Vapor Power STR User manual

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Vapor Power International LLC
551 S County Line Road, Franklin Park, Il 6
0115
Phone: [phone] Fax: [phone]
Instruction Manual
STR
MODEL
‘RESISTO-FLO’
ELECTRIC
BOILER

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Vapor Power International LLC
551 S County Line Road, Franklin Park, Il 60115
Phone: [phone] Fax: [phone]
FOREWORD
The STR “Resisto-Flo”Electric Steam Boiler is designed to provide a compact
packaged unit requiring a minimum of electrical and plumbing connections at the
jobsite.
When installed according to these instruction, the boiler will provide years of
reliable, low maintenance service.
Review both the installation and electrical drawings thoroughly before installing this
boiler. A description of this boiler can be found in Bulletin 300, which is included at
the end of this text.

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Vapor Power International LLC
551 S County Line Road, Franklin Park, Il 60115
Phone: [phone] Fax: [phone]
1.0 INSTALLATION CLEARANCES
1.1 GENERAL
Locate boiler on a level surface. Be sure the location you select permits
access to the control cabinet and allows for element removal as dimensioned
on the installation drawing, and also that it is in accordance with the
minimum spacing specified on the UL label, if provided.
CAUTION
ALL BOILERS EXCEPT MODELS STR 1638 THRU 1654 ARE TO BE MOUNTED
ON NONCOMBUSTIBLE FLOORING.
1.2 MECHANICAL CLEARANCES
The clearances shown below are required for perimeter servicing of the
boiler. Note: Front clearance to be 42”if opposing wall is conductive.
36"
F
R
O
N
T
18"
18"
MODELS STR 1638
THRU STR 1654
36"
24"
18"
MODELS STR 3656
THRU STR 4686
24"
36"
18"
18"
MODELS STR 2438
THRU STR 3062
18"
F
R
O
N
T
F
R
O
N
T

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Vapor Power International LLC
551 S County Line Road, Franklin Park, Il 60115
Phone: [phone] Fax: [phone]
1.3 THERMAL CLEARANCES
Minimum thermal clearances should be maintained. If the boiler is UL listed,
minimum clearances will be indicated on the UL Label. Otherwise, consult
local codes and use good engineering judgement.
CAUTION
THE BOILER ROOM TEMPERATURE SHOULD NOT EXCEED 30º C (86ºF),
WHICH SHOULD LIMIT THE TEMPERATURE WITHIN THE CONTROL
CABINET TO A MAXIMUM OF 40ºC (104ºF).

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Vapor Power International LLC
551 S County Line Road, Franklin Park, Il 60115
Phone: [phone] Fax: [phone]
2.0 MECHANICAL INSTALLATION
2.1 STEAM SUPPLY
Install a steam stop valve on the steam outlet of the boiler and pipe to the
equipment to be supplied with steam.
NOTE: IF THE BOILER IS TO BE CONNECTED TO A COMMON HEADER WITH ONE
OR MORE OTHER BOILERS, TWO STOP VALVES ARE REQUIRED BY CODE,
ONE OF WHICH SHOULD BE A NON RETURN TYPE, WITH A 1”VENT
PLACED IN THE LINE BETWEEN THE TWO VALVES.
Steam piping from the boiler to the equipment must be pitched to assure
proper drainage of condensate formed in the steam line.
NOTE: IT IS RECOMMENDED THAT ALL PIPING BE CHECKED FOR LEAKS BEFORE
INSULATING.
2.2 WATER SUPPLY AND CONDENSATE RETURN
If a direct water feed is used (ie, no condensate return), the main water supply
must have a pressure at least 10 pounds greater than the maximum boiler
operating pressure.
If a gravity-feed condensate return is installed, the return must have a head at
least 1.1 times the boiler operating pressure (psi=0.454 x feet-of-head).
If a condensate return system is used, the pump should be sized to deliver
approximately (0.015 x KW) gpm at normal operating pressure and at least
the steaming rate at the maximum boiler operating pressure. The receiver
tank size (gal) should be at least three times the pump capacity (gpm).
2.3 BLOWDOWN
2.3.1 BOTTOM
If not factory installed, the slow opening blowdown valve, supplied with the
boiler, should be installed on the bottom drain

