Takagi T-K1 User manual

T-K1 Instantaneous Water Heater
Installation Manual and Owner’s Guide
Flash Water Heater
Model T-K1
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
Takagi Industrial Co. USA Inc.
3-B Goodyear
Irvine, CA 92618
Toll Free [phone]
www.takagi-usa.com
FOR YOUR SAFETY
This product must be installed by a
professional service technician, licensed
person or gas fitter qualified in water
heater installation, when installed in the
Commonwealth of Massachusetts and/or
any state.
Warning
Operation creates carbon monoxide gas
and flue gases, which can cause serious
injury or death. Improper installation
and/or operation, or installation by an
un
q
ualified
p
erson
,
will void warrant
y
.
ng.
WARNING:
If the information in this manual is not
followed exactly, a fire or explosion may
result, causing property damage,
personal injury or death.
• Do not store or use gasoline or other
flammable vapors or liquids in the
vicinity of this or any other appliance.
• WHAT TO DO IF YOU SMELL
GAS
• Do not use any appliance.
• Do not touch any electrical
switch, do not use any phone in
your buildi
• Immediately contact your gas
supplier from another location.
Follow the gas supplier’s
instructions.
• If you cannot reach your gas
supplier, call the fire department.
• Installation and service must be
performed by a qualified installer,
service agency or the gas supplier.

Table of Contents
Specifications…………………………….. 1
For Your Safety…………………………... 2
Operation…………………………………. 3
General…………………………… 3
Turning It On……………………… 3
Turning It Off……………………… 3
Temperature……………………… 3
Flow……………………………….. 4
Freeze Protection………………... 4
Installation………………………………… 5
General…………………………… 5
Accessories………………………. 5
Electrical Connections…………... 5
Wiring Diagram…………………... 6
Gas Supply Piping………………. 7
Water Plumbing………………….. 8
Pressure Relief Valve……………. 8
Wall Hanging Installation………... 9
Standing Installation……………... 9
Outdoor Installation……………… 9-10
Indoor Installation………………... 10-11
Combustible Air Supply…. 10
Exhaust Venting…………. 11
Manufactured Home (Mobile Home)
Installation………………………….11
Indoor……………………… 11
Outdoor……………………. 11
Initiating the Appliance…………... 12
Initial Operation…………………... 12
Space Heating Application………. 13
Dual Purpose Heating 14
Applications………………………. 15
Storage Tank……………... 15
Recirculation……………… 15
Maintenance……………………………… 18
Before Operating 16
Danger 17
Maintenance 18
Troubleshooting………………………….. 18-19
Optional Items……………………………. 20
TK-RE01………………………….. 20
TK-BK01………………………….. 20
TK-TV01…………………………... 20
TK-TV03…………………………... 20
Exploded Diagram……………………….. 21
Parts List………………………………….. 22
Flow Charts……………………………….. 23
Specifications
Natural Gas Input Min. 37,000 Btu
Max. 165,000 Btu
LPG Input Min. 35,000 Btu
Max. 165,000 Btu
Gas Connection ¾” NPT
Water Connections ¾” 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 3.5” WC
Propane 4.0” WC
Weight 60 lbs.
Dimensions 24.5”x16.5”x8.3”
Ignition Electronic Ignition
Electrical Supply AC 120 V
***
• Inlet gas pressure must not exceed the above
maximum values.
• For gas pressures lower than 5” WC for natural
gas, call the manufacturer.
• Before installing in areas over 4,500 feet above
sea level, contact the manufacturer for high
altitude adjustment instructions.
• Check the rating plate to insure this product
matches your specifications.
• Takagi - USA is constantly improving our
products, therefore specifications are subject
to change without prior notice.
1

