TSI HM685 OWNER’S MANUAL

HYDRONIC MANOMETER

MODEL HM685

OWNER’S MANUAL

P/N 6006820, REVISION B

JANUARY 2014

SHIP TO/MAIL TO:

TSI Incorporated
500 Cardigan Road
Shoreview, MN 55126-3996
USA

U.S.
Technical Support:

[phone]/[phone]

Fax:

[phone]

E-mail address:

[e-mail]

Website:

http://www.tsi.com

INTERNATIONAL

Technical Support:

(001 651) 490-2811

Fax:

(001 651) 490-3824

HYDRONIC MANOMETER

MODEL HM685

OWNER’S MANUAL

P/N 6006820, REVISION B

JANUARY 2014

Manual History

The following is a manual history of the Hydronic Manometer
Model HM685 Owner’s Manual (P/N 6006820).

Revision Date

A May 2013
B January 2014

ii Hydronic Manometer Model HM685

Part Number

6006820 / Revision B / January 2014

Copyright

©TSI Incorporated / 2013–2014 / All rights reserved.

Address

TSI Incorporated / 500 Cardigan Road / Shoreview, MN 55126 / USA

Fax No.

651-490-3824

E-mail Address

[e-mail]

Limitation of Warranty
and Liability

(effective June 2011)

(For country-specific terms and conditions outside of the USA, please visit

www.tsi.com.)

Seller warrants the goods sold hereunder, under normal use and service as
described in the operator's manual, shall be free from defects in workmanship and
material for twenty-four (24) months, or if less, the length of time specified in the
operator's manual, from the date of shipment to the customer. This warranty period is
inclusive of any statutory warranty. This limited warranty is subject to the following
exclusions and exceptions:

Warranty

a. Hot-wire or hot-film sensors used with research anemometers, and certain other

components when indicated in specifications, are warranted for 90 days from the

date of shipment;
b. Pumps are warranted for one year or 3000 hours; whichever comes first;
c. Parts repaired or replaced as a result of repair services are warranted to be free

from defects in workmanship and material, under normal use, for 90 days from the

date of shipment;
d. Seller does not provide any warranty on finished goods manufactured by others or

on any fuses, batteries or other consumable materials. Only the original

manufacturer's warranty applies;
e. Unless specifically authorized in a separate writing by Seller, Seller makes no

warranty with respect to, and shall have no liability in connection with, goods which

are incorporated into other products or equipment, or which are modified by any

person other than Seller.
The foregoing is IN LIEU OF all other warranties and is subject to the LIMITATIONS

stated herein. NO OTHER EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR
PARTICULAR PURPOSE OR MERCHANTABILITY IS MADE. WITH RESPECT TO

SELLER’S BREACH OF THE IMPLIED WARRANTY AGAINST INFRINGEMENT,
SAID WARRANTY IS LIMITED TO CLAIMS OF DIRECT INFRINGEMENT AND
EXCLUDES CLAIMS OF CONTRIBUTORY OR INDUCED INFRINGEMENTS.

BUYER’S EXCLUSIVE REMEDY SHALL BE THE RETURN OF THE PURCHASE

PRICE DISCOUNTED FOR REASONABLE WEAR AND TEAR OR AT SELLER’S
OPTION REPLACEMENT OF THE GOODS WITH NON-INFRINGING GOODS.

TO THE EXTENT PERMITTED BY LAW, THE EXCLUSIVE REMEDY OF THE
USER OR BUYER, AND THE LIMIT OF SELLER'S LIABILITY FOR ANY AND ALL
LOSSES, INJURIES, OR DAMAGES CONCERNING THE GOODS (INCLUDING
CLAIMS BASED ON CONTRACT, NEGLIGENCE, TORT, STRICT LIABILITY OR
OTHERWISE) SHALL BE THE RETURN OF GOODS TO SELLER AND THE
REFUND OF THE PURCHASE PRICE, OR, AT THE OPTION OF SELLER, THE
REPAIR OR REPLACEMENT OF THE GOODS. IN THE CASE OF SOFTWARE,
SELLER WILL REPAIR OR REPLACE DEFECTIVE SOFTWARE OR IF UNABLE TO
DO SO, WILL REFUND THE PURCHASE PRICE OF THE SOFTWARE. IN NO
EVENT SHALL SELLER BE LIABLE FOR LOST PROFITS OR ANY SPECIAL,
CONSEQUENTIAL OR INCIDENTAL DAMAGES. SELLER SHALL NOT BE
RESPONSIBLE FOR INSTALLATION, DISMANTLING OR REINSTALLATION

