Precision Boilers FTS Series User manual

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Installation and
Operating Instructions
Precision Flextube Boilers
FTS Series
STEAM BOILERS

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FOR YOUR SAFETY
This manual supplies information on the application, installation and operation of Model MCH Boilers.
Review all application and installation procedures completely before proceeding with the installation.
Consult the Precision Flextube Boilers’ Factory or local Factory Representative with any problems or
questions regarding this equipment. Experience has shown that improper installation causes most
operation problems.
WARNING
Improper installation, adjustment, alteration, service or maintenance can cause injury or property
damage. Read this manual thoroughly and follow the instructions herein.The MC Series Boilers shall be
installed according to the procedures detailed in this manual, or the Precision Flextube Boilers Limited
Warranty may be voided. The installation must conform to the requirements of the local jurisdiction
having authority, and to the latest edition of the National Fuel Gas Code, ANSI Z223.1. Any modifications
to the boiler or its gas / oil controls may void the warranty. If field installation requires modifications,
consult either the local Precision Flextube Boilers’ Representative or the Factory.
RETAIN THESE INSTRUCTIONS NEAR THE EQUIPMENT FOR READY REFERENCE
Installation and Operating Instructions
Precision Flextube Boilers
FTS Series HOT WATER BOILERS

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TABLE OF CONTENTS
ITitle page ................................................................1
II Introduction............................................................2
III Index ...................................................................... 3
1.0 GENERAL INFORMATION
1.1 General Description ............................................ 4
1.2 Receiving Shipment ............................................ 5
1.3 Engineering Assistance .......................................5
1.4 Warranty ............................................................. 5
2.0. BOILER INSTALLATION
2.1 Receiving ............................................................. 5
2.2 Placement ...........................................................6
2.3 Piping Connections ............................................. 6
2.4 Fuel Supply Piping...............................................7
2.5 Electrical Connections.........................................8
2.6 Combustion Air Supply .......................................9
2.7 Combustion Gas Exhaust Connection ................9
2.8 Before Placing the Boiler into Operation ......... 10
2.9 Firing Rate Adjustments ................................... 10
3.0 SAFETY AND CONTROL DEVICES
3.1 Flame Supervisory System................................ 11
3.2 Flame Detection System ...................................11
3.3 Low Water Cut-Off ............................................ 11
3.4 Combination Low Water Cut-Off & Feeder...... 12
3.5 Combination Low Water Cut-Off Level Ctrl...... 12
3.6 Modulating Level Control ................................12
3.7 Pressure Control................................................12
3.8 High Pressure Limit –Auto Reset .....................12
3.9 High Pressure Limit- Manual Reset ..................12
3.10 Safety Valves ...................................................13
4.0 BOILER START-UP
4.1 Limit Circuit Cut-Out Test .................................13
4.2 Steam Temperature Operating Control ...........13
4.3 Additional Controls ...........................................13
4.4 Burner Start-Up.................................................13
4.5 Boil-Out .............................................................13
5.0 BOILER OPERATION
5.1 Curing ................................................................14
5.2 Water Chemistry ...............................................14
6.0 OPERATING INSTRUCTIONS
6.1 Temperature Controls.......................................15
6.2 High Temperature Limit –Auto Reset ..............15
6.3 High Temperature Limit –Manual Reset .........15
6.4 Forced Draft Adjustment ..................................16
7.0 MAINTENANCE
7.1 General ..............................................................16
7.2 Procedures ........................................................16
8.0 SHUTDOWN ......................................................16
9.0 EXTENDED SHUTDOWN ...................................17

