TSI/Alnor HM685 User manual

HYDRONIC MANOMETER

MODEL HM685

OWNER’S MANUAL

P/N 6006820, REVISION E

FEBRUARY 2017

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M a n u a l H i s t o r y

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
C June 2015
D February 2016
E February 2017

ii Hydronic Manometer Model HM685

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(effective February 2015)
Seller warrants the goods, excluding software, sold hereunder, under normal use and

service as described in the operator's manual, to 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:

W a r r a n t y

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. This warranty does not cover calibration requirements, and seller warrants only that

the instrument or product is properly calibrated at the time of its manufacture.
Instruments returned for calibration are not covered by this warranty;

f. This warranty is VOID if the instrument is opened by anyone other than a factory

authorized service center with the one exception where requirements set forth in the
manual allow an operator to replace consumables or perform recommended cleaning;

g. This warranty is VOID if the product has been misused, neglected, subjected to

accidental or intentional damage, or is not properly installed, maintained, or cleaned
according to the requirements of the manual. 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

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iii

OTHERWISE) SHALL BE THE RETURN OF GOODS TO SELLER AND THE

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.

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, BUSINESS
INTERRUPTION, OR ANY SPECIAL, INDIRECT, CONSEQUENTIAL OR
INCIDENTAL DAMAGES. SELLER SHALL NOT BE RESPONSIBLE FOR

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

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C o n t e n t s

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 ....................................................... 2-8

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

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

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

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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

Temporary Adjustments to the Cv (Kv) Value ................................. 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 ............................................................................................... 5-9

Output ............................................................................................ 5-10

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

Inputs ............................................................................................. 5-11

Output ............................................................................................ 5-12

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

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

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

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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A b o u t T h i s M a n u a l

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

F o r m a t t i n g a n d T y p o g r a p h y

 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.

T e c h n i c a l A s s i s t a n c e — H e l p !

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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1. Serial number label
(back panel) )

2. Calibration label
(back panel)

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

S a f e t y I n f o r m a t i o n

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.

L a b e l s

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

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D e s c r i p t i o n o f C a u t i o n / W a r n i n g S y m b o l s

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 S

 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.

 Never charge non-rechargeable batteries by setting battery-type

selection switch to NiMH when using alkaline or other non­rechargeable 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.

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C a u t i o n s

 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.

 Never connect the HM685 Hydronic Manometer or accessories to

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

 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.

 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.

 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.

 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.

 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.

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

provided with the instrument.

 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.

 Never use Alkaline and NiMH batteries together on the same

instrument.

 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.

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xiii

C H A P T E R 1

I n t r o d u c t i o n

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

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I n s t r u m e n t D e s c r i p t i o n

 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:

Figure 1-1

HM685 Meter Description

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U n p a c k i n g

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

6009857

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

Introduction 1-3

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K e y p a d

▲▼

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

G e t t i n g Sta r t e d

Each key and its function are described below.

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2-1

P o w e r i n g t h e I n s t r u m e n t

C a u t i o n s

 Only use TSI P/N 6009857, 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.

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

provided with the instrument.

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.

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.

With the battery-type selection switch set to NiMH, the manometer will
initiate charging the batteries whenever the AC adapter is connected.

Not e

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.

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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.

C a u t i o n s

 Never use Alkaline and NiMH batteries together on the same

instrument.

 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

7. Replace the battery compartment cover.

such that its terminals make contact with the spring contacts within the
battery compartment.

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Not e s

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 s

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

provided with the instrument.

 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.

 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.

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

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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.

Not e s

 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.

I n s t r u m e n t S t a r t - 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, you
are given the option to zero the gauge pressure sensor or skip the zero
process prior to proceeding to the Pressure Measurement Screen.

Z e r o i n g t h e M a n o m e t e r

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

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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.

Not e s

 Zeroing the gauge pressure sensor requires you 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.

Not e s

 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.

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C o n n e c t i n g t h e M a n o m e t e r t o t h e T e s t P o i n t s

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.

Not e

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.

Not e

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.

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Attaching the Hoses to the Test Points

High Side

Pressure

Temperature

Low Side

Pressure

Differential

Pressure

Battery Status
or Power
Input Type

Current

Test ID

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.

Not e

If the hoses are connected in the inverse orientation (i.e., High pressure
(red) hose to the lower line pressure), the displayed High-side 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.

P e r f o r m i n g P r e s s u r e M e a s u r e m e 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.

Pressure Measurement Screen

*Shown with two optional accessory temperature probes attached.

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High-Side Gauge Pressure

The High-side gauge pressure
measurement is indicated as High on the
manometer display. The gauge pressure
readings can be positive or negative values
in the range of -20 to 300 psi (-138 to
2068 kPa).

Low-Side Gauge Pressure

The Low-side gauge pressure reading is
indicated as Low on the manometer
display. It represents a calculated value
determined from the measured High-side
gauge and Differential pressure as follows:

Low P = High P – dP

Differential Pressure

The Differential pressure measurement is
indicated as dP on the manometer display.
The differential pressure readings can be
positive or negative values in the range of
±300 psi (±2068 kPa).

Continuous Pressure Measurements

The HM685 Hydronic Manometer continuously measures and displays
pressure readings whenever the manometer is in the Pressure
Measurement or Flow Measurement screen, with the exception of when
the READ key is pressed. When the READ key is pressed, the displayed
readings are averaged measurements taken over the sampling period as
defined by the Log Mode and Log Settings. The display is updated once
per second.