iii

COSTS OR CHARGES. No Action, regardless of form, may be brought against Seller

Trademarks

CompuDat is a trademark of TSI Incorporated. TSI and the TSI logo are registered
trademark of TSI Incorporated. Microsoft, Excel, Windows, and Vista are registered
trademarks of Microsoft Corporation.

more than 12 months after a cause of action has accrued. The goods returned under
warranty to Seller's factory shall be at Buyer's risk of loss, and will be returned, if at all,
at Seller's risk of loss.

Buyer and all users are deemed to have accepted this LIMITATION OF WARRANTY
AND LIABILITY, which contains the complete and exclusive limited warranty of Seller.
This LIMITATION OF WARRANTY AND LIABILITY may not be amended, modified or
its terms waived, except by writing signed by an Officer of Seller.

iv Hydronic Manometer Model HM685

Contents

Manual History ............................................................................................ ii

Warranty ..................................................................................................... iii

About This Manual .................................................................................... ix

Formatting and Typography .................................................................. ix

Technical Assistance—Help! ................................................................ ix

Safety Information ..................................................................................... xi

Labels .................................................................................................... xi

Description of Caution/Warning Symbols ............................................ xii

Caution .............................................................................................. xii

Warning ............................................................................................. xii

Caution or Warning Symbols ............................................................ xii

CHAPTER 1 Introduction ........................................................................ 1-1

Instrument Description ........................................................................ 1-2

Unpacking ........................................................................................... 1-3

CHAPTER 2 Getting Started ................................................................... 2-1

Keypad ................................................................................................ 2-1

Powering the Instrument ..................................................................... 2-2

Using the AC Adapter ...................................................................... 2-2

Battery Installation ........................................................................... 2-2

Battery Charging .............................................................................. 2-4

Instrument Start-up ............................................................................. 2-5

Zeroing the Manometer ....................................................................... 2-5

Zeroing the Gauge Pressure Sensor ............................................... 2-5

Zeroing the Differential Pressure Sensor ........................................ 2-6

Connecting the Manometer to the Test Points.................................... 2-7

Attaching the Hoses to the Manometer ........................................... 2-7

Bleeding the Entrained Air ............................................................... 2-7

Attaching the Hoses to the Test Points ........................................... 2-8

Performing Pressure Measurements .................................................. 2-8

Accessing the Pressure Measurement Screen ............................... 2-8

Pressure Measurement Screen ....................................................... 2-9

Continuous Pressure Measurements .............................................. 2-9

Discrete Pressure Measurements ................................................... 2-9

Performing Flow Measurements ....................................................... 2-10

Accessing the Flow Measurement Screen .................................... 2-10

Flow Measurement Screen ............................................................ 2-10

Continuous Flow Measurements ................................................... 2-11

Discrete Flow Measurements ........................................................ 2-11

Performing Temperature Measurements .......................................... 2-11

Connecting the Temperature Probe .............................................. 2-11

v

Setting Units of Measure ................................................................... 2-12

Storing Discrete Measurements ........................................................ 2-12

Disconnecting the Manometer from the Test Points ......................... 2-13

CHAPTER 3 Main Menu ........................................................................... 3-1

Zero Gauge Pressure .......................................................................... 3-1

Flow Setup .......................................................................................... 3-2

Select Cv/Kv Factor ......................................................................... 3-2

Select Factor Type ........................................................................... 3-3

Enter Cv/Kv Value ........................................................................... 3-3

