Laars H Series User manual

Installation
Laars H Series
Tankless Heater Models
LCTEH005, LCTEH006
LCTEH010 & LCTEHV010,
LCTEH015 & LCTEHV015,
LCTEH018 & LCTEHV018,
LCTEH025
Voltage options:
208V Single & Three-Phase
240V Single & Three-Phase
277V Single-Phase
380V Three-Phase
400V Three-Phase
415V Three-Phase
480V Single & Three-Phase
238-54232-00 REV 4/21
Doc#11099

Installation
2
Table of Contents
Pre-Installation Information ................................................................................................................................................ 3-4
Storage Instructions ............................................................................................................................................................... 4
Mounting Heater .................................................................................................................................................................... 5
Plumbing Installation .......................................................................................................................................................... 6-7
Electric Installation ................................................................................................................................................................. 8
Start Up Check List ................................................................................................................................................................. 9
Start Up ................................................................................................................................................................................ 10
Digital Controller Operation ................................................................................................................................................. 11
NEMA 4/4X Digital Controller Operation ............................................................................................................................. 12
Perform Operational Test No. 1 ........................................................................................................................................... 13
Perform Operational Test No. 2 ........................................................................................................................................... 13
Product Options ................................................................................................................................................................... 14
Maintenance ........................................................................................................................................................................ 15
Troubleshooting .............................................................................................................................................................. 16-17
Special Installation and Operating Instructions .............................................................................................................. 18-19

Installation
3
DANGER
Tip over hazard. System can crush you resulting in serious injury or death. Read and follow precautions in this
installation manual that accompanied the heater for instructions on how to safely transport and mount. DO NOT
transport with the heater in the vertical position. This heater is top heavy and should not be placed in the vertical
position until the site is prepared to anchor the heater to the wall or the legs to the floor.
WARNING
Read this manual BEFORE using this equipment. Failure to read and follow all safety and user information could result
in death, serious personal injury, minor burns, property damage, or damage to the equipment. Keep this manual for
future reference. Failure to comply with proper installation and maintenance instructions could contribute to the
heater’s failure.
A qualified plumber or electrician should install and service this system. Install system according to these instructions
and in compliance with national and local codes.
ASSE standard 1016, 1069, or 1070 listed devices should be used at fixtures to prevent possible injury. Severe bodily
injury including scalding, chilling, and/or death may result depending upon system water pressure changes and/or
supply water temperature changes.
For safe operation of the heater, observe all warning labels as indicated.
Water heater system under pressure. DO NOT open enclosure while in operation.
These heaters should never be used to provide “anti-scald” or “anti-chill” service.
Hazardous voltage inside enclosure may result in serious burns or death. Disconnect power supply before performing
any work in the enclosure.
Failure to ground this system may result in death or serious injury.
Make sure that all water supply lines have been flushed and then completely turned off before beginning installation.
Debris in supply lines can cause valves to malfunction.
CAUTION
Hot pipes! DO NOT touch. May cause minor burns.
NOTICE
These heaters DO NOT provide protection from supply or outlet pipe freezing.
Consult local building and plumbing codes prior to installation. Should these codes differ from the information in the
manual, follow the local codes. Inquire with governing authorities for additional local requirements.
Regular checking and cleaning of the heater’s internal components and check stops is necessary for maximum life and
proper product function. Periodic inspection and yearly maintenance by a licensed contractor is required. Corrosive
water conditions, and/or unauthorized adjustments or repairs could render the heater ineffective for its intended
service. Frequency of cleaning and inspection depends upon local water conditions. For heaters with adjustable
output temperatures, check and adjust as needed at initial installation and on a quarterly basis.
IMPORTANT
Read this entire installation manual to ensure proper installation. When finished with the installation, file this
manual with the owner or maintenance department. Compliance and conformity to local codes and ordinances is the
responsibility of the installer. Product warranties may be found under "Resources" on our website at www.laars.com.
Separate parts from packaging and make sure all parts are accounted for before discarding any packaging material. If
any parts are missing, do not begin installation until you obtain the missing parts.

