drain plugs. Remove the
drain plugs to drain all the water out of the
unit.
6. Wait a few minutes to ensure all water has
drained from unit.
7. At this time, please check the water filter
located within the cold inlet. With a tiny
brush, clean the water filter of any debris
which may have accumulated and reinsert
the filter back into the cold water inlet.
8. Securely screw the drain plugs back into
place. Hand- tighten only
Do not use this appliance if any part has
been submersed under water.
Immediately call a qualified service
technician to inspect the appliance and to
replace any damaged parts.
FOR YOUR SAFETY, READ
BEFORE OPERATING:

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To re-start your appliance, follow these
steps:
1. Make sure all hot water taps are closed
and the drain plugs are securely attached.
2. Purge the water line of debris.
3. Open the manual water shut-off valve
located on the water supply line.
4. Open all the hot water taps to verify water
flows to the taps. Then close the hot water
taps.
5. Open the manual gas shut-off valve located
on the gas supply line.
6. Turn on the power supply to the T-H1
Appliance.
Note: Do not reverse the hot outlet and cold
inlet connections to the T-H1 Appliance. This
will not activate the appliance.
Pressure Relief Valve
The FLASH T-H1 has a high-temperature shut
off switch built in as a standard safety feature
(called a Hi-Limit switch) therefore a “pressure
only” relief valve is required.
This unit does not come with an approved
pressure relief valve. An approved pressure
relief valve must be installed on the hot water
outlet. The pressure relief valve must conform
to ANSI Z21.22 or CAN 1-4.4 and installation
must follow local code.
The discharge capacity must be at least
199,000 BTU/H. The discharge piping for the
pressure relief valve must be directed so that
the hot water cannot splash on anyone or on
nearby equipment. Attach the discharge tube
to the pressure relief valve and run the end of
the tube to within 6" from the floor. This
discharge tube must allow free and complete
drainage without any restrictions.
If the pressure relief valve installed on the T-
H1 discharges periodically, this may be due to
a defective thermal expansion tank or defective
pressure relief valve.
The pressure relief valve must be manually
operated periodically to check for correct
operation.
Condensate Drain
The T-H1 has a built-in condensed water
neutralizer cartridge that reduces the pH level
of any condensed water. Follow the code
requirements of the local authority having
jurisdiction regarding the disposal of
neutralized condensate. In the absence of
such regulations, Takagi suggests the
neutralized condensate can be disposed of into
a standard drain. Connect a drain tube from
the condensate water drain port (depicted
below) located on the underside of the unit to a
standard drain.
COLDHOT GAS
H
OT
GAS
COLD
H
OT
GAS
COLD Condensate
water drain

- 13 -
ELECTRICAL CONNECTIONS
WARNING: Follow the electrical code
requirements of the local authority having
jurisdiction. In the absence of such
requirements, follow the latest edition of the
National Electrical Code ANSI/NFPA 70 in the
U.S. or the latest edition of CSA C22.1
Canadian Electrical Code, Part 1, in Canada.
The appliance must be electrically grounded.
Do not attach the ground wire to either the gas
or the water piping. Plastic pipe or dielectric
unions may isolate the appliance electrically.
CAUTION: When servicing or replacing parts
within the T-H1, label all wires prior to
disconnection to facilitate an easy and error
free reconnection. Wiring errors can cause
improper and dangerous operation. Verify
proper operation after servicing.
The FLASH T-H1 appliance requires AC 120V
60 Hz electrical power supply that is properly
grounded.
•An on/off switch controlling the main power
to the TH-1 must be provided for service
reasons;
•Connect the power supply to the TH-1
exactly as shown in the wiring diagram;
•A green screw is provided in the junction
box to ground the connection.
Wiring diagrams are also located on the
inside panel of the appliance.
INITIAL OPERATION
For your safety please read before
operating the unit for the first time.
Once you have properly installed the unit and
before firing it for the first time, check the gas
and water connections for leaks. Open the
main gas supply valve to the unit using only
your hand to avoid any spark. Never use tools.
If the knob will not turn by hand, do not try to
force it; call a qualified service technician.
Force or attempted repair may result in a fire or
explosion due to gas leaks. Be sure to check
next to the bottom of the unit because some
gases are heavier than air and may settle
towards the floor.
CAUTION: IF YOU SMELL GAS:
1. Do not try to start the appliance.
2. Do not touch any electric switch; do not
use any phone in your building.
3. Immediately call your gas supplier from
a neighbor’s phone. Follow the gas
supplier’s instructions.
4. If you cannot reach your gas supplier,
call the fire department.
This appliance does not have a pilot light. It is
equipped with an electronic ignition device
which automatically lights the burner. Do not
try to light the burner manually. Check for
proper venting and combustible air to the
appliance. Purge the gas and water lines to
remove any air pocket. Do not use this
appliance if any part has been submersed
under water. Immediately call a qualified
service technician to inspect the appliance and
to replace any parts that have been under
water.
Once the above checks have been completed,
follow these steps to turn on your unit:
1. Close the manual gas control valve located
on the gas line.
2. Fully open the manual water control valve
on the water supply line.
3. Open a hot water tap to verify that water is
flowing to that tap. Then close the hot
water tap.
4. Fully open the manual gas control valve
installed.
5. Turn on the 120 volt 60 Hz power supply to
the FLASH T-H1 appliance.

