Haws 8760 Guide

HAWS®P/N 0510000456 Rev.5 10/19 Model 8760 Page 1 of 29
1455 Kleppe Lane Sparks, NV 89431-6467 [phone] Fax [phone]
E-mail: [e-mail]  Website: www.hawsco.com
No. 0510000456(5)
Model 8760
Tempering Skid with Shower and Eyewash
General Area Classification & Class I Division 2
INSTALLATION, OPERATION
&
MAINTENANCE INSTRUCTIONS

HAWS®P/N 0510000456 Rev.5 10/19 Model 8760 Page 2 of 29
DISCLAIMER
For technical support, contact:
Haws Services | [phone] | www.hawsco.com/services
IMPORTANT
Read this installation manual completely to ensure proper installation, then file it with the owner or
maintenance department. Compliance and conformity to drain requirements and other local codes and
ordinances is the responsibility of the installer.
S
eparate 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.
Flush the water supply lines before beginning installation and after installation is complete. Test the unit
for leaks and adequate water flow. Main water
supply to the emergency fixture should be “ON” at all
times. Provisions shall be made to prevent
unauthorized shutoff. Please refer to the enclosed
instructions for flushing the unit prior to use.
The ANSI Z358.1 standard requires an uninterrupted supply of potable water. Haws plumbed Model
8760 requires the user to supply 45-90 PSI flowing water pressure to the unit inlet connection.
The inspection and testing results of this equipment should be recor
ded weekly to verify proper
operation. This equipment should be inspected annually to ensure compliance with ANSI Z358.1.
Installation and maintenance of this system must be completed by a qualified plumber and electrician in
accordance to the information contained in this installation manual and in compliance with all national
and local codes. When making electrical connections, be sure to follow all lockout-tag out safety
procedures.
It is recommended that all water supply and electrical connections be made at temperatures above
freezing (32ºF (0ºC)). Failure to do so may result in major product and/or property damage.

HAWS®P/N 0510000456 Rev.5 10/19 Model 8760 Page 3 of 29
TABLE OF CONTENTS
Tempering Skid with Shower and Eyewash.............................................................................................1
General Area Classification & Class I Division 2.....................................................................................1
DISCLAIMER................................................................................................................................................2
TABLE OF CONTENTS ...............................................................................................................................3
PERFORMANCE SERIES 8760 MODEL CONFIGURATIONS...................................................................4
SHIPPING, HANDLING AND STORAGE ....................................................................................................5
INSTALLATION PROCEDURE....................................................................................................................6
Checklist for start-up ..............................................................................................................................9
Tank Control ..........................................................................................................................................11
Alarm Modes – US & [CANADA] ..........................................................................................................11
Messages................................................................................................................................................12
Real Time Clock (RTC)..........................................................................................................................12
Flow Alarms ...........................................................................................................................................13
Fault Condition Notification .................................................................................................................13
Maintenance Required Notification .....................................................................................................13
Tank Monitor..........................................................................................................................................14
Tank History...........................................................................................................................................14
Setting Current Time and Date on the Controller ..............................................................................14
PREVENTATIVE MAINTENANCE.............................................................................................................15
Weekly ....................................................................................................................................................15
Monthly...................................................................................................................................................15
Quarterly.................................................................................................................................................15
Annually..................................................................................................................................................16
SYSTEM DRAIN AND CHECK PROCEDURE:.........................................................................................17
MAINTENANCE, TESTING, REPAIR ........................................................................................................20
Blending Valve System .....................................................................................................................20
Combination Shower/Eyewash ........................................................................................................20
Freeze and Scald Valve.....................................................................................................................20
Y-Strainers..........................................................................................................................................21
TROUBLESHOOTING................................................................................................................................22
SPARE PARTS...........................................................................................................................................23
DRAWINGS ................................................................................................................................................26
Generalized Installation Drawing (8760.21.31-GA).........................................................................26
Generalized Electrical Schematic (8760.2X.31-E)...........................................................................27
Generalized Piping and Instrumentation Diagram (8710.21.31 & 8760.21.31 P&ID)...................28
LIMITED WARRANTY................................................................................................................................29