Installation
4
Pre-Installation Information
General Information
The H Series Tankless Water Heater provides instant and precise temperature-controlled hot water. To ensure proper
performance, install the heater according to the following installation instructions and in compliance with applicable
national and local codes.
Flow rates and temperature figures are important for proper sizing If needed to meet certain temperature demands,
flow control devices are readily available See temperature rise table for specifications Contact Laars representatives for
further information on available flow control devices.
Operation and Setup
H Series heaters supply an unlimited amount of hot water with specific flow and temperature rise capabilities. These
heaters are energy efficient, reliable, and provide optimum performance in the most demanding applications.
Application Specific Requirements
The H Series can be used in many different applications that require custom tuning for specific applications to maximize
performance of the heater.
For use in a re-circulation loop, the incoming loop temperature should not exceed 140°F (60°C).
For applications utilizing quick close valves or solenoid valves, it is important to install a hammer arrestor or surge tank
close to the point of use to absorb pressure spikes.
Installation Considerations
Maximum operating pressure: 150 psi (10 bar)
ASME maximum operating pressure: 160psi (11 bar)
Standard flow activation: 1.5 gpm (5.7 lpm)
Certifications
Electric Tankless Water Heaters are certified by ETL to UL499, cETL listed to CSA-C22 2 No 88 and third party certified to
NSF/ANSI 372.
WARNING For safe operation of the heater, observe all the warning labels as indicated.
Storage Instructions
NOTICE! Keep Electric Tankless Water Heaters stored in original packaging until installation.
Recommended storage criteria:
Store Electric Tankless Water Heaters where temperatures exceed 35°F (2°C) at all times.
Indoor storage is recommended.
Minimize excessive on-site transport to reduce risk of shock and impact damage.
Packaging
Box dimensions approx: 30" x 15" x 6" (762mm x 381mm x 152mm)
All boxes must be stacked evenly and horizontally.
Safety issues related to packaging:
 Product should be transported with the care associated to packages labeled “FRAGILE” even if packaging is not
marked accordingly.
 Standard safety procedures for forklift transport and large items less than 1000lbs (454 kgs) should be followed at
all times.

Installation
5
1 Mounting Heater
WARNING HIGH VOLTAGE SHOCK. Disconnect power supply before performing any work inside
the heater enclosure.
Installation should be performed by a qualified plumber or electrician.
For best results, install heater as close as possible to the point of use.
Long pipe runs are not recommended. A heat loss of 1°F for every 10ft (3 meters) of uninsulated pipe can occur.
When determining a mounting location, give consideration to the location of the main electrical panel and ensure
accessibility of the cabinet enclosure door and other plumbing for service/maintenance.
Set heater in a vertical, upright position with the
water outlet located at top.
Depending on the application, the unit may also
be installed rotated clockwise 90° with the inlet
and outlet to the right.
Mount heater to the wall using the (4) mounting
brackets on the back of the enclosure. Bolt the
heater to the vertical surface. Mounting holes
are designed for a maximum bolt tize of ¼”
(6mm) bolt diameter..
Heater should be mounted on a vertical surface
and securely hold a minimum of 45 pounds. Use
lead or plastic anchors when mounting directly
onto concrete or block walls.
Install the pressure and temperature relief valve
on hot water outlet immediately following the
union.
NOTICE! Valve must empty into a drain.