Discrete Pressure Measurements

Taking a discrete pressure measurement allows for measurement and
display of a single time-averaged reading taken over the sampling period
as defined by the Log Mode and Log Settings. Discrete pressure
measurement values are displayed on-screen for a period of 4 seconds
and then returns to continuous measurement mode. See Chapter 4, Data

Logging, for more details on setup.

1. Press the READ key.

2. Allow the manometer to stand undisturbed until the reading is
complete.

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P e r f o r m i ng F l o w M e a s u r e m e n t s

Temperature

Current

Test ID

Current Cv (Kv)

Factor Name

Differential

Pressure

Battery Status or

Power Input Type

Cv/Kv Value

Flow

The flow reading is indicated as Flow on the manometer
display. It represents a calculated value determined from the
measured Differential pressure and user entered values for
the valve flow coefficient (Cv or Kv) and fluid specific gravity.

Cv/Kv

The valve flow coefficient is indicated as Cv (Kv) on the
manometer display.

Notes:

 The Cv (Kv) value of the measured valve must be known

in order to obtain meaningful flow readings.

 100 different Cv (Kv) names and values can be stored in

the instrument (Reference Chapter 3, Flow Setup).

 The Cv (Kv) value can be temporarily edited within the

Flow Measurement screen by pressing the ▲ or ▼ key to
enter an edit mode. Use the ▲ or ▼ keys to change the
value. Press ESC to leave the edit mode. See Chapter 3,

Flow Setup, Temporary Adjustments to the Cv (Kv) Value.

The HM685 Hydronic Manometer allows for continuous calculation and
display of flow. While in the Flow Measurement screen, the manometer
makes and displays continuous pressure measurements, calculates and
displays continuous flow readings, and allows for discrete data storage to
the memory.

Not e

The Cv (Kv) value of the measured valve must be known in order to obtain
meaningful flow readings.

Accessing the Flow Measurement Screen

The Flow Measurement screen is accessed by pressing the FLOW key
from the Pressure Measurement screen.

Flow Measurement Screen

*Shown with two optional accessory temperature probes attached.

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Continuous Flow Measurements

The HM685 Hydronic Manometer continuously measures and displays flow
readings whenever the manometer is in the Flow Measurement screen,
with the exception of when the READ key is pressed. When the READ key
is pressed, the displayed readings are averaged measurements taken over
the sampling period as defined by the Log Mode and Log Settings. The
display is updated once per second. See Chapter 4, Data Logging, for
more details on setup.

Discrete Flow Measurements

Taking a flow measurement allows for measurement and display of a
single time-averaged reading taken over the sampling period as defined by
the Log Mode and Log Settings. Discrete pressure or flow measurement
values are displayed on-screen for a period of 4 seconds and then returns
to continuous measurement mode. See Chapter 4, Data Logging, for more
details on setup.

1. Press the READ key.

2. Allow the manometer to stand undisturbed until the reading is
complete.

P e r f o r m i n g T e m p e r a t u r e M e a s u r e m e n t s

The HM685 Hydronic Manometer accessory temperature probe is a 1/8”
diameter, stainless steel sheathed immersion probe designed for
measurement of water line temperatures. When using the accessory
temperature probe, the HM685 Hydronic Manometer is equipped to make
and display continuous temperature measurements in both the Pressure
and Flow Measurement screens. Two temperature probes can be
connected to the instrument to measure upstream and downstream
temperature simultaneously.

Connecting the Temperature Probe

Connect the keyed 3-pin plug of the accessory temperature probe to the
mating connector located on the right-hand side of the manometer.

Not e

A locking nut is provided on the accessory temperature probe plug to allow
for a more secure attachment when connecting to the manometer.

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S e t t i n g U n i t s o f M e a s u r e

Gauge Pressure

psi, inH2O, ftH2O, inHg, kPa, mH2O, mmHg,
and bar

Differential Pressure

psi, inH2O, ftH2O, inHg, kPa, mH2O, mmHg,
and bar

Flow

USGPM, UKGPM, l/s, l/m, m3/h

Temperature

°F or °C

The units of measure for gauge pressure, differential pressure, flow, and
temperature are adjusted within the Setting Menu. See Chapter 6, Settings

Menu for more details. Available unit settings are as follows:

S t o r i n g D i s c r e t e M e a s u r e m e n t s

Taking a discrete measurement allows for measurement, display, and
storage of a single time-averaged reading taken over the sampling period.
Discrete measurement values are stored to the memory (current Test ID)
and displayed on-screen for a period of four (4) seconds. See Chapter 4,

Data Logging for more details on data logging and adjusting the log mode,

sample interval, and log settings.

1. Press the READ key (from the Pressure or Flow Measurement
screen).

2. Allow the manometer to stand undisturbed until the reading is complete
(time of completion is dependent on the time constant setting).

Not e

Discrete measurements stored from the Pressure Measurement screen will
not contain flow data.

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D i s c o n n e c t i n g t h e M a n o m e t e r f r o m t h e

C a u t i o n s

 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.

 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.

 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.

T e s t P o i n t s

The following provides a guideline for disconnecting the manometer from
the test points once measurements have been completed.

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

2. Disconnect the High pressure (red) hose from the higher line pressure
test point.

3. Disconnect the Low pressure (blue) hose from the lower line pressure
test point.

Not e

If additional measurements at another location/system containing the same
fluid are to be made, it is not necessary to proceed to step 4 and drain the
fluid entrained within the hoses at this time. The fluid remaining within the
hoses will help minimize the time necessary to bleed entrained air prior to
making subsequent measurements.