- 14 -
6. Now you are ready to enjoy hours of
endless hot water.
NORMAL OPERATION
To turn on your T-H1 appliance:
1. Open a hot water tap.
2. The burner ignites. The “Fire On” lamp
lights.
3. Mix cold water with the hot to get the
correct temperature water.
To turn off your T-H1 appliance:
1. Close the hot water tap
“Fire On” lamp extinguishes.
FLOW
The flow rate through the FLASH T-H1 is
limited to a maximum of 10.2 GPM. The
temperature setting, along with the supply
temperature of the water will determine the
flow rate output of the unit. Please refer to the
temperature/gallons per minute chart at the
back of this manual to determine the likely flow
rates based on your local ground water
temperature and your desired outlet water
temperature combination.
Based on the United States Department of
Energy method of testing appliance output, the
T-H1 is rated for 285 gallons per hour (GPH),
or 4.8 gallons per minute (GPM), when raising
the water temperature by 77°F (for example
from 43°F to 120°F). Refer to the following
chart of typical household plumbing fixture flow
rates to determine what the FLASH T-H1 can
do in a household application.
Household Flow Rates
Appliance / Use Flow Rate
(GPM)
Lavatory Faucet 1.0
Bath Tub 4.0
Shower 2.0
Kitchen Sink 1.5
Dishwasher 1.5
Washing Machine 2.0
Taken from UPC 1997
W
ARNIN
G
Hot Appliance temperatures over 125°F
can cause severe burns instantly or death
from scalding. The outlet hot water
temperature of the FLASH T-H1 appliance
is factory set at 122°F. Feel the water
temperature before bathing or showering.
Do not leave children, the disabled or the
elderly unattended as they are at the
highest risk of being scalded.
Temperature limiting valves are available,
ask professional person.

- 15 -
TEMPERATURE SETTINGS
There are 4 preset temperatures that you can
select from by adjusting the dipswitch settings
on the computer board. The temperature has
been preset at the factory to122ºF (50ºC). The
computer will electronically control this
temperature. At a fixture, mix cold water with
hot to get the water temperature you desire. If
you desire a hot water temperature other than
the 4 preset settings, please purchase the
optional temperature remote controller (part
No. TM-RE10). With this optional TM-RE10
you can set the temperature from 99ºF to
182ºF. Please carefully read the instructions
prior to installing the TM-RE10 as failure to do
so could damage the temperature controller
and/or the appliance, which will void the
warranty.
Hot Water Output Temperature Setting:
With the FLASH T-H1 Appliance, the output
hot water temperature can be adjusted either
manually from the main computer board’s
dipswitches or with the optional remote
controller (Part TM-RE10, from 99°F to 182°F).
The dipswitches can set four hot water output
temperatures 113°F, 122°F, 140°F, and 182°F
(the factory set temperature is 122°F).
Temperature setting
Only change black switches. Do not adjust any another switches.
Installation setting
Only change black switches. Do not adjust any another switches..