HAWS®P/N 0510000456 Rev.5 10/19 Model 8760 Page 4 of 29
DESCRIPTION OF PRODUCT
Haws Corporation Performance Series model 8760 tempered water system is situated upon a fiberglass
skid. The bright yellow, fiberglass skid is waterproof, chemically resistant, and protected with UV inhibitors
for a long-lasting finish. Large green graphics identify the unit as an emergency shower/eyewash station.
The unit includes a local area light for user safety and comfort.
This system includes several configurations; please reference the Performance Series 8760 Model
Configurations table shown below.
Hot water, generated via 4kW or 6kW immersion heater (determined by tank size), is stored in a chosen
tank size of 119, 120, 200 or 330 gallons. Hot and cold water are mixed with an engineered blending
system to provide warm water for one or two (in the case of a 330-gallon tank) combination shower/eyewash
unit(s) running at a maximum of 30 GPM. The ASSE 1071 certified blending system is a safe, prepackaged,
fully engineered and tested system for blending large volumes of hot and cold water specifically designed
for emergency showers and eyewashes. The system provides multiple levels of protection to prevent
scalding, including a high temperature shutoff valve. Also included is a pressure relief cold-water bypass
that allows full cold flow in the event of a hot water shut off. There are no electrical components in the
blending system.
The 8760 skid includes a Haws®combination shower and eyewash that is protected with freeze and scald
valves. A flow switch activates the alarm system when the shower and/or eyewash are in use. The alarm
system includes both visual and audible alarm and a silencing circuit with auto reset. Dry contacts are
provided for remote alarm hookup.
PERFORMANCE SERIES 8760 MODEL CONFIGURATIONS
8760.2X.3XX
8760
.2X
.3X
X
.21
119 Gallon
.31
NEMA 4
Blank (No Number) = Standard
480V, 3PH
.22
120 Gallon
.32
C1D2
1
208V, 1PH
.23
330 Gallon
2
208V, 3PH
.25
200 Gallon
3
240V, 1PH
4
240V, 3PH
5
600V, 3PH

HAWS®P/N 0510000456 Rev.5 10/19 Model 8760 Page 5 of 29
SHIPPING, HANDLING AND STORAGE
Performance
Series Model
Description
Dimensions
W x L x H
Weight
Dimensions
W x L x H (Crated)
Weight
(Crated)
8760.21.3X
Indoor Tempered
Water Shower and
Eyewash System 60” x 60” x 102”
1200 lbs.
69” x 69” x 106”
1550 lbs.
8760.22.3X
1200 lbs.
1550 lbs.
8760.23.3X
1700 lbs.
2100 lbs.
8760.25.3X
1250 lbs.
1600 lbs.
Recommended Equipment, Materials and Supplies to be provided by Installer:
•Concrete slab rated to support a minimum of 6,000-pound load requirement.
•(4) 3/4” minimum diameter by 1-1/2" minimum length anchor bolts with washers.
•A forklift capable of lifting 5,000 lbs. should be utilized to transport the unit from truck to site. The
unit should be lifted from the rear, or equipment end, and low to the ground.
•Electrical Supply Materials (if applicable).
•Plumbing Supply Materials (if applicable).
•Freeze protection equipment for the water supply leading up to the enclosure (if applicable).
Storage
The unit should be stored in a clean, dry place until ready for installation unless otherwise specified.
WARNING: DO NOT connect power before plumbing and supply and drain lines. Connections
should be performed by a certified electrician and plumber only.

HAWS®P/N 0510000456 Rev.5 10/19 Model 8760 Page 6 of 29
INSTALLATION PROCEDURE
a. Remove unit from crate.
b. The unit should be secured on a level site, using the supplied brackets and suitable anchoring
devices. Suggested anchoring devices are 3/4” minimum diameter by 1-1/2" minimum length
anchor bolts with washers.
c. If the skid shower is to be placed over a drain, the drain should be able to handle a flow of 35 GPM;
otherwise, the slab should allow the water to drain away from the skid (see Figure 1). Haws strongly
recommends careful planning for unit drainage. The unit discharges hundreds of gallons of water,
which can cause significant property damage if not drained properly.
Figure 1. Example of Slab with Drain Trough
WARNING: Failure to allow water to drain may result in premature failure of the skid, voiding of
product warranty, and property damage. (See System Drain and Check Procedure on page 17)
d. The expansion tank should be pre-charged with compressed air to a pressure equal to the water
supply pressure. An air fitting (Schrader valve) is accessible on the top of the expansion tank,
under the plastic cap (see Figure 2).

