Miura EX-100 User manual

Please ensure that operation manual is read and observed in full
by all persons working with the steam boiler.
Please also ensure that it is stored in a location where it may be
easily accessed.
INFORMATION IN THIS MANUAL MAY BE CHANGED
WITHOUT ANY NOTICE.
MIURA STEAM BOILER
OPERATION MANUAL
EX-100 EXH-200
EX-150 EXH-250
EX-200 EXH-300
EX-250 EXNH-300
EX-300
EXN-300
Operation Manual Number: T539-998-9004 Date of issue : Aug. 16, 2017

1
Main Sections
1. INTRODUCTION 4
2. ESSENTIAL BOILER WATER TREATMENT 13
3. COMPONENT NAMES & FUNCTIONS 19
4. BASIC PRECAUTIONS 26
5. PRE-OPERATION INSPECTION 32
6. USING BOILER CONTROLS 36
7. PREPARING FOR STARTUP 47
8. OPERATING THE STEAM BOILER 52
9. INSPECTION & MAINTENANCE 57
10. BREAKDOWN & COUNTERMEASURES 82
11. SPECIFICATIONS 94
12. APPENDIX 96

2
Table of Contents
Main Sections.......................................................................................................................................... 1
Table of Contents..................................................................................................................................... 2
1 INTRODUCTION .............................................................................................................................. 4
1.1 Safety Indicators..................................................................................................................................5
1.2 Glossary ..............................................................................................................................................6
1.3 Introduction..........................................................................................................................................7
1.4 Features .......................................................................................................................................... 7-7
1.5 Description...........................................................................................................................................9
1.6 Acts & Regulations ............................................................................................................................11
1.7 National Regulatory Organizations ...................................................................................................12
2 ESSENTIAL BOILER WATER TREATMENT.................................................................................. 13
2.1 Flow Chart .........................................................................................................................................14
2.2 Water Treatment Guidelines..............................................................................................................16
3 COMPONENT NAMES & FUNCTIONS ......................................................................................... 19
4 BASIC PRECAUTIONS .................................................................................................................. 26
4.1 Items to Check before Use................................................................................................................27
4.2 Clothing Requirements for Safe Operation .......................................................................................28
4.3 Warning Labels..................................................................................................................................28
4.4 Dealing with Abnormal Conditions ....................................................................................................29
4.5 Precautions for Boiler Usage.............................................................................................................30
4.6 Fire Extinguishers & First Aid Boxes .................................................................................................30
4.7 Prohibition of Unapproved Modification ............................................................................................31
4.8 When Reselling or Relocating...........................................................................................................31
5 PRE-OPERATION INSPECTION ................................................................................................... 32
6 USING BOILER CONTROLS ......................................................................................................... 36
6.1 Using the Fuel Selector Switch .........................................................................................................37
6.2 Names & Functions of Control Panel Items ......................................................................................37
6.3 Working with the Display ...................................................................................................................38
6.3.1 Display Content ..................................................................................................................... 38
6.3.2 Using the Display (“DATA” & “SELECT”) ............................................................................... 39
6.3.3 Display Content for Heat Management Mode........................................................................ 40
6.3.4 Display Content for User Setting Mode.................................................................................. 41
6.3.5 Display Content for Fault History Mode ................................................................................. 44
6.4 Confirming Gauge Readings .............................................................................................................45
6.5 Operating the Main Steam Valve.......................................................................................................46
7 PREPARING FOR STARTUP......................................................................................................... 47
8 OPERATING THE STEAM BOILER ............................................................................................... 52
8.1 Boiler Startup for Gas-fired Combustion ...........................................................................................53