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1.0 GENERAL INFORMATION
PRECISION has made a commitment to product improvement and follows a continuing quest for
the highest standards of product performance. In pursuing this policy of continuous development
of products, the manufacturer reserves the right to vary any details in this manual without notice.
1.1 General Description
The Model MCS is a watertube boiler in which water is inside the tubes and combustion gases
are outside the tubes; it consists of three major components, the support structure, the
pressure vessel, and the casing. This particular boiler is designed to combine the higher
efficiencies of some firetube designs with the rapid responses typical of watertube designs.
1.1.1 Support Structure
The boiler is built on a heavy duty fabricated steel structure. This steel structure is designed to
support the movement and ‘rigors’ of shipping as well as the operating weight of the boiler.
The support structure is not designed to withstand heat generated by the boiler, and is
insulated from that heat. The support should be located above floor level on an elevated
housekeeping pad.
1.1.2 Pressure Vessel
The pressure vessel is constructed of carbon steel designed and tested to ASME code
requirements. The pressure vessel carries an ASME National Board number as registered with
the National Board, and includes the following major components:
1.1.2.1 Upper and Lower Headers
The lower header (mud drum) distributes water to the heat exchanger section of the boiler;
water then flows from the heat exchanger section to the upper header (steam drum) where the
steam separates from the water. Thus, separation is further aided by a mechanical steam
separator located in the header below the steam discharge nozzle. The headers are drilled to
exact dimensions for connection and support of the heat exchanger section. There are also
downcomers connected between the upper and lower headers at each end of the boiler. The
downcomer allows a natural circulation to recycle water flow from the upper header to the
lower header.
1.1.2.2 Heat Exchanger
The heat exchanger section is constructed of heavy gage steel tubes connected between the
top and bottom headers. These tubes are constructed in a ‘serpentine’ fashion and are
designed to require the combustion gases to take a long route to the boiler exhaust. This
additional time allows more heat exchange and effectively increases the heat exchanger
capacity. The tubes form a tangent waterwall, which surrounds the combustion chamber on
the top, bottom and side opposite the headers. Tubes are normally attached to the header
with ferrules, which are driven into the headers and head in place by bolted ‘keeper’ plates.
This arrangement allows for simple and easy tube replacement if the need occurs.

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1.1.3 Boiler Casing
The boiler casing system consists of both an inner and outer casing, and contains all combustion
gases in their route to the boiler exhaust. By containing all the gases, the inner casing keeps
the boiler room free of exhaust gas. The boiler inner casing is constructed of heavy gage
reinforced steel plate and is insulated with layers of mineral wool and ceramic fiber to protect
the steel and retain the heat to effect higher boiler efficiency. The outer casing is separated
from the inner casing with fiberglass insulation which protects personnel from high heat and
allows a cooler boiler space. Access to the boiler combustion area is normally done by
removing a boiler side wall. The wall on the
header side of the boiler is designed to be easily removed.
1.2 Receiving Shipment
Some accessory items may be shipped in separate packages. Verify the receipt of all packages
listed on the packing slip. Inspect everything for damage immediately upon delivery, and advise
the carrier of any shortages or damage. File any such claims with the carrier. The carrier, not
the shipper, is responsible for shortages and damage to the shipment, whether visible or
concealed.
1.3 Engineering Assistance & Customer Service
Consult the Local Precision Flextube Representative or Factory regarding any questions or
problems which may come up involving the specification, installation or operation of Precision
Flextube Boilers equipment. An experienced engineering staff is ready to assist in assuring their
proper application and performance.
1.4 Warranty
Precision Flextube Boilers are covered by a limited warranty. A copy of the warranty will be
provided after all documents have been processed. Make all warranty claims to an authorized
Precision Boilers’ representative, or directly to the Factory. Claims must include the unit serial
number and model (per the name plate), installation date, and name of the installer. Shipping
and labor costs are not included in the warranty coverage.
2.0 BOILER INSTALLATION
2.1 Receiving
Electrical equipment can be damaged if exposed to adverse weather. The unit should be stored
inside. The electrical panel and controls must be covered with plastic throughout all
construction to avoid accumulation of dust and moisture on the controls and other
components.
Care must be taken not to damage controls or to deform the unit’s casing during removal of the
crate. When using pry bars or fork lifts, be certain to support the unit on the shipping skids or
the channel base.