Edit Cv/Kv Name ............................................................................. 3-4

Select Fluid ...................................................................................... 3-5

CHAPTER 4 Data Logging ...................................................................... 4-1

Menu ................................................................................................... 4-1

Log Mode ............................................................................................ 4-1

Log Settings ........................................................................................ 4-2

Choose Test .................................................................................... 4-3

Name Test ........................................................................................... 4-3

View Data ............................................................................................ 4-4

Choose Test .................................................................................... 4-4

View Stats ........................................................................................ 4-4

View Samples .................................................................................. 4-4

Delete Data ......................................................................................... 4-5

% Memory ........................................................................................... 4-6

CHAPTER 5 Calculations Menu ............................................................. 5-1

Brake Power ........................................................................................ 5-1

Inputs ............................................................................................... 5-2

Heat Flow ............................................................................................ 5-4

Inputs ............................................................................................... 5-4

Calculating Cv/Kv ................................................................................ 5-6

Inputs ............................................................................................... 5-7

Output .............................................................................................. 5-8

Pump Law Impeller Diameter .............................................................. 5-8

Inputs ............................................................................................... 5-8

Output .............................................................................................. 5-9

Pump Law Delta P ............................................................................ 5-10

Inputs ............................................................................................. 5-10

Output ............................................................................................ 5-11

Pump Law Brake Power .................................................................... 5-12

Inputs ............................................................................................. 5-12

Output ............................................................................................ 5-13

CHAPTER 6 Settings Menu..................................................................... 6-1

Beeper ................................................................................................. 6-2

Select Units ......................................................................................... 6-2

Differential Pressure and Gauge Pressure ......................................... 6-3

Flow ..................................................................................................... 6-3

Temperature ........................................................................................ 6-4

Time Constant ..................................................................................... 6-4

Contrast ............................................................................................... 6-5

vi Hydronic Manometer Model HM685

Set Time .............................................................................................. 6-5

Set Date .............................................................................................. 6-6

Time Format ........................................................................................ 6-6

Date Format ........................................................................................ 6-7

Number Format ................................................................................... 6-7

Backlight .............................................................................................. 6-8

Auto Off ............................................................................................... 6-8

CHAPTER 7 Calibration .......................................................................... 7-1

Calibration Differential Pressure and Calibration Gauge Pressure..... 7-2

Calibration Temperature 1 and 2. ....................................................... 7-3

Restore Factory Calibration ................................................................ 7-3

CHAPTER 8 Maintenance and Troubleshooting .................................. 8-1

Routine Maintenance .......................................................................... 8-1

Draining the Hoses .......................................................................... 8-1

Draining the Manometer Valve ........................................................ 8-1

In-Line Flow Restrictor ..................................................................... 8-2

Cleaning the In-line Flow Restrictors ............................................... 8-2

Cleaning the Instrument Housing .................................................... 8-2

Calibration ........................................................................................... 8-3

Troubleshooting .................................................................................. 8-3

Technical Contacts .............................................................................. 8-5

CHAPTER 9 USB Downloading to a Computer .................................... 9-1

Installing the USB Software ................................................................ 9-1

Connecting the Manometer to the Computer ...................................... 9-2

First Time Connection ...................................................................... 9-2

Software Interface ............................................................................... 9-6

HM685 Data Download Steps ......................................................... 9-7

HM680 Download Instructions ......................................................... 9-9

Downloading Data ............................................................................. 9-10

APPENDIX A Specifications .................................................................. A-1

APPENDIX B Compliance ...................................................................... B-1

Contents vii

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viii Hydronic Manometer Model HM685

About This Manual

This manual explains how to set up, operate, and maintain the TSI®
Hydronic Manometer Model HM685. Please read it thoroughly before using
the instrument.

Formatting and Typogr a phy

 Step-by-step instructions are numbered: 1, 2, 3, etc., set flush-left

against the inside margin.

 References to keys on the manometer and the instrument's displayed

readout are represented in bold typeface. In addition to the different
typeface, displayed messages appear in quotes.