3
8.2 Boiler Startup for Oil-fired Combustion..............................................................................................54
8.3 Inspection during Operation ..............................................................................................................55
8.4 Boiler Shutdown ................................................................................................................................56
9 INSPECTION & MAINTENANCE ................................................................................................... 57
9.1 Preparing for Possible Freezing........................................................................................................58
9.1.1 Bleeding Water to Protect against Freezing........................................................................... 58
9.2 Maintenance during Extended Inactivity ...........................................................................................59
9.3 Regular Maintenance Tasks and Timing ...........................................................................................60
9.4 Spare Parts........................................................................................................................................62
9.5 Overview of Inspection ......................................................................................................................63
9.5.1 Checking the Chemical Feeder.............................................................................................. 63
9.5.2 Checking the Water Softness................................................................................................. 64
9.5.3 Checking the Steam Pressure ............................................................................................... 65
9.5.4 Checking the Gas Pressure................................................................................................... 65
9.5.5 Checking the Oil Pressure ..................................................................................................... 66
9.5.6 Checking the Combustion Condition...................................................................................... 67
9.5.7 Blowdown & Testing of the Low Water Level Interlock........................................................... 67
9.5.8 Cleaning the Feed-water Strainer .......................................................................................... 70
9.5.9 Cleaning the Feed-water Tank ............................................................................................... 72
9.5.10 Inspecting the Safety Valve.............................................................................................. 73
9.5.11 Safety Sensors Check...................................................................................................... 74
9.5.12 Cleaning the Oil Strainer...................................................................................................... 75
9.5.13 Cleaning the Y-type Oil Strainer ........................................................................................... 76
9.5.14 Cleaning the Air Filter .......................................................................................................... 78
9.5.15 Cleaning the Burners (oil-fired)............................................................................................ 79
10 BREAKDOWN & COUNTERMEASURES .................................................................................. 82
10.1 Alarm and Red Status Lamp – Alarm ................................................................................................83
10.2 Yellow Status Lamp – Caution...........................................................................................................84
10.3 Action to be Taken before Ordering Repairs .....................................................................................85
10.3.1 Bleeding Air from the Feed Water Pump.............................................................................. 88
10.3.2 Inspecting Water Level Probes ............................................................................................ 89
10.3.3 Resetting the High Pressure Limit Shutoff Switch................................................................ 89
10.3.4 Resetting Blower Overcurrent.............................................................................................. 90
10.3.5 Bleeding Air from the Oil Pump (for oil-fired combustion) .................................................... 91
11 SPECIFICATIONS ...................................................................................................................... 94
12 APPENDIX.................................................................................................................................. 96

4
1 INTRODUCTION

5
1.1 Safety Indicators
The following headings are used within this manual in order to ensure safe and efficient operation of your
steam boiler.
Please ensure that you fully understand the meaning of each and use the boiler accordingly.
WARNING
CAUTION
NOTE
Meaning of safety
indicators
The number contained within this symbol indicates a relevant
page.
This symbol is used to indicate forbidden actions.
Specific details of these actions will be presented together
with the symbol.
Important information from the point-of-view of
preventing boiler malfunction and ensuring
efficient operation, or information that will prove
useful during operation of the steam boiler.
Failure to use the steam boiler correctly could
possibly lead to injury of the user or to property
damage.
Failure to use the steam boiler
orrectly could possibly lead to serious injury or
death of the user.

6
1.2 Glossary
Please use the following table to confirm the meanings of special terms used within the operation manual.
Term Meaning
Low water level
interlock
The action of preventing ignition when the normal water level has not been
achieved.
Pre-purge Purging with air from the boiler’s combustion chamber before the start of
combustion.
Post-purge Purging with air from the boiler’s combustion chamber after the end of
combustion.
Pilot ignition Ignition of the pilot burner.
Pilot only A condition wherein only the pilot burner is lit.
Main ignition Ignition of the main burner.
Low fire A condition wherein combustion takes place at approximately 50% of maximum
combustion performance.
High fire A condition wherein the boiler is operating at maximum combustion performance.
Scale The buildup of water impurities such as calcium and magnesium on water tubes.
Sludge Impurities that precipitate inside the boiler.
Untreated water Water that has not yet been treated.
Soft water Water which has had calcium and magnesium removed.
Boiler makeup (water) Treated water that is supplied to the boiler, or the act of sending this water.
Equivalent evaporation The mass of steam generated in one hour when water at 212°F is changed into
steam at 212°F.
Carry over The unwanted discharge of moisture or impurities in the steam.
Blowdown The discharge of water contained within the boiler.
Water tube A tube making contact with combustion gas on the outside, and through which
boiler water flows.
Deaerator A device used to heat the boiler makeup water in order to reduce the level of
oxygen dissolved in it.
Cavitation A situation where air enters a pump and prevents normal operation.

