Filter
Top Products
Troubleshooting Guide
Start Up Conditions
THERMAL EXPANSION
Water sup,ply systems may, because of such events as high line
pressure, frequent cut-offs, the effects of water hammer among
others, have installed devices such as pressure reducing valves,
check valves, back flow preventers, etc._to control these types of
problems. When these devices are not equipped with an internal
oy-pass, and no other measures are taken, the devices cause the
water system to be dosed. As water is heated, it expands (ther-
mal expansion) and closed systems do not allow for the expan-
sion of heated water.
The water within the water heater tank expands as it is heated and
increases the pressure of the water system. If the relieving point of
the water heater's temperature-pressure relief valve is rea_ed, the
valve will relieve the excess pressure. The temperature-pressure
relief valve is not intended for the constant relief of thermal
expansion. This is an unacceptable condition and must be cor-
rected.
It is recommended that any devices installed which could create a
dosed system have a by-pass and/or the system have an expan-
sion tank to relieve the pressure built by thermal expansion.
Thermal expansion tanks are available from Sears stores and
through the Sears Service Centers. Contact the local plumbing
inspector, water su_.plier and/or the Sears Service Center for
assistance in controlling these situations.
Thermal Expansion Tank Specifications
Model
Number
153.331020
153.331050
Tank Capacity
In Gallons
2
5
Dimensions in Inches
Diameter Length
8 inches 12_ inches
11 inches 14_ inches
Pipe Fitting
On Tank
_" Male
_" Male
HOT
COLD
WATER HEA13ER
COLD WATER
INLET FITTING
HOT COLD
WATERHEATER 0)
• COLDWATER PRESSURE
INLETFn-rlNG REDUCING
VALVEWITH
BY-PASS
(1) 1
EXPANSION
TANK
(2)
PRESSUREGAUGE
WATER
SHUTOFF
RECOMMENDED INSTALLATION
(VERTICAl. MOUNTING)
FLOOR,CEIUNG
joist, ETC.
STRAPPING
(i)
EXPANSION
o)
PRESSURE
REDUCING INLETCOL
VALYEWITH WATER
BY-PASS SHUTOFF
Expansion Tank Sizing Chart
Water Heater Capacity (Gallons)
Inlet*
Water
Pressure
40psi
50psi
60psi
70psi
80psi
30 J 40 :50 66 82
Expansion
Tank 2 I 2 2 5 5
Capacity 2 2 2 5 5
Needed 2 2 5 5 5
2 2 5 5 5
2 5 5 5 5
*Highest recorded inlet water pressure in a 24 hour period or
regulated water pressure.
NOTE: Expansion tanks are pre-charged with a 40 psi air
charge. If the inlet water pressure is higher than 40 psi, the
expansion tank's air pressure must be adjusted to match that
pressure, but must not be higher than 80 psi.
PRESSUREGAUGE
ALTERNATE RECOMMENDED
INSTALLATION
(HORIZONTAL MOUNTING)
STRANGE SOUNDS
Possible noises due to expansion and contraction of some metal
parts during periods of heat-up and cool-down do not represent
harmful or dangerous conditions.
21