Leslie Controls F-1240LDW Constantemp Double Wall Low pressure steam-water Heater - Manual (Page 2)

Installation, Operating and
Maintenance Instructions
90/4.5.5
Rev. 0
SECTION I
INSTALLATION
1. 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.
2. CONNECTION OF STEAM TRAP DISCHARGE
PIPING – The Steam trap must discharge onto an
atmospheric or sub-atmospheric system. The
Condensate should be free flowing with no lift. If
steam supply pressure is greater than 5 psig, then the
MAXIMUM elevation of the trap discharge line above
the Heater is to be no more than 6 feet. If the steam
supply pressure can vary or if the maximum efficiency
is required, the best results under all operating
conditions will be obtained if the trap discharges to an
atmospheric or sub-atmospheric line located below the
level of the trap.
3. A safety valve must be installed in inlet steam piping
if steam pressure to Heater can exceed, 150 psig for
steel exchangers. See Piping Installation Drawing No.
35513C for details.
4. A pressure gauge must be installed in the inlet steam
piping close to Heater.
5. 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.
6. Install a thermometer in hot water outlet piping close
to Heater.
OPERATION
1. 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 re-
proportioning 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.
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 re-tightening
pipe plug.
3.
Loosen set screw in temperature adjuster (14)
lock nut (13) and move lock nut away from cover
plate (16) (See Fig. 1). Check Capacity and
WARNING: When connecting heater to other than
copper pipe use dielectric unions,
(isolators) to prevent possible galvanic
action.
NOTE: An adequate trap system must be provided to
insure that inlet steam piping to Heater is
properly drained.
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.
NOTE: 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.