7
1.3 Introduction
MIURA Boiler Co., Ltd. began North American activities in 1988, when the manufacturing plant in Brantford,
Ontario, was established. Subsequently, our engineering department developed procedures to meet ASME
codes and to gain listing approval from UL, CSA. The United States corporate sales office, MIURA Boiler,
Inc., was then established and has since developed relationships with national, state and city inspectors and
agencies.
Our North American network consists of branches in Atlanta, Chicago, Los Angeles, New York, Texas and
Ontario. The parent company, MIURA Boiler Ltd. of Japan, is the leading manufacturer of boilers and other
thermal equipment in the Pacific Rim region with steam boiler market share in Japan excess of 55%.
Operating factories in seven countries, our production volume now exceeds 140,000 units per year.
As a result of design necessities in Japan — such as limited space and a total dependence on foreign
energy — the MIURA Steam Boiler has been engineered with a highly efficient, vertical water tube, once-
through, forced-flow design. Featuring a compact unit with low water content, the MIURA Boiler is designed
to be run with simple push-button controls and a minimum amount of maintenance. Operation is quiet,
radiant heat losses are minimal, and steam quality is second to none. Furthermore, MIURA Boilers are often
installed in a multiple boiler network.
MIURA Boilers, in combination with the patented MIURA Multiple Installation panel, allow the required
horsepower to be brought on and off line quickly in order to meet sophisticated production needs with
maximum fuel economy. The MIURA Advantage — proven in the field over fifty years of excellent service —
is the ability of our boilers to reach full output steam from a cold start in less than five minutes using the least
amount of energy and having the lowest environmental impact. In recognition of its compact, safe, and cost-
effective design, the high-efficiency MIURA Boiler has won numerous awards from engineering societies and
gas associations.
1.4 Features
The MIURA Steam Boiler features a once-through, forced flow, low water content, water-tube design, which
can achieve full output within five minutes. What’s more, this boiler is designed to be run with simple push-
button controls and a minimum amount of maintenance. Using the patented MIURA BL11 computer
controller, we can monitor precise characteristics of boiler operation from our offices and provide fast,
accurate feedback data. Radiant heat losses are minimal and steam quality is second to none. In addition,
MIURA Boilers are often installed in a multiple boiler network.
MIURA Boilers, in combination with the patented MIURA Multiple Installation panel, allow the required
horsepower to be brought on and off line quickly in order to meet sophisticated production needs with
maximum fuel economy. The high-efficiency MIURA Boiler has received numerous accolades in Japan,
including awards from the Japanese Society of Mechanical Engineers and the Japanese Gas Association.
This boiler is characterized by compact, safe, cost-saving performance — an advantage that is underscored
by our greater than 55% steam boiler market share in Japan.
Some of the standard features of the EX model are as follows:
UL, c-UL approved and labeled boiler design (FM available)
“HIGH GAS” and “LOW GAS” pressure switches
“LOW AIR” pressure switch
Main gas line and pilot line regulators
Dual pilot-gas solenoid valves
Dual main-gas fluid actuator valves and a plugged leak-test port (vent valve also available)
Forced-draft blower and motor
Thermocouples on water tubing in order to prevent overheating due to low water or scale build up
Two independent low-water fuel cutoffs, one featuring a manual reset

8
Two independent water volume controls
Intermittent Automatic Blowdown system with a strainer and manual shutoff valve
Control Steam Pressure transducer with a backup control pressure switch.
High steam limit pressure switch featuring a manual reset
ASME safety relief valves for the boiler and an optional economizer
Completely enclosed, heavy gauge casing
ASME stamped pressure vessel with internal inspection ports
External steam separator
Digital steam-pressure display with a back up pressure gauge
MIURA BL11 Microprocessor Boiler Control featuring a user-friendly digital display
Communication interface functionality
Display of hours of operation and logging of the seven most recent faults
Oil pump with motor and oil solenoid valves for oil fired boilers