Installation
6
2 Plumbing Installation
Install shutoff valve above (upstream of) the
heater inlet.
Components Needed:
 (2) Union 3/4"
 Shutoff Valve
 Pressure and Temperature Relief Valve (150 psi/10 bar)
 Y-Strainer (100 mesh) or Inline Filter (150 microns)
 (2) Gate or Ball Type Valves
 Drain pipe
 Water hammer arrestor (recommended)
 Elbows, nipples and fittings as needed
CAUTION To avoid damage to the electronics or internal
wiring, do not perform any brazing or sweat
soldering inside the enclosure.
NOTICE! Failure to install proper filtration may result in a
flow switch malfunction.
NOTICE! To avoid water damage, install a drain pipe from
the pressure relief valve to an unrestricted drain.
If end use fixture is not at the highest point in the
plumbing loop, then an automatic air vent valve must
be added at the highest point in the system or at any
drop to eliminate trapped air.
Install one union on the water inlet side of the heater
and another union upstream of the 100 Mesh (150
micron) y-strainer.
Install one union on the water outlet side of the
heater and another after the T & P Relief Valve.
Install the pressure relief valve (150 psi/10 bar) and
outlet plumbing of heater per code requirements and
route relief valve discharge to drain. Make sure no
shutoff valve is between the water heater outlet and
the relief valve, as well as no shutoff valve between
the relief valve discharge and drain. Ensure plumbing
is secure and not subject to vibrations.
WARNING The heater must be lying flat to do any
soldering on the inlet or outlet tubes. Soldering on
the inlet or outlet tubes in the upright position can
damage internal components. Damage caused by
dripping solder or flux can make your heater
inoperable.
Use 3/4" hard copper tubing or pipe as needed.
Dimensions, Plumbing and Electrical Configurations
V Series heaters have 1/2" inlet and outlet and require 1/2" copper tubing.

Installation
7
2 Plumbing Installation cont…

Installation
8
3 Electric Installation
WARNING Install product to rated line voltage in
accordance with current local and
national codes and regulations.
WARNING All heaters must be fused in
accordance with National Electric Code
(NEC) for the full load amperage listed
on the nameplate rating for each
heater.
WARNING Failure to properly ground the unit(s)
per the National Electric Code could
result in injury or death.
ELECTRICAL SPECIFICATIONS FOR HEATER
(Single-Phase)
kWattsAmpsVoltageModel Min Wire Size
12 AWG*613480LCTEH006J
10 AWG*1021480LCTEH010J
06 AWG*1838480LCTEH018J
10 AWG*622277LCTEH006E
03 AWG*1865277LCTEH018E
10 AWG*521240LCTEH005D
08 AWG*625240LCTEH006D
06 AWG*1042240LCTEH010D
04 AWG*1563240LCTEH015D
03 AWG*1875240LCTEH018D
10 AWG*524208LCTEH005H
08 AWG*629208LCTEH006H
04 AWG*1048208LCTEH010H
03 AWG*1572208LCTEH015H
03 AWG*1887208LCTEH018H
ELECTRICAL SPECIFICATIONS FOR HEATER
(Three-Phase)
Min Wire SizekWattsAmpsVoltageModel
12 AWG*1013480LCTEH010S
10 AWG*1822480LCTEH018S
06 AWG*2551480LCTEH025S
10 AWG*1521415LCTEH015P
08 AWG*1826415LCTEH018P
10 AWG*1522400LCTEH015N
08 AWG*1826400LCTEH018N
10 AWG*1016380LCTEH010M
10 AWG*1523380LCTEH015M
08 AWG*1828380LCTEH018M
06 AWG*1536240LCTEH015L
06 AWG*1843240LCTEH018L
08 AWG*1028208LCTEH010K
06 AWG*1542208LCTEH015K
06 AWG*1850208LCTEH018K
*Based on the NEC Table 310.15 for 75°C insulated copper wire @ 30°C
Ambient. Aluminum wire requires larger gauges.
Not all available (optional) voltages are listed in the
table.
For standard enclosures, remove the four screws
and take the bottom cover off. For NEMA 4/4X
enclosures, open the enclosure door.
NOTICE! Any option that requires field wiring must be
done with 600V cable per the schematic that
was shipped with the heater.
NOTICE! Use a 4-core cable or multi-stranded machine
tool wire from an approved isolating 3-pole
switch or circuit breaker.
NOTICE! Make sure the electrical cable is the correct
size to carry 100% of the full load current. See
table for proper wire sizes.
Standard: A pre-cut hole is already sized for
conduit connection. Skip to step C.
NEMA 4/4X: Using a hole punch, cut a hole the
proper size for the conduit connection; large
enough for the wire size for each heater. The
connectors need to be rated NEMA 4/4X to
ensure proper sealing of the enclosure.
Run wires through the appropriate size conduit.
Connect wires to the system terminal block or
fused disconnect inside the enclosure.
Connect the ground wire to the stud provided
with the “Ground” label beneath it.
If unit is ordered with a D1 or DC controller,
option, the DB9 connector for hookup on a
standard unit is located on the upper left/hinge
side of the cabinet. Please review the appropriate
Special Instruction & Operation Instructions
section for information regarding controller
programming and wiring. Proceed to the Start Up
Checklist once the steps in the Special Installation
& Operation Instructions section have been
completed or if you do not have this option.

