Page 1
PT Diaphragm Non-Code
Expansion Tanks
INSTALLER: PLEASE LEAVE THIS MANUAL FOR THE OWNER’S USE.
INSTRUCTION MANUAL
V1000001B
WARNING: California proposition 65
warning! This product contains chemicals
known to the state of California to cause
cancer and birth defects or other reproductive harm.
Safety Instruction
This safety alert symbol will be used in this
manual to draw attention to safety related
instructions. When used, the safety alert
symbol means ATTENTION! BECOME ALERT! YOUR
SAFETY IS INVOLVED! FAILURE TO FOLLOW THE
INSTRUCTIONS MAY RESULT IN A SAFETY HAZARD.
WARNING: Explosion or Rupture Hazard.
A relief valve must be installed to prevent
pressure in excess of local code requirement
or maximum working pressure
designated in the Product Manual, whichever is less.
Do not expose Product to freezing temperatures or
temperatures in excess of 140°F. Do not adjust the
pre-charge or re-charge this Product except for any
adjustments at the time of the initial installation,
especially if Product is corroded, damaged or with
diminished integrity. Adjustments to pre-charge must
be done at ambient temperature only. Failure to
properly size the Product or follow these instructions
may result in excessive strain on the system and may
lead to Product failure, serious or fatal personal injury,
leakage, and/or property damage.
WARNING: Read carefully the product
installation, operating and maintenance
instructions. Failure to follow the instruc-
tions and warnings in the manual may result
in serious or fatal injury and/or property damage, and
will void the product warranty. This product must be
installed by a qualifi ed professional. Follow all
applicable local and state codes and regulations, in the
absence of such codes, follow the current editions of
the National Plumbing Code and National Electric
Code, as applicable.
DESCRIPTION
Many local codes require back fl ow preventers. Since this
seals off the system, an expansion tank is required or
the relief valve will discharge on every heating cycle. The
thermal expansion tanks eliminate this wasteful, costly,
and dangerous practice. The thermal expansion tank is
designed to be used with water temperatures to 140° F
(60° C). DO NOT USE A STANDARD TANK. The sizing chart
will allow you to choose the correct size expansion tank
for your application. When water is heated, it expands.
Provision must be made for this expansion in a closed hot
water heating system. The Bell & Gossett Series PT
pre-charged diaphragm tank stores the expanded hot
water and returns air-free water to the system when the
temperature drops.
OPERATIONAL LIMITS
MODEL NUMBER
MAXIMUM LIMITATIONS
PRESSURE
TEMPERATURE
FACTORY
PRE-CHARGE
PT-5, PT-12, PT-25V
PT-30V, PT-42V, PT-60V,
PT-80V, PT-180V, PT-210V
140 STET
(1035 kPa)
100 PSIG
(689 kPa)
140°F (60°C)
38 PSIG
(262 kPa)
Page 2
WARNING: This product, like most products
under pressure, may over time corrode,
weaken and burst or explode, causing
serious or fatal personal injury, leaking or
fl ooding and/or property damage. To minimize risk, a
licensed professional must install and periodically
inspect and service the Product. A drip pan connected
to an adequate drain must be installed if leaking or
fl ooding could cause property damage. Do not locate in
an area where leaking could cause property damage.
INSTALLATION INSTRUCTIONS
A. PRE-INSTALLATION
WARNING: System fl uid under pressure and/
or at high temperatures can be very
hazardous. Before servicing, reduce system
pressure to zero or isolate the vessel from
the system. Allow system to cool below 100°F and
above 35°F. Failure to follow this instruction may result
in serious personal injury and/or property damage.
B. INSTALLATION
Install Bell & Gossett Series PT pre-charged diaphragm
expansion tanks on the cold water supply (CWS) line at a
point between the water heater and back fl ow preventer,
check valve or pressure reducing valve.
1. Visually inspect expansion tank and check for damage
prior to installation.
WARNING: If the expansion tank is
damaged, it must be replaced. Failure to
follow this instruction may result in serious
personal injury or death and property
damage.
2. Bell & Gossett Series PT diaphragm tanks are factory
pre-charged to 38 PSI (262 kPa). Adjust pre-charge to
equal system fi ll pressure.