9
1.5 Description
MIURA Steam Boiler presents to most inspectors in the field with an unfamiliar design. The purpose of this
section is to address common questions and to familiarize the inspector with a general overview of MIURA
boiler design and operational characteristics.
The MIURA boiler design comprises straight water tubes between upper and lower annular headers. Both
headers are encased in a castable refractory, leaving only the tubes exposed to combustion gases. There is
very little water and consequently very little energy stored within the steam boiler. Water remains exclusively
inside the tubes, with only incidental bubbling in the upper header. Therefore, the design features no natural
circulation such as the riser or downcomer effect common to natural circulation boilers.
Water is forced into the bottom header and tubes by means of a feed water pump. The water is flashed into
steam in the tubes, realizing a dynamic bubbling system that also cools the tubes. This bubbling action may
be best described as a “steam gradient,” with more steam at the top of the tubes than at the bottom. Steam
is accumulated in the upper header, with a final separation in the external separator. Condensate separated
in the external separator is fed back into the lower header.
As a result of this steam gradient characteristic, there are no strictly defined steam and water levels, and
thus, the boiler requires no sight glass. Furthermore, special modifications are incorporated into the boiler
construction and safety system in order to accommodate this.
First of all, two probes are placed directly into the top of the tubes. One probe is long, for low-water cutoff;
the other is short, for feed water control. This water volume control relies on electrical conductance, and the
bubbling action of the boiler water cools the tubes. As the volume of water in the steam boiler is consumed,
there is less bubbling at the top of the tubes, decreasing conductivity. Once the effective conductance
reaches a pre-determined level, the system triggers a ten-second delay before the feed water pump is turned
on. The pump continues to run until the bubbles re-establish effective contact with the probe. If the water
volume drops and loses an effective contact with the low-water cutoff probe, the boiler will shut down.
Secondly, probes are inserted into a water column (LVC) located on one side of the boiler. The water control
system relies on a more conventional, electrical conductance approach — specifically, when water contacts
a probe, a circuit is formed. Three probes control the boiler feed, with a short probe for high-fire, a medium
length probe for low-fire, and a long probe for low water cutoff. This safety configuration may seem confusing
to the inspector who encounters the MIURA Steam Boiler in the field for the first time, particularly because a
water column typically indicates a fixed water level. This is not true for Miura’s steam boilers, because of the
low water content and the fierce boiling action of the steam gradient. Control of this dynamic system has
been made possible by adding a special modification of the water column in order to create an artificial level.
The flanged pipe leading from the boiler body runs through the column, with three holes drilled in the pipe to
create an orifice effect. With this orifice effect, the artificial level oscillates — especially with the fluctuation of
the system load. This oscillation is desired and is directly proportional to the volume of water in the boiler
tubes.
Either of these feed water control systems can operate without the other for reliable feed water control.
However, the combination of these two systems provides double low-water safety and has thus been labeled
the Two-way Water Volume Control System.
Third in the list of safety modifications are thermocouples, attached directly to the tubes. These
thermocouples measure the temperature of the tubes and will shut down the boiler if a low water volume
condition is detected due to insufficient bubbling, if dry fire occurs. Boiler will caution by yellow sign if scale
buildup is detected. Scale formation reduces heat transfer rates and is therefore monitored directly based on
any increase in tube surface temperature. The early detection of scale formation is an important factor in
maintaining a high-efficiency boiler. According to the US National Bureau of Standards, 1/4" of scale buildup
on heating units requires up to 55% more energy to attain the same temperature.
The boiler will not operate should any of these low-water safeties fail. Only through tampering could the
boiler operate without these safeties and give rise to a dry fire condition. Even in the unlikely event that such

10
a situation should occur, by the time the tubes superheat to the level required to overcome the steel’s tensile
strength, the amount of energy contained in the remaining water would be so small that the possibility of a
pressure explosion is negligible. The MIURA Steam Boiler design has been used for more than 35 years,
and over 200,000 units are presently in operation worldwide. There is no record of ANY pressure vessel
explosion.
Steam is produced within five minutes from cold start-up and selected tubes can be visually inspected
through two-inch openings located in the top and bottom headers. A full inspection is typically completed
within 30 minutes.
All MIURA steam boilers are annotated as a forced flow steam generator (with no fixed steam or water level)
on the pressure vessel’s P-3 form and registered with the National Board. The complete packaged steam
boiler is listed as a standard with UL, and c-UL, and it can be tuned to meet FM and/or ASME-CSD1
requirements at the customer’s request.
Please note that all flanges used on our EX boilers are class 150 (EXH uses class 300) and comply with
ASME/ANSI standard B16.5. The class 150 stamping refers to a standard classification, and not the
Maximum Allowable Working Pressure (MAWP). This specification matches the 170 PSI MAWP rating of the
EX boiler.
CAUTION
All steam systems require continuous, appropriate water treatment. This treatment is mandatory from the
time of installation of your MIURA Steam Boiler. Failure to follow the recommended water treatment and
maintenance procedures could shorten the service life (and efficiency) of your boiler and could also affect the
warranty. The scale and overheat thermocouples may, in some cases, not be able to shut down the boiler
before troubles occur.