HAWS®P/N 0510000456 Rev.5 10/19 Model 8760 Page 7 of 29
Figure 2. Top of Expansion Tank
e. The connection provided for the water supply is a 1-1/2” NPT union. Supply lines are required to
be capable of supplying 30 GPM of potable water at a dynamic pressure of 45-90 psi. The water
supply line should run for a few minutes prior to connection to eliminate any debris before it enters
the equipment.
f. Electrical supply connection must be made to the disconnect switch (see Figure 3).
Figure 3. Disconnect Switch Junction Box
CAUTION: Do not switch on power to the unit until all water connections are made and the tank and
piping are full of water.
g. Once all water and power connections are made, open the supply water inlet valve and fill the
system. While water is flowing into the system, open the emergency shower to facilitate air removal
from the system. After water flows freely from the shower for several minutes, turn the shower off.
Inspect plumbing for leaks and repair as necessary. During transit, some plumbing may have
become loose, allowing water to leak from the threads.

HAWS®P/N 0510000456 Rev.5 10/19 Model 8760 Page 8 of 29
CAUTION: Before turning on the power, close all electrical boxes.
h. At this point the power can be turned on. The tank water must be allowed to heat up before the
blending system will function properly. Heating can take up to 12 hours, depending on supply water
temperature and size of immersion heater and tank. The area/alarm light may blink until tank
temperature set point is reached.
NOTE: The emergency shower or eyewash (see Figure 4) should be utilized for testing of the blending
system. Refer to the Maintenance, Testing, and Repair section of the TWBS.HF Blending System Manual
document for proper adjustment and operation.
Figure 4. Eyewash
WARNING: Unit includes a freeze protection valve which may help prevent damage in the event of
accidental short-term exposure to low temperatures. This unit is not designed for exposure to
freezing conditions. It is recommended that installation be indoors in a non-freezing location.

HAWS®P/N 0510000456 Rev.5 10/19 Model 8760 Page 9 of 29
Checklist for start-up
CHECKLIST
Complete
OK
Inspector
Initials
Pre-connection Check
Check all components for any connections or connectors that may have loosened
during shipping.
System Flush (All Electrical Power off for System Flush)
Verify that a minimum of 45 psi and maximum 90 psi is supplied to the inlet of the hot
water tank.
Drain is attached and able to handle a flow of 35 GPM.
System water supply is connected and all water supply valves opened.
Water is clear and free of any contamination, particles, or discoloration.
Connections
System is charged with water and all air is evacuated from the system.
Expansion tank Schrader valve is charged with air equal to water static inlet pressure.
Connect remote monitoring via plant control system (if applicable).
Applying Power to the System
Verify that the proper voltage is present.
Verify that equipment ground is properly connected.
Apply power to the system.
The tank heater set point is preset in the program. It may take 12 hours for the tank to
reach the operating temperature. Once the tank has reached operating temperature for
a minimum of 1 hour, press the “↑” arrow and record these values in the chart provided
in the Tank Monitor section of the program narrative included in this manual.
Verify that the exterior lights are illuminated (if equipped). The exterior light may flash
off for 1 second at 5 second intervals until the tank has reached operating
temperature. See Logic Narrative for more information.
HAWS®Shower and Eye/Facewash
Flow water through an eyewash or shower.
Verify that the exterior light flashes at 1 second intervals and that the audible alarm
sounds.
Press the alarm silence button and verify that the exterior light is flashing, and the
audible alarm is silent.
Deactivate the shower or eyewash that is active, verify that the exterior light is not
flashing, and that the audible alarm is silent.
Blending Valve
When shower is activated read the center temperature gauge directly above the
blending valve to ensure to the readout is 85ºF (29ºC) ± 5ºF
Programmable Logic Controller Display
Set the current time and date in the controller (see instructions on page 14).