Installation
9
4 Start Up Check List
Plumbing

System is set in a vertical, level, and upright position with the outlet located at the top. System is mounted
to the wall using the (4) mounting brackets on the back of the enclosure or bolted to the floor with the
optional leg kit.

Confirm installation of shutoff valve above (upstream of) the union on the inlet connection Confirm
installation of a Y-strainer (100 mesh screen) or inline filter (150 micron) between the inlet shutoff valve
and the heater.

Pressure and temperature relief valve is installed on tepid water outlet immediately following the union No
valve or restriction is between the relief valve and the system or the relief valve and drain Shutoff valve is
installed after pressure and temperature relief valve on outlet if required by local or national plumbing
codes.

If the hot water process is not at the highest point in the plumbing loop, then an automatic air vent valve
must be added at the highest point in the system plumbing loop to eliminate trapped air.
Electrical

Verify supply voltage matches the indicated voltage on the Serial Tag. Serial Tag is located within the heater
enclosure on the upper left corner of the back plate (mounting plate).

Appropriate conduit is installed properly, secured and sealed to unit enclosure per NEC and hazard location
requirements.

Appropriate conductors for unit routed through conduit and secured to power block inside the enclosure
All electrical is installed in accordance with national and local electrical codes, including fuse size and rating.

Appropriate earth ground is installed to the lug provided on enclosure backplate.

Installation
10
5 Start Up
WARNING Make sure the circuit breaker for the heater is OFF.
Be sure that plumbing and electrical are complete per Start Up Check List.
Slowly turn on water supply to the unit with the
enclosure door open and the circuit breaker in
the off position.
Energize the electrical service to the unit by
switching on the two or three pole swich or
circuit braker. Unit is now in the ready state.
Slowly turn on the water outlet valve, activate
the connected process requiring heated water
(faucet, shower, etc.), then flush the system for 5
minutes to ensure all air is purged from the
system.
NOTICE! Failure to bleed air properly will
damage elements and cause heater
malfunction.
Turn on the connected process; observe
output temperature rise to setpoint.
On standard controller, set point and output
temperatures are located side by side. On
the NEMA 4/4X controller, the top portion of
the tempearture controller displays output
temperature, bottom displays setpoint
temperature.
Turn off the connected process and check the
entire system to verify leak-free installation.
If unit is ordered with the D1 option, the
controller is shipped with this option
deactivated. Contact a Laars representative
to get the unlock code to activate the
option.
Secure the enclosure cover (standard) or door
(NEMA 4/4X).
NEMA 4 is standard on model LCTEH025.
When startup is complete, leave the two or
three pole switch or circuit breaker in the
ON position. The digital display should read
ambient temperature and OFF.