WARNING: Excessive pressure can cause
tank to explode. Exercise care when fi lling
a tank with air so the pressure does not ex-
ceed that required of does not exceed the
working pressure of the tank as stamped on the nameplate. Failure to follow these instructions will result in
serious personal injury or death and property damage.
3. Replace and tighten cap on air fi tting.
4. The location selected should be indoors in an area not
subject to freezing.
5. The items which must be installed in sequence in the
cold water line are:
a. The EXPANSION TANK must be installed at least 18
inches (46 cm) away from the cold water inlet fi tting on
the water heater
b. The PRESSURE GAUGE, and
c. The PRESSURE REDUCING VALVE, if required.
6. The expansion tank is designed to be supported by the
piping system in the vertical position. If however, the
expansion tank must be installed horizontally, it must be
supported by adequate strapping (not supplied).
7. The expansion tank, pipes, and connections may in
time leak. Put the expansion tank in a place where a
water leak will not damage anything. The expansion tank
should be located in an area where water leakage from
the tank or connections will not result in damage to the
area around the expansion tank or to the lower fl oors of
the structure.
WARNING: A residential tank must be
installed vertically or horizontally. Do not
install on a dead end pipe or in an overhead
joist space. *See Figure 1 for installation.
1. The water supply and power (electricity or gas) must
be shut off during the installation of the valves and
expansion tank. Follow the instructions found on the
water heater and in the owner’s manual.
2. Install expansion tank, pressure gauge and pressure
reducing valve, if required.
3. Once tank and other components are installed, fi ll
system and check for any leakage. Make repairs if
necessary.
4. Before initial fi ring of the water heater, open a hot
water fi xture and draw water until all air is removed from
the system. Turn the water heater temperature control
to desired ending temperature level (See water heater
instructions).
5. To relieve initial thermal expansion, slightly open a
hot water faucet. Continue until water heater aquastat
temperature is satisfi ed. Once heater is at its operating
range, no further bleeding of expanded water is required.
6. The system water heater and expansion tank will now
be operational. The expansion tank will absorb pressure
increases caused by thermal expansion to a level well
below the water heater relief valve setting.
Recommended inlet water pressure is 60 PSI (414 kPa) or
less. Refer to the pressure gauge. Adjust the
pressure reducing valve to increase or decrease the
pressure as required. Open a nearby faucet allowing
water to run briefl y then close the faucet. Check the
pressure gauge again and make additional adjustments
as necessary. This process may need to be repeated
several times before the pressure can be adjusted to 60
PSI (414 kPa) or less.
Page 3
WARNING: RUPTURE OR EXPLOSION
HAZARD Like most pressurized tanks, this
tank can over time corrode, weaken, and
burst or explode. Failure to follow this
instruction may result in serious personal injury or death
and property damage.
WARNING: CHLORINE & AGGRESSIVE
WATER HAZARD The water quality can
signifi cantly infl uence the life of your
product. You should test for corrosive
elements, acidity, total solids, and other relevant
contaminants, including chlorine and treat your water
appropriately to insure satisfactory performance and
prevent premature failure. Failure to follow this
instruction may result in serious personal injury or
death and property damage.
SYSTEM VENTING AND PURGING
After initial venting and purging of air from the system,
more air will be released from the water as it is heated.
Therefore, it is recommended that a Bell & Gossett air
separator be installed on the main.
OPERATING INSTRUCTIONS
1. The expansion tank is typically installed in the bottom
of an air separator. Its sealed-in air pre-charge prevents
water from entering the tank until the system pressure
exceeds the pre-charge pressure
2. As the water temperature rises, expanded water enters
the expansion tank’s water reservoir. The pre-charge air
chamber absorbs the pressure increase, keeping system
pressures below the relief valve setting.
3. As water temperature decreases the pressure in the
air chamber forces water back into the system until the
expansion tank is empty.
Air
Cushion
Air
Cushion
If the system has multiple loops or zones, the supply
water for all loops and zones must pass through the air
separator for complete and continuous air removal. In
case the piping arrangement does not permit the
installation of a single air separator on the main, air
separators should be installed on each loop or zone. In
this event, only one expansion tank is required for the
system.
