Bell & Gossett DN0136C User Manual

Domestic® Pump

WARNING

Vacuum Heating Units

INSTRUCTION MANUAL

DN0136

REVISION C

Series VCD™ and VCL

INSTALLER: PLEASE LEAVE THIS MANUAL FOR THE OWNER’S USE.

™

SAFETY

INSTRUCTIONS

This safety alert symbol will be used in this manual and on

the unit safety instruction decals to draw attention to safety
related instructions. When used, the safety alert symbol means
ATTENTION! BECOME ALERT! YOUR SAFETY IS INVOLVED!
FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT
IN A SAFETY HAZARD.

DO NOT PRESSURIZE TANK.
ISOLATE TANK DURING LEAK TEST.
DO NOT RESTRICT VENT.
DO NOT PLUG OVERFLOW.
OPEN INLET VALVES SLOWLY.

EXPLOSIBLE

(2) All Units

DN0483 (Small) - DN0484 (Large)

DO NOT USE AS A FLASH TANK.

FAILURE TO FOLLOW
INSTRUCTIONS COULD RESULT
IN SERIOUS INJURY OR DEATH.

EXPLOSIBLE

ISOLATE TANK

DURING LEAK TEST

(2) All Units

DN0485 (Small)

DN0486 (Large)

If the decals as noted below are missing or are illegible contact

your local B&G representative for a replacement.

1. Electrical connections to be made by qualified Electrician in
accordance with all National, State and Local codes.

2. Motor must have properly sized starter with properly sized
heaters to provide overload and undervoltage protection.

3. If pump, motor or piping are operating at extremely high or
low temperatures, guarding or insulation is required.

4. Operating personnel should be trained in the operation of
vacuum/condensate return units.

TM

WARNING

SERIES HV

MODEL

SERIAL

GPM PSI PUMP

CFM IN HG. PUMP

DWGS

POWER V. PH. HZ 60

CONTROL V. PH. 1 HZ 60

TOTAL LARGEST MOTOR
F.L. AMP F.L. AMP

DN0016

DN0116 Units with Panel

TM

Morton Grove, Illinois 60053

CAUTION

DO NOT RUN PUMP DRY,
SEAL DAMAGE MAY OCCUR.

INSPECT PUMP SEAL
REGULARLY FOR LEAKS,
REPLACE AS REQUIRED.

FOR LUBRICATION
REQUIREMENTS, CONSULT
SERVICE INSTRUCTIONS.

FAILURE TO FOLLOW
INSTRUCTIONS COULD
RESULT IN INJURY OR
PROPERTY DAMAGE.

P70644 All Units

P70644

2

DESCRIPTION

The Series VCD and Series VCL vacuum heating units are

designed to serve the dual purpose of pumping accumulated
condensate back to the boiler feed tank and maintaining
vacuum in the condensate system.

These units have separate compartments for the vacuum pro­ducer (the hurling water chamber) and for the condensate (the
condensate receiver).

The 25VCD and 50VCD models have both compartments inte­grally cast in one casting while the 100 and 150 VCD models
have separate compartments bolted together with external lift
pipes connecting them.

Series VCL units are customized to user specifications and
constructed using a choice of rectangular cast iron condensate
receivers, underground receivers, or cylindrical steel receivers.
In the case of steel condensate receivers, the vacuum unit can
be mounted on this receiver or mounted separately and field
piped. All models will have one or two condensate pumps and
one or two vacuum pumps as specified.

A variety of control options are available and furnished as spec­ified. When control panels are factory supplied, electrical dia­grams are shipped in the cabinets.

Receivers and hurling chambers are non-code cast iron or
steel.

PRELIMINARY INSPECTION

Assure that there is no shipping damage.

Assure that nameplate ratings agree with job specifications and
actual conditions.

HANDLING

Use care in installing unit. Utilize Lifting Eyes equally when

slinging.

LOCATION

Place unit for easy access to all parts. Allow adequate space

for servicing. Check ambient conditions.

NOTICE/TEMPERATURE LIMITS

Motors are designed to operate in 104°F (40°C) max. ambient.

Insulate or ventilate as required.

PIPING (General)

Pipe the unit per the Representative Piping Diagram. Locate

and support piping so as to not load the pump discharge.

WARNING: EXPLOSIBLE

Do not pressurize 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.

CAUTION: UNIT LIFTING EYE

Use unit lifting eyes only to lift unit as shipped from

factory. Unit must be empty and disconnected from pipes,
anchors and other restraints. Use proper rigging pro­cedures. Failure to follow these instructions could result in
injury or property damage.

CAUTION: NOT A CHEMICAL PUMP

Inject boiler feed compounds from chemical feed tank

into boiler feed piping – never into condensate tank. Failure
to follow these instructions could result in injury or property
damage.

FIG. 1

100 & 150 VCD CONFIGURATION

SERIES VCL (NOT SHOWN) USES SIMILAR PIPING

25 & 50 VCD CONFIGURATION

REPRESENTATIVE PIPING DIAGRAM

PIPING (Returns)

Gravity return 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.

SUCTION PIPING

Suction piping between the condensate receiver and the

vacuum producer should be at least as large as the inlet to the
vacuum producer.

PIPING (Vent)

Install a vent pipe to atmosphere. Pipe to be size of vent port

on unit. Do not restrict or reduce vent opening or exceed 20
feet vertical height unless an overflow connection is provided.