4. Place the open end of the Low pressure (blue) hose in a suitable
receptacle or near a drain.

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

6. Turn the shut-off ball valve on the Low pressure (blue) hose to the
open position to discharge the pressurized fluid out of the open end of
the Low pressure (blue) hose.

7. Elevate the High pressure (red) hose and turn its shut-off ball valve to
the open position to allow for draining of the remaining entrained fluid.

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C H A P T E R 3

M a i n M e n u

The Main Menu is accessed by pressing the ENTER key from either the
Pressure or Flow Measurement screens.

Z e r o G a u g e P r e s s u r e

Zero Gauge Pressure zeros the manometer’s gauge pressure sensor.
Refer to Zeroing the Manometer in the Getting Started chapter for
instructions.

3-1

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F l o w S e t u p

Use Flow Setup to set values for key factors that impact measured
flow values.

Select Cv/Kv Factor

Allows input up to 100 valve flow coefficients (Cv/Kv factors) to calculate
flow from differential pressure. These are typically coefficients provided by
the balancing valve manufacturers and can be dependent on the type of
valve and the valve setting in the case of variable valves. Within Flow
Setup 100 user-programmed valve flow coefficients (Cv or Kv) that are
stored within the instrument are selectable. The most recent selected Cv
(Kv) factor is the default when entering the Flow Measurement screen.

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Select Factor Type

Enter Cv/Kv Value

A known Cv/Kv Value is required of the measured valve to obtain accurate
flow readings.

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Edit Cv/Kv Name

Up to 100 different Cv/Kv names and values can be stored. Edit the name
of the selected Cv (Kv) factor.

Temporary Adjustments to the Cv (Kv) Value

The Cv (Kv) value can be temporarily changed without going into the Flow
Setup menu. When the Flow Measurement screen is showing, press the up
or down arrow key to enter a mode where the Cv (Kv) value can be edited.
This edit mode is indicated by:

 The factor name changes to “*TEMP*”

 An up/down arrow appears in front of the value to be edited

Once you are in the edit mode, press and hold the up or down arrow keys
to change the Cv (Kv) value. The new, temporary value will automatically
be used to calculate flow and is stored when logging data. It does not
change any of the 100 stored Cv (Kv) values.

To leave the edit mode and resume using your originally selected Cv (Kv)
value, press the ESC key. The edit mode is also canceled whenever you
enter the Flow Setup menu.

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Select Fluid

Water

Select Water to automatically determine the specific gravity
based upon the measured temperature of the fluid (Tprobe).

Note: If the accessory temperature probe is not connected,

you will have the option of manually entering the fluid
temperature (T-entered).

Other

Select Other to prompt for entry of the fluid’s specific gravity.

Note: When Other is selected as the fluid type, the entered

value for specific gravity will not be compensated with
changes in temperature.

Defines the fluid for the manometer to account for the fluid’s specific gravity
when calculating flow. The fluid type of the system being measured is
Water or Other.

Specific Gravity

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Entered Temperature

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M e n u

C H A P T E R 4

D a ta L o g g i n g

Access the Data Logging Menu by pressing the DATA key from either the
Pressure or Flow Measurement screens or from the Main Menu.

L o g M o d e

The HM685 is programmable to store measurement to memory in the
following logging formats:

 Auto-save

 Cont-key

 Cont-time

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4-1

Auto-Save
Logging

In Auto-save mode, user samples are automatically logged
to memory at the end of the sampling period. To start
logging, press the Read key.

Cont-.key
Logging

In Cont-key Logging mode, logging starts by press the
Read key. The instrument continues logging until the Esc
key is pressed.

Cont.-time
Logging

In Cont-time mode, readings start by pressing the Read
key. The instrument continues taking samples until the time
set in “Sample Time” elapses or the Esc key is pressed.

L o g S e t t i n g s

Log Settings defines the frequency period with which the manometer will
log sample readings. When the Log Mode is set to Cont-Time, this setting
is also used to define the length of the test in hh:mm:ss.

Not e

It is recommended that the logging interval must be set at a time period

that is greater than or equal to the current setting of the time constant.

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N a m e T e s t

Choose Test

Use the Choose Test screen to choose the Test where the samples
(readings) will be stored.

Name Test screen allows customizing the Test ID name of the selected
test using 10 characters maximum. Use the arrow keys to move the cursor
to a desired location, press Enter to accept. This feature can be used to
logically name measurement locations for future analysis or report
generation; e.g., Conference Room 1, Break Room, Machine Shop, etc.

Data Logging 4-3

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V i e w D a t a

The View Data screen allows you to choose the data you want to review.

Choose Test

Select any of the 100 available Test IDs within the instrument. All new data
stored is saved to the most recently selected Test ID.

View Stats

Displays statistics (average, minimum, and maximum) of a selected Test
ID and the number of samples and date/time the samples were taken.

 AVG (average of all values stored in TEST ID.)

 MIN (lowest value stored in TEST ID)

 MAX (highest value stored in TEST ID)

 SUM (sum of all values stored in TEST ID)

Note: SUM is only presented for flow readings.

View Samples

Displays the total number of readings to be stored as part of the continuous
unattended data logging.

Not e

The instrument can store a maximum of 4000 different samples. These
samples can be distributed over one or all of the available Test IDs.

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D e l e t e D a t a

Delete All

Delete all samples stored to the instrument, as well as
restoring the factory set default names to each of the
Test IDs.

