Haws TWBS.EW.H Guide

09/19 Model TWBS.EW.H Page 1 of 11
1455 Kleppe Lane Sparks, NV 89431-6467 [phone] Fax [phone]
E-mail: [email protected]  website: www.hawsco.com
No. 0002080380 (12)
IF YOU NEED ASSISTANCE FROM OUR TECHNICAL SERVICE DEPARTMENT, MAKE
SURE YOU CAN IDENTIFY THIS WATER HEATER BY HAVING THE SERIAL NUMBER.
Model No. TWBS.EW.H
Serial No.
INSTALLER/ CONSUMERRESPONSIBILITIES
PLEASE TAKETHE TIME TO READ NOT ONLYTHIS MANUAL BUT ALSO
THE WARRANTY CARD ENCLOSED.WARRANTY OF THIS HEATERWILL DEPEND ON
PROPER INSTALLATION,OPERATION,AND REQUIRED MAINTENANCE. THE
WARRANTY SHALL BE VOID IF THE DESIGN OR STRUCTURE OF THE WATER
HEATERHAS BEEN ALTERED IN ANYWAYWHATSOEVER.THE MANUFACTURER OF
THIS WATERHEATERWILL NOT BE LIABLE FOR ANY DAMAGES BECAUSE OF
FAILURETO COMPLYWITH THE INSTALLATION
AND OPERATINGINSTRUCTIONS OUTLINED ON THE FOLLOWING
PAGES. IFYOUREQUIREANYHELPOR HAVEANYQUESTIONS
RELATINGTOTHE
INSTALLATIONOR PERFORMANCE OF THIS HEATER,PLEASE CALL OUR
TECHNICAL SERVICEDEPARTMENT:
800-766-5612 OR CUSTOMER SERVICE 1-888-640-4297
HAVETHE INFORMATION LISTED BELOW BEFORE CALLING.
WARNING
BEFORE ATTEMPTING INSTALLATIONOF THIS UNIT OR MAKING ANYADJUSTMENTS
TO THE UNIT ALWAYSBE SURE MAIN CIRCUIT BREAKER IS OFF TO PREVENT DANGER
OFSERIOUS ELECTRIC SHOCK.
Model TWBS.EW.H
Tempered Water Blending System
INSTALLATION, OPERATION
&
MAINTENANCE INSTRUCTIONS

09/19 Model TWBS.EW.H Page 2 of 11
RECOMMENDED TOOLS: Teflon thread seal tape, adjustable pipe wrenches, (Quantity 4)
rust resistant wall anchors (3/16” diameter). Do not use pipe dope.
LOCATION OF UNIT: The Model TWBS.EW.H should be located as near as possible to the
point of use. It must be installed in a vertical position with the inlet and the outlet at the bottom.
SUPPLY LINE: The minimum recommended line size is 1/2" IPS with 45-90 psi (3-6 ATM)
flowing pressure at supply inlet. Cold supply temperatures should range from 35⁰F to 75⁰F.
Where sediment or mineral content is a problem, an inlet filter is recommended.
ELECTRICAL CONNECTIONS: The unit requires 480 VAC/3-phase/60Hz power in a “Delta”
configuration, including three power leads, and a ground conductor, each sized for the
system’s maximum amperage of 24A. The maximum power draw of the system is 20kW.
The customer is responsible for providing a local fused disconnect switch or circuit breaker
sized accordingly.
PLUMBING CONNECTIONS: Inlet supply is female 1/2" NPT, Outlet is female 1/2” NPT.

