Bell & Gossett DN0135D Domestic Pump Vacuum Heating Units Series VL - Manual (Page 4)

4
PIPING (Returns)
Gravity r eturn lines from system must be properly pitched down
to unit inlet. Returns must also be trapped to prevent steam
entry into the unit. An inlet basket strainer is recommended.
Install gate valve in return line for testing pump shut off vacuum,
closing off hot returns when cleaning strainer, etc. Do not install
check valve in return line. Avoid elbow or tee located closer
to strainer inlet than 10 times inlet diameter. If unavoidable
relocate vacuum switches to top of nearest “entry” point on
return main unless a portion of return is below pump inlet. If
returns are lower than pump inlet an accumulation tank is rec-
ommended. Accumulator tank may not be necessary if low
length of return is not lower than 24" below pump inlet or
longer than 30'. See TYPICAL PIPING-LOW RETURNS (page
5). High pressure steam traps should empty into uninsulated
flash tank where condensate will cool before entering unit.
DISCHARGE LINE
Install union, check valve, steam cock and gate valve at unit in
each discharge line. Steam cock to be adjusted to cause pump
to operate at specified pressure. If discharge line is more than
100' long, install pipe 1 or 2 sizes larger than discharge valve
tapping.
ELECTRICAL WIRING & CONTROLS
Connect power wiring per the National Electric Code. Recheck
nameplate vs specifications and conditions. All single phase
motors have internal thermal protection.
Three phase motors must use starters with properly sized over-
load relays. Overload relays furnished are designed for manual
reset.
W ARNING: HIGH VOLTAGE ELECTRICITY
Disconnect and lock out power befor e connecting or
servicing unit. Failure to follow these instructions could
result in serious injury or death.
PUTTING THE UNIT INTO SER VICE
1. Assure that the unit is piped in accordance with instruc-
tions.
2. Isolate tank before performing any system leak test. Do not
pressurize the tank as part of the leak test. Failure to do this
can result in serious injury or death.
3. Check floats for free operation.
4. Check power leads in accordance with wiring diagram
enclosed in control cabinet (when furnished).
5. Install drain plugs.
6. Fill receiver half full of water to prime pump(s) and prevent
possible damage to pump seals. Avoid freezing conditions
after unit receiver has been filled.
7. Check for proper rotation of all three phase motors.
Rotation must be clockwise looking down on the motor as
indicated by directional arrow on pump casting. If pump
runs backwards, interchange two wires (3 phase only).
8. Throttle plug cock in discharge line until pressure at pump
(while pump is discharging) approaches pump rated pres-
sure. Tighten plug nut to secure adjustment.
9. Remove start-up label (below) from panel (if applicable)
after complying with instructions.
10. If possible, observe operation thru several cycles using
Selector or Vacuum Switch settings as noted below.
The vacuum switches are adjusted and tested at the factory for
proper operation. The vacuum switch on a single unit and the
lead switch of a duplex unit is set to close at 3" Hg vacuum and
open at 8". The lag switch of a duplex unit is set to close at
2
1 / 2 " and open at 8".
These settings are suitable for all normal installations including
those having an accumulator tank or lift fitting. If settings must
be readjusted refer to manufacturer’s instructions.
POSITION WHEN USED OPERATION
“V acuum and Float” or “FL-Vac’’ Normal position
Pumps operate on either low
vacuum or high condensate
“Float Only” or “Float”
Sometimes used for night and week-end service. Pump starts and stops on
This setting is not recommended for use with lift fitting. condensate level change
“Continuous” or “Hand”
Testing and for unusually high
Continuous
lift conditions in return lines.
“Off” (Duplex Units only) Adjust controls, inspect pump Prevent operation of motor
SELECTOR OR V ACUUM SWITCH SETTINGS
WARNING: HIGH VOLTAGE
Disconnect and lock out power befor e connecting or
servicing unit. Failure to follow these instructions could result
in serious injury or death.
CAUTION: DO NOT REVERSE
Reverse operation can cause extensive damage to
pumps. Jog the motor to test for direction of rotation. Failure
to follow these instructions could result in injury or property
damage.
CAUTION: DO NOT RUN DRY.
SEAL DAMAGE MAY OCCUR.
Inspect pump seal r egularly for leaks. Replace as required.
Failure to follow these instructions could result in injury or
property damage.
ELECTRICIAN/INST ALLER/OPERATOR
REMOVE AND DESTROY THIS T AG AFTER —
1. ASSURING THAT ALL PUMPS ROTATE CLOCKWISE PER ARROWS CAST
ON VOLUTES. (JOG PUMP MOMENTARILY TO TEST – INTERCHANGE
ANY TWO MOTOR POWER WIRES TO REVERSE 3PH MOTORS.)
2. ASSURING THAT SHIPPING LOCKS HAVE BEEN REMOVED FROM ALL
FLOAT SWITCHES.
DN0098
W ARNING: EXPLOSIBLE
Do not pr essurize receiver. Isolate receiver during leak
test. Do not plug overflow. Do not restrict vent opening to
atmosphere. Open valves slowly. Failure to follow these
instructions could result in serious injury or death.