Delete Test

Delete all samples within the current Test ID as well as
restoring its factory set default name.

Delete Sample

Delete discrete samples within the current Test ID. The
▲ and ▼keys toggle between the individual data
samples.

Note: Test ID statistics automatically recalculate upon

deletion of an individual stored sample.

Delete discrete samples, an entire Test ID, or all data stored to the
instrument at this menu.

Note: Deleted data cannot be retrieved.

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% M e m o r y

% Memory displays the total memory available. Delete All, under Delete
Data, clears memory and resets to 100 percent.

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Press READ

button to

auto calculate

differential

pressure

C H A P T E R 5

C a l c u l a t i o n s M e n u

The HM685 Hydronic Manometer is capable of performing a variety of
calculations useful in evaluating hydronic system performance. The
Calculations Menu is accessed by pressing the CALC key from either the
Pressure or Flow Measurement screens.

B r a k e P o w e r

This Calculations Menu option determines pump brake power.

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5-1

Inputs

Flow

The pump flow rate.

dP

The pressure drop measured across the pump.

Note: The pressure drop across the pump can be

entered as a real-time measurement. With the
value for differential pressure highlighted, press
the READ key. The field will begin updating with
measured values of differential pressure. Press
the READ key again to discontinue real-time
updates.

Press READ

button to

auto calculate

differential

pressure

The following inputs are necessary for calculating brake power. Use the ▲
and ▼ keys to select the parameter, and the ◄ and ► keys to change the
value of the highlighted field. Units for the inputs are driven by what was
last set in the Pressure and Flow Measurement screens.

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Efficiency

The pump efficiency (as a percent).

Notes:

 The pump efficiency should be provided by the

manufacturer.

 If the pump efficiency is not known, allowing for an

efficiency factor of 70 % is a good rule-of-thumb.

Power Units

The calculated pump brake power (BP) automatically
updates as the input parameters are changed. Using the
▲ and ▼ keys to scroll, and the ◄ and ► keys to change
the selected field, the unit of measure for brake power
can be adjusted.

Available units for brake power are: bhp, W, and kW.

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H e a t F l o w

Upstream

Temperature

Downstream

Temperature

Press READ
button to
auto calculate

T1 and T2

T1

The upstream fluid temperature of the device being
measured.

Note: The upstream temperature can be entered as a

real-time measurement if the accessory
temperature probe is connected. With the value for
the upstream temperature highlighted, press the
READ key. The field will begin updating with
measured values of temperature. Press the READ
key again to discontinue real-time updates.

T2

The downstream fluid temperature of the device being
measured.

Note: The downstream temperature can be entered as a

real-time measurement if the accessory
temperature probe is connected. With the value for
the downstream temperature highlighted, press
the READ key. The field will begin updating with
measured values of temperature. Press the READ
key again to discontinue real-time updates.

Flow

The flow rate through the device.

Note: The flow rate through the device can be entered

as a real-time measurement. With the value for
flow highlighted, press the READ key. The field
will begin updating with calculated values of flow.
Press the READ key again to discontinue real-time
updates.

This Calculations Menu option allows for determination of heat flow.

Inputs

The following inputs are necessary for calculating heat flow. Use the ▲
and ▼ keys to select the parameter to be updated, and the ◄ and ► keys
to change the value of the highlighted field. Units for the inputs are driven
by what was last set in the Pressure and Flow Measurement screens (with
the exception of specific heat).

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Specific Heat

The specific heat of the system fluid.

Note:

The unit of measure for specific heat is driven by that
selected for heat flow as follows:

 Heat flow in Btu/hr → specific heat in Btu/lb°F
 Heat flow in W or kW → specific heat in kJ/kg°C

The default specific heat is that of water: 1.00 Btu/lb°F
(4.19 kJ/kg°C)

Specific Gravity

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Heat Flow
Units

Heat Flow measurement can display in Btu/hr, W, or
KW units.

The calculated heat flow (HF) automatically updates as
the input parameters are changed. Using the ▲ and ▼
keys to scroll, and the ◄ and ► keys to change the
selected field, the unit of measure for heat flow can
be adjusted.

Available units for heat flow are: Btu/hr, W, and kW.

Differential

Pressure

Flow

Coefficient

C a l c u l a t i n g C v / K v

This Calculations Menu option allows for determination of a valve flow
coefficient (Cv or Kv).

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Inputs

Differential
Pressure (dP)

The pressure drop across the valve.

Flow

The flow rate through the valve.

Specific
Gravity

The specific gravity of the system fluid.

The following inputs are necessary for calculating the flow coefficient. Use
the ▲ and ▼ keys to select the parameter to be updated, and the ◄ and
► keys to change the value of the highlighted field. Units for the inputs are
driven by what was last set in the Pressure and Flow Measurement
screens.

Calculations Menu 5-7

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Output

Actual Flow

Actual Impeller

Diameter

Desired Flow

Required Impeller

Diameter

The calculated valve flow coefficient (Cv or Kv ) automatically updates as
the input parameters are changed.

Not e

Whether a Cv or Kv value is being calculated is dependent on the type (Cv
or Kv ) set for the current selected valve flow coefficient (Reference

Chapter 3, Flow Setup).

P u m p L a w I m p e l l e r D i a m e t e r

This Calculations Menu option allows for determination of required pump
impeller size. The calculation is based upon the following affinity law: Flow
varies directly as the change in impeller diameter.