Technical Assistance — Help!

For technical assistance or questions about the instrument or this manual,
or if the HM685 Hydronic Manometer needs repair or recalibration, call
Technical Support at [phone] or [phone].

ix

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x Hydronic Manometer Model HM685

1. Serial number label
(back panel) )

2. Calibration label
(back panel)

3. European symbol for
non-disposable item.
Item must be recycled.

Safety Information

Carefully read each of the following safety warnings prior

to using the HM685 Hydronic Manometer.

This section gives instructions to promote safe and proper handling of the
HM658 Hydronic Manometer.

I M P O R T A N T

There are no user-serviceable parts inside the instrument. Refer all repair
and maintenance to a qualified factory-authorized technician. All
maintenance and repair information in this manual is included for use by a
qualified factory-authorized technician.

Labels

Identification and calibration labels are attached to the outside of the
hydronic manometer housing.

xi

Description of C aution/Warning Symbols

C a u t i o n

Failure to follow the procedures prescribed in this manual might result in

irreparable equipment damage. Important information about the operation
and maintenance of this instrument is included in this manual.

W A R N I N G

Warning means that unsafe use of the instrument could result in serious

injury to you or cause damage to the instrument. Follow the procedures
prescribed.

Warns that uninsulated voltage within the instrument may
have sufficient magnitude to cause electric shock.
Therefore, it is dangerous to make contact with any part
inside the instrument.

Warns that the instrument is susceptible to electro-static
dissipation (ESD) and ESD protection procedures should be
followed to avoid damage.

Indicates the connector is connected to earth ground and
cabinet ground.

W A R N I N G

Never use the HM685 Hydronic Manometer or accessories on potable

water systems or other systems which may be used to convey fluids for
human or animal consumption.

W A R N I N G

Never charge non-rechargeable batteries by setting battery-type

selection switch to NiMH when using alkaline or other non-rechargeable
batteries. Fire, explosions, or other hazards may result.

Appropriate caution/warning statements are used throughout the manual
and on the instrument that require you to take cautionary measures when
working with the instrument.

Caution

Warning

Caution or Warning Symbols

The following symbols may accompany cautions and warnings to indicate
the nature and consequences of hazards:

Carefully read each of the following safety warnings prior

to using the HM685 Hydronic Manometer.

xii Hydronic Manometer Model HM685

C a u t i o n

Never use the HM685 Hydronic Manometer to measure the pressure of

volatile, flammable, or otherwise hazardous fluids or gasses. The
instrument is not designed to be intrinsically safe, nor is it designed for
use with caustic or corrosive chemicals.

C a u t i o n

Never connect the HM685 Hydronic Manometer or accessories to

systems which exceed the instrument’s maximum pressure specification
(300 psi; 2068 kPa).

C a u t i o n

Observe proper safety precautions and wear appropriate personal

protective equipment, including gloves and eyewear, when working on
high pressure or high temperature systems. Ruptured or leaking lines
pose a potential risk of serious personal injury.

C a u t i o n

When using the HM685 Hydronic Manometer, verify all hose connections

are secure prior to taking pressure measurements. Loose connections
may result in the discharge of pressurized water or air, posing a potential
risk of serious personal injury.

C a u t i o n

Exercise caution when disconnecting the HM685 Hydronic Manometer

from a pressurized system. Water or air discharged under pressure
poses a potential risk of severe injury.

C a u t i o n

Exercise caution in using the HM685 Hydronic Manometer near electrical

equipment. Water spray associated with purging or disconnecting hoses
presents a potential risk of damage to such equipment.

C a u t i o n

Thoroughly drain and dry the HM685 Hydronic Manometer hoses and

internal piping after each use. This will help in limiting the potential for
growth of hazardous microorganisms.

C a u t i o n

Never plug into the instrument any power supply other than the one

provided with the instrument.

C a u t i o n

Always make certain that the battery switch is in the correct position for

the type of battery being used (Alkaline/NiMH). Failure to do so may
result in Fire, Explosions or other hazard.

xiii

C a u t i o n

Never use Alkaline and NiMH batteries together on the same instrument.