Installation
11
6
Digital Controller Operation
The preprogrammed digital controller is mounted through the bezel on the enclosure door. The digital
controller will be powered but the bottom display will read OFF until water is flowing through the heater. The
bottom display will then display the setpoint temperature (see Digital Controller Operation section for more
information).
Refer to table and drawings below for instructions on changing the desired set point temperature of the
controller.
Keys and Displays Function
Setpoint Up and Down
Buttons
In the Home Page, adjusts the set point in the right display. In other pages, changes
the upper display to a highter or lower value, or changes a parameter selection
Infinity Key Back to Home page
Advance Key Advances through parameter prompts
Output Indicators (1-5) Number lights indicate activity of outputs 1 through 5. A flashing light indicates
retransmit activity.
Setpoint Temperature
(Right Side Display)
Displays:
 Setpoint
 Percent Power
 Temperature Units °F or °C
 Menu Prompt name
 Alarm Code
Output Temperature
(Left Side Display)
Displays:
 Actual process temp. of outgoing water
 Prompt parameter value
 Error Code

Installation
12
7
NEMA 4/4X Digital Controller Operation
The preprogrammed digital controller is mounted through the bezel on the enclosure door. The digital
controller will be powered but the bottom display will read OFF until water is flowing through the heater.
The bottom display will then display the setpoint temperature (see Digital Controller Operation section for
more information).
Refer to table and drawings below for instructions on changing the desired set point temperature of the
controller.
Keys and Displays Function
Setpoint Up and Down
Buttons
In the Home Page, adjusts the set point in the right display. In other pages, changes
the upper display to a highter or lower value, or changes a parameter selection
Infinity Key Back to Home page
Advance Key Advances through parameter prompts
Output Indicators (1-5) Number lights indicate activity of outputs 1 through 5. A flashing light indicates
retransmit activity.
Setpoint Temperature
(Right Side Display)
Displays:
 Setpoint
 Percent Power
 Temperature Units °F or °C
 Menu Prompt name
 Alarm Code
Output Temperature
(Left Side Display)
Displays:
 Actual process temp. of outgoing water
 Prompt parameter value
 Error Code

Installation
13
8 Perform Operational Test No. 1 Ensure the enclosure door is closed prior to performing
operation test.
Set the 3-pole switch or circuit breaker to the ON
position.
Press the up or down arrow keys to adjust the set
temperature. The controller displays the temperature
of water measured at the outlet.
Start the water flow through the heater by starting
the process or fixture this heater is connected to in
order to activate heater.
Test water temperature and stability at outlet by viewing the display (in red) the temperature of water
exiting the heater.
When flow rate reaches approximately 0.5gpm
(1.9lpm), the flow sensor recognizes this condition
and begins the heating process.
When the flow switch activates:
 The display changes from OFF to the output
temperature, verifying power supply connection to
the heating elements via the triac switches.
 Element load lights may be solid or flash in unison
as heating elements modulate depending on the
hot water demand.
 Digital temperature controller sows water
temperature. Additional programming is not
necessary.
Heater will not energize heating elements if the inlet
water temperature is equal to or greater than the
temperature set on the digital controller.
9 Perform Operational Test No. 2 Each model has precise specifications for temperature
rise capabilities.
Turn on hot water faucet/fixture/process. The heater
should activate immediately.
Turn off hot water faucet/fixture/process.
The flow switch will deactivate and shut off power to
the heater.
If the water flow exceeds maximum heating capacity of the heater, the temperature of water at the outlet may be lower
than the temperature selected on the controller. See table below to determine maximum temperature rise capabilities.
Temperature Rise (GPM & F°)
208V, 240V,
277V, 480V kW
1 gpm
ΔT °F
1.5 gpm
ΔT °F
2 gpm
ΔT °F
2.5 gpm
ΔT °F
3 gpm
ΔT °F
3.5 gpm
ΔT °F
4 gpm
ΔT °F
5 gpm
ΔT °F
6 gpm
ΔT °F
7 gpm
ΔT °F
LCTEH005 5 34 23 17
LCTEH006 6 41 27 20
LCTEH010 10 68 45 34 27 23 20 17
LCTEH015 15 102 68 51 41 34 29 26
LCTEH018 18 122 82 61 49 41 35 31
LCTEH025 25 171 114 85 68 57 49 43 34 28 24
Temperature Rise (LPM & C°)
208V, 240V,
277V, 480V kW
3.8 lpm
ΔT °C
5.7 lpm
ΔT °F
7.6 lpm
ΔT °C
9.5 lpm
ΔT °C
11.4 lpm
ΔT °C
13.3 lpm
ΔT °C
15.1 lpm
ΔT °C
18.9 lpm
ΔT °C
22.7 lpm
ΔT °C
26.5 lpm
ΔT °C
LCTEH005 5 19 13 9
LCTEH006 6 23 15 11
LCTEH010 10 38 25 19 15 13 11 9
LCTEH015 15 57 38 28 23 19 16 14
LCTEH018 18 68 46 34 27 23 19 17
LCTEH025 25 95 63 47 38 31 27 24 19 16 13