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Inputs

Flow1

The actual system flow rate.

Diam1

The actual pump impeller diameter.

Flow2

The desired system flow rate.

The following inputs are necessary for calculating the required impeller
diameter. Use the ▲ and ▼ keys to select the parameter to be updated,
and the ◄ and ► keys to change the value of the highlighted field. Units
for the inputs are driven by what was last set in the Flow Measurement
screen (with the exception of impeller diameter).

Calculations Menu 5-9

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Impeller Dia Units

The impeller diameter in inches or millimeters.

Actual Flow

Actual Differential

Pressure

Desired Flow

Required

Differential

Pressure

Output

The calculated required impeller diameter (Diam2) to achieve the desired
flow will automatically update as the input parameters are changed. Using
the ▲ and ▼ keys to scroll, and the ◄ and ► keys to change the selected
field, the unit of measure for impeller diameter may be adjusted. Available
units for impeller diameter are: in, and mm.

P u m p L a w D e l t a P

This Calculations Menu option allows for determination of required pump
pressure drop. The calculation is based upon the following affinity law:
Pump pressure drop varies as the square of flow.

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Inputs

Flow1

The actual system flow rate.

dP1

The actual pump pressure drop.

Flow2

The desired system flow rate.

The following inputs are necessary for calculating the required pump
pressure drop. Use the ▲ and ▼ keys to select the parameter to be
updated, and the ◄ and ► keys to change the value of the highlighted
field. Units for the inputs are driven by what was last set in the Pressure
and Flow Measurement screens.

Calculations Menu 5-11

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Output

Actual Flow

Actual Pump

Brake Power

Desired Flow

Required Pump

Brake Power

Flow1

The actual system flow rate.

The calculated required pump pressure drop (dP2) to achieve the desired
flow will automatically update as the input parameters are changed. The
units for pump pressure drop are driven by what was last set in the
Pressure and Flow Measurement screens.

P u m p L a w B r a k e P o w e r

This Calculations Menu option allows for determination of required pump
brake power. The calculation is based upon the following affinity law: Pump
brake power varies as the cube of flow.

Inputs

The following inputs are necessary for calculating the required pump brake
power. Use the ▲ and ▼ keys to select the parameter to be updated, and
the ◄ and ► keys to change the value of the highlighted field. Units for the
inputs are driven by what was last set in the Pressure and Flow
Measurement screens (with the exception of brake power).

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BP1

The actual pump brake power.

Flow2

The desired system flow rate.

Output

The calculated required pump brake power (BP2) to achieve the desired
flow will automatically update as the input parameters are changed. Using
the ▲ and ▼ keys to scroll, and the ◄ and ► keys to change the selected
field, the unit of measure for pump brake power may be adjusted. Available
units for pump brake power are: bhp, W and kW.

Calculations Menu 5-13

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C H A P T E R 6

S e t t i n g s M e n u

The Settings menu allows customization of the instrument display.

General settings include:

 Beeper

 Select Units

 Differential Pressure and Gauge Pressure

 Flow

 Temperature

 Time Constant

 Contrast

 Set Time

 Set Date

 Time Format

 Date Format

 Number Format

 Backlight

 Auto Off

Navigate to the Settings menu by pressing the Enter key at the Pressure
or Flow display.

Use the arrow keys to select an option or to change the settings for each
option.

Press the Enter key to accept the selected setting.

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B e e p e r

The Beeper setting changes the keypad press with an audible beep
or silent.

 Enable sets an audible beep

 Disable provides no audible beep

S e l e c t U n i t s

Select Units adjusts the format of the delimiter in both displayed and stored
data for differential pressure, gauge pressure, flow, and temperature.

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D i f f e r e n t i a l P r e s s u r e a n d G a u g e P r e s s u r e

Highlight either differential pressure or gauge pressure and press the Enter
key. Use the arrow keys to highlight the appropriate measurement and
press the Enter key to accept.

Flow

At the Select Units screen, highlight Flow and press the Enter key.
Highlight the appropriate measurement and press the Enter key to accept.

Settings Menu 6-3

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T e m p e r a t u r e

T i m e C o n s t a n t

Temperature readings can display in °C or °F.

 At the Select Units menu, highlight Temperature and press the Enter

key to select the desired setting.

The current value of the time constant is adjustable. Available settings
include 1, 5, 10, 20, and 30 seconds.

Not e s

 The time constant is the period over which the manometer averages

measurements. Example: with the time constant equal to ten (10)
seconds, the displayed reading represents the average of
measurements taken over the previous ten (10) seconds.

 Increasing the time constant will serve to improve measurement

stability, particularly when measuring systems with fluctuating
pressures.

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C o n t r a s t

The Contrast menu allows contrast adjustment to the manometer display
based on the surrounding lighting environment. Setting selections range
from 0 to 10. The higher the settings number, the darker the contrast of
the display. Use the up and down or left and right arrow keys to adjust
contrast.

S e t T i m e

The Set Time menu sets the instrument’s real-time clock. The digit
selected to change will flash. Use the arrow keys to select the hour/minute
digits and to adjust accordingly. Press the Enter key to confirm. The time
format of 12 or 24 hour is set at the Time Format menu.

Settings Menu 6-5

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S e t D a t e

The date is programmed to the instrument at the Set Date menu. The digit
selected to change will flash. Use the arrow keys to select the date, month,
or year and to adjust the date accordingly. Press the Enter key to confirm.

T i m e F o r m a t

The time format displays the time in a 12 or 24 hour format.