C a u t i o n

Always use the hoses with the provided Flow Restrictor connected in

line with the shut-off valves to prevent “Water Hammer.” Water Hammer
is a fast moving shock wave of pressure caused by sudden changes in
the system such as a valve being opened or closed or a pump being
turned on or off.

xiv Hydronic Manometer Model HM685

C H A P T E R 1

Introduction

The HM685 Hydronic Manometer is an easy-to-use instrument designed
for the accurate measurement of pressure and calculation of flow in non­potable water and air systems. Features of the manometer include the
following:

 Single-function keys for ease of use
 Simultaneous measurement and display of High-side gauge and

Differential pressure

 Direct calculation and display of Low-side gauge pressure
 Direct calculation and display of flow
 Data logging with calculated statistics
 Output port for downloading stored data to a computer
 User-selectable units of measure
 User-selectable time constant
 Easy-to-read, LCD with backlight
 Power supplied via AC adapter or batteries (alkaline or

rechargeable NiMH)

 Internal NiMH battery charging
 Automatic power shutoff
 Splash-proof case
 Rugged carrying case for storage of meter, hoses, accessories, tools,

and paperwork

 Two Temperature ports for simultaneous low and high side

temperature measurements

1-1

Instrument Description

 Meter
 4-inch temperature

probe

 Hard carrying case
 (2) 6-foot (1.8 m)

hoses with shut-off
valves & filters

 (2) P/T gauge

adapter probes

 (2) B&G readout

probes

 (2) ¼” Flare male ×

¼” male NPT

fittings

 (2) Female ¼” NPT

to Male ¼” ISO
Parallel Pipe

Threads

 (2) Female ¼” NPT

to Male ¼” ISO
Tapered Pipe

Threads

 AC adapter
 (4) NiMH batteries
 Carrying strap
 Owner’s manual
 NIST traceable

certificate

Keypad

AC Power
Adapter

Input Port

USB Port

Bottom Port Cover

LCD Display

Temperature Probe

Port 2

Temperature Probe

Port 1

Pressure

Ports

Neck/Hanging
Strap Clips

Valve Handle

The HM685 Hydronic Manometer includes:

1-2 Hydronic Manometer Model HM685

Figure 1-1
HM685 Meter Description

Unpacking

Item

Part No.

4 in. (10 cm) long, 0.125 in. (3.175 mm) dia. Temperature probe

801290

Carrying case

1319409

Blue and red hose kit with shut-off valves and flow restrictor

6006813

P/T gauge adapter probes (2)

632360004

B&G readout probes (2)

632360010

AC adapter

6004983

4 AA-size NiMH battery

1208048

Battery holder

1801206

Carrying strap

2913011

Owner’s manual

6006820

USB Cable

1303754

CompuDat CD

1083575

Pocket screw driver

3012054

Item

Part No.

Accessory fittings kit (USA only)

HMFIT

4 in. (10 cm) long, 0.125 in. (3.175 mm) dia. Temperature probe

801290

External battery charger with (4) AA NiMH batteries (USA only)

801093

As unpacking the instrument and accessories, check the components
against the packing list. If any parts are missing or damaged, notify TSI
immediately. Tables 1-1 and 1-2 list standard and optional components for
the HM685 Hydronic Manometer.

Table 1-1

Standard Components

Table 1-2

Optional Components

Please register your HM685 promptly through our website at

http://register.tsi.com. Registration of your product allows us to notify you of

product updates.

Introduction 1-3

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1-4 Hydronic Manometer Model HM685

Keypad

▲▼

The ▲and ▼keys are used to navigate through menus or to select

an item to change. When entering text, these keys change the
highlighted letter/number.

◄►

The ◄ and ► keys are used to change the selected item. When

entering text, these keys move the cursor to the desired location in
a left/right or up/down direction.

ESC

The ESC key returns to the previous screen or to cancel an
operation without saving changes.

