Hubbell ST, STH User Manual

OPERATING AND MAINTENANCE MANUAL FOR

STEAM FIRED WATER HEATER

ELECTRIC HEATER COMPANY

BASE MODEL “ ST and STH ”

HUBBELL ELECTRIC HEATER COMPANY

P.O. BOX 288

STRATFORD, CT 06615

PHONE: [phone]
FAX: [phone]

INTERNET: http://www.hubbellheaters.com/

-- IMPORTANT --

Always reference the full model number and serial number when calling the factory.

WARNING / CAUTION

1. Tank is to be completely filled with water and all air is to be vented before energizing.

2. Due to the rigors of transportation, all connections should be checked for tightness before heater
is placed in operation.

3. Safety relief valve must be installed in tapping provided.

4. KEEP AWAY FROM LIVE ELECTRICAL CIRCUITS.
Do not perform any maintenance, make any adjustments, or replace any components inside the
control panel with the high voltage power supply turned on. Under certain circumstances,
dangerous potentials may exist even when the power supply is off. To avoid casualties, always
turn the power supply safety switch to off, turn the charge or ground the circuit before
performing any maintenance or adjustment procedure.

5. Generalized instructions and procedures cannot anticipate all situations. For this reason, only
qualified installers should perform the installation. A qualified installer is a person who has
licensed training and a working knowledge of the applicable codes regulation, tools, equipment,
and methods necessary for safe installation of a steam fired water heater. If questions regarding
installation arise, check with your local plumbing and electrical inspectors for proper
procedures and codes. If you cannot obtain the required information, contact the company.

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TABLE OF CONTENTS

SECTION TITLE PAGE #

I GENERAL DESCRIPTION AND CONSTRUCTION 9

II INSTALLATION AND OPERATION 13

III SCHEDULED MAINTENANCE AND SERVICING 18

IV ADJUSTMENT OF TEMPERATURE REGULATORS 25

V TROUBLESHOOTING 28

VI MISCELLANEOUS CHARTS AND FORMULAS 30

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4

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NOMENCLATURE FOR PARTS

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NOMENCLATURE FOR ACCESSORY PARTS

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SECTION I - GENERAL DESCRIPTION AND CONSTRUCTION

GENERAL DESCRIPTION

This book describes a packaged steam powered water heater that is a stationary, self-contained unit.
The complete assembly on a standard unit consists of the storage tank, immersion heating coil, steam
regulator, steam drip trap, condensate trap, steam strainer, condensate strainer, vacuum breaker, and
an ASME rated combination temperature and pressure safety relief valve. Optional equipment may
be supplied with your unit. Please consult the product drawing for details specific to your assembly.
The unit is factory assembled, insulated, jacketed, primed, painted, piped, tested, and ready for
service connections.

CONSTRUCTION

TANK

Standard Tank Construction:

The standard storage tank is constructed of all welded carbon steel, designed and built in accordance
with ASME Section VIII and stamped, certified, and registered with the National Board of Boiler and
Pressure Vessel Inspectors. It is internally lined with specially formulated Hydrastone cement to a 5/8­inch minimum thickness for superior protection and tank longevity.

Optional Tank Linings:

1. Phenolic – An epoxy coating applied in two coats to a total thickness of 10-12 mils. Typically
used in process applications using low conductivity deionized (DI), distilled, or food grade
water.

2. Copper – A 3lb./sq. ft. copper sheet approximately 0.0646-inches thick covers all interior
surfaces. All copper sheet seams are factory tested to ensure long lasting protection of the steel
vessel.

3. Flame-Spray Copper – Molten copper is sprayed on the interior surfaces to a thickness of 5-6
mils. The copper bonds to the steel, and an additional overcoat of Phenolic lining is applied on
the copper to seal all pores.

4. Galvanizing – The steel pressure vessel is pickled and hot dipped in molten zinc to create a
barrier which internally and externally protects the steel vessel for cold and hot water storage.

Optional Non-Ferrous Tank Materials:

1. Copper-Silicon – A copper-silicon alloy offers tremendous tank longevity due to its ability to
withstand the cycling effects induced from changes in water temperature and pressure. This
material is suitable for storage of hot potable water in a variety of commercial and industrial
applications.

2. 90/10 Copper-Nickel – A 90% copper and 10% nickel alloy similar to copper-silicon, but with
added strength and corrosion resistance. Typically used in applications with corrosive
environments (salt water) or critical applications.

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3. Stainless Steel – Stainless steel (type 304, 316, or 316L) is well suited for high purity
applications requiring a corrosion resistant tank with minimal leaching of impurities into the
water. Well suited for process, RO, and DI water systems in the pharmaceutical, food, and
electronic industries.

TANK CONNECTIONS

The heater is supplied with separate cold water and hot water connections. A connection is provided for
mounting a combination safety temperature and pressure relief valve. An overflow line should be
utilized from the relief valve outlet to a floor drain. See drawing for locations and sizes.

OUTER SHELL, INSULATION, AND SUPPORTS

The tank is encapsulated in 2-inches of high-density fiberglass insulation. The protective shell is
constructed of galvaneel and is coated with a durable silver hammertone finish. The entire vessel is
supported on heavy-duty integrally welded steel supports for sturdy floor mounting.

STEAM HEATING COIL

The water heater is supplied with a high quality factory installed 2-pass U-tube heating coil constructed
from 20-gauge ¾-inch O.D. single wall copper tubing designed for a maximum working pressure of
150 psi. The tubing is installed in a heavy-duty fabricated steel head with threaded NPT steam and
condensate connections. Each assembly is fastened to a corresponding tank flange using a gasket and
hex head steel bolts and nuts. Specialized heating coil construction may be included. These options
include: double wall tubing with a leak detection port, or special materials (stainless steel, 90/10
copper-nickel, other) for the tubes and/or head. See drawing for complete details.

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