HAWS®P/N 0510000456 Rev.5 10/19 Model 8760 Page 10 of 29
LOGIC DIAGRAM AND NARRATIVE
The program allows for monitoring and controlling the tank temperatures. When no faults are present, the
tank temperature, tank heater status, and flow status are displayed (see Figure 5). There are several alarm
points that are continuously monitored. These alarms are shown on the display as long as the fault is
active. Alarm conditions may also be monitored by connecting to a Distributed Control System (DCS) via
interposing relays and terminals provided. See generalized electrical schematic for details (page 26). A
fault history is also provided to assist in monitoring the system performance. Additionally, the tank heater
performance can be monitored to assist in determining when maintenance is required.
Figure 5. PLC Display
Accessing the different functions is accomplished by depressing the appropriate key(s) on the display. The
table below lists the key functions:
Key
Function
←
Display Fault History
↑
Display Tank Heater Monitor
→
Display Current Time
↓
Display Current Date
0
Reset High Tank Temp Alarm
0 & 2
Local Alarm Light Function (Off)
1 & 3
Local Alarm Light Function (On)

HAWS®P/N 0510000456 Rev.5 10/19 Model 8760 Page 11 of 29
The following table lists the inputs and outputs used in the system.
NOTE: For model specific program, please contact Haws Services at 1-800-766-5612.
Input
Function
Output
Function
I-00
Flow Switch *
Q-00
Tank Heater Contactor
I-01
Horn Silence Button *
Q-01
Space Heater Contactor *
I-02
Level Switch
Q-02
Alarm Light *
I-03
Booth Thermostat *
Q-03
Horn *
AI-02
Tank Temperature Thermocouple
Q-04 (TC Q-00)
Customer Contact (Trouble)
AI-03
Booth Temperature Thermocouple *
Q-05 (TC Q-01)
Customer Contact (Flow) *
*Not used on this model
The program consists of a series of charts (sub-routines) that are grouped according to function. Each
chart will be discussed in the following sections.
Tank Control
When the tank temperature is below 163°F (72°C), or 144ºF (62ºC) for Canada, the tank heater contactor
will close and the heater elements will be energized. When the temperature rises above 166°F (74°C), or
146ºF (63º) for Canada, the contactor will open and the element will become de-energized.
A low-level condition or an over-temperature condition (that has not been addressed) will prohibit the
contactor from closing even if the temperature is below the set point. If the tank thermocouple reading falls
below 32°F (0°C) a potential thermocouple failure is present and the tank heater contactor will not close.
The customer trouble alarm contacts are monitored in this section of the program. The following conditions
will de-energize output Q-04 (customer contact trouble) when a potential fault is present:
Alarm Modes – US & [CANADA]
Low Tank Temperature under 155°F (68°C) & [135°F (57°C)]
High Tank Temperature over 168°F (76°C) & [150°F (66°C)]
High Tank Temperature over 175°F (79°C) & [155°F (68°C)] REQUIRES MANUAL RESET
Low Tank Level
NOTE: Each alarm mode will display an alarm message on the PLC display, and the area light will flash
once every 5 seconds. The high-temperature alarm for the tank is designed to give a warning by displaying
an alarm message, changing the state of the customer general trouble contact, and flashing the exterior
light at a 5 second interval 5 degrees before the temperature rises to a point that requires a manual reset
of the heating equipment. Should the alarm not be addressed before reaching the high set point, the system
will require additional attention and a manual reset.

HAWS®P/N 0510000456 Rev.5 10/19 Model 8760 Page 12 of 29
Messages
The display messages are controlled in this chart. When no alarm modes are present, the display will
present the following conditions:
Tank Heater On (when active)
Flow Switch On (when active)
Tank Temperature
When a single alarm mode, also called fault condition, is present, the display will indicate which alarm mode
is present. If more than one alarm exists, the display will cycle through each alarm at 4 second intervals.
Each message will automatically clear when the condition is no longer active or when the corrective action
has been taken. This program also records a message to the “Fault History” chart, which will assign the
time and date when the alarm occurred using the Real Time Clock (RTC) module. Timer counter (TC-05
in conjunction with TC-06) will keep track of the 4 second timing intervals and advance the message display
to the next active alarm (if present).
Real Time Clock (RTC)
The RTC module is used to record the date and time for the Fault History (alarm modes).
NOTE: If “NO RTC” is shown on PLC display (see Figure 6), remove RTC module by disconnecting from
PLC, re-attach, and cycle the power. If “NO RTC” is still shown, please contact Haws Services at
1-800-766-5612 as you may need a replacement part.
Figure 6. No RTC – Real Time Clock Display