For Your Safety
PLEASE READ THIS MANUAL CAREFULLY
AND FOLLOW IT EXACTLY FOR YOUR
SAFETY.
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 USA or the CGA standard,
CAN/CGA B149.1 or .2 Installation Codes for
Gas Burning Appliances 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 to install your Flash
Water Heater. Insure that your heater will have
enough combustible air, proper ventilation, and
locate your heater 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. Do not install this unit if these
requirements can’t be met.
5. If a problem should occur, turn off all hot water
taps and turn off the gas. Call a trained
technician, the Gas Company, or the
manufacturer.
WARNING: Do not disconnect the electrical supply
if the temperatures will be near freezing. The
Freeze Prevention Device will only work if the unit
has proper electrical power. The Freeze
Prevention Device is rated for temperatures down
to 5º F (-15º C) in a wind free environment. The
wind chill factor will cause the Flash Water Heater
to freeze and be damaged at temperatures above
5º F (-15º C). Refer to the sections on Winterizing
and the Freeze Prevention Device for more
information.
6. WARNING: Before bathing or showering
always check the water temperature. Do not
leave children or the infirm unsupervised in the
shower or bath. The water temperature is set
at 120º F (50º C) from the factory to maximize
the amount of hot water you can use. Water
temperature over 125º F can cause severe
burns instantly or death from scalds.
7. WARNING: Do not use this appliance if any
part has been underwater. Immediately call a
certified and trained technician to inspect and
service the unit if necessary.
8. WARNING: Do not store or use gasoline or
other flammable vapors or liquids in the vicinity
of this or any other appliance.
9. WARNING: Do not reverse the water and gas
connections, this will damage your heater and
can cause severe injury or death from scalds.
Follow the diagram below when installing your
Flash water heater.
Rating plate
2

Operation
General
The Flash Water Heater is an instantaneous,
tankless water heater designed to efficiently supply
domestic or commercial hot water. The principle
behind the Flash water heater is simple: Once a
hot water tap is opened, the Flash’s flow sensor
detects that hot water is needed, and automatically
commands the computer to electronically ignite the
burners, and heat water.
During operation, the computer monitors the water
temperature and flow rate, and controls the gas
flow and fan speed to maintain a constant output
temperature. After the burners are ignited the “fire
on” lamp will be lit.
A minimum of 0.75 gallons per minute is required
to turn the burners on, but after the burners are
ignited, the flow rate can drop to 0.6 gallons per
minute without the burners turning off.
As long as water, gas and electricity are connected,
there will be an endless flow of hot water. To turn
on your water heater, just open a tap. To turn the
heater off, just close the tap.
Turning It On
To turn on the Flash water heater
1. Open a hot water tap, or turn on water
demanding appliance.
2. Unit will detect flow, burners will ignite, “Fire
On” lamp will light up.
3. If necessary, mix in cold water to get a
comfortable temperature.
Turning It Off
To turn off the Flash water heater
1. Close the hot water tap, or turn appliance off.
2. Flow will diminish, unit will shut off.
3. “Fire On” lamp will go out.
Temperature
The output temperature of the T-K1 has been
factory set for a maximum 120°F (50°C). This is
electronically controlled by the computer and
cannot be adjusted without a TK-RE01
temperature controller. Further adjustment may be
made by mixing in cold water with the hot to obtain
the ideal water temperature.
The actual outlet temperature is dependent on the
inlet water temperature and the flow rate
demanded. Consult the flow charts on the last
page of this unit to determine the possible outlet
temperature and flow rate combinations.
WARNING:
Temperatures above 125º F (52º C) can cause
severe burns or death from scalding. Children, the
disabled and the elderly are at a high risk of being
injured. Feel the water temperature before bathing
or showering. Do not leave children, disabled
persons, or the elderly unsupervised.
3