11
1.6 Acts & Regulations
There are a number of codes, standards, laws, and regulations for boilers and related equipment that should
be considered. Regulatory requirements are dictated by a variety of sources and are focused primarily on
safety. This equipment shall be installed in accordance with the current regulations, codes, and
specifications of the applicable municipal, national, provincial, state, and/or federal agencies. Authorities
having jurisdiction should be consulted before the commencement of installation work. For more information
on how the various rules affect boiler selection and operation, you may want to contact your local MIURA
authorized representative or the engineering firm designing your boiler installation. Here are some essential
rules to take into consideration:
a. The boiler industry is tightly regulated by the American Society of Mechanical Engineers
(ASME) and ASME codes, which control boiler design, inspection, and quality assurance. All
boiler pressure vessels, including economizers, should have an ASME stamp.
b. All pressure vessels should be inspected and registered with the National Board.
c. In Canada, the design of all boilers, pressure vessels, fittings, and piping must be registered
with your local province as required in CSA B51.
d. The insurance company insuring your facility or boiler may dictate additional requirements.
Boiler manufacturers can provide special boiler trim according to the requirements of major
insurance companies such as FM. Special boiler trim items usually take the form of added
safety controls. Some industries — such as food processing, brewing, or pharmaceuticals —
may also have additional regulations that have an impact on the boiler and boiler room.
e. UL or c-UL approval may be required in order to verify safe boiler performance.
f. A full-time boiler operator may be required. Operator requirements depend on the boiler’s size,
pressure, heating surface area, and volume of water. Boilers can be selected to minimize
operator requirements, either by choosing a boiler that is exempt from certain rules, or by
installing special equipment that gives the operator more freedom within the facility. Contact
your local boiler inspector for more details.
g. Most state, provincial, and local authorities have a permit that must be acquired in order to
install and operate a boiler. Additional restrictions may apply in non-attainment areas where air
quality does not meet the national ambient air quality standards and where emission regulations
are more stringent. Be sure to investigate these requirements before purchasing a boiler.
h. Most states or provinces require an annual boiler inspection, and additional requirements may
also apply to piping.
i. Most regional authorities have established a maximum temperature at which water can be
discharged to the sewer system. In such a case, a blowdown separator or blowdown tank will be
required.
j. U.S. Federal emission standards — including permit and report-related procedures — apply to
all new boilers with inputs over 10-million BTU/Hr.
k. Boiler ratings are based on operation at sea level. For operation at elevations above 2,000 feet
(600 m), ratings must be reduced at a rate of 4% per 1,000 feet (300 m) above sea level.

12
1.7 National Regulatory Organizations
In order to obtain assistance in the identification of, and compliance with, codes and regulations, we
recommend contacting your actual insurance provider as well as utility companies. A partial list of agencies
having jurisdiction over boiler installation and operation is given below. This list is comprehensive, but by no
means all-inclusive.
UNDERWRITERS LABORATORIES T.S.S.A.
333 Pfingsten Rd. 3300 Bloor St., West
Northbrook, IL 16th Floor, Centre Tower
60062 Toronto, Ontario M8X 2X4
[phone] [phone]
NATIONAL BOARD N.F.P.A.
1055 Crupper Ave. 1 Batterymarch Park
Columbus, OH P.O. Box 9101
43229 Quincy, MA 02269-9101
[phone] [phone]
A.S.M.E. FACTORY MUTUAL RESEARCH CORPORATION
345 East 47th St. 1151 Boston-Providence Turnpike,
New York, NY Norwood, MA 02062
10017 [phone]
[phone]
AMERICAN NATIONAL STANDARD INSTITUTE
AMERICAN GAS ASSOCIATION 11 West 42nd Street,
1515 Wilson Boulevard New York, NY 10036
Arlington, VA 22209
ENVIRONMENT PROTECTION AGENCY
OCCUPATIONAL SAFETY & HEALTH
ADMINISTRATION
LOCAL BUILDING AND CONSTRUCTION
INSPECTORS
LOCAL FIRE MARSHAL
FOOD & DRUG ADMINISTRATION
LOCAL BOILER INSPECTORS

