Hubbell ST Operating instructions

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.
2

SECTION TITLE PAGE No.
I GENERAL DESCRIPTION AND CONSTRUCTION 7
II INSTALLATION AND OPERATION 9
III SCHEDULED MAINTENANCE AND OPERATION 12
IV ADJUSTMENT AND TEMPERATURE REGULATORS 18
V TROUBLESHOOTING 20
VI MISCELANEOUS CHARTS AND FORMULAS 22
3

4

NOMENCLATURE FOR PARTS
5

NOMENCLATURE FOR ACCESSORY PARTS
6

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 5/8-inch 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.
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.
7

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.
STEAM OPERATING CONTROLS
The steam operating controls are factory selected, sized, piped, and tested to ensure
reliable operation. Steam controls can be shipped loose, upon request, for in the field
installation by others. All steam components are factory plumbed with schedule 40
black iron pipe and ready for steam and condensate connections. A cast iron ‘Y’
strainer with 20 mesh screen protects the steam controls and coil from dirt and debris
in the steam supply.
Traps
Two traps should be utilized in the immediate steam piping system of the water heater.
The first trap in the system is a drip trap that is designed to collect condensate from the
main steam line before entering the steam regulator. Additionally, a main condensate trap
should be located in the condensate line after the steam coil. This trap ensures that the
steam remains in the coil and releases its energy before exiting the coil and traveling
down the condensate line. There are various types of traps available. The following may
be included in your water heater package:
1. Drip Trap
a. Thermostatic (Standard)
b. Cast Iron Float and Thermostatic type
c. Cast Steel Float and Thermostatic type
2. Main Trap
a. Cast Iron Float and Thermostatic type (Standard)
b. Cast Steel Float and Thermostatic type
c. Bucket
Steam Control Valves
1. Pilot Operated (Standard) – A high quality cast iron pilot operated steam
control valve comes with the standard unit. It is the most widely used type of
valve for water heating applications. In this type of valve, a temperature pilot
device utilizes steam to operate the main valve. No external power source is
required other than steam. This highly dependable temperature control system is
suitable for most commercial and industrial applications.
2. Self Operating – This valve design includes a bulb and capillary assembly
charged with a thermally responsive vapor. The expansion / contraction of the
8

vapor acts upon the valve bellows in order to control the flow of steam through
the valve. No external power is required for operation.
3. Pneumatically Operated – In this configuration the building air supply feeds a
factory installed temperature controller that operates the steam control valve.
The temperature controller sends a precise air signal to the steam control valve
which adjusts the flow of steam into the heating coil. The temperature controller
is fully adjustable from 50° - 250 ° F and requires 20 psi air at a maximum
consumption of 0.5 SCFM.
4. Electronically Operated – This control valve is similar to a pneumatically
operated system, except in this case the temperature controller is a sophisticated
digital display electronic device which outputs a 4-20 ma signal to a compact
motor mounted on the steam control valve in order to proportionally control the
flow of steam to the heating coil. The temperature controller displays set point
as well as actual water temperature and is available with an RS485
communications port for remote control.
OPTIONS
The following optional features may be included in your water heater. Reference the
drawing specific to your heater for further details.
Single Solenoid Safety System
A single solenoid safety system closes the steam supply to the control valve should the
temperature in the tank reach the high limit set point. This option requires 120-volt, 5-
amp electrical service.
Double Solenoid Safety System
A double solenoid safety system dumps over heated water in the storage tank to drain
in addition to closing the steam supply to the control valve. This option requires 120-
volt, 5-amp electrical service.
Anticipator Control System
The anticipator control system forces incoming cold water over the control valve
sensing bulb in order to begin heating water immediately.
Skid Mounting
Optionally, the unit may be mounted on heavy duty all welded I-beams.
Circulating Pump Package
An intra-tank circulation pump package with On/Off switch to continuously circulate
water within the tank and thereby reduce stratification may be installed. An all bronze
circulator pump.
Dial Temperature and Pressure Gauge
A combination temperature (70° - 250° F) and pressure (0 – 200
psi) gauge with 2½-inch dial may be factory installed in the tank.
SECTION II –INSTALLATION AND OPERATION
WARNING / CAUTION
DO NOT TURN ON THE STEAM SUPPLY to this unit until heater is completely
filled with water and all air has been released. If the heater is NOT filled with water
when the steam supply is turned on, damage to the heating coil may result.
For protection against excessive pressures and temperatures, local codes require the
installation of a temperature-and-pressure (T&P) relief valve certified by a nationally
recognized laboratory that maintains periodic inspection of production of listed
9

equipment of materials, as meeting the requirements for Relief Valves and Automatic
Gas Shutoff for Hot Water Supply Systems. ANSI Z21.22-1971. THE CUSTOMER
IS RESPONSIBLE TO PROTECT PROPERTY AND PERSONNEL FROM HARM
WHEN THE VALVE FUNCTIONS.
All water heaters have a risk of leakage at some unpredictable time. IT IS THE
CUSTOMER'S RESPONSIBILITY TO PROVIDE A CATCH PAN OR OTHER
ADEQUATE MEANS, SO THAT THE RESULTANT FLOW OF WATER WILL
NOT DAMAGE PROPERTY.
If unit is painted or insulated on the job site, care should be taken not to paint or
insulate over the A.S.M.E. nameplate. This plate should be accessible and legible at
all times to inspectors, and information from this plate must be used when ordering
parts from the factory.
The tank should be fully drained in the event the steam has been turned off and if there is
danger of freezing. If tank is drained and to be left empty for more than 8 hours, at least
2-inches of water should be left in the bottom of cement lined tanks to prevent lining
from drying and cracking.
WATER HEATER PLACEMENT
1. Adequate space should be provided for removal of heating element.
2. Unit should be level to permit proper drainage
PIPING INSTALLATION
NOTE: The most effective means for preventing deterioration from accelerated
corrosion due to galvanic and stray current is the installation of dielectric
fittings/unions. The installation of these fittings is the responsibility of the installing
contractor.
1. All integral components have been properly sized to meet design conditions.
Piping to the unit should be sized to meet the design conditions, as dictated by
good engineering practices.
2. Refer to the enclosed drawing for location of piping connection.
3. Install the combination temperature and pressure safety relief valve in the tapping
provided. Note that this is required by law for safety considerations.
Outlet to floor drain
Installintoprovidedtapping
Manual Release
Lever
TemperatureProbe
4. Install a relief valve overflow pipe to a nearby floor drain. CAUTION: No valve
of any type should be installed between the relief valve and tank or in the drain
line.
HOOK-UP OF AIR AND WATER OPERATED CONTROLS
1. Most air or water operated valves on Hubbell water heaters are controlled by
Powers Accritem. Occasionally, a Robertshaw Fultrol is furnished which
operates identically to the Powers control except supply and output connections
are reversed in location. Controls are normally mounted on the back side of the
tank shell.
10