HAWS®P/N 0510000456 Rev.5 10/19 Model 8760 Page 13 of 29
Fault History
The fault history chart records the time and date of the last occurrence of each fault. When the “left arrow”
key is depressed, the time and date of each alarm will be listed on the display. There will be a 4 second
delay before the first alarm is displayed. Each alarm will be listed for 4 seconds if the “left arrow” key is
depressed. The time and date of each alarm are stored in registers R-004 through R-021. Once the “left
arrow” key is released, the display will return to the normal condition display if no alarms are present. If
there are alarm modes in the system, the display will return to the alarm mode display when the “left arrow”
key is released.
Flow Alarms
Flow is monitored via a flow switch connected to I-00. When the flow switch is activated, output Q-05
(customer contact flow) will de-energize and engage the customer flow contacts. The flow switch will also
energize the horn via Q-03. The exterior light is also controlled in this chart. The exterior light remains on
during normal operation. When flow is detected, the exterior light will flash on and off at 1 second intervals.
Fault Condition Notification
If a fault is active and there is no flow detected, the light will flash once every 5 seconds. This function
gives the user an indication of a fault condition if the unit is not connected to plant Distributed Control
System (DCS) via dry contacts provided on the electrical panel layout. To properly connect DCS to dry
contacts, please refer to the model-specific electrical schematic. It is possible to override this function by
simultaneously depressing the “0” and “2” key. Flag F-026 controls this function. It is set as retentive to
maintain the selection after a power outage. These intervals are controlled by TC-00 through TC-04.
NOTE: If a model-specific electrical schematic is not present or additional information is required to connect
DCS to unit, please contact Haws Services at 1-800-766-5612.
Maintenance Required Notification
On units containing the “Preventative Maintenance Required” notification feature, the area light will flash
once every 10 seconds when preventative maintenance is required. The notification is factory set to activate
after one year of operation and reactivates each following year.
The operating procedure is as follows:
•To view remaining time until Preventative Maintenance is Required, press Shift + 5
•To toggle Preventative Maintenance Required feature on/off, press Shift + 9
oTo reset the timer, turn the Preventative Maintenance Required feature off then back on.
The timer will start from 0.
oOn/off toggle can also be triggered by the following push button sequence using the alarm
horn silence button.

HAWS®P/N 0510000456 Rev.5 10/19 Model 8760 Page 14 of 29
Press 3 times within 2 seconds, wait 2-5 seconds, and press 3 times within 2
seconds
oActivation of the Preventative Maintenance Required Feature is indicated by 3 short flashes
of the area light accompanied by 3 blips of the alarm horn.
oDeactivation of the Preventative Maintenance Required Feature is indicated by 4 short
flashes of the area light accompanied by 4 blips of the alarm horn.
Tank Monitor
The tank monitor chart provides a means of monitoring the tank heater performance. This chart records
the actual amount of time that the tank heater contactor is on via registers R-050 through R-052. Counter
TC-14 cycles the chart through the last 3 on/off cycles of the tank heater contactor. TC-13 records the
actual on time of the contactor. When the unit is initially placed in service and has reached operating
temperature for several hours, the on/off cycles should be recorded in the table below. Pressing the “up
arrow” key will display the last three cycles. Each cycle will be displayed for 4 seconds as long as the key
is depressed.
CYCLE
ON/OFF
TIME
1
2
3
These values can be checked on a routine basis. If the amount of time that the tank heater is on has
increased, it may be an indication that the tank heater needs service or repair.
Tank History
This tank history chart controls the display messages recorded by the tank monitor chart. TC-15 sets the
time that each message is displayed. TC-16 is used to increment from “Heater on time 1” through “Heater
on time 3”.
Setting Current Time and Date on the Controller
1. Press the “SHIFT” and “OK” buttons to enter the menu.
2. Press “4” to enter setup.
3. Press “1” to set date or “2” to set time.
4. After date or time is set, press the “SHIFT” and “↑” key to return to setup menu.
The Time and Date can be verified by pressing the “→” or “↓” keys while in the normal operating screen.