The ENTER key selects a menu item or accepts changes made
within a menu item and returns to the previous screen. From either
the Pressure or Flow Measurement screens, pressing the ENTER
key accesses the Main Menu.

READ

Pressing the READ key initiates taking a time-averaged reading
based on Log Mode and Log Settings. After taking the reading, the
values are stored to memory (current Test ID) and displayed on
screen for a period of four (4) seconds or until the READ key has
been pressed again. The READ key also updates the calculations
with current readings in the CALCULATIONS Menu. See Chapter 4
for more details on Data Logging and adjusting the log mode,
sample interval and log settings.

Press the BACKLIGHT key to turn the display’s backlighting on
or off.

Note: Backlighting has a significant impact on battery life. Use

backlighting only when working in areas where you cannot
read the display with existing light.

DATA

Press the DATA key from either the Pressure or Flow
Measurement screens to access the Data Logging Menu.

PRESS

Press the PRESS key from the Flow Measurement screen to
access the Pressure Measurement screen.

Press the key to turn the HM685 Hydronic Manometer on or off.

CALC

Pressing the CALC key from either the Pressure or Flow
Measurement screens provides access to the Calculations Menu.

FLOW

Pressing the FLOW key from the Pressure Measurement screen
provides access to the Flow Measurement screen.

C H A P T E R 2

Getting Started

Each key and its function are described below.

2-1

Powering the Instru m ent

C a u t i o n

Only use TSI P/N 6004983, the AC adapter supplied with the
instrument, when powering the HM685 Hydronic Manometer
externally. Do not connect the AC adapter or car adapter provided with

the battery optional charger (801093) or any other AC adapter to the
HM675/685. Using any other power cable or power supply may cause
damage to the device and void the warranty.

W A R N I N G

Never charge non-rechargeable batteries by setting battery-type selection
switch to NiMH with alkaline or other non-rechargeable batteries. Fire,
explosions, or other hazards may result.

C a u t i o n

Never plug into the instrument any power supply other than the one
provided with the instrument.

The HM685 Hydronic Manometer is equipped to power either by four (4)
AA-size batteries (alkaline or rechargeable NiMH) or the AC adapter.

Using the AC Adapter

The AC adapter allows the HM685 Hydronic Manometer to power from a
standard AC wall outlet. When using the AC adapter, the batteries (if
installed) are bypassed. The AC adapter also charges the NiMH type
batteries (if installed) in the unit.

Note: With the battery-type selection switch set to NiMH, the manometer

will initiate charging the batteries whenever the AC adapter is
connected.

Battery Installation

To install/replace the batteries:

1. Turn the manometer off and locate the battery cover on the back of
the unit.

2. Loosen the screw on the battery compartment cover and lift to remove.

3. Remove the battery holder. Tapping the backside of the meter against
your hand may assist in removing the battery holder.

4. Remove the old batteries and replace with fresh batteries (alkaline or
rechargeable NiMH). Ensure that the batteries are correctly oriented
within the battery holder.

2-2 Hydronic Manometer Model HM685

5. Set the battery-type selection switch to indicate the type of batteries to

Battery Type
Selection Switch

W A R N I N G

Do not use Lithium batteries in this instrument. Fire, explosions, or other

hazards may result.

Cau t i o n

Never use Alkaline and NiMH batteries together on the same instrument.

C a u t i o n

Always make certain that the battery switch is in the correct position for

the type of battery being used (Alkaline/NiMH). Failure to do so may
result in Fire, Explosions, or other hazard.

be used (alkaline or rechargeable NiMH).

Figure 2-1

Location of Battery-Type Selection Switch

6. Reinstall the battery holder. Ensure the battery holder orientation is
such that its terminals make contact with the spring contacts within the
battery compartment.

7. Replace the battery compartment cover.

Getting Started 2-3

Notes:

W A R N I N G

Do not use Lithium batteries in this instrument. Fire, explosions, or other

hazards may result.

C a u t i o n

Never plug into the instrument any power supply other than the one

provided with the instrument.