Page 6 of 18
Vapor Power International LLC
551 S County Line Road, Franklin Park, Il 60115
Phone: [phone] Fax: [phone]
NOTE: PER CODE, BOILERS WITH GREATER THAN 100 GALLONS NORMAL WATER
CONTENT MUST HAVE 2 BLOWDOWN VALVES IN SERIES. A QUICK
OPENING VALVE IS RECOMMENDED FOR THE REDUNANT BLOWDOWN
VALVE AND SHOULD BE MOUNTED UPSTREAM OF THE SLOW-OPENING
VALVE..
Blowdown piping must be at least the same size as the blowdown valves and
must be directed to an unrestricted discharge drain, separator or tank,
depending on the local code requirements. Pitch the pipe toward the drain so
that the boiler will drain completely by gravity.
NOTE: IF THE POINT OF BLOWDOWN DISCHARGE IS ABOVE THE BOILER
BLOWDOWN CONNECTION, THEN AN ADDITIONAL VALVE SHOULD BE
ADDED TO FACILITATE DRAINING THE BOILER BY GRAVITY (IE, WITHOUT
BOILER PRESSURE).
2.3.1 SURFACE BLOWDOWN
If the boiler is supplied with an automatic surface blow down valve, pipe to a
point common with the bottom blowdown piping.
2.3.2 WATER COLUMN BLOWDOWN
If the boiler is not supplied with a water column blowdown valve, install such
a valve on the bottom cross of the water column and pipe to a point common
with the bottom blowdown piping.
2.4 SAFETY VALVE(S)
The ASME approved safety valves(s), supplied with the boiler, should be
factory set at or below the design pressure of the boiler as stated on the boiler
nameplate.
NOTE: THE SYSTEM OPERATING PRESSURE MAY BE LIMITED BY THE SYSTEM
COMPONENTS OTHER THAN THE BOILER, IT IS THEREFORE ADVISABLE
TO CHECK THE SAFE WORKING PRESSURE OF ALL COMPONENTS IN THE
SYSTEM AND IF NECESSARY, REPLACE THE SAFETY VALVE WITH A VALVE
SET AT A LOWER PRESSURE, BUT WITH SUFFICIENT CAPACITY (3.5 x KW =
LBS/HR REQ’D) TO ASSURE COMPLETE SYSTEM PROTECTION.

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Vapor Power International LLC
551 S County Line Road, Franklin Park, Il 60115
Phone: [phone] Fax: [phone]
Safety valve discharge should be piped (using full size pipe with no
restrictions) so that steam is directed away from electrical components and to
a place where no injuries to personnel can result in the event of a valve
discharge. If the valve discharge is piped vertically upward, a seat drain must
be provided to eliminate condensate back pressure on the valve seat.
2.5 LOW WATER CUTOFF/PUMP CONTROL
On the ball/float type low water cutoff/ pump control, check that the float
blocking plug has been removed and replaced with a solid plug.
2.6 PRESSURE LIMIT CUTOUTS
Check that the high pressure cutoffs are plumb as indicated by the internal
leveling pendulum which must swing freely and point to the index mark on
the case.
2.7 HYDRO TEST
Good practice, as well as, most local codes, dictates that a hydro-static test, at
a pressure equal to the safety valve setting, of the entire boiler system be
performed prior to boiler start up. All leaks, both boiler and piping, should be
“stopped”at this time.
NOTE: SMALL LEAKS (LESS THAN 2 DROPS PER MINUTE) BETWEEN THE BODIES
OF THE ELEMNT COMPRESSION FITTING AND THE ELEMENT FLANGES
USUALLY STOP DURING THE FIRST FEW DAYS OF BOILER OPERATION.
LARGER LEAKS, HOWEVER MAY NECESSITATE TIGHTENING OF THE
COMPRESSION FITTING BODY. THIS IS ACCOMPLISHED BY FIRST
REMOVING THE ASSOCIATED WIRES/JUMPERS, AND THEN TIGHTENING
THE COMPRESSION BODY.
CAUTION:
DO NOT TORQUE COMPRESSION BODY OVER 70 FT LBS (brass) or 110 FT LBS (SS)
NOTE: ALL PIPING, VALVES, AND FITTINGS MUST MEET THE REQUIREMENTS OF
LOCAL REGULATING CODES. THE RESPONSIBILITY FOR THE INSTALLA-
TION OF THIS BOILER RESTS WITH EITHER THE OWNER OR THE
INSTALLING CONTRACTOR.