HAWS®P/N 0510000456 Rev.5 10/19 Model 8760 Page 15 of 29
PREVENTATIVE MAINTENANCE
Weekly
•Verify the tank temperature readout on the display reads 165º F ± 2ºF (74ºC ± 1ºC) and 145°F ±
2ºF (63°C ± 1°C) for Canada (see Figure 5).
•Verify area light is operational.
•Verify shower and eyewash flow per ANSI requirements.
•Verify temperature gauge on center pipe of blending valve (see Figure 7) reads 84ºF ± 5ºF (29ºC
± 2ºC) flowing.
Figure 7. Blending Valve
Monthly
•Verify eyewash flows. Alarm light and horn should activate when water is flowing. Verify that
remote alarms connected to plant controls are functioning.
•Verify shower flow. Alarm light and horn should activate when water is flowing. Verify that remote
alarms connected to plant controls are functioning.
•Check for evidence of leakage on freeze and scald valves.
•Verify correct operation of blending valve. See Maintenance, Testing, and Repair section located
on page 20.
Quarterly
•Flush Y – strainers (if installed).

HAWS®P/N 0510000456 Rev.5 10/19 Model 8760 Page 16 of 29
Annually
•Check tank heater for excessive mineral build up on heating coils. Clean or replace if necessary.
•Check operation of tank level switch (see Figure 8).
•Check condition of tank anode(s).Replace if necessary.
•Drain tank and verify level switch operation.
Figure 8. Level Switch
•All emergency showers and eye/face washes shall be inspected annually to assure conformance
of ANSI Z358.1. This includes, but is not limited to, proper installation, accessible locations,
proper flow rate, and temperature of flushing fluid. Please refer to the most current standards
document for more information.
NOTE: If the blending valve temperature reading is incorrect, adjust the blending valve by turning the
socket head cap screw located on the bottom of the center section of the valve body.Turning the screw
clockwise will lower the outlet temperature, while counterclockwise will raise the outlet temperature (see
Figure 9). Maximum outlet temperature is approximately 85°F. Outlet temperature will be measured most
accurately by the temperature gauge when water is flowing through the valve.
Figure 9. Blending Valve

HAWS®P/N 0510000456 Rev.5 10/19 Model 8760 Page 17 of 29
SYSTEM DRAIN AND CHECK PROCEDURE:
WARNING! System contains HOT water! Failure to DISCONNECT POWER AND ALLOW WATER IN
HOT WATER TANK TO COOL sufficiently prior to draining may cause SEVERE INJURY OR DEATH!
Always follow safe Lock Out – Tag Out procedures.
1. Turn off power at system disconnect switch. Lock Out and Tag Out according to your company’s
procedures.
2. Allow system hot water tank to cool below 100°F. Cooling could take many hours depending on
the ambient temperature. This process can be sped up by opening the shower and allowing the
blending valve to consume the hot water from the tank in the blending process. While the shower
is running, monitor the blending valve hot water inlet mechanical temperature gauge. When the
blending valve hot water inlet temperature gauge drops below 100°F WHILE FLOWING, the tank
temperature will be low enough to facilitate safe system draining.
a. If you will be running the shower to drop the tank temperature, this may be an appropriate
opportunity to also perform an annual test of the shower for ANSI Z358.1 compliance for
flow and pattern. If so, be aware that a full 15-minute duration of tepid water may be
modestly shortened because the tank heater would not be operating.
3. When the hot water tank has cooled sufficiently, shut off the shower if it has been activated, and
turn off the main inlet water supply ball valve located on the skid where the water supply connects.
This is a lockable ball valve and Haws recommends locking this valve in the off position any time
the system is to be drained.
4. If necessary, connect a drain hose to the drain connection at the back of the skid and route to a
safe drain location (or to the shower drain if unit is connected to a drain pipe). Do not open drain
valve until step 8.
5. Confirm that the power is disconnected.
6. Unscrew and remove the cover on the Level Switch (see Figure 8).
7. Using a multimeter, check continuity across the wired terminal block between the pin labeled “C”
and the pin labeled “NC”. If the tank is full, as it should be at this point, the multimeter should
indicate electrical continuity exists between these two pins. (Note this Double Pole, Double Throw
switch has two identical terminal blocks and testing should be done on the one that is wired.) If the