Even with a Bell & Gossett air separator installed on the
main or mains, it is recommended that Bell & Gossett air
vents be installed on high points in the system.
It is also recommended that manual (key or coin type) air
vents be installed at higher points on the radiation.
Back Flow Preventer Check Valve
Relief Valve
CWS
PT Tank
Water
Heater
Hot Water
Air
Cushion
Air
Cushion
Air
Cushion
Air
Cushion
Models PT-5
and PT-12
The selection, application, installation and servicing of
this product should be performed by a qualifi ed
professional within all applicable safety and code
requirements.
Models PT-25V
and PT-475
Typical Instillation
Figure 1
Page 4
SERVICE INSTRUCTIONS
1. Check the expansion tank periodically for signs of
external leakage or corrosion. If any is found, the tank
must be replaced.
WARNING: Signs of leakage or corrosion are
indications the tank may have failed.
Periodically check the expansion tank for
signs of external leakage or corrosion. If
found, the tank must be replaced. Failure to follow
these instructions may result in serious personal injury
or death and property damage.
2. If a HVAC system is shut down for long periods or
emptied for any reason, it is necessary to follow the following procedure:
a. Fill system.
b. Vent air from system (see system venting and purging).
c. Bring system up to maximum operating temperature.
Before fi lling and starting the operation of a HVAC
system, a properly applied and sized pressure relief valve
must be installed and in good operating order.
WARNING: Improper use of air charging
valve during venting of air pressure from
tank will create a hazardous condition due
to the escape of high velocity gas and/or
liquid. Depress the center valve core stem, as with a tire
valve to slowly vent off gas pressure. Do not remove
the valve core until pressure in expansion tank has
reached zero. Failure to follow these instructions could
result in serious personal injury or death and property
damage.
c. Check for faulty fi ll valve operation. First, close manual
shutoff located before the fi ll-valve; then, draw system
pressure down to pre-set pressure (see TABLE 1) open
shut-off valve and observe system for pressure build-up
several hours later. If pressure build up beyond set
pressure is found, replace fi ll valve following the
manufacturer’s instruction.
d. Check for service water entering system from any other
source such as a defective tankless heater or indirect fi red
water storage tank. Use same procedure as above after
shutting off possible water source. Replace defective
device if found following manufacturer’s instruction.
During fi lling and start-up after servicing, the system
pressure should be closely monitored to ensure the
pressure does not exceed the pressure relief valve rating.
Consult the applicable pressure relief valve
manufacturer’s instructions as necessary.
3. If the system pressure is too high:
a. Check gauge calibration.
b. Check to see if expansion tank has lost its air charge.
NOTE: To check the expansion tank air pressure with a tire
gauge, either:
1. Disconnect the expansion tank from the system or,
2. Draw off system water until boiler pressure reads zero
or isolate the expansion tank from the system in domestic
water systems, and bleed pressure from the system. All
drains must be kept open during servicing of the
expansion tank. (Expansion tank must be empty of
expanded system water.)
3. Then check tank pressure with tire gauge.
WARNING: System fl uid under pressure
and/or at high temperatures can be very
hazardous. Before servicing, reduce system
pressure to zero or isolate the vessel from
the system. Allow system to cool below 100o F and
above 35o F. Failure to follow this instruction may result
in serious personal injury and /or property damage.
4. If pressure relief valve drips water:
a. First, check system pressure. If too high, follow steps
3.a., b., c., and d. above.
b. If pressure relief valve continues to drip water, even at
reduced pressure, fl ush relief valve by quickly raising lever
several times. If drip continues, replace relief valve
following manufacturer’s instruction.
c. If multiple expansion tanks are installed in the system,
check pressure of each for possible air leaks. Be sure air
valve caps are on tight. Multiple tanks should be in the
same location.
Xylem Inc.
8200 N. Austin Avenue
Morton Grove, Illinois 60053
Phone: (847) 966-3700
Fax: (847) 965-8379
www.xyleminc.com/brands/bellgossett
Bell & Gossett is a trademark of Xylem Inc. or one of its subsidiaries.
© 2012 Xylem Inc. V1000001B May 2012
Loading...