- 16 -
FREEZE PROCTECTION DEVICES
This unit comes equipped with heating blocks
and automatic ‘no-flow’ burning to prevent
freezing which can damage the heat
exchanger. For this freeze prevention system
to operate, there has to be electrical power to
the unit. The freeze prevention devices will
not work if the electrical power source is
disconnected. Even if TM-RE10 in “off”
mode, it will be switched to “on”
automatically to prevent the heat exchanger
from freezing. Damage to the heat exchanger
caused by freezing temperatures due to power
loss is not covered under the warranty.
The unit has been rated for temperatures down
to 0ºF (-18ºC) in a wind free environment. If
you install the appliance in an area that is
subject to temperatures (including wind chill)
below 0ºF (-18ºC), this will void the warranty
and Takagi will not be responsible for any
damage to the heat exchanger as a result of
freezing. In any areas subject to freezing
temperatures, Takagi strongly recommends
the use of its back flow prevention flue damper
(Part No. TK-TV03) to reduce the amount of
cold air entering through the exhaust venting
when the appliance is off.
If you will not be using your appliance for a
long period of time or if the temperatures
(including the wind chill) will drop below 0ºF (-
18ºC), turn off your appliance and drain the
unit of water (see ‘Unit Draining & Filter
Cleaning’ section above for draining
instructions). This will keep your unit from
freezing and being damaged.
For indoor installation in areas where the
temperature will be well below freezing for
extended periods of time, use the included
“Extension cable” to relocate the internal
thermostat located on the cabinet to the
outdoors. This will sense the ambient air
temperature and turn on the internal
appliance blocks on to prevent the heat
exchanger from freezing.
CAUTION: Only the pipes within the appliance
are protected by the anti-freeze devices on the
T-H1. Any hot or cold water pipes located
outside of the unit will not be protected.
Properly protect and insulate these pipes from
freezing.
MAINTENANCE AND SERVICE
WARNING: Turn off the electrical power
supply and close the manual gas control
valve and the manual water control valve
before servicing.
Do this immediately after installation.
1. Clean the cold-water inlet filter (figure
below).
2. Be sure that all openings for combustion
and ventilation air are not blocked.
3. Check that the exhaust vent pipe is not
blocked.
4. Check the gas pressure.
5. Keep the area around the appliance clear.
Remove any combustible materials,
gasoline or any flammable vapors and
liquids.
The unit should be checked once a year or as
necessary by a licensed technician. If repairs
are needed, any repairs should be done by a
licensed technician.
The following systems and parts should be
checked at least once a year:
1. Venting system
2. Burner
3. Manual operation of the pressure relief
valve to ensure correct operation.
4. Periodic cleaning of the water filter (figure
above).
5. Heat exchanger. Remove the thermistor
and check for a mineral coating. A mineral
coating on the thermistor requires flushing
the heat exchanger with a de-scaling
solution. Scale build up will void your

- 17 -
warranty and shorten the life of your
appliance.
Common Trouble Shooting
The T-H1 can burn gas at a maximum input
rate of 199,000 BTU/H. This puts a limit on the
possible output temperature and flow
capabilities. If the water doesn’t seem hot
enough, compare the flow and temperature
that is being attained to the T-H1 flow vs.
temperature chart (See flow chart on the last
page of this manual). If the unit is not
performing according to the chart, first check
that the gas supply pipe is sized properly and
that the gas pressure is within the required
range. If the gas line is sized properly, check
the plumbing for mixing valves, thermostatic
valves, anti-scald devices, single handled
faucets with built in temperature or pressure
compensators valves and hot and cold crossed
connections. If the unit is performing in
accordance with the flow chart, it may be
undersized for the application. If the unit is
performing according to the chart, the output
temperature can be adjusted using the TM-
RE10 or the dipswitches on the unit.
It Takes Too Long to Get Hot Water
The T-H1 takes three seconds to ignite and
three more seconds to heat the incoming
ground water up to the set temperature. The
time it takes to deliver hot water from the T-H1
to your fixtures depends on the length of piping
between the two. The longer the distance, the
more time it will take. If you would like to
receive hot water to your fixtures quicker, you
may want to consider a hot water recirculation
system.
The T-H1 Will Not Initiate
First check the flow rate through the unit. If the
flow is less than .75 GPM, the unit will not
initiate. Check the filter for any debris or
damage. If you have installed a combination
system (a T-H1 doing both domestic hot water
and space heating), completely isolate the
heating system temporarily to ensure flow is
not backfeeding through your heating system
to supply the domestic water (by-passing the
T-H1).
If neither of those remedies start the unit, press
the lower grey button marked “test (off)” on the
GFCI inside the unit. If the red light above it
does not come on, there is a problem with the
electrical supply to the unit. If that red light
does come on, hit the “reset (on)” button and
open a hot water faucet to re-try the unit. If the
problem persists, contact Takagi for
instructions.
ERROR CODES
All Takagi units are self diagnostic for safety
and convenience when trouble shooting. If
there is a problem with the installation or the
unit, it will display a numerical error code on
the TM-RE10 (if installed) or at the bottom left
corner of the computer board to communicate
the source of the problem. Consult the
following chart for the cause of an error code:
The T-H1 consists of five major control
operations: Temperature control, Gas control,
Water control, Burner Control, and Main
computer control.
ERROR CODE CHART:
Error Symptom Error Symptom Error Symptom
031 Wrong Gas Type 391 Abnormal Thermocouple 741 Main remote control Trouble
101 Insufficient Gas Supply 510 Abnormal Main Gas Valve
111 Ignition failure 611 Abnormal Fan Motor 751 Temperature Remote
control Trouble
121 Flame Loss 651 Abnormal Bypass Valve 761 Multi-system Controller
211 Vent Pipe Obstruction 661 Abnormal Output Adjustment Valve
311 Output Thermistor Failure 701 Abnormal Mixing Thermistor 921
Neutralizer ‘Replacement
Needed’ warning
321 Inlet Thermistor Failure 711 Abnormal Gas Solenoid Valve 931 Neutralizer error
331 Mixing Thermistor Failure 721 Computer Pre / Post Check Problem 991 Abnormal Burning
Error Code as
Three digit Numeric
numbers