Flow
The flow rate through the T-K1 is limited to a
maximum of 5.3 GPM. The flow rate, along with
the supply temperature of the water will determine
the outlet temperature of the water. Consult the
flow charts on the last page of this manual to
determine the possible outlet temperature and flow
rate combinations. Based on the United States
Department of Energy method of testing water
heater output, the T-K1 is rated for 216 gallons per
hour, or 3.6 GPM, at a 77°F rise above the inlet
temperature. Refer to the following chart of typical
household flow rates to determine what the T-K1
can do in a household application. Remember that
for bathing, cold water will be mixed for a
comfortable temperature, increasing the flow
output rate.
Washing Machine 2.0
Taken From UPC 19
Freeze Prevention
This unit comes equipped with heaters that
discourage the unit from freezing. 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.
The unit has been rated for temperatures down to
5º F (-15º C) in a wind free environment. The wind
chill factor will cause the unit to freeze at
temperatures above 5º F (-15º C), even if the unit
is installed indoors.
For indoor installation in areas where the
temperature will be well below freezing for
extended periods of time, extend the internal
thermostat to the outdoors, and install a TK-TV03
backflow prevention kit so that cold air will not
backflow into the flue and cause the unit to freeze.
Do not install the water heater in an area with
extremely cold weather. This will void your
warranty and Takagi Industrial Co. USA Inc. will
not be responsible for any damage that occurs.
WARNING: The pipe heaters are located on the
Flash Water Heater only. Any hot or cold water
pipes located outside of the unit will not be
protected. Properly protect and insulate these
pipes from freezing.
If the heater will not be in use for a long period of
time or if the temperatures will drop below 5º F (-
15º C) with the wind chill factor, turn off heater and
drain the unit of water. This applies to indoor and
outdoor installations. This will keep the unit from
freezing and being damaged.
Follow these instructions carefully:
1. Turn off the power supply to the Flash Water
Heater.
2. Close manual gas control valve.
3. Close manual water shut off valve.
4. Open all hot water taps in the house.
(Bathroom, kitchen, laundry room, etc.). When
the water flow has ceased, close all hot water
taps.
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
97
5. Have a bucket or pan ready to catch the water
from the unit’s drain plugs. Remove the drain
plugs to drain the water out of the unit.
6. Let drain for 5 minutes.
7. Securely screw the drain plugs back into place.
Follow these steps when it is again safe to use the
water heater:
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 manual water control valve located on
the water supply line.
4. Open all the hot water taps to verify water
flows to the taps. Close hot water taps.
5. Open manual gas control valve located on the
gas supply line.
6. Turn on the power supply to the Flash Water
Heater.
4

Installation
General
All gas water heaters require careful and correct
installation to ensure safe and efficient operation.
This manual must be followed exactly.
1. Read the For Your Safety section in the
beginning of this manual.
2. This unit is not capable of being used as a pool
or spa heater.
3. The regulator is preset at the factory. It is
computer controlled and should not need
adjustment.
4. Suitable for potable water heating only. Well
water or hard water may cause scale problems
that will not be covered by the manufacturer’s
warranty.
5. Maintain proper space for servicing. Install the
unit so that it can be connected or removed
easily.
6. Install so that the electrical power can be
switched off if necessary.
7. Avoid installing in an area with high levels of
dust, sand or debris. Particles may clog the air
vent, reduce fan function, or cause improper
combustion.
8. 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.
Accessories
Check that all the parts listed below were
This section is for the installer. The installer is
responsible for the correct installation of your
Flash Water Heater.
For Your Safety:
Only a certified and trained service technician
or qualified plumber may service or install
your product.
included with the unit.
Please keep this owner’s manual in a safe
place for future reference. Copies of this
manual are available from TAKAGI-USA
Electrical Connections
The T-K1 requires a 60 Hz 120 VAC electrical
power supply, and it should be properly grounded
in accordance with the most recent edition of the
National Electrical Code, ANSI/NFPA 70 and any
local codes. In Canada, all electrical wiring to the
heater should be installed in accordance with the
Canadian Electrical Code, CSA C22.1 Part 1, and
any local codes. Do not rely on the gas or water
piping to ground the metal parts of the heater.
CAUTION: Label all wires prior to disconnection
when servicing controls. Wiring error can cause
improper and dangerous operation. Verify proper
operation after servicing.
• A means for switching off the 120 VAC power
supply must be provided.
• Wire the heater exactly as shown in the wiring
diagram.
• A green screw is provided in the junction box
for the grounding connection. Refer to the
following wiring diagram. Wiring diagrams are
also printed on the inside panel of the
appliance
5

Wiring Diagram
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. Wires are available through the manufacturer.
6