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D a t e F o r m a t

Three date settings are selectable based on your preference and include:

 Month/Date/Year

 Date/Month/Year

 Year/Month Date

N u m b e r F o r m a t

Settings Menu 6-7

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B a c k l i g h t

The Backlight feature illuminates the display in low light conditions.

Backlight options include:

 Auto (automatically turns on backlight in low-light condition)

 Disable (no backlighting)

 Enable (backlight is always on)

A u t o O f f

Automatic shutoff extends battery life by turning off the instrument if the
keypad is inactive for a period of thirty (30) minutes.

Shutoff options include:

 Disable (instrument does not power off after inactivity)

 Enable (instrument powers off after 30 minute inactivity)

Not e

The automatic shutoff feature is disabled whenever data logging is active.

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C H A P T E R 7

C a l i b r a t i on

On the calibration screen, you can either adjust the factory calibration
value so their measurements meet another standard or can restore factory
calibration settings to the instrument in case you believe the calibration of
the instrument has changed.

The following items can be seen in each section of the calibration screen.

1. The magnitude of user adjustment

2. The factory calibrated measurement value

3. The measurement value after performing the user adjustment.

This allows you to change measurement calibration by a specific amount
and to change back to factory calibration if necessary.

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C a l i b r a t i o n D i f f e r e n t i a l P r e s s u r e a n d C a l i b r a t i o n G a u g e P r e s s u r e

The Span Factor is used to adjust the pressure readings on the meter. It is
multiplied by the factory calibrated pressure to yield the displayed
pressure value.

Example - If you determine that differential pressure is reading 2.3% too
low, you enter a Span Factor of 1.023 and afterward all differential
pressure values will be multiplied by 1.023.

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C a l i b r a t i o n T e m p e r a t u r e 1 a n d 2

The temperature User Offset is added to temperature measurements to
yield the displayed temperature value.

Example - If you determine that temperature probe 1 is reading 0.5°C too
high, enter a User Offset of -0.5°C and afterward all temperature values
from probe 1 will be shifted down by 0.5°C

R e s t o r e F a c t o r y C a l i b r a t i o n

Factory calibrations for differential pressure, gauge pressure, and
temperatures can be restored using below menu options.

Calibration 7-3

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C H A P T E R 8

M a i n t e n a n c e a n d
Troubl e s h o o t i n g

The HM685 Hydronic Manometer has been designed to provide long-term
field use with minimum required maintenance. As with any precision
electronic device, proper care, maintenance, and handling will ensure its
accurate and reliable operation.

I M P O R T A N T

There are no user-serviceable parts inside this instrument. Opening the
instrument case may void the warranty. TSI recommends that you return
the HM685 Hydronic Manometer to the factory for any required
maintenance or service not described in this manual.

R o u t i n e M a i n t e n a n c e

The following guidelines should be followed whenever storing the HM685
Hydronic Manometer:

Draining the Hoses

Fluid within the High (red) and Low (blue) pressure hoses should be
properly drained whenever the instrument is being stored after use.

1. Disconnect the manometer hoses from the test points (Reference

Chapter 2, "Disconnecting the Manometer from the Test Points").

2. Disconnect the High (red) and Low (blue) pressure hoses from the
manometer.

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

4. Using a suitable high pressure air source, blow the entrained liquid
from both hoses.

Draining the Manometer Valve

Fluid within the manometer valve should be properly drained whenever the
instrument is being stored after use.

1. Disconnect the High (red) and Low (blue) pressure hoses from the
manometer.

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

3. Hold the manometer with the pressure ports directed downward to
allow liquid to drain from the unit.

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

Flow Restrictor

Shut-Off Valve

Short Hose Section

5. Hold the manometer with the pressure ports directed downward to
allow liquid to drain from the unit.

Not e

The HM685 Hydronic Manometer should be stored with the valve handle in
the MEASURE position.

In-Line Flow Restrictor

The blue and red hose assemblies include flow restrictors. The flow
restrictors must be used to prevent damage to the pressure sensors from
unexpected water hammering or pressure spikes and also acts as a filter.

Do not use the HM685 Hydronic Manometer without the flow restrictors

installed in the hose assemblies or sensor damage or clogging will occur.

Cleaning the In-line Flow Restrictors

These flow restrictors should be flushed periodically with clean water to
minimize potential clogging.

1. Disconnect the hose from the manometer.

2. Turn the shut-off ball valve on the hose to the closed position.

3. Connect the straight female flare fitting (farthest from the hose shut-off
valve) on the hose to a suitable water source.

4. Place the open end of the hose in a suitable receptacle or near a drain.

5. Turn the shut-off ball valve on the hose to the open position and allow
water to flush through for several minutes.

6. Using a suitable high pressure air source, blow the entrained water
from the hose.

7. Repeat with the second hose.

Not e

If necessary, remove the flow restrictor for further cleaning or flushing.
Reattach to hose assembly when complete.

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C a l i b r a t i o n

Cleaning the Instrument Housing

The HM685 Hydronic Manometer may be cleaned using a soft, damp,
clean cloth.

Not e

Solvents or abrasive cleaners should never be used to clean the
instrument housing, keypad, or display.

TSI recommends that the HM685 Hydronic Manometer receive an annual
calibration. TSI will verify calibration of the instrument and re-issue a
certificate of calibration with traceability to NIST. This “annual checkup”
helps to ensure the specified accuracy of the instrument is maintained.