09/19 Model TWBS.EW.H Page 3 of 11
INTRODUCTION
What is the HAWS TWBS.EW.H?
The HAWS TWBS.EW.H is an instantaneous water heating system for use on emergency
eyewashes where hot water is not supplied. When there is a demand for water at the eyewash,
the heater will instantaneously heat the water to 80º F. The unit requires 480VAC/3-phase/60Hz
power in a ”Delta” configuration, including three power leads and a ground conductor, each
sized for the system’s maximum amperage of 24A. The maximum power draw of the system is
20 kW.The customer is responsible for providing a local fused disconnect switch or circuit
breaker sized accordingly. The Haws TWBS.EW.H incorporates thermally activated and
pressure activated safety features that prevent scalding and improper flow to the eyewash, even
in the event of main unit failure.
How does the TWBS.EW.H operate?
The heart of the TWBS.EW.H is an instantaneous heater that maintains the output water
temperature at 80º F. On the warm water outlet we include a high limit shut off valve, which
reads the output temperature. When the output temperature exceeds the factory pre-set limit of
95º F, the valve shuts down the output from the heater.
On the cold-water side, we include a bypass valve. Should the heater become blocked or the
high limit shut off valve closes, the bypass valve will open, allowing the incoming cold water to
bypass the system and proceed directly to the eyewash.
These two back-up components permit the temperature level of the heated water to be
maintained and permit the flow of cold water should the heater fail.
Performance Features of the HAWS TWBS.EW.H System
Essentially, the HAWS TWBS.EW.H provides fail-safe protection against scalding or blocked
flow. There are two types of failures that can occur with any water heating system. They are as
follows:
1. The heater can fail and provide an unregulated flow of hot water.
2. The heater can fail so as to provide an insufficient and/or blocked flow of warm water.
The unique HAWS TWBS.EW.H provides a high limit shut-off valve and a bypass valve to
address both failure modes.
Capacity
HAWS TWBS.EW.H produces up to 4 gpm at a 45-psi dynamic inlet pressure. The warm water
heater is designed to activate by individual electronic flow rate switches, at a minimum turn on
flow rate of no less than .95 gpm. This unit is sized for one eyewash.
Max
output
@480V
Current
Per phase
Temperature Rise (⁰F)GPM
2.0 gpm
3.0 gpm
4.0 gpm
T3 EE Only
5 gpm
T3 EE Only
6 gpm
20kW
24 AMPS
68
46
34
27
23

09/19 Model TWBS.EW.H Page 4 of 11
INSTALLATION PROCEDURE
This installation must conform to the latest requirements of the National Electrical Code and all
applicable state and local codes. This information is available through your local authorities. You
must understand and comply with these requirements before beginning this installation. Haws
recommends your heater be installed by a licensed plumber and electrician.
For additional information, read and follow manufacturers “Instantaneous Water Heater”
installation and owner’s manual supplied with unit.
CAUTION: THIS UNIT IS INTENDED FOR INDOOR USE ONLY.
APPLICATION
The standard TWBS.EW.H is sized to heat enough water for one eyewash at a time. This Water
Heating System should be installed in close proximity to the eyewash. It should be clearly
identified, with easy access and free from obstructions. Supply lines connected to this unit must
be heat traced if subject to freezing temperatures. If the piping network from the heater (located
indoors) to the fixture passes through a cold area, piping should be heat-traced with self-
regulating heat tape. Any heat-traced piping should be protected with scald protection bleed
valves. Additionally, should the TWBS.EW.H be mounted at a distance greater than 50 feet from
the eyewash, these runs should be evaluated by a plumbing engineer. Complicated chains of
eyewashes, long piping runs, and recirculating loops should all be evaluated by a qualified
engineer.
NOTE: If for any reason the heater is starved of water while power remains on, the unit may be
damaged. Also, the heating elements only turn on under flow, so any water within the heater
will be subject to atmospheric conditions most of the time. Therefore, the heater should never
be stationed outdoors or in a freezing environment.
GENERAL
To obtain optimum performance and energy savings from your Haws heater, the unit should be
located as near as possible to the point of use. The unit must only be installed in a vertical
position with the inlet and outlet at the bottom.
The power is activated by individual electronic flow switches located in each of the three heating
modules. These modules will be damaged by excessive heat; do not solder any pipes that are
in contact with the heater.
Also ensure pipes are clear of installation debris before fitting the heater, otherwise the switches
could jam in the “on” position. The unit must be connected to its own individual electrical flow
circuit protected by a suitably rated three pole breaker. The maximum voltage which can be
applied across any heating module is 480 volts.
WARNING
Improper installation, adjustment, alteration, service or maintenance can cause DEATH,
SERIOUS BODILY INJURY OR PROPERTY DAMAGE. Refer to this manual for assistance
or consult the local electric utility for further information
WARNING
Failure to ground the system may result in death or serious injury.