Installation
14
Output heating capacity is reduced if these heaters are installed on 415V, 400V, or 380V 3-ph.
Contact a Laars representative to supply this information.
Satisfactory performance of the heater is dependent upon a specific flow rate vs temperature rise capability
.
If the
desired temperature is not achieved, please verify the following:
1.
Circuit breaker is on and rated for the maximum power draw
.
2.
Heater is drawing the proper current for the supply voltage on all three phases
.
3. All element load indicator lights are lit (not flashing) indicating maximum power draw and maximum amperage
is being drawn.
4. Flow rate and temperature rise in the water heating process are compatible with the heater specifications
.
5. Verify there is no additional supply of cold water entering the line downstream of the heater
.
Product Options
AL High-Low Temperature Alarm: Alerts user to an over or under temperature situation.
FDS Fused Disconnect: Internal fused disconnect interlocks with enclosure door when energized, prohibiting access
to a live cabinet
.
Select the FDS option for an additional level of safety and convenience at the heater location
.
LS (Level Sensor): Prevents accidental dry fire.
T170, T180 & T190 High Temperature Option: High temperatures as indicated (maximum of 170°F/76.7°C,
180°F/82.2°C, 190°F/87.8°C).
D1 Control Interface: Provides 4–20ma communication interface with temperature controller
.
DC Control Interface: Is an RS-485 Modbus RTU and allows Building Management Systems to view heater outlet.
TE2 Corrosive Fluid Protection: The TE2 option is a single layer of Xylan Fluoropolymeric coated heat exchanger with
bright annealed stainless steel elements, FDA Approved for Food Contact (use in deionized water applications).
N4X (NEMA 4X Enclosure): The optional NEMA 4X corrosion resistant enclosure is designed for harsher environments
and made from 16 gauge 304 stainless steel.
N4 (NEMA 4 Enclosure): The optional 18 gauge, NEMA 4 enclosure with ANSI61 gray, corrosion resistant paint.
NEMA 4 is standard on model LCTEH025.