To calibrate the instrument, please ship TSI the complete package that
includes the meter and accessory temperature probe. Everything should be
packed carefully within the carrying case and then inside a shipping box.
The original shipping box and packaging (carton and foam) is preferred.

 The instrument model number

 The instrument serial number

 A purchase order number (unless under warranty)

 A billing address

 A shipping address

T r o u b l e s h o o t i n g

The following table lists the symptoms, possible causes, and
recommended solutions for common problems encountered with the
instrument. If your symptom is not listed, or if the recommended solutions
do not address your problem, please contact the factory.

Maintenance and Troubleshooting 8-3

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Symptom

Possible Causes

Corrective Action

No display

Unit not turned on.

Low or dead batteries.

Dirty battery contacts.

AC adapter not connected.

Press On/OFF key.

Replace or recharge the batteries.

Clean the battery contacts.

Plug in AC adapter.

“ “
flashing on display

Low battery charge.

Dirty battery contacts.

Replace or recharge the batteries.

Clean the battery contacts.

“8888”
flashing on display

The indicated measurement is
out of range.

The allowable ranges for pressure and
temperature measurements are shown on
the specifications page.

“-----”
on display

The temperature sensor is
unplugged

The pressure measurement is
out of the meter’s range.

Try one of the below two steps:

1. Plug in temperature probe.

2. Return the pressure measurement to
the correct range

Instrument
unresponsive to
pressure

Hoses are clogged

Make sure hoses and flow restrictors are
unclogged from any debris by following
instructions on Cleaning the In-line Flow

Restrictors.

Error Message

Possible Causes & Corrective Action

"Lithium Battery Low”

The battery which runs the real-time clock and saves data logging
information is depleted and should be replaced. Please return the
unit to factory to replace the battery.

"Reading Logged Data”

There was a problem with the logged data. You should download
their logged data as soon as practical and then execute the “Delete
All” command to re-initialize data logging. If the lithium battery is
depleted, this could also cause an error reading logged data.

"Saved Measurement Params”

There was a problem with the measurement parameters read from
memory. They should be checked to make sure they still represent
your desired settings. Measurement parameters are Cv/Kv,
selected fluid, time constant, and measurement units.

"Saved User Config”

There was a problem with the user configuration read from
memory. It should be checked to make sure it still represents your
desired settings. These are settings that do not impact
measurements – contrast, logging mode, log sample intervals,
backlight setting time & date format, decimal setting (commas or
periods), beeper enable setting and auto power-down setting

"Saved Pressure Zero”

There was a problem with a pressure zero reading read from
memory. Differential pressure and gauge pressure should both be
re-zeroed.

The following table lists error messages which can be displayed should the
instrument detect a problem. Should any of these error messages recur
repeatedly, the instrument should be returned to the factory for servicing.

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C H A P T E R 9

U S B D o w n l o a d i n g t o a
C o m p u t e r

The HM685 Hydronic Manometer allows for downloading of stored data to
a computer by using the included Windows®-based CompuDat™–USB
downloading program and USB interface cable.

I n s t a l l i n g t h e U S B S o f t w a r e

Successful installation of the CompuDat™–USB downloading software is
completed as follows:

1. Insert the CompuDat–USB Software CD into the computer CD drive.

2. Allow the Autorun program to initiate the installation.

Not e

If the program fails to start automatically, run the file setup.exe located on
the CD.

3. Follow the on-screen instruction to properly install the program.

Notes

 You must have administrative rights on the computer in order to

successfully install the included USB downloading software.

 Restart the computer (as prompted) upon completing the installation

prior to first running the USB downloading program.

 The CompuDat-USB 2.0 program is also compatible with the HM680

meter.

9-1

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C o n n e c t i n g t h e M a n o m e t e r t o t h e C o m p u t e r

The HM685 Hydronic Manometer is connected to the computer using the
provided USB interface cable. The meter must be powered on in order to
properly establish communication.

First Time Connection

The first time the meter is connected to the computer, you will be prompted

to complete the following New Hardware installation.

Not e

The screens shown here are from a Windows® XP (32-bit only) system
installation. Windows® 7 (32- and 64-bit) system screens will differ.
Windows® 7 screen images are also shown below.

1. Select Automatic Install and click Next.

Figure 9-1

Found New Hardware Wizard

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Figure 9-2

Windows 7 Found New Hardware Wizard

2. Click Continue Anyway for Windows® XP system. Windows® 7 system
will install the driver automatically.

Figure 9-3

Hardware Installation

USB Downloading to a Computer 9-3

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3. Click Finish for Windows® XP system. No action needed for
Windows® 7 system.

Figure 9-4

Completing the Found New Hardware Wizard

Figure 9-5

Windows® 7 Installation Notification

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4. Verify that the meter driver has installed successfully by checking the
device manager. Go to Device Manager using the following steps:

a. Click on the Windows Start button.

b. Go to Control Panel, then Administrative Tools then select

Computer Management

c. Double-click on Device Manager.

Figure 9-6

Confirm Meter Software Installation

USB Downloading to a Computer 9-5

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S o f t w a r e I n t e r f a c e

With the HM685 meter connected to the computer, double-click on the
CompuDat-USB 2.0 icon on computer’s desktop. All downloadable data
stored to the instrument will be presented in a form similar to as follows:

When launching the software with more than one supported meter
connected, the following screen appears. Select the meter from which you
want to download data. If only one meter is connected, either the screen
for HM680 files and folders or the screen for HM685 displays.