13
2 ESSENTIAL BOILER WATER TREATMENT

14
2.1 Flow Chart
NOTE
Tap water and well water contain a wide range of dissolved impurities in varying amounts.
If this water is used without removing the impurities in advance, buildup of scale, carry-over, corrosion, and
other similar factors would have a detrimental effect on the boiler’s efficiency and service life. For this reason,
the installation of water treatment equipment and thorough control of water quality are critical.
At MIURA, we believe that the above flowchart sets forth a standard for water treatment system.
■ Hard-Leak Alarm (Colormetry)
Monitors the soft water treated in
the water softener.
■ Chemical Feeder
Feeds chemicals into the boiler in
order to prevent it from corroding.
■ Water Softener
The water supply is usually hard water.
The water softer converts this to soft water.

15
■ Boiler Makeup Tank
Two different varieties of
boiler makeup tank are
available – namely, the water
tank and the deaerator tank.
Main feed water valve
Main gas valve
Gas
Main fuel valve
Oil Fused
disconnect or
over current
protection/
disconnect
Main
power
■ Once-through Steam Boiler
Water delivered to the inside of
the tubes is heated by the
combustion of fuel using a burner.
As a result of this heating, the
boiler water successively
evaporates to form steam, which
is then supplied to the load
application.

16
2.2 Water Treatment Guidelines
Basic
Proper water management/treatment is essential for steam boiler operations. Any one or the combination of
the following three major issues can potentially halt your daily activities; corrosion (including condensate
return corrosion), scaling, and carryover. The objective of boiler water treatment is to support your
uninterrupted daily steam boiler operation and to allow our valued customers to obtain good quality steam
economically.
MIURA water treatment proposal
MIURA recommends that customers utilize the available genuine water treatment equipment and chemical,
“BOILERMATE®,” for MIURA boilers. MIURA boilers are designed with a unique pressure vessel which allow
for once-through water flow, high-heat transfer, and small package system. This makes the water content of
MIURA boilers much smaller than that of conventional boilers, leading to a difference in boiler water behavior
compared to conventional design. Focusing on our steam system needs, MIURA water treatment products
are continuously researched, developed, and optimized to work best with our equipment.
System integrated water softeners
One of the most common causes of boiler damage is scale. MIURA offers a solution through our System
Integrated Water Softener - MW series; featuring split flow regeneration and MIURA Online Maintenance.
Due to advanced integral sensors, the whole regeneration process is monitored so that the softener will
reliably supply softened water. In the case that a non-MIURA softener is used, we strongly recommend
installing a polisher (an additional softener after the main softener) to maintain production of highly softened
water (<1ppm).
Colormetry
The conventional method of testing water hardness is through manual testing. MIURA’s hardness detecting
equipment, “Colormetry”, functions as an automatic monitoring system for make-up water. This device
automatically handles the test reagent injection, mixing, and evaluation. It also functions as an optional
upgrade component for MW series softeners and can integrate with the MIURA Online Maintenance System.
When the Colormetry detects a hardness leak in the make-up water, the MW softener can switch the service
resin tank automatically in order to continue supplying softened water.
BOILERMATE®
BOILERMATE® chemicals are designed to help provide customers with seamless operation of MIURA
boilers and save cost on steam when utilized as recommended. Conventional boiler water treatment may not
satisfy MIURA’s boiler water guidelines. We recommend customers to utilize our BOILERMATE® silica
program for corrosion inhibition and chelant/polymer type dispersant; to ensure your MIURA boiler’s optimum
condition over its entire life.
CAUTION: Proper water treatment MUST be used from the time the boiler is first operated.
NOTE: MIURA cannot be responsible for any problems encountered with the boiler due to unsuitable water
treatment. Sulfite type oxygen scavenger programs may not be effective for the MIURA steam boiler if the
feed water temperature is too low.
Phosphate type treatments create excess solids that are not water-soluble. As such, this type of treatment
may result in scaling.