Installation
15
Maintenance
Preventative maintenance is important for optimal performance of the heater
.
To ensure the heater works properly,
always keep the inside of the enclosure dry
.
Moisture inside an enclosure increases the humidity, which condenses
on cooler surfaces
.
This can cause electrical problems and reduce the efficiency of enclosure insulation. To prevent
problems, perform the following:
•
Verify the interior of the enclosure is dry
.
•
Verify there are no leaks in seals of enclosure and that in high humidity environments all enclosure egresses
are properly sealed.
•
Ensure plugs are in place on back side of enclosure
.
•
Check seals monthly during temperatures above 32°F (0°C) and weekly during temperatures below 32°F (0°C)
.
•
Bimetal manual reset safeties are set to trip at 175°F (79°C)
.
If this temperature is reached, the bimetal
manual safeties will trip and need to be reset
.
•
All heaters require filtration of 150 microns or smaller to ensure proper operation. Y-strainers or additional
filtration should be verified and cleaned at least every 6 months or more often in areas where hard water
sediment is present in the water.
To clean the Y-Strainer:
1. Turn the power off at the circuit breaker panel.
2. Shut off the installer supplied cold water isolation valve to the heater.
3. Relieve pressure in the plumbing lines.
4. Position a bucket under the cold water inlet to catch any water that may still be in the pipe.
5. Loosen the plumbing connection on the Y-strainer to get to the screen.
6. Remove screen and clean out debris. Use a wire brush to clean smaller particles from the screen.
7. Once the screen is clean, put it back into the Y-strainer housing and secure the plumbing connection.
8. Before switching the power back on, bleed the air out of the lines by turning heater water supply back on
and the plumbing fixture or process farthest from the heater.
9. With the air purged, turn on all circuit breakers supplying the water heater.
•
At the same time the Y-strainer or additional filtration is cleaned, it is a good practice to also check all valves
connected to the system. With no water flow through the heater, work both the inlet ball valves and the
outlet gate valves open and shut to break up any calcium deposits that may have formed from the valve being
open for an extended period of time. Power to the heater does not need to be turned off to do this.

Installation
16
Troubleshooting for Controller
Problem Solution
No Power Verify power is on
.
Turn power off
.
Check continuity of all internal fuses in control
transformer, heating elements or optional fused disconnect
circuits
.
Check all field service circuit breakers or fuses
.
Check system temperature limit control to make sure it has not
activated due to excessive heat exchanger temperature or faulty
sensor
.
Turn power off
.
Check for loose or disconnected wires
.
Check the incoming service connection. Voltage must match
name plate rated voltage. Labels are located on the upper left of
back plate (Serial Number Label).
Alarms do not occur. Make sure alarm set points are correct.
Make sure alarm is not latched.
Make sure alarm side settings are correct.
Make sure alarm type settings are correct.
Make sure alarm controller is not in diagnostic mode.
Alarms do not clear. Check power limit setting.
Check operation mode.
Check alarm output function.
Check temperature setting.

Installation
17
Basic Troubleshooting
Problem Solution
The heater does not work or works intermittently.
1. Flow switch works properly.
2. At the wires from the flow switch, ohm meter should
read Open without flow and Closed with flow.
3. Water flow through the heater is adequate to activate
the flow switch at 0.5 gpm (1.9 lpm) or at the low flow
options of 0.15 (0.6 lpm) or 0.25 (0.9 lpm) gpm.
4. Heater is wired with the proper breaker and wire size.
5. Refer to Electrical Specificaitons for Heater table in
section 3 for proper requirements.
Unit is receiving voltage from all three phases of the
power source. A load voltage reading is also helpful.
Turn power OFF before recording any Ohm readings.
If the above steps do not solve the problem, some additional checks may be performed. Follow the schematic
to perform the following continuity checks:

High temperature bimetals (Manual Reset Safeties)
.

Optional ground fault breaker must be in the closed position for the unit to work.

All internal breakers must be in the ON position for the unit to work.
For additional information on Troubleshooting or other information, contact Laars Technical Support.
Please have Model No
.
and Serial No
.
available when seeking technical assistance
.
Serial No
.
tag is located
in the enclosure on the upper left hand corner of the back plate
.
Please record and maintain this information at all times:
H Series Model No.
Serial No.