09/19 Model TWBS.EW.H Page 5 of 11
WATER SUPPLY
The minimum recommended supply line is 1/2" IPS COLD. Cold supply temperatures should
range from 35°F to 75°F. Outlet connection is a 1/2" NPT dielectric union. We recommend a
manual bypass loop with appropriate tamper resistant shut-off valves to allow for heater water
system maintenance or service without interrupting emergency eyewash operation.
INSTALLATION PROCEDURE...
PROCEDURE
Use Teflon thread seal tape on all water connections. Do not use pipe dope. This unit
should be mounted as close to the point-of-use as possible.
STEP 1: Mount unit on wall (This unit is intended for indoor use only) per attached
installation drawing. Bolt dia. 3/16” fasteners through heater box. Unit must be installed
in the vertical only, with the inlet and outlet at the bottom. The cold water inlet is on the
right hand side and the hot water outlet is on the left. Under no circumstances can
these be changed. Leave a minimum of 8” clearance above the unit to facilitate
heating element replacement.
STEP 2: Flush supply piping thoroughly prior to connecting to inlet unions. Connect outlet union
to piping leading to eyewash. Check for leaks. Run water through the supply pipe to
remove all debris from the pipe before connecting the heater: Failure to do so could
cause damage to the flow switch. Run water through the supply pipe to remove all
debris from the pipe before connecting the heater. Failure to do so could cause
damage to the flow switch.
The unit should be installed in the plumbing system in such a way that there is no
tendency for the unit to be starved of water. For example: an excessive draw-off of
cold water just before the unit. Also, do not fit an unrestricted hot water draw-off point
below the heater as this will tend to empty the heater by siphoning.
NOTE
ALL MOUNTING AND PLUMBING MUST BE COMPLETE BEFORE
YOU PROCEED WITH ELECTRICAL HOOK-UP. TEST THE
INSTALLATION FOR LEAKS BEFORE CONNECTINGTHE
ELECTRICAL SUPPLY.

09/19 Model TWBS.EW.H Page 6 of 11
ELECTRICAL HOOK-UP
This heater must have its own independent circuit using four wires; three live and one earth
ground, of the appropriate rating protected by the correctly rated three pole breaker.
STEP 1: ELECTRICAL CONNECTION: a 1-3/8” hole on the bottom of the unit is provided for
customer connection. Customer to supply 480VAC/3-phase/60Hz power in a ”Delta”
configuration, including three power leads and a ground conductor, each sized for the system’s
maximum amperage of 24A. The customer is responsible for providing a local fused disconnect
switch or circuit breaker sized accordingly. The maximum power draw of the system is 20 kW.
STEP 2: TEST FUNCTION OF UNIT
Turn on eyewash. Carefully monitor initial few minutes of flow with hand in eyewash flow. Check
to ensure initial flow does not contain brief shots of hot water. See troubleshooting if any
problems.
IMPORTANT: REPEAT TEST PROCEDURE WEEKLY!
THIS UNIT MUST NOT BE CONNECTED IN STAR CONFIGURATION
WARNING
FAILURE TO GROUND THE SYSTEM MAYRESULT IN DEATH OR
SERIOUS INJURY
WARNING
HAZARD OF ELECTRICAL SHOCK! BEFORE BEGINNING ANY WORK ON THE
INSRALLATION, MAKE SURE THE ELECTRICAL SUPPLY TO THE HEATER IS TURNED
“OFF”. FALIURE TO DO THIS COULD RESULT IN DEATH, SERIOUS BODILY INJURY,
OR PROPERTY DAMAGE.
WARNING
WATER HEATERS EQUIPPED FOR ONE VOLTAGE ONLY: CHECK THE RATING PLATE
ON THE FRONT OF THE UNIT. DO NOT USE THIS WATER HEATER WITH ANY
VOLTAGE OTHER THAN THE ONE SHOWN ON THE MODEL RATING PLATE. FAILURE
TO DO SO CAN RESULT IN DEATH, SERIOUS BODILY INJURY, OR PROPERTY
DAMAGE. IF YOU HAVE ANY QUESTIONS OR DOUBTS CONSULT YOUR ELECTRIC
COMPANY.

09/19 Model TWBS.EW.H Page 7 of 11
COMMISSIONING YOUR HEATER
1) With inlet and outlet BALL VALVES fully open, turn on a hot water outlet.
2) Run for 3 minutes.
3) Switch on electric supply at circuit breaker panel.
4) The power indicator lights should now come on.
NOTE: At this point water temperature may not be hot. “EE”units are preset to deliver tepid
water only.
5) Using the OUTLET BALL VALVE slowly reduce water flow until desired temperature is
achieved at hot water outlet.
NOTE: The water temperature is regulated by the flow through the heater. The lower the flow
the higher the temperature and vice versa.
6) If water does not achieve desired temperature, please call technical services.
TROUBLESHOOTING
SYMPTOM: NO HEAT - INDICATOR LIGHT OFF
1) ELECTRIC SUPPLY IS OFF - Turn on the main circuitbreaker.
2) NO OR LOW WATER FLOW
Ensure that the minimum flow rate to turn on your heater is met: 0.95 GPM. Also check
that the inlet filter screen is clear from any debris.
3) WATER CONNECTIONS ARE REVERSED
Cold water inlet = right side, hot water outlet = left side.
4) ELEMENT BURNED OUT TURN OFF THE MAIN BREAKER!
IMPORTANT
Before switching “on”the power at the main circuit breaker panel make sure
that the hot water circuit is free of air pockets or premature failure of the heating
element will occur. To do this open all hot water fixtures one at a time for
several minutes until the water flow is continuous and free from “gulping”and
from visible air pockets.

