Leslie Controls F-1240LDW User Manual
Installation, Operating and
90/4.5.5
Maintenance Instructions
Rev. 0
Constantemp Double Wall Low pressure steam-water Heater
F-340LDW,F-640LDW, F-940LDW and F-1240LDW
Table of Contents
SECTION I...................................................................................................................................................................................2
INSTALLATION....................................................................................................................................................................... 2
OPERATION............................................................................................................................................................................. 2
SECTION II.................................................................................................................................................................................. 2
START-UP PROCEDURE ........................................................................................................................................................ 2
TO DRAIN UNIT FOR PROLONGED SHUT-DOWN ........................................................................................................... 3
SECTION III................................................................................................................................................................................ 7
MAINTENANCE OF SYSTEM COMPONENTS.................................................................................................................... 7
ACTUATOR ASSEMBLY........................................................................................................................................................2
VALVE PLUG ASSEMBLY.....................................................................................................................................................2
CONTROL VALVE ASSEMBLY ............................................................................................................................................ 2
MAINTENANCE OF SYSTEM COMPONENTS HEAT EXCHANGER............................................................................... 2
SECTION IV - TROUBLE SHOOTING GUIDE..................................................................................................................... 2
Recirculating Systems................................................................................................................................................................ 2
Heat Exchanger and Blending Valve ......................................................................................................................................... 3
Table of Figures
FIGURE 1..................................................................................................................................................................................... 4
FIGURE 2..................................................................................................................................................................................... 6
Figure 3 .........................................................................................................................................................................................2
Figure 5 .........................................................................................................................................................................................2
Figure 6 .........................................................................................................................................................................................2
F-340LDW ....................................................................................................................................................................................2
F-640LDW ....................................................................................................................................................................................3
F-940LDW ....................................................................................................................................................................................4
F-1240LDW ..................................................................................................................................................................................5
Installation, Operating and
Maintenance Instructions
SECTION I
INSTALLATION
WARNING: When connecting heater to other than
copper pipe use dielectric unions,
(isolators) to prevent possible galvanic
action.
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 shutoff or no load condition.
6. Install a thermometer in hot water outlet piping close
to Heater.
NOTE: An adequate trap system must be provided to
insure that inlet steam piping to Heater is
properly drained.
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
90/4.5.5
Rev. 0
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.
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.
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.
NOTE: BEFORE making any water temperature or
3. Loosen set screw in temperature adjuster (14)
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
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
adjuster (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 set-point 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 adjuster in
small increments while adjusting, as total rotary
movement of adjuster 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.
TO DRAIN UNIT FOR PROLONGED
SHUT-DOWN
(Where drainage is necessary)
1. Turn off steam supply and water supply.
2. Open a vent line in high point of system piping.
3. Remove relief valve to drain water from control
valve.
4. Open drain connections in steam and condensate
lines.
5. Be sure all water is drained from hot water
control valve and system if there is any danger of
freezing.
6. When restarting system, tighten all connections
and close all vents. Follow instructions shown in
Section II - Start-up Procedure to put Heater back
in operation.
Installation, Operating and
90/4.5.5
Maintenance Instructions
Rev. 0
FIGURE 1
Note 1: Requires four (4) R/N 45840 and two (2) R/N 59478
Note 2: Furnished with Heater Coil but may be ordered separately.
Note 3: Includes seal plate (#21), screws (#17) and lock washers (#18)
✡ Recommended spare parts
* These parts should be on hand, plus recommended spare parts, when overhauling equipment.
F-340LDW
Capacity and
Adjustment Table
(Capacity in GPM)
Numbers in brackets are
approximate Gain Adjustor
settings in degrees.
*Maximum water temperature
setting for F-340LDW
is 150 0F
** Steam pressure is measured
at the Heat Exchanger inlet.
Inlet
Water
Temp
0
40
F
Set
Point
0
F
2 5 10 15
120 27
(250)
140 20
(300)
150 17
(300)
160 * * * *
F-340LDW
Steam
Pressure
psig
20 (240) 30
(230)
22
(300)
19
(300)
24
(300)
21
(300)
30
(220)
27
(300)
23
(300)
180 * * * *
60
120 30
(220)
140 23
(250)
150 20
(280)
30
(210)
25
(240)
22
(270)
30
(200)
27
(230)
24
(270)
30
(190)
30
(220)
27
(260)
160 * * * *
180 * * * *
FIGURE 2
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