C a u t i o n

Always make certain that the battery switch is in the correct position for

the type of battery being used (Alkaline/NiMH). Failure to do so may
result in Fire, Explosions or other hazard.

C a u t i o n

Never use Alkaline and NiMH batteries together on the same instrument.

 The NiMH batteries included with the instrument may require

recharging prior to first use.

 Fully charged batteries should enable the instrument to operate for a

period of at least twelve (12) hours

 Setting the battery-type selection switch properly will prevent unwanted

charging of non-rechargeable alkaline batteries and provide charging
of NiMH batteries when the AC adapter is connected.

 A battery charge life remaining indicator is shown on the display

whenever the manometer is powered by batteries, and turned on.

 When using NiMH batteries, the indicator of battery charge life

remaining will not be accurate due to their inherent non-linear voltage
drop with power use.

 Due to the danger of battery leakage, remove batteries from the battery

compartment prior to storage.

 Never mix battery types.
 For maximum battery life, ensure backlight is “off” when not needed.

Battery Charging

The HM685 Hydronic Manometer allows for internal charging of AA-size
type NiMH (only) batteries. Charging of the batteries is initiated as follows:

1. Turn the manometer off and locate the battery cover on the back of
the unit.

2. Loosen the screw on the battery compartment cover and lift to remove.

3. Remove the battery holder. Tapping the backside of the meter against
your hand may help in removing the battery holder.

4. Verify the batteries installed are rechargeable type NiMH.

5. Set the battery-type selection switch to NiMH.

2-4 Hydronic Manometer Model HM685

6. Reinstall the battery holder. Ensure the battery holder orientation is
such that its terminals make contact with the spring contacts within the
battery compartment.

7. Replace the battery compartment cover.

8. Plug in the AC adapter.

Notes:

 Full charge of the batteries is achieved within four (4) hours.
 Fully charged batteries should enable the instrument to operate for a

period of at least twelve (12) hours.

 The manometer is fully operational while charging batteries.
 Never attempt to charge battery types other than AA-size rechargeable

NiMH.

 For maximum battery life, ensure the backlight is “off” when not

needed.

 Never mix battery types.
 NiMH batteries should only be charged at room temperature. Starting

with batteries that are too cold or too warm can cause the charge cycle
to terminate early.

Instrument Start -up

Upon turning the HM685 Hydronic Manometer on, the meter engages in a
brief self-check while displaying the serial number, model number, and
revision of the instrument being used. While completing the self-check, the
user is given the option to zero the gauge pressure sensor or skip the zero
process prior to proceeding to the Pressure Measurement Screen.

Zeroing the Manometer

The HM685 Hydronic Manometer is equipped with both a gauge and
differential pressure sensor, allowing for simultaneous measurement and
display of High-side gauge and Differential pressure. The gauge and
differential pressure sensors are zeroed independently of one another.

Zeroing the Gauge Pressure Sensor

To ensure the most accurate gauge pressure (High P) measurements, the
HM685 gauge pressure sensor should be zeroed prior to taking readings
on each new system. When not in the instrument start-up sequence, the
gauge pressure sensor is zeroed as follows:

1. Enter the Main Menu by pressing the ENTER ( ) key.

2. Select Zero Gauge Pressure.

Getting Started 2-5

3. Follow the on-screen instruction to complete the gauge pressure
sensor zeroing process.

4. Allow the manometer to stand undisturbed for five (5) seconds until the
zero gauge pressure sensor function has completed.

Notes:
 Zeroing the gauge pressure sensor requires the user to disconnect the

High pressure (red) hose; as such it is often most convenient to zero
the gauge pressure sensor as part of the start-up sequence (i.e.,
before hoses have been connected).

 The zero offset of the gauge pressure sensor is sensitive to

temperature changes. If moving the manometer between areas of
extreme temperature difference, it is best to allow the meter to settle to
the new temperature prior to zeroing.