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2.2 Placement
2.2.1 Foundation
The boiler location should be prepared before uncrating the boiler. A concrete boiler
foundation is recommended; the foundation should be level and designed to adequately
and uniformly support the boiler operating weight. An existing concrete floor may be used only
if it is determined that it will be adequately and uniformly support the boiler operating weight.
CAUTION: DO NOT INSTALL BOILER ON COMBUSTIBLE FLOORING.
2.2.2 Clearance
See Table 1 for minimum clearances to wall, ceilings or obstructions. The clearances in the
Table 1 are intended as general recommendations only. Local codes must be adhered to and
minimum clearances established accordingly. Provisions must also be made for service,
accessibility and clearance for piping and electrical connections. Do not obstruct combustion
air and ventilation openings with piping, etc. All boilers must be installed in a large space
compared to the boiler physical size.
NOTE: Adhere to all applicable local codes regarding boiler installation and clearances. Be sure
to keep burner and controls covered at all times while work is in progress.
Table 1
BOILER CLEARANCES
Clearance
From / To
Model #
MCH-1
(9.5 –60 bhp)
Model #
MCH-2
(60 –110 bhp)
Model #
MCH-3
(120 –200 bhp)
Above Boiler
18”
18”
18”
Front of Boiler
42”
42”
42”
Back of Boiler
24”
24”
24”
Header Side of
Boiler
28”
28”
28”
Tube Side of Boiler
18”
18”
18”
NOTE: Standard Boilers have headers on left side.
2.3 Piping Connections
2.3.1 General
Boiler service piping should not be routed along the header side of the boiler. Maintain
clearances are shown on the dimensional drawing for servicing of the boiler tubes. See the
boiler dimensional drawing provided for minimum clearance dimensions for the gas (fuel

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piping) train and burner. All piping should be designed, supported and installed to avoid any
piping weight transmitted to the boiler / burner connections.
CAUTION: THE BOILER IS NOT DESIGNED TO SUPPORT EXTERNAL PIPING LOADS.
2.3.2 Process Flow Connections
The process system feedwater and steam connections are shown on the boiler dimensional
drawing. The necessary code valves for feedwater, steam supply, and blowdown are normally
supplied with the boiler. To allow for inspection and cleaning, the drain valve can be opened
after the boiler is isolated and de-energized.
2.3.3 Safety Relief Valve(s)
A connection is provided in the top of the boiler for the relief valve(s). The relief valve
discharge piping must be, as a minimum, the same size as the safety valve discharge opening.
All safety valve discharge piping must be independently supported with no weight carried by
the valve. Over-tightening screwed joints can distort valve seats. Pipe the relief valve outlet(s)
to the floor drain (Section IV boilers) or to overhead discharge outside safely away from
personnel (Section I boilers).
2.3.4 Boiler Air Vent / Expansion Tank Connection
The boiler is provided with a 3/4” vent valve located on the top of the low water cutoff bridle.
This connection is for venting air on boiler filling operations and hydrostatic testing.
2.3.5 Drain Connection
A drain valve is installed at the boiler drain connection. Piping, the same pipe size as this valve,
should be routed to a suitable drain point. Drain piping should be terminated within two feet
from the drain valve for easy viewing.
2.4 Fuel Supply Piping
2.4.1 General
The installation must conform completely to the requirements of the authority having
jurisdiction, or in absence of such, requirements shall conform in the U.S. to the current
National Fuel Gas Code, ANSI Z223.1, or in Canada to the current Installation Code for Gas
Burning Appliances and Equipment code (CAN/CGA B139-M91), or Oil Burning Equipment code
(CSA B139-M91), and applicable regional regulations for the class; which should be followed
carefully in all cases. Consult the local gas utility company for inspection and authorization of
all gas supply piping and flue connections. The regulator vent line must be vented to outside of
the building on any boiler equipment with electric gas pilot ignition.
2.4.2 Gas Supply Connections
Gas supply connections must comply with the National Fuel Gas Code (NFPA 54). Gas pressure
must be regulated to the required pressure for the burner. (Standard (Power Flame burners
require a range of 5 –12 inches of water pressure.) Consult the local gas company for all
inspection and authorization of all gas supply piping and flue connections. Gas connections
should be made with unions or flanges so that the boiler gas train components and burner may
be easily removed for service, if necessary. A
drip leg or sediment trap must be installed in the gas supply line near the connection to the
burner gas valve train.