09/19 Model TWBS.EW.H Page 8 of 11
Using an ohmmeter test the resistance of the heating element across the two threaded
termination rods on top of the element.
See the front cover of this manual for the correct value.
If the resistance is much greater than the correct value, call your supplier for a
replacement element.
SYMPTOM: NO HEAT OR LOW TEMPERATURE WITH INDICATOR LIGHT ON
1) WATER FLOW TOO HIGH
Reduce the water flow by using an outlet ball valve. Temperature rise is 41° at 4 GPM.
2) INCORRECT POWER SUPPLY
Make sure that the unit is connected to the voltage supply specified on the rating label on
the front cover of the unit and no other.
3) ELEMENT BURNED OUT- TURN OFF THE MAIN BREAKER!
Repeat the steps from paragraph 4 above.
4) THERMOSTAT ADJUSTMENT SCREW NOT TURNED UP
Turn the thermostat adjustment screw clockwise in small increments until the indicator light
remains on. Take care not to force the screw past its stop position.
REPLACEMENT PARTS
DESCRIPTION
QUANTITY
Temperature Gauge, 1/2”
1
Heater
1
Bypass Valve, 1/2"
1
Hot Shut-off Valve, 1/2”
1
For more information about Haws products, see our website: www.hawsco.com.
© 2019 Haws®Corporation –All Rights Reserved
HAWS® and other trademarks usedin these materials are the exclusive property of Haws Corporation.

09/19 Model TWBS.EW.H Page 9 of 11

09/19 Model TWBS.EW.H Page 10 of 11

4-1/4"
108mm
6"
152mm
8"
203mm
MINIMUM CLEARANCE
ABOVE UNIT
34-5/8"
879mm
POWER IN
(NOT SUPPLIED)
12-1/4"
311mm
UNIT MUST BE INSTALLED
IN THE VERTICAL POSITION
OR PERMANENT DAMAGE TO
THE HEATER WILL RESULT
UP
7-1/4"
184mm
1"
25mm
10-13/16"
275mm
10-1/2"
267mm
4X
3/16"
4.8mm
MOUNTING
HOLES
COLD
INLET
HOT
OUTLET
EYEWASH
(NOT SUPPLIED)
NOTES:
1. CAUTION: THIS UNIT IS INTENDED
"FOR INDOOR USE ONLY"
TEMPERATURE
GAUGE
HOT
SHUTOFF
VALVE
PRESSURE
BYPASS
VALVE
50 MICRON
FILTER
1/2" IPS
DIELECTRIC
UNION
(INLET & OUTLET)
HEATER
480VAC
3 PHASE
20kW
1"
25mm
1-3/4"
44mm
(CAUTION:THIS
UNIT IS
INTENDED
FOR INDOOR
USE
ONLY)
3. DIMENSIONS MAY VARY BY:
± 1/2" [12.7mm].
15-1/4"
387mm
2. USE TEFLON THREAD SEAL TAPE
ON ALL WATER CONNECTIONS.
DO NOT USE PIPE DOPE.
APPROVED:
DRAWN:
PART NUMBER
SCALE: SHEET OF
REVISION
DRAWING TYPE: SIZE: A
BY:ECN NO.
PAGE
DATE:
DATE:
ECN:
REVISED PER
CHK'D.:
Haws Corporation - All Rights Reserved. HAWS and other trademarks used in these materials are the exclusive property of Haws Corporation.
CR
MODEL(S)
1455 KLEPPE LANE
SPARKS, NEVADA 89431
[phone] FAX [phone]
E-MAIL: [email protected]
WEBSITE: WWW.HAWSCO.COM
THIS DOCUMENT IS TRUE AND CORRECT AT TIME OF PUBLICATION. CONTINUED PRODUCT IMPROVEMENTS
MAKE SPECIFICATIONS AND MEASUREMENTS SUBJECT TO CHANGE WITHOUT NOTICE.
RTM
04/30/04
12
0002080380.D
TWBS.EW.H
1:10
11
IR 09/17/19
4796
DP
11 OF 11
INSTALLATION
5418
2019
FV