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GENERAL PRODUCT DESCRIPTION
SIZE: Seisco Water Heaters are manufactured in
two basic sizes, a large four-chamber unit (15 _" x 15 _" x 6 _") and a
smaller two-chamber unit (15 _" x 10 _" x 6 _"). The same advanced
microprocessor technology and thermoplastic construction are used in
both sizes. Therefore, many of the parts are interchangeable.
MODELS: There are three to four models of each
size available. The four-chamber models are RA-18, RA-22, RA-28, and
RA-32. These models are designed generally for domestic water heating in
whole house and booster applications. The two-chamber models are RA-9,
RA-11, & RA-14. The two-chamber models are designed for space heating
applications and point-of-use in commercial applications. The available
models and their descriptions are listed on pages following this
section. Refer to Tankless Water Heater Applications for more design and
application details.
FEATURES: There are no moving parts or flow
restricting devices used in Seisco heaters. Seisco uses a unique flow/no
flow detection system utilizing its temperature sensors for flow
detection. In standby, the heater maintains a very subtle temperature
gradient and flow is detected when there is a change in the gradient.
The advanced microprocessor control turns the power on through a set of
relays and turns the power off when flow stops. The most important
feature may be the patented "Power Sharing" technology which provides
for evenly distributed power to the heating elements. This in turn,
helps eliminate scalding potential, scaling and sediment build-up. Also,
the control logic allows the power level to vary which is beneficial in
minimizing the use of power for periods of less demanding usage.
CONSTRUCTION: Seisco heating chambers are modular
and molded of light weight thermoplastic materials. The chamber is
specifically engineered for durability in harsh water heating
environments and capable of withstanding extreme temperature swings and
pressure changes. Heating elements, sensors and detection devices, that
come in contact with the water, are machined in brass or made of copper
to help resist corrosion. Standard 1 _ inch, flanged screw-type heating
elements are utilized which are interchangeable with heating elements
available at local hardware stores.
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SAFETY AND MAINTENANCE: Seisco was designed with
a complete array of dependable safety features to prevent harm to the
user and the heater. There are several redundant safety features as
well. They include, dual high temperature switches on independent
circuitry in addition to the control's internal high temperature shut
down. Dual low level detectors are used to prevent dry firing of the
heating elements and a leak detector is mounted on the casing that in
the event of a leak, sounds an alarm to the user. Although the control
board is protected against electrical surges, additional heater
protection is achieved when the relays are opened during periods of
standby, providing no path for the surge to reach the heating elements.
Also, the chamber is designed with a patented venting system that
continuously vents harmful gasses and air during operation. The
microprocessor control is programmed to provide self diagnostics that
significantly reduces trouble shooting and service time. In the event of
a problem with the heater, the control emits a visual or optional
built-in audible code. There is no maintenance required of the Seisco.
However, there are clean-out plates below the heater chamber to allow
removal of sand and grit that may build-up from a well water system.
POWER RATING: The four-chamber models contain
four electric heating elements whose combined wattage is the total power
rating of the heater. For instance, the standard RA-28 model contains
four 7000 watt elements for a total of 28,000 watts, or 28 kilowatts
(kW) of power. The two-chamber model, RA-14, contains only two 7000 watt
elements for a total power rating of 14,000 watts, or 14 kilowatts (kW).
However, because of Seisco's "Power Sharing" technology, the heater may
not always use the maximum available power. The power output can vary
with flow rate and temperature rise. Refer to the Product Specifications
Table for the maximum power ratings of each model.
HEATING OUTPUT: The heating output of the Seisco
is simply the total kilowatt power rating of the combined heating
elements converted to BTUs using 3,413 BTU/kW. For instance, the RA-28
has a total power rating of 28 kW or a 95,564 BTU heat output rating.
The four-chamber models have the higher output ratings; 61,434 BTUs for
the RA-18 model, and 75,086 BTUs for the RA-22 model. The lower output
two-chamber models, are; 47,782 BTUs for the RA-14, 37,543 BTUs for the
RA-11, and 30,717 BTUs for the RA-9. These ratings vary with the
operating voltage or service voltage to the heater. Refer to the Product
Specifications Table for the BTU ratings of each model.
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VOLTAGE RATING: Seisco heaters are manufactured
with common 240 volt (AC) heating elements designed for optimum
operation on a standard residential 240 volt (AC) electric service.
Also, the Seisco will operate at 208 VAC, a typical commercial voltage,
with standard 240 VAC heating elements. However, when operating the
heater at 208 VAC, the power rating and the heat output rating is
significantly reduced. Seisco models can be special ordered with 208 VAC
heating elements to help maximize the power and heating output. Refer to
the Product Specifications Table for details on the various voltage
ratings.
MAXIMUM CURRENT RATING: Each Seisco Model has a
maximum electrical current rating (or amp rating) equivalent to the sum
of the heating element ratings. For example, a four-chamber model,
RA-28, operating at 240 VAC has four heating elements, each with a
maximum rating of 29 amps. The maximum current rating or total current
rating of the RA-28 is therefore 116 amps or the sum of the four heating
elements. However, because of Seisco's "Power Modulating Technology",
the actual current measured during relatively low flow rates and/or low
temperature rises can be less than the maximum rating of the heater
during operation. Refer to the A (max) or maximum amp rating under
"Electrical" in the Product Specifications Table for each model.
TEMPERATURE RISE: The temperature rise must be
determined in order to help choose the appropriate Seisco heater. The
rise can be determined by knowing the input water temperature and the
desired output temperature of the heater. The Seisco's output
temperature is typically set for about 120 degrees F at the factory.
Therefore, if the input or cold water inlet temperature is 50 degrees F,
then the temperature rise is the difference or 70 degrees F. If the
desired output temperature is 125 degrees F, then the temperature rise
would be 75 degrees F. With the temperature rise determined, the Product
Specification Table provides the associated flow rate capacity of the
various Seisco models.
FLOW RATE: The flow rate for each model is given
in the "Temperature Rise" table of the Product Specification Table.
Along with the temperature rise, the flow rate must also be determined
in order to choose the appropriate Seisco heater. The flow rate is
determined by the type of faucet and also, life style. Refer to the
chart below for typical faucet flow rates in the home. However, if the
desired life style in the home requires running multiple faucets at the
same time, then the flow rates must be added together to determine the
peak flow demand. The Seisco or the possibility of multiple Seisco's
should be selected to match the peak flow rate.
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Below are typical flow rates for new residential
construction. There may be exceptions with new designer type fixtures
and faucets. For instance, large custom body spa showers, whirl pool and
Jacuzzi tubs may have faucets with flow rates ranging from 7 gpm to 14
gpm. However, a combination of multiple Seisco heaters (preferably
plumbed in a parallel configuration) can be installed to match these
higher flow rates. The same peak design approach would be necessary for
the anticipated life style of multiple flow rates occurring at the same
time. Otherwise, use the table below and match the Seisco according to
the peak flow and associated temperature rise of a single tub or shower.
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