Gas Supply Piping
Check the rating plate to make sure that the unit
was built for the type of gas available in the area.
The gas supply piping should be sized according
to the Applicable Plumbing Code for a maximum
draw of 165,000 BTUH. First determine the
effective length of the gas supply line by
measuring the actual length of piping, and then
adding 5 ft. for every elbow or “T” to the actual
length. Use the charts below to determine the pipe
diameter necessary to accommodate the BTU
demand of the unit. If there are more gas drawing
appliances on the line, size according to the
maximum amount of BTU demand.
The gas supply pressures must be within the
ranges of the following chart:
Natural Gas
Supply Pressure
Min. 5” WC
Max. 10.5” WC
Propane Gas
Supply Pressure
Min. 11” WC
Max. 14” WC
Insufficient gas supply pressure can cause the
Flash Water Heater to lose efficiency or not work
at all.
WARNING: Fire or explosion may result if the
maximum supply pressures are exceeded.
The manifold gas pressure should be at maximum
3.5” WC for natural gas, and 4.0” WC for propane.
Always use approved connectors to connect the
unit to the gas line. Always purge the gas line of
any debris before connecting to the water heater.
WARNING: Conversion of this unit from natural
gas to propane or propane to natural gas cannot
be done in the field. Contact your local retailer or
distributor to get the correct unit for your gas type.
Always install a manual shutoff valve on the gas
supply line in case of an emergency, or if service
or maintenance is necessary.
This appliance and its individual shut-off valve
must be isolated from the gas supply piping
system by unplugging the unit and turning off the
main gas valve during any pressure testing of the
gas supply piping system at test pressures equal
to or less than ½ PSI.
When all of the connections have been made,
check the gas line for leaks. Apply soapy water to
all gas fittings and connections, if bubbles form,
there may be a leak.
Natural Gas Supply Piping
Based on 0.60 specific gravity for natural gas at .5” WC pressure drop
DOE standard is 1100 BTU per cubic ft. of natural gas
Pipe
Size Cubic Feet of Natural Gas
Length 10’ 20’ 30’ 40’ 50’ 60’ 70’ 80’ 90’ 100’ 125’ 150’ 200’
½” 174 119 96 82 73 66 61 56 53 50 44 40 34
¾” 363 249 200 171 152 138 127 118 111 104 93 84 72
1” 684 470 377 323 286 259 239 222 208 197 174 158 135
1 ¼” 1404 965 775 663 588 532 490 456 428 404 358 324 278
1 ½” 2103 1445 1161 993 880 798 734 683 641 605 536 486 416
2” 4050 2784 2235 1913 1696 1536 1413 1315 1234 1165 1033 936 801
Propane Supply Piping
Based on 11” WC supply pressure
Pipe
Size kBTU of Propane
Length 10’ 20’ 30’ 40’ 50’ 60’ 70’ 80’ 90’ 100’ 125’ 150’ 200’
½” 275 189 152 129 114 103 96 89 83 78 69 63 55
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
7

Water Plumbing
Follow local guidelines for the length of the
plumbing line in order to ensure that there is
enough water pressure for all the fixtures on the
line. First, calculate the effective length of the
plumbing line by measuring the total length of pipe,
and then adding to this 5’ for each elbow or tee in
the line. Use the following chart to determine the
total number of fixture units on the line, and then
compare with the chart at the bottom of this page
to find the pipe diameter and water pressure
necessary.
Install with control valves on the inlet and outlet,
and use removable unions or connectors to
facilitate maintenance or service if necessary.
If the water heater is installed in a closed water
system, means shall be provided to control thermal
expansion. Contact the water supplier or a local
plumbing inspector on how to control this situation.
Purge the water line of air, and clean the filter
before initial operation.
WARNING:
Do not reverse the hot outlet and cold supply line
connections to the Flash Water Heater. Make sure
the hot and cold lines are connected as in the FOR
YOUR SAFETY section at the front of this manual.
Pressure Relief Valve
An approved pressure relief valve must be
installed in any installation with this unit. The
pressure relief valve must be installed on the hot
line out of the unit, with no check valves or control
valves between the unit and the relief valve.
The Pressure relief valve must be rated for 150
PSI, and have a discharge capacity of 165,000
BTU. Connect the discharge opening of the relief
valve to a suitable drain to prevent water damage
should discharge occur.
If the pressure relief valve discharges periodically,
this may be due to thermal expansion in a closed
water supply system. Contact the water supplier or
local plumbing inspector on how to correct this
situation.
Do not plug the pressure relief valve. The line
should have no reduced fittings or other
restrictions and should allow for complete drainage
of valve and line. The pressure relief valve should
be manually operated once a year to check for
correct operation.
Should overheating occur or the gas supply fail to
shut off, turn off the manual gas control valve to
the appliance.
Length to the End of Hot Water Line and Recommended Fixture Units
Pipe
Size Pressure Range 30 to 45 PSI Pressure Range 46 to 60 PSI Pressure Range 60+ PSI
Length 100' 200' 300' 400' 100' 200' 300' 400' 100' 200' 300' 400'
3/4" 3-12 1-6 1-5 0-4 5-17 3-11 2-8 1-6 6-20 4-13 3-10 2-8
1" 12-25 6-17 5-13 4-12 17-36 11-25 8-20 6-18 20-39 13-32 10-26 8-22
1-1/4" 25-48 17-32 13-25 12-21 36-78 25-52 20-39 18-33 39-78 32-74 26-54 22-43
Fixture Unit Per Fixture (from UPC)
Plumbing Fixture
Description
Fixture
Unit
Combination Bath / Shower 4
Whirlpool Bath 4
Shower 2
Lavatory 1
Clothes Washer 4
Dishwasher 1.5
Kitchen Sink 1.5
8