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2.4.3 Fuel Oil Supply Piping
Fuel oil supply piping must be sized by a qualified engineer or contractor; pipe size must be
adequate to supply the required fuel flow. Oil supply connections must comply with NFPA 31.
Any additional local or state codes must also be adhered to. Oil supply lines must be sized for
the circulation rate of the burner pump. This is referred to as the suction gear capacity of the
pump. If a transfer pump is used, it must have a pumping capacity no less that the total suction
gear capacity of all burner pumps on the system. Refer to Burner Manual for the suction gear
capacity of standard oil pumps. Two-pipe oil systems are recommended in all cases, although a
one-pipe system might be acceptable on smaller boilers (under 6 gph). Two-pipe systems tend
to have fewer problems with air entrainment in the oil. Air in the oil will cause nuisance
problems and delayed ignition.
NOTE: Use pipe compound, which is resistant to the action of liquid petroleum gas. Do not use
Teflon tape.
2.4.4 Gas Piping Leak Test
After completion of the gas piping, the installation must be checked for leaks, using a soap and
water solution. Disconnect the boiler and gas train from the gas supply piping during any
pressure testing of the gas supply system.
2.4.5 Venting of Gas Train Components
The gas pressure regulator, diaphragm gas valves, vent valves, and gas pressure switches must
be vented outside the boiler room; minimum pipe or tubing size if 1/4”.
All gas train components must be independently routed. Vents routed to a common pipe can
experience pressure in the event of a leak. This pressure is a false back-pressure to other
components and can cause malfunctions. Vent piping should terminate in a downward
direction and be free of restrictions.
2.5 Electrical Connections
IMPORTANT: All electrical connections must conform to the National Electrical Code and to all
other applicable State and Local Codes. Most forced draft boilers require a 3-phase power
connection. See boiler wiring diagram and equipment list for details. The boiler must be
grounded in accordance with the American National Electrical Code, ANSI / NFPA #70 –Latest
Edition.
The boiler is supplied with burner(s) from various burner manufacturers. The burner
manufacturer’s ‘AS BUILT’ wiring diagram is provided as part of the documentation package
supplied with the boiler. Specific questions related to the burner controls and burner wiring is
referenced to that drawing. Controls are added to the boiler to allow the boiler to perform its
designed function. These controls are found on the Wiring Diagram provided; the drawing is
WD –‘Boiler Serial Number’.
Any questions not answered by the provided information may be answered by a call to the
Factory.

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2.6 Combustion Air Supply
2.6.1 Combustion Air –General
Complete combustion of natural or propane gas requires approximately ten cubic feet of air (at
sea level and 70°) for each 1000 BTU of boiler input. In reality, additional air is required to
achieve complete combustion. Additional air is required for the proper operation of the
appliance draft diverter or barometric damper.
WARNING: Failure to provide an adequate air supply will result in boiler damage and hazardous
conditions in the building (fire and asphyxiation hazard as well as equipment damage). Please
note the following:
a. Positive means for supply an ample amount of outside air, allowing complete combustion of
the gas, must be provided.
b. Moveable combustion air dampers, automatic or manually adjustable, must be electrically
interlocked with the boiler to prevent boiler operation if the dampers are closed.
c. Combustion air openings must never be blocked or obstructed in any manner. The boiler
room must be at a positive or neutral pressure relative to the outdoors. Negative pressure, in
the boiler room, will result in downdraft problems and incomplete combustion due to lack of air
2.6.2 Ventilation Air
In addition to air needed for combustion, sufficient air must be supplied for ventilation,
including air required for personnel comfort and proper working conditions in the boiler room.
In colder climates, if needed for personnel comfort, provision should also be made to heat the
boiler room.
CAUTION: PROTECTION FROM COMBUSTION AIR CONTAIMINATION: Where corrosive or
flammable process fumes are present in the vicinity of the boiler room or the air stream for the
combustion air supply, it is essential that suitable means be provided for their safe disposal.
The boiler room and the combustion air supply must not be exposed to these fumes. Such
fumes include, but are not limited to, carbon monoxide, hydrogen sulfide, ammonia, chorine
and halogenated hydrocarbons.
NOTE: Halogenated hydrocarbons are particularly injurious and corrosive after exposure to
high temperatures.
2.7 Combustion Gas Exhaust Connection
2.7.1 Code Compliance
The installation must conform to the requirements of NFPA 54, the National Gas Code (ANSI
Z2223.1), Part 7, “Venting of Equipment”, or to the applicable requirements of all local building
codes. For factory-built and listed chimney systems(such as type B vent), consult the system
manufacturer’s instructions for correct installation procedures. Gas vents may be of any of the
construction types listed in this manual. No portion of a venting system may extend into or
pass through any circulating air duct or plenum.
NOTE: Additional state and local codes may apply and must be consulted.