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Vapor Power International LLC
551 S County Line Road, Franklin Park, Il 60115
Phone: [phone] Fax: [phone]
3.0 ELECTRICAL INSTALLATION
3.1 ELECTRIC POWER SUPPLY
Check the boiler nameplate for the KW rating, voltage, phase and ampacity.
Check for the electrical supply to be certain it conforms with the boiler
requirements.
Make electrical connections to main terminals housed within the top portion
of the boiler control cabinet. Minimum wire size is given both on the
electrical schematic and near the boiler terminals. On boilers which require
multiple conductors per phase, be certain that phasing is correct and that
circuits are not “mixed”before energizing the boiler.
3.2 GROUNDING
Connect an equipment ground (minimum copper wire size is indicated on
both the wiring schematic and the panel near the grounding lug) to the
grounding lug located within the control cabinet.
NOTE: ELECTRICAL INSTALLATION MUST BE MADE IN STRICT ACCORD WITH (1)
THE BOILER’S ELECTRICAL SCHEMATIC, (2) THE NATIONAL ELECTRICAL
CODE, AND (3) LOCAL ELECTRICAL CODES.
3.3 CONTROL CIRCUIT POWER SUPPLY
On boilers which are not supplied with a control transformer, a fused 120 volt
power supply must be connected to the 2-pole terminal block housed within
the top of the control cabinet. Refer to the boiler’s electrical schematic for
required ampacity.

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Vapor Power International LLC
551 S County Line Road, Franklin Park, Il 60115
Phone: [phone] Fax: [phone]
4.0 OPERATING INSTRUCTIONS
NOTE: PRIOR TO START UP, ANY HEATER OR CONTROL CABINET WHICH HAS
BEEN EXPOSED TO DUSTY, WET, AND/OR HUMID CONDITIONS MUST BE
THOROUGHLY CLEANED AND DRIED OUT. THE BUILD UP OF DUST AND
RUST MAY RESULT IN EXCESSIVE DAMAGE UNLESS THE FOLLOWING
PRECAUTIONS ARE UNDERTAKEN:
A. All electrical components should thoroughly cleaned and dried, and checked
for loose connections.
B. All electrical terminals should be thoroughly cleaned and dried, then hi-
potted or meggered to assure there are no shorts to ground.
C. Boiler should be inspected for stray objects, metal scraps, etc., which may
have accumulated during installation. All such materials must be removed
from the boiler prior to start up.
D. All power wiring connections should be checked to assure tight connections.
NOTE: HYDRO STEAM INDUSTRIES, AS MANUFACTURER OF THIS BOILER, WILL
NOT BE RESPONSIBLE FOR DAMAGES INCURRED AT THE TIME BOILERS
ARE STARTED UP UNLESS THE ABOVE STEPS HAVE BEEN TAKEN TO
ASSURE THE BOILERS ARE PROPERLY PREPARED FOR STARTUP.
NOTE: MAXIMUM OPERATING CONDITIONS AS STATED ON THE BOILER
NAMEPLATE ARE NOT TO BE EXCEEDED
4.1 GENERAL
The following section of this manual should be read in its entirety prior to
operating the boiler.
4.2 PRELIMINARY CHECKS AND ADJUSTMENTS
4.2.1 Pressure Control (Boilers supplied with proportioning step controls)
A. Pressure Setting –Most Model STR Boilers are provided with a
proportioning type pressure control system which regulates the boiler
output to match the system demand. This control should be set at the
required operating pressure but shall not exceed 90% of the safety valve

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Vapor Power International LLC
551 S County Line Road, Franklin Park, Il 60115
Phone: [phone] Fax: [phone]
set pressure. Proper system operation can be checked via the pressure
gauge mounted on the boiler’s sensing manifold.
B. Response/Range Adjustment - For boilers supplied with solid state step
controls. A “span”adjustment on the control adjusts the response/
differential of the control.
C. Interstage Time Delay –Most solid state step controls now include
adjustable interstage time delays. Some even include different delays for
steps-on and steps-off which can be adjusted to minimize contactor cycles
while still maintaining the required responsiveness of the control. Check
the vendor-supplied literature provided at the rear of this manual.
4.2.2 Pressure Control (Boilers supplied with one or more non-proportioning
pressure controls)
Smaller STR boilers are provided with one or more independent pressure
controls which switch on or off heating elements in accordance with their
temperature setting. The differential between the pressure settings should
be set in accordance with system requirements.
4.2.3 Pressure Limit Cutouts
Check that the Honeywell “Limitrol”pressure limit switches are plumb using
external leveling indicator, which must swing freely and point to the index
mark on the case, and is set approximately 10% greater than the pressure
control but not to exceed 94% of the safety valve set pressure.
4.2.4 Auxiliary Controls
Other controls supplied with the boiler (eg, KW limit controls, cycle or delay
timers, etc) should be set per the Engineer’s specifications.