Outdoor Clearances
Wall Hanging Installation
For a wall mount installation, use TK-BK01
brackets to securely attach the T-K1 to the wall.
Locate the heater as desired, but follow all
applicable local codes, as well as the indoor or
outdoor clearances that apply to the installation.
Piping side 12”
Front (Maintenance
space)
24”
Floor
Non combustible
base Min. 3” off the
ground
Back of heater 1”
Non piping side 2”
Top of heater 36”
Standing Installation
If the unit is to be installed standing on a surface,
adjust the legs so that the unit stands securely and
is level (legs can be adjusted up to 1”).
Do not install the unit standing directly on a
combustible surface. Use a 3” non-combustible
base.
If this unit is installed under an overhang, there
must be a 36” clearance from the top of the unit to
the overhang, and the surrounding area must be
open in front and on the sides of the unit.
Use the included L brackets to connect the unit to
a wall to ensure that it does not fall over. These
brackets will maintain the required 1” clearance
between the back of the unit and a combustible
surface.
WARNING: Do not have the flue terminal pointing
toward any opening into a building. Do not locate
your heater in a pit or any location where gas and
water can accumulate.
Outdoor Installation
WARNING: Do not install the heater where water,
debris, or flammable vapors may get into the flue
terminal. This may cause damage to the heater.
Follow all local codes, or in the absence of local
codes, follow the codes for Installation of Gas
Burning Appliances; National Fuel Gas Code ANSI
Z221.23 in USA or CAN/CGA B149.1 or .2 in
Canada. For outdoor installation, do not remove
the vent cap from the top of the appliance.
Locate the water heater in an open, unroofed area,
and maintain the following minimum clearances
from combustible and noncombustible materials.
9

WARNING: United States regulations forbid
installing the unit within 4’ of any opening into any
building. Similar Canadian regulations forbid the
unit from being installed within 10’ of any opening
into any building.
WARNING: Improper installation can cause
nausea or asphyxiation from carbon monoxide and
flue gases which could result in severe injury or
death. If you experience problems with the water
heater in altitudes above 4,500 feet, contact the
manufacturer for instructions.
Remove the vent cap from the top of the unit, and
connect the Category III exhaust flue to the 4”
round connector underneath.
Cut the black jumper wire loop on the pressure
switch to activate the unit’s indoor installation
safety features.
WARNING: Do not install the unit directly on a
combustible surface such as carpeting, wood
floors, etc. If it is necessary to install the unit
standing on a surface, install a 3” noncombustible
base between the unit and the surface.
Indoor Installation
Follow all local codes, or in the absence of local
codes, follow the codes for Installation of Gas
Burning Appliances; National Fuel Gas
Code ANSI Z221.23 in USA or CAN/CGA B149.1
or .2 in Canada.
Combustible Air Supply
WARNING: In an indoor installation, the T-K1
must be connected to a Category III special gas
vent in order to direct the dangerous exhaust
byproducts to the outdoors.
The T-K1 must be installed in a location where the
proper amount of combustible air will be available
to it at all times. If the unit is installed in a confined
space, there must be permanent openings
supplying air to the unit.
10