17
Daily operation
MIURA has no warranties to cover damage due to improper water treatment and failure to maintain the
specifications listed below.
MIURA MAKE-UP WATER MAINTENANCE CHECK
To keep your MIURA boilers running in optimum condition, be sure to check the following daily:
a) CHEMICAL FEED PUMP
i. Proper chemical feed.
ii. No air in the chemical feed pump or lines.
b) WATER SOFTENER
i. Boiler Make-up water is completely soft (use a test kit sensitive to less than 1.0 PPM).
ii. Make sure the water softener timer or softener flow meter is working every day.
iii. Make sure the by-pass valve is closed and inlet and outlet valves are open.
iv. Make sure there is no hardening (caking) of the salt in the brine tank. In case of salt hardening
or “bridging”, break the salt into small pieces to allow for proper brine concentration.
v. If applicable, make sure the polishing water softener is working properly.

18
WATER TREATMENT GUIDELINES FOR MIURA STEAM BOILERS
The chemistry values given in the table below have been specially designed for Miura steam boilers. These
guidelines helps to attain the longest possible life for boilers operating under standard conditions. Continuous
maintenance and monitoring is key to preventing water related issues.
Parameter Units
Make-
up
Water
Feed Water Boiler Water
Condensate
Water
Pure
Water
3
Soft Water Pure
Water
3
Soft Water
Silica
Program
Sulfite
Program Silica Program Sulfite Program
pH - 7.0-9.0 7.0-9.0
2
7.0-9.0
2
7.0-9.0
2
11.0-11.8 11.5-12.4 11.5-12.4 7.0-9.0
10
EC µS/cm <1500
1
≤20
3
<600 <500 <2500 <4000
5
<3000
6,8
<4000
5
<3000
6,8
-
Hardness ppm 0 0 0 0 <3.0 <3.0 <3.0 <3.0 <3.0 <1.0
C loride ppm - - - <150 <400
5
<300
6
<400
5
<300
6
-
C loride +
Sulfate ppm - - - - <500 <1000
5
<750
6
<1000
5,9
<750
6,9
-
Silica ppm - - - - 150-500
4
150-500
4,5
110-500
4,6
150-500
4,5
110-500
4,6
-
Sulfite ppm - - - -
(20
-
50
5
/
10-20
6
)
7
- - 20-50
5
10-20
6
-
Iron ppm <0.3 <0.3 <0.3 <0.3 <3.0 <3.0 <3.0 <3.0 <3.0 <3.0
Note 1. The limitation of make-up water conductivity 1500 µS/cm is related to the limitation of water softener
make-up water.
Note 2. Feed water pH with condensate return 7.0-9.0. Feed water pH may vary from 5.8-9.0 with no water
treatment chemicals. For carbon steel feed water tanks, the recommended range is 8.0-9.0.
Note 3. Pure water is less than 20µS/cm (without chemical). When feed water EC>20µS/cm, refer to soft
water treatment program. If pure water is a mix of RO water and soft water, refer to soft water treatment
program.
Note 4. Silica concentration is dependent on feed water quality, please contact your Miura representative for
changes in dosage.
Note 5. Value is based on the Boiler Operation Pressure below 150Psi.
Note 6. Value is based on the Boiler Operation Pressure when 150Psi<P<300psi.
Note 7. Silica program is recommended when pure water is used for boiler feed.
Note 8. Site specific circumstances may influence recommended values, contact your Miura representative.
Note 9. Sulfate values from non-silica type chemical programs are not included in totals.
Note 10. pH 8.0-9.0 is strongly recommended.
ADDITIONAL NOTES:
1.Sulfite oxygen scavenger programs may not be effective for Miura steam boilers if the feed water
temperature is too low.
2.Phosphorus containing water treatments creates excess solids that are not water-soluble. This type of
treatment may result in scaling.
END USER RESPONSABILITIES:
1.Water test must be performed every day. Miura recommends to record the results from the daily test.
Refer to your contract terms and conditions or contact your Miura representative for guidelines about
daily water test and log.
2.A full water test (not just hardness) for all water types should be done every month. Refer to your
contract terms and conditions or Miura representative for the frequency for a full water test.
Test results should be compared to the above WATER TREATMENT GUIDELINES FOR MIURA
STEAM BOILERS.
3.Consult or retain a qualified water treatment professional to follow these guidelines.

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3 COMPONENT NAMES & FUNCTIONS