Installation
18
Special Installation and Operating Instructions
Tankless Water Heaters with Optional D1 or DC Controller Options
Pin-Out Diagram for Electrical Wiring
The controller is shipped with the D1 option deactivated. Contact Laars to get the unlock code to activate the
ption.
DC Option Pin-Out D1 Option Pin-Out
Pin Name Description Pin Name Description
T+/R+2 RS-485 Transmit/Receive
Non-Inverting Input/Output Negative3 Return Current Path for +Current, Pin 4
3 Signal
Ground +Current4Signal Ground Supply 4-20mA Current to Set Heater Temperature
T-/R-4 RS-485 Transmit/Receive
Inverting Input/Output Negative7 Return Current Path for +Current, Pin 8
1, 5,
6-9 +Current8No Connection--
Supply 40-20mA Current to
Monitor Heater
Temperature
1, 2, 5,
6, 9 No Connection

Installation
19
Table of Parameters for DC Option: RS-485 Modbus
Parameter Name Range Map 1 Map 2 Default Data Type
Read/
Write H Series Meaning
Analog Input -1999.000 to 9999.000 °F
-1128.000 to 5537.000 °C 360 360 -- Float R Process Value
Analog Input Error
None (61)
Open (65)
Fail (32)
Shorted (127)
Measurement Error (140)
Bad Calibration Data (139)
Ambient Error (9)
RTD Error (141)
Not Sourced (246)
362 362 None UINT R Process Value Sensor Error
Calibration Offset -1999.000 to 9999.000 °F
-1128.000 to 5537.000 °C 382 382 Factory Set Float RWES Process Value Calibration
Digital in 5 Inactive (41)
Active (5) 1328 1568 -- UINT R Flow Activation
Digital out 6 Off (62)
On (63) 1042 1162 -- UINT R AL Only Alarm Status
EZ-KEY Inactive (41)
Active (5) 1328 1608 -- UINT R EZ-Key
Control Mode Active
Off (62)
Auto (10)
Manual (54)
1882 2362 Auto UINT R Control Loop Mode
Heat Power 0.0 to 100.0% 1904 2384 -- Float R Duty Cycle Output %
Set Point -1999.000 to 9999.000 °F
-1128.000 to 5537.000 °C 2172 2652 -- Float R Heater Set Point
Remote Set Point
No (59)
Yes [phone] No UINT RWES Remote Set Point Enable
Remote Set Point Type
Auto (10)
Manual (54) 2202 2682 No UINT RWES Remote Set Point Control Mode
Process Value -1999.000 to 9999.000 °F
-1128.000 to 5537.000 °C 402 402 Float R Process Value
Control Mode
OFF (62)
Auto (10)
Manual (54)
1880 2360 Auto UINT RWES Control Loop Mode
Close Loop Set Point
40-160 std
40-170 T170 Option
40-180 T180 Option
40-190 T190 Option
2160 2640 Factory Set Float RWES
Heater Set Point
Open Loop Set Point 0 to 100.0% 2162 2642 -- UINT RWES Manual Mode Set Point
Display Units
Fahrenheit (30)
Celsius (15) 1838 2308 °F UINT RWES Controller Display Units
Address Modbus 1-247 2482 2962 1 UINT RWE Modbus Address
Baud Rate
9600 (188)
19200 (189)
38400 (190)
2484 2964 9600 UINT RWE Modbus Baud Rate
Parity Modbus
None (61)
Even (191)
Odd (192)
2486 2966 None UINT RWE Modbus Parity
Modbus Units Fahrenheit (30)
Celsius (15) 2490 2970 °F UINT RWE Communication Units
Modbus Word Order
Low-High (1331)
High-Low (1330) 2488 2968 Low-High UINT RWE Modbus Word Order
Non-Volatile Save
Yes (106)
No (59) 2494 2974 Yes UINT RWE
If set to yes, all values to the
control will be saved from
EEPROM
NOTICE! For adjusting Modbus address, baud rate and
parity, customer needs to set on controller per
manufacturer's (Watlow) manual.
Legend
Uint=Unsigned 16 bit int string=ACSII (8 bit per character)
Dint=Long 32 bit float=IEEE 754 32 bit
RWES=Readable, Writeable, EEPROM (saved), User Set (saved)