If the openings will bring air directly from the
outdoors, two openings are required, and they
should be sized to give a minimum free area of
one square inch for every 4000 BTUH of the
maximum input rating of the unit.
If the openings will bring air from another indoor
area, they should be sized to give a minimum free
area of one square inch for every 1000 BTUH of
the maximum input rating of the unit.
One of these openings should be within 12” of the
ceiling, and the other should be within 12” of the
floor.
Exhaust Venting
This water heater must be vented in accordance
with the section on venting of equipment in the
latest edition of the National Fuel Gas Code.
This is a Category III appliance, and must be
vented accordingly. The following are UL listed
manufacturers: Z-Flex Inc. ProTech Systems
FasNSeal, Z Vent II and Heat-Fab Inc. Saf-T Vent.
Follow the vent pipe manufacturer’s instruction
when installing the vent pipe. Do not common
vent this appliance with any other vented
appliance.
The venting system must not exceed a length of
21 ft. minus 5 ft. for every elbow. Do not use more
than 3 elbows.
No. of Elbows Max. Vertical or
Horizontal Length
0 21 ft.
1 16 ft.
2 11 ft.
3 6 ft.
If the horizontal vent run exceeds 5 ft., the
following criteria must be observed:
• There must be a 2 ft. vertical run off the top
of the heater before the horizontal run
begins.
• The horizontal run must be supported at 3’
intervals.
• The vent run should be pitched up towards
the termination at ¼” per foot.
The unit can be vented either up and out the roof,
or directly through a wall. If the unit will be vented
through a wall, use Takagi USA Inc. optional part,
the TK-TV01 vent terminator, or an equal Category
III vent part. Locate the vent terminator according
to ANSI Z223.1/NFPA 54 and applicable local
codes.
Maintain the following clearances to any
combustible surface in an indoor installation:
Indoor Clearances
Piping side 6”
Front (Maintenance
space)
Suggested 24”
Min. 4”
Floor Noncombustible base
Back of heater 1”
Non piping side 2”
Top of heater 11”
Manufactured Home (Mobile Home) Installation
This appliance must be installed in accordance
with the Manufactured Home Construction and
Safety Standard, (Title 24, CFR; Part 3280) and
ANSI A119.5/NFPA 501D. In addition, install in
accordance with the following instructions, the
instructions supplied with any venting, local codes,
utility company requirements for the installation of
water heaters in manufactured homes (mobile
homes), and the latest edition of the National Fuel
Gas Code, ANSI Z221.3/NFPA 50.
Locate the heater in an enclosure separating the
unit from the internal atmosphere of the
manufactured home or trailer. All combustion air
must be obtained from the outside atmosphere,
and the flue gases must be discharged directly
outdoors through a gas vent. There must be no
opening from the interior of the home or trailer into
the water heater enclosure.
Indoor Installation
Follow indoor installation instructions as set out in
an earlier section of this manual, except that
combustion air must not be taken from the inside
of the home or trailer.
Outdoor Installation
Follow outdoor installation instructions as set out in
an earlier section of this manual.
If the unit is to be installed in a recessed area,
connect a gas vent to the unit, which will direct
exhaust gases out of the recessed area.
Min. 32"
Min. 3"
Indoors Outdoors
Min. 3"
11