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2.7.2 Flue Gas Economizers
When applying flue gas economizers, care must be taken to assure that:
a. Proper draft must be maintained. This requires that the gas side pressure drop be
considered and that the economizer exchanger be designed so as to allow cleaning.
b. The vent system materials must be considered, regarding resistance from corrosion, which
might result from the lower flue gas temperature.
c. In general, it is recommended that the boiler manufacturer be consulted when a flue gas
economizer is to be added.
2.8 Before Placing the Boiler into Operation:
2.8.1 Hydrostatic Test of Boiler and System
After completing the boiler and burner installation, the boiler connections, fitting, attachments
and adjacent piping must be inspected for leaks by filling the unit with water. The pressure
should be gradually increased to a pressure just below the setting of the boiler safety relief
valve(s).
Remove the boiler header side panel (see dimensional drawing in this manual). Inspect the
tube to header joints to be certain that all tube fittings are sealed. Minor leaks in fittings and
attachments (although the boiler is hydrostatically tested at the Factory,) can develop from
shipping vibration or from installation procedures. It is often necessary to retighten such fitting
after the installation and after the boiler has been operated for some time. Replace the tube
access panel before proceeding to start boiler.
2.8.2 Test of Gas Piping
Reference gas system test under Section 2.4.4.
2.9 Firing Rate Adjustment –Forced Draft Boiler(s)
Refer to the burner manufacturer’s manual on the forced draft burner for start-up and
adjustment procedures. Do not attempt to start burner before all safety systems are checked
and fully operational. Insure the burner management system is properly installed and
operational. Do not attempt to start or operate if an accumulation of fuel is observed.
2.9.1 On / Off Firing Systems
2.9.1.1 Combination Gas Valves (VR850 or VR852)
The minimum input on these gas valves is NOT adjustable. The maximum input must be
properly set as outlined in the burner instructions. See the manufacturer’s instructions
on the VR850 or VR852 valves included in the Burner Manual for further information.
2.9.1.2 Dual Diaphragm Gas Valve High / Low By –Pass System
The minimum input on this control system is NOT adjustable. The maximum input must be
properly set as outlined in the burner instructions. This system consists of two V48A (120 volt
coil) or two V88A (24 volt coil) diaphragm gas valves which are piped in parallel. The minimum
input is controlled by or orifice plug installed in a coupling in the by-pass piping (low fire valve
piping) sized for approximately 1” WC manifold pressure at low fire for natural gas (2” WC if
propane gas). When the high fire gas is not activated,
gas flows only through the bypass piping. When the high fire gas valve is activated, gas will flow
through valves achieving full input.