Zeroing the Differential Pressure Sensor

To ensure the most accurate differential pressure (dP) measurements and
calculated flow (Flow) values, the HM685 differential pressure sensor
should be zeroed prior to taking readings on each new system. The
differential pressure sensor is zeroed as follows:

1. Go to the Measurement Screen.

2. Turn the valve handle on the manometer to the BYPASS position.

3. The instrument will automatically zero the differential pressure sensor.
Follow the on-screen instructions and return the knob to MEASURE
once this is done.

Notes:
 Any pressures applied to the hoses will not affect the dP zeroing

function. This feature allows for successful zeroing of the differential
pressure sensor while maintaining connections to the system under
test.

 Zeroing of the differential pressure sensor is initiated any time the

valve handle has been turned to the BYPASS position while in the
Pressure or Flow Measurement screens. This feature allows for
successful zeroing of the differential pressure sensor while entrained
air is being purged from the hoses.

 The zero offset of the differential pressure sensor is sensitive to

temperature changes. If moving the manometer between areas with
extreme temperature difference, it is best to allow the meter to settle to
the new temperature prior to zeroing.

2-6 Hydronic Manometer Model HM685

Connecting the Manomet e r to the Test Points

Attaching the Hoses to the Manometer

1. Connect the straight female flare fitting on the High pressure (red)
hose to the male fitting on the top of the manometer marked with a
plus (+) sign.

2. Connect the straight female flare fitting on the Low pressure (blue)
hose to the male fitting on the top of the manometer marked with a
minus(-) sign.

Bleeding the Entrained Air

To ensure the most accurate pressure measurements, all entrained air
within the hoses should be purged as follows:

1. Turn the shut-off ball valve on both the High and Low pressure hoses
to the closed position.

2. Turn the valve handle on the manometer to the MEASURE position.

3. Using an appropriate fitting, connect the open end of the High pressure
(red) hose to the test point with the higher line pressure.

4. Attach the appropriate fitting to the open end of the Low pressure
(blue) hose.

5. To ensure all the air is bled from the hoses, hold the open end of the
Low pressure (blue) hose in an upright position over a suitable
receptacle or near a drain.

6. Turn the shut-off ball valve on both the High and Low pressure hoses
to the open position.

7. Turn the valve handle on the manometer to the BYPASS position to
allow the liquid flow to displace the entrained air.

Note: Zeroing of the differential pressure sensor is initiated any time the

valve handle has been turned to the BYPASS position while in the
Pressure or Flow Measurement screens. This feature allows for
successful zeroing of the differential pressure sensor while
entrained air is being purged from the hoses.

8. Once the liquid is flowing steadily from the Low pressure (blue) hose,
turn the valve handle on the manometer to the MEASURE position.

Note: The time to fully prime the hose with fluid may take up to one

minute depending on the line pressure. Higher line pressure will
reduce the bleed time.

Getting Started 2-7

Attaching the Hoses to the Test Points

1. As indicated previously, use an appropriate fitting to connect the open
end of the High pressure (red) hose to the test point with the higher line
pressure.

2. Using an appropriate fitting, connect the open end of the Low pressure
(blue) hose to the test point with the lower line pressure.

Note: If the hoses are connected in the inverse orientation (i.e., High

pressure (red) hose to the lower line pressure), the displayed High­side gauge pressure (High P) will be less than the Low-side gauge
pressure (Low P), and the Differential pressure (dP) and resulting
calculated flow (Flow) will be negative.

Performing Pres s ure Measureme n t s

The HM685 Hydronic Manometer allows for simultaneous measurement
and display of the High-side gauge and Differential pressure. The
calculated Low-side gauge pressure is also displayed. While in the
Pressure Measurement screen, the manometer makes and displays
continuous pressure measurements, and allows for data storage to the
memory.

Accessing the Pressure Measurement Screen

The Pressure Measurement screen is accessed by pressing the PRESS
key from the Flow Measurement screen, or by pressing the ESC key from
any of the primary menus (Main Menu, Data Logging Menu, and
Calculations Menu) when that menu was accessed from the Pressure
Measurement screen.

2-8 Hydronic Manometer Model HM685