- 18 -
Wiring Diagram A wiring diagram is located on the inside front panel of the appliance. Electrical Rating: 120 VAC, 60 Hz, 0.8 A. Note: If any of the original wiring supplied with this appliance must be replaced, it must be replaced with appliance wiring material (180c)
or its equivalent. Replacement wires are available through Takagi.

- 19 -
OPERATING INSTRUCTIONS
1. STOP! Read the safety information above or in the Owners Manual.
2. Turn off all electric power to the appliance.
3. Do not attempt to light the burner by hand.
4. Turn the gas manual gas valve located on the outside of the unit clockwise ↻to the
off position.
5. Wait five (5) minutes to clear out any gas. If you then smell gas. STOP! Follow "B"
in the safety information above on this label. If you don't smell gas, go to next step.
6. Turn the manual gas valve located on the outside of the unit counter clockwise ↺
to the ON position.
7. Turn on all electrical power to the appliance.
8. If the appliance will not operate, follow the instructions “to Turn Off Gas to
appliance" and Call your service technician or gas supplier.
FOR YOUR SAFETY READ BEFORE OPERATING
WARNING: If you do not follow these instructions exactly, a fire or
explosion may result causing property damage, personal injury or loss of
life.
A. This appliance does not have a pilot. It is equipped with an ignition device that
automatically lights the burner. Do not try to light the burner by hand.
B. BEFORE OPERATING smell all around the appliance area for evidence of leaking
gas. Be sure to smell next to the floor because some gas is heavier than air and will
settle on the floor.
WHAT TO DO IF YOU SMELL GAS.
•Do not try to light any appliance.
•Do not touch any electric switch, do not use any phone in your building
•Immediately call your gas supplier from a neighbor's phone. Follow the gas
supplier's instructions.
•If you cannot reach your gas supplier, call the fire department.
C. Use only your hand to turn the gas valve knob. Never use tools. If the knob will not
turn by hand, don't try to repair it. Call a qualified service technician. Force or
attempted repair may result in a fire of explosion.
D. Do not use this appliance if any part has been under water. Immediately call a
qualified service technician to inspect the appliance and to replace any damaged
parts.
TO TURN OFF GAS TO APPLIANCE
1. Turn off all electric power to the appliance if service is to be performed.
2. Turn the manual gas valve located on the outside of the unit clockwise ↻to the off
position.

- 20 -
Vapors from flammable liquids will explode and catch fire causing death or severe burns.
Do not use or store flammable products such as gasoline, solvents or adhesives in the
same room or area near the appliance.
WARNING: Do not install water heater where flammable products will be stored.
Read and follow water heater warnings and instructions. If owner's manual is
missing, contact the retailer or manufacturer.
W
ARNING
The outlet hot water temperature of the T-H1 appliance is factory set at 122 °F.
WARNING: Use this appliance at your own risk. The set outlet water temperature can
cause severe burns instantly or death from scalds. Test the water before bathing or
showering. Do not leave children or the infirm without supervised.
DANGER
Hot Appliance temperature over 125 °F can cause severe
burns instantly or death from scalding.
Children, disabled and elderly are at the highest risk of
being scalded. Feel water temperature before bathing or
showering. Temperature limiting valves are available, ask
p
rofessional
p
erson.
DANGER
Keep flammable products:
1. Far away from appliance.
2. In approved containers.
3. Tightly closed
4. Out of children's reach
Vapors:
1. Cannot be seen
2. Vapors are heavier than air
3. Go a long way on the floor
4. Can be carried from other rooms
to the main burner b
y
air currents.
WARNING: California Proposition 65 lists chemical substances known to the state to
cause cancer, birth defects, death, serious illness or other reproductive harm. This product
may contain such substances, be their origin from fuel combustion (gas, oil) or
components of the product itself.