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2.9.2 Lo / Hi / Lo Firing Rate Control Systems
These system firing rates are usually controlled by a hydraulically actuated valve system. High
firing rate is completely open and is not adjustable. Minimum firing rate is adjustable by
controlling the valve in low fire position. Consult the manual provided by the valve
manufacturer for instructions for this adjustment. Only highly qualified technicians will be able
to make this adjustment.
3.0 SAFETY AND CONTROL DEVICES
3.1 Flame Supervisory System
The boiler forced draft burner is supplied with a Burner Management System. This is a solid
state device consisting of sensors, relays, timers and switches. Its function is to safely manage
the firing system and to monitor all safety devices. The burner management system detects the
main or pilot flame, depending on the type of device, and controls the gas valves accordingly.
Its functions are strictly governed by Codes and are not accessible or adjustable. The flame
supervisory system must be tested to assure that it will shut off the main gas valves in case of a
boiler malfunction. Additional information including operating sequence and troubleshooting
information may be found in the manufacturer’s instructions in the Burner Manual.
3.2 Flame Detection System
Boiler burners are equipped with a flame detection system which, if a flame is not sensed or is
not sensed at the proper time, will automatically shut the boiler down by closing all fuel valves.
3.2.1 Flame Detection System Types
The flame detection system, is either the thermocouple type (such as a combination gas valve
or pilotstat), flamerod type, or electronic photocell type (such as the RA890 or RM7895). The
purpose of this device is to detect the pilot and / or main flame, depending of the type of
device. The device must be checked or proper operation. See the Burner manual for the
correct test procedure.
3.2.2 Automatic (Electric) Ignition Type
On burners equipped with automatic electrically-ignited pilots, follow the procedures described
in the burner manual and test the controls for proper operation.
3.3 Low Water Cut-Off
If the boiler operates without sufficient water, it could overheat and burn out the heat transfer
tubes. This very serious condition has been known to cause a boiler to explode. Boilers are
supplied with at least one float or electric probe-type low water cut-off designed to sense the
level of the water in the upper drum. It operates to shut off the burner if the water level drops
its set level. The low water cut-off must be operationally tested by manually lowering the
boiler water level [by opening the drain valve(s)].
The burner should cycle off when the water level drops below the actuation point of the low
water cut-off. When the water level is restored, the burner should cycle back on. Depress the
manual reset button of devices which require manual reset in order to restore the boiler to
operation. Carefully read the enclosed manufacturer’s literature on the installed low water cut-
off devices(s), particularly the sections on operation and maintenance.

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3.4 Combination Low Water Cut-Off & Feeder
The low water cut-off / feeder supplied with some smaller boilers serves as a low water cut-off
(see above) and also causes make-up water to be added to the boiler, before the level drops to
the cutoff point. This type control is usually mounted above the boiler for system make-up and
must be operationally tested to assure that both the make-up water is introduced as needed
and that the cutoff actuates when the water level drops a preset distance below the control
point. Carefully read the enclosed manufacturer’s literature on the installed low water cut-off
controls, particularly the sections on operation and maintenance.
3.5 Combination Low Water Cut-Off and Level Control
The combination Low Water Cut-Off and Level Control is supplied as a standard on most MCS
boilers. The level control actuates either a solenoid valve (low pressure boilers) or a feed pump
circuit (high pressure boilers). If the water level falls a preset distance below the control point,
the low water cutoff shuts off the burner until the proper level is re-established, at which time
the burner cycles back on.
3.6 Modulating Level Control
Modulating level controls, either electric or pneumatic, are usually furnished on the larger MCS
boilers. The control, either directly or indirectly, controls the actuation of a modulating
feedwater control valve to maintain proper water level.
NOTE: Care should be taken to avoid too fast a fill rate, as this may affect a low water condition
due to a rapid cooling of the water and a collapse of the steam bubbles.
3.7 Pressure Control
The pressure control is set to desired operating pressure. The boiler pressure control is not
actual safety device, but is the primary control element. This is true for all controls except
those used for on / off firing, which also function as the auto-reset high pressure limit.
3.8 High Pressure Limit –Auto Reset
The high pressure limit is a safety device set for a pressure higher than the control pressure set
point. In the event the pressure control fails, the boiler may continue to call for heat until
stopped by the high pressure limit. This device is incorporated into the burner management
system and causes the burner to shut off until the pressure lowers and the limit automatically
resets. If the high pressure limit shuts down the boiler, the pressure control has failed and it
should be replaced.
3.9 High Pressure Limit –Manual Reset
The manual reset high pressure limit is a safety device set for a pressure higher than the
automatic high pressure limit. This high pressure limit is also incorporated into the burner
management system to automatically shut down the burner in the event both the pressure
control and the automatic reset high pressure limit fail. This pressure limit requires an operator
to manually reset the device and should not reset until the reason for the shutdown is known.