Figure 9-7

Instrument Selection Screen

Figure 9-8

HM685 Data Download Screen

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HM685 Data Download Steps

1. Highlight the test (row) in test list or just left mouse click like Windows
operation to select the test/tests.

2. Select tests and click Download Selected button to download
selected tests or click Download All button to download all tests.

3. The following screen is shown when downloading starts.

Figure 9-9

HM685 Download Test Data Screen

4. When download finishes, a dialog similar to the following appears.

Figure 9-10

HM685 Data Download Screen

5. Click OK button and a dialog similar to the standard windows file save
as dialog appears.

6. Change the filename or use default and click Save button.

USB Downloading to a Computer 9-7

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Figure 9-11

HM685 Download Test Screen

7. Test/tests will be saved to one file.

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8. If HM680 is selected and OK is clicked, the screen shown below will

All TestIDs

The All TestIDs file contains all data stored to each of
the instrument’s 100 available Test IDs.

Cv Factors

The Cv Factors file contains all data associated with the
instruments 100 available Cv/Kv valve coefficients.

TestIDs Folder

Each TestIDs folder contains files for each of the Test ID
numbers indicated (example: the folder “TestIDs 1-10”
will contain files of stored data for Test ID 1 through Test
ID 10). TestIDs folders can be downloaded in their
entirety or opened for access to individual Test ID files.

display. Follow instructions for downloading data from HM680.

Figure 9-12

HM680 USB Folders and Files

HM680 Download Instructions

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D o w n l o a d i n g D a t a

Downloading stored data is completed as follows:

1. Single-click the desired file/folder to highlight.

2. Click the Save As icon in the toolbar.

The Save As option may also be used from the file pull-down menu.

3. Choose the filename, file type, and directory to save data to.

 Double-clicking or using the Open menu option allows for automatically

opening the selected file using an appropriate application (i.e.,
Microsoft® Excel® spreadsheet) upon having saved the file to the
computer.

 TSI recommends that you do not save data files in the C:\Program

Files directory when running on a Windows® 7 operating system in a
multi-user environment.

Not e

Not e s

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Range

Differential Pressure ................

Gauge Pressure ......................

Flow

1 ..............................................................

Operating Temperature ...........

Storage Temperature ..............

Temperature Probe .................

Liquid Media ............................

±300 psi (±2068 kPa)

-20 to 300 psi (-138 to 2068 kPa)
(-40 to 610 in. Hg)

± 99,999 USGPM
( ±6309 l/s, ±22,712 m3/h)

40 to 113°F (5 to 45°C) electronics

-4 to 140°F (-20 to 60°C)

-40 to 250°F (-40 to 121°C)
32 to 180°F (0 to 82°C)

Resolution

Pressure (best) ........................

Flow (best) ...............................

Temperature ............................

0.001 psi (0.01 kPa) (0.01 in. Hg)

0.0001 USGPM (0.00001 l/s)

0.1°F (0.1°C)

Accuracy

Pressure2 .................................

Flow .........................................

Temperature ............................

±1% of reading +.072 psi (0.5 kPa)
(0.15 in.Hg)

per pressure accuracy + valve deviation
±0.5% of reading +1.2°F (0.7°C)

Units

Pressure ..................................

Flow .........................................

Temperature ............................

psi, in. H2O, ft H2O, kPa, mm Hg, in. Hg,
m H2O, bar

USGPM, UKGPM, m3/h, l/s, l/m
degrees F, degrees C

Statistics .................................

min, max, average, sum up to 4000
readings

Data Storage ..........................

100 Test IDs, 4000 combined readings,
time and date stamped

Logging Interval .....................

user selectable (1 to 3600 seconds)

Time Constant ........................

user selectable (1, 5 10, 20, and 30
seconds)

Display ....................................

LCD with backlight

Dimensions (meter only) ........

11.1 in. × 4.7 in. × 3.5 in.
(28.2 cm × 11.9 cm × 8.8 cm)

Pressure Connection ............

¼” 37° Flare Fitting, Male

Weight with Batteries ............

2.65 lb. (1.20 kg)

A P P E N D I X A

Specifications

Model HM685 Hydronic Manometer specifications are as follows

(specifications are subject to change without notice).

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A-1

Power Requirements .............

four AA-size cells, alkaline or
rechargeable NiMH (included), or AC
adapter (included) 9 VDC, 2 A, regulated

Battery Life3 ............................

minimum of 12 hours with backlight on
minimum of 18 hours with backlight off

Recharge Time .......................

4 hours (internal charger)

Warranty .................................

2-year factory warranty

1

The flow reading is a calculated value determined from the measured Differential pressure,

user entered valve flow coefficient (Cv or Kv), and fluid specific gravity.

2

Accuracy statement applies from -15 to 250 psi (-103 to 1724 kPa).

3

The minimum battery life stated will occur after the NiMH batteries have been recharged

2 to 3 times after initial charge.

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CE Marking

EN61326 / EN 55011, Class B: Radiated Emissions
EN61326 / EN 55011, Class B: Conducted Emissions
EN61000-4-2: Electrostatic Discharge Immunity
EN61000-4-3: Electromagnetic Field Immunity
EN61000-4-4: Burst Immunity
EN61000-4-5: Surge Immunity
EN61000-4-6: Conducted PS Immunity
EN61000-4-8: Rated Power-Frequency Field Immunity
EN61000-4-11: Voltage Dips\Short Interruptions Immunity

RoHS Marking

Yes

A P P E N D I X B

C o m p l i a n c e

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B-1