PIPING (Overflow)

Pipe overflow port to drain using an overflow loop when con-

densate temp will exceed 200ºF. (93°C).
The overflow port on the hurling chamber acts as the overflow

for both the vacuum producer and condensate return units.
Pipe to a suitable drain.

Series VCL units have a high level (overflow control) float
switch to start the vacuum pumps when the lower receiver is at
the “full” level. The vacuum pumps will siphon condensate from
the receiver into the hurling chamber.

Excess condensate will then overflow out of the hurling cham­ber to drain.

FLOAT SWITCHES & MECHANICAL ALTERNATORS

Floats are locked in place to prevent damage during shipment.

Remove shipping locks. Check factory settings. Floats and
mechanical alternators are adjustable for various levels of oper­ation. The lead pump should start with tank

3

/4 full and shut off
at 2" or more above pump inlet. Lag pump should start before
the tank overflows. Settings should avoid “short cycling” of the
pump.

Vacuum switch adjustment is explained on the following page.
An electric alternator (when furnished) must operate off the
lead vacuum switch.

ELECTRICAL WIRING & CONTROLS

Connect power wiring per the National Electrical Code.

Recheck nameplate vs specifications and conditions. All single
phase motors have internal thermal protection.

Three phase motors must use starters with properly sized over­load relays. Overload relays furnished are designed for manual
reset.

EQUALIZING LINE

A vacuum may be formed on radiation side of system when

steam stops flowing in mains. This vacuum may be higher than
return line vacuum, which would prevent condensate from
flowing back to pump. To correct this in an unzoned system,
install equalizer line as shown. To correct this in a zoned sys­tem, install equalizer line for each zoned section or install a
vacuum breaker on supply line on radiation side of each zone
valve.

ACCUMULATOR TANK

An accumulator tank may be used to facilitate lifting conden-

sate. The accumulator tank will be fitted with a float switch to
start the vacuum pump as accumulator fills. The vacuum pump
will then siphon condensate into the condensate receiver.

The vacuum sensor line in an accumulator tank system must
sense the vacuum in the accumulator tank as shown on the low
return piping diagrams. (Figure 9, page 5.)

3

ZONE CONTROL

VALVE

STEAM MAIN

M

TO ZONE

RETURN MAIN

WARNING: HIGH VOLTAGE ELECTRICITY

Disconnect and lock out power before connecting or

servicing unit. Failure to follow these instructions could
result in serious injury or death.

FIG. 2 EQUALIZING CONNECTIONS FOR ZONED SYSTEMS

SEQUENCE OF OPERATION

There are two separate and independent cycles of operation

in the VCD design – one of air evacuation and the other for
condensate return. This is accomplished by completely sep­arating the air pumps from the condensate storage receiver
and water pumps. Fig 3 below illustrates a single, two com­partment receiver, divided horizontally, where the air pumps
operate from the upper compartment or separation chamber
while the water pumps operate from the lower compartment
or condensate receiver. The unit below is similar except that
the air pump separation chamber and condensate receiver are
separate units, connected as shown in Figure 4. The operation
for both types of construction is identical.

AIR EVACUATION CYCLE

The independent air evacuation cycle begins when the vacuum

switch, responding to system requirements, starts the centrifu­gal “air” pump. This pump circulates “hurling” water from the
separation chamber through the multi-jet nozzle, venturi and
returns it to the separation chamber. The water, forced at high
velocity across the gap between nozzle and venturi, entrains air
and gases in multiple jet streams, creating a smooth, steady
vacuum in the condensate receiver and system. The mixture is
discharged through the venturi into the separation chamber
where the air and gases separate from the “hurling” water and
are vented. When the desired vacuum has been produced in
the system, the vacuum switch stops the pump, and the check
valve at air inlet to separation chamber closes. preventing the
return of air to the system.

Replacement of the hurling water evaporated from the separa­tion chamber is controlled by a solenoid valve connected to the
water supply and actuated by a float switch.

CONDENSATE RETURN CYCLE

The condensate return cycle begins when a float switch starts

a water pump on condensate rise. The condensate is pumped
into the boiler feed system until the preset low float switch set­ting has been reached.

DUPLEX PUMPS

The second or lag pump of duplex water and/or air pumps

functions if the first or lead pump fails and automatically oper­ates to double the capacity in the event of abnormal demand.

TEMPERATURE LIMIT SWITCH

Some units may be equipped with temperature limit switches.

When located on the separation chamber, it is used to admit
cooling water if the hurling temperature exceeds a predeter­mined limit.

A condition may be encountered where the temperature of the
condensate fluctuates intermittently to critically high levels,
where operation under vacuum could cause the condensate to
vaporize. A temperature limit switch can be installed on the
condensate receiver to prevent the air pump(s) from operating
where such a condition exists. Upon temperature drop the vac­uum switch(es) will again control operation of the air pump(s).

VACUUM SWITCH ADJUSTMENTS

The vacuum switches are adjusted and tested at the factory for

proper operation. The vacuum switch on the single unit and the
lead switch of the 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" and open at 8".

These settings are suitable for all normal installations including
those having an accumulator tank or lift fitting when properly
piped. If settings must be readjusted, refer to manufacturer’s
instruction.

4

FIG. 4 100 & 150 VCD LIFT PIPE ASSEMBLIES

FIG. 3

CUT-AWAY VIEW OF VCD PUMP WITH 50 VCD RECEIVER

25 VCD RECEIVERS ARE SIMILAR

CUT-AWAY VIEW OF VCD PUMP WITH 100 VCD

OR 150 VCD RECEIVERS