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If both the pressure control and the automatic reset high pressure limit have failed, they should
be replaced immediately.
3.10 Safety Valve(s)
If all control and electrical safety devices fail, the safety valve(s) will open to prevent over-
pressurizing the boiler. Proper operation of the Boiler Safety Valve is critical to safe boiler
operation. The best and recommended method for testing the safety valve is to have it
pressure tested and certified by a testing agency licensed to perform this work. It is further
recommended this be done on an annual basis as a minimum interval.
4.0 BOILER STARTUP
4.1 Limit Circuit Cut-Out Test
All boiler temperature limits, as well as the Low Water Cutoff, should be periodically tested.
The pressure control set point can be raised to higher setting to test the operation of a limit.
Only qualified technicians should perform these tests. Insure the set points are returned to the
desired setting after testing is complete.
4.2 Steam Temperature Operating Control
The Boiler Pressure Controller regulates the burner to obtain the desired supply water
pressure. This control senses the boiler pressure and turns the boiler burner ON / OFF
according or regulates the firing rate. This control must be operationally tested. Turn the
pressure setting on the control to a pressure less than the boiler pressure (as shown on the
boiler pressure gauge). The control should turn the burner off. Restore the control setting to
normal. The burner should cycle on.
4.3 Additional Controls
Additional controls may be provided as specified by the purchase order. Please refer to the
manufacturer’s literature on these devices. All such devices must be operationally tested to
assure reliable operation of the boiler and system.
4.4 Burner Start-Up
Please refer to the section provided by the burner manufacturer. The burner manufacturer’s
instructions are to be strictly followed.
4.5 Boil-Out
Before placing the boiler into service, the boiler waterside must be thoroughly cleaned of all
possible manufacturing residues to eliminate fouling and foaming; both of which will reduce
boiler efficiency and service and may cause system problems due to excessive carryover.
4.5.1 Procedure
Always follow the recommendations of a Water Treatment Professional. It is strongly
recommended a Water Treatment Company be retained for water treatment and periodic
testing and consulting.
4.5.2 Alternate Procedure
In the event a water treatment service is not available, the following procedure may be used.

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4.5.2.1 Make a caustic solution using the following ‘recipe’.
CAUTION: This procedure requires the mixing of caustic compounds. Appropriate protective
gear and procedures must be used when mixing these chemicals. Only qualified professionals
should perform this procedure.
For each 120 gallons of water, add:
1. One pound of caustic soda (50% pure sodium hydroxide)
2. One pound TSP (tri-sodium phosphate), commonly found in many building supply centers.
3. One pound powdered laundry detergent. (Example: Tide)
Mix the required amount of solution and pour into the boiler.
NOTE: The removal of the safety relief valve may provide the best “point of pouring”.
Start-up the boiler –at low fire –and operate until the water temperature is 150°F and 0 psig.
Do not allow the temperature to exceed 150°.
4.5.2.2 Fire the boiler as necessary to maintain the temperature between 120 and 150°F.
4.5.2.3 After four hours, drain the boiler. Fill and drain several times until a pH measurement
indicates all caustic has been removed.
5.0 BOILER OPERATION
5.1 Curing
Before placing the boiler into operation, it is imperative to cure refractory. In the Precision
Boilers MCH Series, it is only necessary that the boiler be placed into operation for
approximately 45 minutes at low fire. This will ensure any collected moisture is slowly
dispersed and will not harm the boiler.
5.2 Water Chemistry
A water chemistry program is strongly recommended. A water chemistry specialist should be
retained to monitor and maintain water chemistry in the boiler and hot water system. Every
effort should be made to minimize the formation of sludge and / or scale. This will increase
boiler system efficiency and increase boiler component lifetime.
NOTE: Heavy scale deposits have been known to cause tube failures.

