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SECTION I
INSTALLATION
• HEATER MAY BE WALL OF FLOOR STAND MOUNTED
— Allow recommended clearances over, under and
around heater shown on Piping Layout Drawing for
maintenance purposes; page 7-8.
WARNING: When connecting heater to other than copper
pipe use dielectric unions, (isolators) to prevent possible
galvanic action.
• CONNECTION OF STEAM TRAP DISCHARGE PIPING
— Trap MUST discharge into an atmospheric or sub-
atmospheric system. Condensate should be free
flowing with no lift. If steam supply pressure is greater
than 5 psig the MAXIMUM elevation of trap discharge
line above Heater is 6 feet. If steam supply pressure
can vary or if maximum efficiency is required, best
results under all operating conditions will be obtained if
trap discharges to atmospheric or sub-atmospheric line
located below level of trap.
• A safety valve must be installed in inlet steam piping if
steam pressure to Heater can exceed 75 psig for
ductile iron exchangers, 150 psig for steel exchangers.
See Piping Installation Drawing No. 90/2.4.1 for details.
An adequate trap system must be provided to insure
that inlet steam piping to Heater is properly drained.
• A pressure gauge must be installed in the inlet steam
piping close to Heater.
• A spring loaded relief valve is incorporated in the
blending valve to relieve excess pressure that can be
caused by thermal expansion of water during a shut-off
or no load condition.
• Install a thermometer in hot water outlet piping close to
Heater.
• OPERATING FEATURES OF LOW PRESSURE
CONSTANTEMP HEATERS — Normally a heat
exchanger having a constant fixed steam supply
pressure and a variable output flow demand allows
water temperature to increase as flow demand
decreased, and decrease as flow demand increases.
This Heater has a unique adjustable gain feature
incorporated in the Heater control system that
automatically compensates in most part for the wide
temperature variations normally encountered when an
uncontrolled steam supply pressure is used.
Compensation is accomplished by reproportioning the
blend ratio of hot and cold water on an automatic
Feedforward basis. The blending valve incorporated a
third window which is normally closed by a seal plate
assembly. In the event that some dirt or foreign material
enters the blending valve preventing its movement, the
yielding spring will allow the diaphragm and stem to
move upward, opening the third window. As seal plate
uncovers third window, it allows cold water to flow into
the blended mix, thus preventing water from becoming
overheated.
STEAM AND WATER OPERATING PRESSURES FOR
MODELS LOW PRESSURE CONSTANTEMP HEATERS
• STEAM PRESSURE — 2 to 15 psig.
• WATER PRESSURE AT COLD WATER INLET OF
HEATER — Maximum water pressure MUST be 5 psig
ABOVE maximum steam pressure used to operate
heater.
SECTION II
START-UP PROCEDURE
1. Turn on cold water supply. With no water flow through
heater, slowly open steam stop valve to heat exchanger
making sure traps are functioning properly to prevent
water hammer.
2. Loosen pipe plug in top of heat exchanger casing and
vent all air from casing before retightening pipe plug.
NOTE: BEFORE making any water temperature or gain
control adjustments, please refer to Capacity and Adjustment
Table (Page 3) and Gain Control Curves Diagram (Page 4) so
that maximum efficiency may be obtained from Heater by
proper use of the information provided by these charts.
3. Loosen set screw in temperature adjustor (14) lock nut
(13) and move lock nut away from cover plate (16) (See
Fig. 1). Check Capacity and Adjustment Table and after
determining Heater capacity shown under your
operating conditions, adjust flow through Heater for
approximately 50% of calculated capacity. Move
temperature adjustor (14) to the right or left until the
desired water temperature is achieved.
4. NOTE: There must be a water flow through Heater in
order to adjust setpoint gain. Operate Heater from
minimum to maximum flow and observe temperature at
both of these extremes. Rotate gain control as shown
on Gain Adjustment Curve Diagram until water
temperature variations are reduced to a minimum.
Move gain adjustor in small increments while adjusting,
as total rotary movement of adjustor is only 30 degrees.
(See Fig. 2)
5. After adjustments are completed, move lock nut (13)
until it is against plate (16) and lock in place with lock
nut set screw.
6. Heater is now adjusted and operating. No other
adjustments should be necessary unless there is a
change in your initial operating conditions. To SHUT
DOWN HEATER close steam stop valve first, followed
by water stop valve.
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