HAWS®P/N 0510000456 Rev.5 10/19 Model 8760 Page 18 of 29
tank has been heating properly, this test SHOULD be positive. If not, check the connections and
confirm the tank is full.
8. Open the system drain valve at the back of the skid to drain the system. To speed up draining,
allow additional air into the tank by opening the ball valve on the Y-strainer in the hot water line and
between the top of the tank and the hot side of the blending valve. Continue until water stops
draining.
9. Using a multimeter, check continuity across the wired terminal block between the pin labeled “C”
and the pin labeled “NC”. If the tank is empty (or below the level of the switch), as it should be at
this point, the multimeter should indicate NO electrical continuity exists between these two pins.
(Note this Double Pole, Double Throw switch has two identical terminal blocks and testing should
be done on the one that is wired.) If the multimeter indicates continuity DOES exist when the tank
is empty, the float may be stuck in the up position, which would require removal and cleaning and/or
replacement of the level switch.
10. For 119, 120, and 200-gallon tanks, remove and inspect the tank “sacrificial” anode rod(s) for
condition. These rods are designed to corrode and deteriorate before other less reactive surfaces
in the system, so some corrosion is normal. If the stainless-steel core can be seen or the rod is
grossly deteriorated, it should be replaced.
11. For 119, 120, and 200-gallon tanks, consider removing and inspecting the tank heater for excessive
mineral buildup on the heater coils. In particular, if significant debris is noticed in the drain water,
the local water is known to be “hard” or have high mineral content, or tank heater monitoring
indicates more and more frequent cycling, consider removing and inspecting/cleaning the
immersion heater. (Electrical disconnection and re-connection should be done by a qualified
electrician) Contact Haws Services for questions at 1-800-766-5612.
12. For 330-gallon tanks, the manway can be carefully removed to allow internal inspection of the
anode rods and immersion heater coils without removal. The tank bottom should also be inspected
for excessive debris and cleaned if necessary. NEVER ATTEMPT TO ENTER THE TANK!
CAUTION: When inspecting, take care not to drop anything in the tank as the glass lining
in the tank could be permanently damaged!
Remove and replace any excessively deteriorated anode rods. If inspection of the heater coils
indicates excessive mineral buildup, remove the heater for cleaning or replacement. (Electrical
disconnection and re-connection should be done by a qualified electrician.)
Contact Haws Services for questions at 1-800-766-5612.

HAWS®P/N 0510000456 Rev.5 10/19 Model 8760 Page 19 of 29
13. Now is also a good time to open and clean out the Y-strainers (one in the inlet water line and one
in the hot water line).
14. When maintenance is complete and any components removed have been replaced, close the
system drain valve and the ball valve on the hot line Y-strainer if it was opened.
15. Unlock and open the inlet water supply valve and allow the system to fill. Opening the shower can
facilitate the exit of air from the system.
16. When the system is full of water, follow appropriate Lock Out-Tag Out procedures to unlock and
turn on the system disconnect switch to restore power to the unit.
17. Allow time for the system to come up to temperature (up to 12 hours) and ensure that all alarms
are clear.

HAWS®P/N 0510000456 Rev.5 10/19 Model 8760 Page 20 of 29
MAINTENANCE, TESTING, REPAIR
Blending Valve System
The TWBS.HF blending valve system (see Figure 10) should require a minimal amount of
maintenance. During scheduled testing, the temperature output should be checked for proper
adjustment. With the shower or eye/facewash activated the outlet temperature should be
approximately 80-85°F.
Figure 10. Blending Valve
NOTE: For more information, refer to the TWBS.HF Blending Valve System O&M manual.
Combination Shower/Eyewash
Verify shower and eyewash flow per ANSI requirements.
NOTE: If shower and/or eyewash does not flow per ANSI requirements or at all, consult Haws Services.
Freeze and Scald Valve
Scald valve should be fully closed at 87°F (36°C) and be fully open at 95°F (35°C). Freeze valve
should be fully opened at 36°F (2°C) or below and closed at 42°F (6°C) or above.
NOTE: If valve does not fully open/close, check valve seat for debris or scale build up. If no debris or scale
is present, consult Haws Services at 1-800-766-5612.
CAUTION: Extreme hot/cold ambient temperatures may cause the valves to open.