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6.0 OPERATING INSTRUCTIONS
6.1 Temperature Controls
The temperature controller senses water temperature and automatically controls the boiler
burner to maintain the water temperature at the desired set point
6.1.1 On / Off Control
In this basic system, the pressure controller senses the boiler pressure and starts or stops the
boiler burner to maintain the pressure set point. The controller has a pressure differential
(adjustable); the set point is the pressure at which the burner comes on and the differential is
the added pressure above the setpoint at which the burner turns off.
6.1.2 Lo / Hi / Lo Control
With this control system, the control is basically the same as the On / Off. The primary
controllers will sense the steam pressure and operates the boiler burner to maintain that
pressure. If system demand is such that the pressure falls below the secondary controller set
point, the burner will move to the High Fire position until the secondary controller is satisfied.
The burner will move back to the Low Fire position and maintain steam pressure until the
primary controller is satisfied.
6.1.3 Modulating Control
Modulating temperature controllers sense the water temperature and send a variable signal to
a firing-rate motor. The firing-rate motor operates the burner controls to vary the firing rate to
maintain the steam pressure set point and system demand. For modulating controllers, the
differential is normally adjustable and sets the ‘tightness’ of control.
6.2 High Temperature Limit –Auto Reset
The On / Off, Lo / Hi / Lo, and Modulating control systems have a high steam pressure limit.
This limit will automatically shut down the burner if its set point is exceeded. When the steam
pressure cools sufficiently, the burner will automatically restart. This limit should not operate
and will only operate if the pressure controller fails. Care should be exercised to insure the
control differential set points do not overlap.
6.3 High Temperature Limit –Manual Reset
All control systems have this safety feature. If the water temperature exceeds the set point of
the control, the burner will automatically shut down. The burner will not start until manually
reset by an operator. This limit will not operate unless the other control systems have failed. If
those systems have failed, a qualified operator should first check the other controls before
resetting the water temperature limit. As in Paragraph 6.2, care must be taken to insure the
temperature differentials do not overlap.

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6.4 Forced Draft Adjustment
Draft adjustments are generally not necessary for daily operation of forced draft boilers. The
air / fuel ratio and draft must be measured as part of the start-up procedure and should be
periodically checked by a boiler service professional.
7.0 MAINTENANCE
7.1 General
The boiler support structure should last the life time of the boiler and require no maintenance.
7.2 Procedures
This boiler is designed and will operate with minimal maintenance. The following procedures
are recommended as a minimum.
7.2.1 Daily:
a. Check water chemistry daily and maintain a Water Chemistry Log.
b. Use the sight glasses to daily view the burner flame. Note any variations and notify a boiler
service professional if necessary.
c. Use the sight daily to view the boiler internal walls. Note the condition of all insulation and
condition of heat transfer surfaces.
d. Check and record the boiler and flue gas temperature, note excessive variations.
NOTE: A rising flue gas temperature usually indicates scaling of tubes and a resulting decrease
in boiler efficiency.
7.2.2 Semi –Annual:
Obtain the services of boiler service professional to check and adjust all burner and burner
control systems as necessary.
7.2.3 Annual:
Open the boiler casing and inspect all internal insulation and tube surfaces Repair as necessary.
8.0 SHUTDOWN
To shut down the boiler, simply switch the main burner control to the ‘Off” position. If the
boiler is to remain off for a long period, turn off the main power supply as well. If possible,
maintain an open vent to an expansion tank while the boiler is shut down. Proper water
chemistry should also be maintained when the boiler is not in service.

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9.0 EXTENDED SHUTDOWN
Follow the same procedure as above. Additionally, when the boiler is shut down for extended
time periods, consult a Water Treatment Professional for a ‘Lay-Up’ procedure. Proper water
chemistry should be maintained when the boiler is not in service.