Initiating the Appliance
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 electronic ignition device,
which automatically lights the burner. Do not
try to light the burner by hand.
b) Before operating, check for gas accumulation
in the area around the appliance. Pay special
attention near the floor, because gas is often
heavier than air, and it may accumulate near
the floor.
c) Do not attempt to open the manual gas shutoff
valve with anything but by hand. Never use
tools. If the valve will not open by hand, do not
try to repair it. Instead, call a qualified service
technician. Force or attempted repair may
result in a gas leak, fire or 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 part that may have been
damaged by being under water.
WARNING: IF YOU SMELL GAS:
• Do not use 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.
Initial Operation
1. STOP! Do not operate without reading the
safety information first!
2. Switch off the electrical power supply to the
heater.
3. Do not attempt to light the burner manually.
4. Turn the manual gas control valve located on
the outside of the unit counterclockwise to the
OFF position.
5. Wait five (5) minutes to clear out any gas. If
you then smell gas, STOP! Follow “b” in the
“Initiating the Appliance” section above. If you
do not detect gas, proceed to the next step.
6. Turn the manual gas control valve located on
the outside of the unit clockwise to the ON
position.
7. Turn on the electrical power to the appliance.
8. Turn on any tap, and the T-K1 will initiate itself.
9. If the appliance will not operate, follow the
instructions in the “Turning Off the Gas Supply
to the Appliance” section following, and call a
service technician or gas supplier.
TURNING OFF THE GAS SUPPLY TO THE
APPLIANCE
Close the manual valve on the gas inlet line. Turn
off the power supply.
Manifold pressure taps.
12

Space Heating Application
The FLASH T-K1 can be used for space heating as well as potable heating of hot water applications.
WARNING
• Toxic chemicals such as used for boiler treatments chemical, alcohol, glycerol and glycol
group will not be introduced into the system when used for potable water and space heating.
• The FLASH T-K1 can be used to supply potable water and space heating and shall not be
connected to any heating system or component(s) previously used with non-potable water
where any chemicals were added to the water heating appliances.
• When the system requires water for space heating at temperatures higher than required for
other used, a means such as a mixing valve shall be installed to temper the water for those
uses in order to reduce scald hazard potential.
• Water temperature over 125 °F can cause severe burns instantly or death from scalds.
• Chemicals such as diluted Glycol can be used for radiant floor, Hydro-warm air or Baseboard
heating only.
Basic system drawings and Schematics.
Heating application only:
Warning: This illustration is for concept only. There are a wide variety of variations to the application of
controls and equipment presented applications. Designers must add all necessary safety and auxiliary
equipment to conform to code requirements and design practice.
For more details, contact Technical Department at [phone]
13

Dual-purpose hot water heating (Domestic and Heating):
Priority Control Devices: It has a capability to make priority system that can be used as a controller flow
sensor, Aquastat, or electronic controller to controlling radiant, Hydro or baseboard heating equipments.
Warning: Follow all local codes, or in the absence of local codes, follow the most recent edition of the
National Standard Code, ANSI Z21. 10.3.
Warning: This illustration is for concept only. There are a wide variety of variations to the application of
controls and equipment presented applications. Designers must add all necessary safety and auxiliary
equipment to conform to code requirements and design practice.
14

Applications
The T-K1 can be installed in a variety of plumbing applications, which will provide more comfortable domestic
hot water. Contact Takagi for information on using this unit as a heat source.
T-K1 with Storage Tank
The maximum flow rate through the T-K1 is 5.3 GPM. If it is necessary to achieve higher flow rates for longer
periods of time, then it can be installed in conjunction with a storage tank. A pump will be necessary to keep
the water hot, and it should be controlled by an Aquastat set at 120°F max., with a 10°F differential. We
suggest a pump of 1/12 hp or greater depending on the system.
Recirculation
This system will need a pump controlled by an aquastat. Set aquastat at 95°F wit a 10-15°F differential.
Use a pump of 1/12 hp or greater, depending on the system.
15

OPERATING INSTRUCTIONS
1. STOP! Read the safety information above or in the Owners Manual.
2. Turn off all electric power to the water heater.
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 water heater.
8. If the water heater will not operate, follow the instructions "to Turn Off Gas to wate
r
heater" and Call
y
our service technician or
g
as su
pp
lier.
FOR YOUR SAFETY READ BEFORE OPERATING
A. This water heater does not have a pilot. It is equipped with an ignition device tha
t
automatically lights the burner. Do not try to light the burner by hand.
B. BEFORE OPERATING smell all around the water heater area for evidence o
f
leaking gas. Be sure to smell next to the floor because some gas is heavier than ai
r
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 o
r
attempted repair may result in a fire of explosion.
D. Do not use this water heater if any part has been under water. Immediately call a
qualified service technician to inspect the water heater and to replace any damaged
parts.
TO TURN OFF GAS TO APPLIANCE
1. Turn off all electric power to the water heater if service is to be performed.
2. Turn the manual gas valve located on the outside of the unit clockwise ↻to the of
f
position.
WARNING: If you do not follow these instructions exactly, a fire o
r
explosion may result causing property damage, personal injury or loss o
f
life.
16

DANGER
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
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 water heater.
The outlet hot water temperature of the TK1 water heater is factory set 120 °F.
WARNING: Use this heater 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.
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.
Keep flammable products:
1. Far away from heater.
2. In approved containers.
3. Tightly closed.
4. Out of children's reach.
DANGER
Hot Water Heater 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 professional
person.
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) o
r
components of the product itself.
Maintenance
17

WARNING: Turn off the electrical power
supply, the manual gas control valve, and the
manual water control valve before servicing.
The unit should be checked once a year or as
necessary by a certified and trained technician. If
repairs are needed, the repairs should be done by
a certified and trained technician.
The following systems and parts should be
checked at least once a year:
1. Venting systems
2. Burners
3. Manual operation of the pressure relief valve to
ensure correct operation.
4. Periodic cleaning of the water filter, refer to
figure below.
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 descaling solution. Scale
build up will void your warranty and shorten the
life of your water heater.
Troubleshooting
Water Isn’t Hot Enough
The T-K1 can burn gas at a maximum input rate of
165,000 BTUH. This puts a limit on the possible
output temperature and flow capabilities (See flow
chart on the last page of this manual). If the water
isn’t hot enough, turn down the flow rate through
the unit. If it still isn’t hot enough, compare the
flow and temperature that is being attained to the
T-K1 flow vs. temperature chart. If the unit is not
performing according to the chart, first check that
the gas supply line is sized properly, and that the
gas pressure is within the required range. If the
gas line is okay, check the plumbing for mixing
valves, thermostatic valves, scald protection,
single handled valves or crossed connections. If
the unit is performing in accordance with the flow
chart, then it may be undersized for the application.
It Takes Too Long to Get Hot Water
The T-K1 takes three seconds to ignite, and three
more to get up to temperature. The rest of the
time needed for hot water to get to a fixture is due
to the length of piping between the water heater
and the fixture. If the unit seems to be taking
longer than six seconds to initiate, check the filter
and flow sensor for any debris or damage.
The T-K1 Will Not Initiate
First check the flow rate through the unit. If the
flow is not .75 GPM or greater, the unit will not
initiate. Check the filter and the flow sensor for
any debris or damage.
Press the lower green button on the GFCI inside
the unit. If the red light above it does not come on,
then there is a problem with the electrical supply to
the unit. If that light does come on, hit the green
reset button above the light, and look for a small
red LED in the lower hole in the middle of the T-K1
circuit plate. If this light is not lit, there is a
problem with the electrical connection between the
GFCI and the circuit plate. Contact Takagi
Industrial Company for Instructions.
18

Error Codes
All Takagi units are self diagnostic for errors. If
there is a problem with the installation or the unit, it
will give a signal, through a pair of flashing lights
on the circuit plate, to communicate the source of
the problem. If the unit has a TK-RE01 remote
control installed, this will give also give a numerical
error code. Consult the following chart for the
meaning of an error code:
RE01 remote
Upper Lower No. Problem Possible parts to check
11 Igniter Computer, Igniter, Flame rod,
gas valve, gas resource
12 Burner flame Computer, Flame rod, gas valve,
gas resource
Blinking Off
72 Pre post
check
Computer, Flame rod, gas valve,
gas resource
14
Computer,
gas valve,
hi-limit
switch,
Computer, hi-limit switch, gas valve
Off Blinking
71 Computer,
gas valve
Computer, gas valve
Blinking Together 45 Fan motor Computer, fan motor
Blinking
Alternately 31
Thermister,
pressure
switch
Computer, thermister, pressure
switch
Off Off Off
Electric
supply
Computer, GFI, fuse, wire
connection,
outer electric resource
DO NOT
TOUCH
WARNING
FT5078
19