Filter
Top Products
Troubleshooting Guide
Start Up Conditions
THERHAL EXPANSION
Water supply systems may, because of such events as high line
pressure, frequent cut-offs, the effects of water hammer among
others, have installed devines such as pressure reducing vales,
check valves, back flowpreventers, e_c ._tocontrol these types of
problems. When these devices are not equipped with an internal
by-pass, and no other measures _e taken, the devices cause the
water system to be closed. 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, tf the relieving point of
the water heater s temperature-pressure relief valve "s reached, the
valve will relieve the excesspressure. The temperatttre-pressure
relief valve is not intendedfor 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
closed system have a by-pass andtor 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 supplier and/or the Sears Service Center for
assistance in controlling these situations.
Thermal Expansion Tank Specifications
Mode,T t C; oT tyD mens ou inInohes1I' peF ttiog
Number Diameter ___Length j On Tank
153o331020 1 2 8inches t2_inches / _"Male
_53.33_o5o15 _ _oches[_4_nchosI _"M_e
Expansion Tank Sizing Chart
Expansion
Tank
Capacity
Needed
Inlet* Water Heater Capacity (Gallons)
_rater
Pressure 30 40 50 [[ 66 82
40psi 2 2 2 [ 5 5
50p,_.... 2 2 I 5...... 5
60psi 2 2 [ 5 [ 5 5
70psi 2 2 5 5 5
80p_ t 2 I 5 t 5 I 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 tanks air pressure must be adjusted to match that
pressure, but must not be higher than 80 psi.
HOT COLD
WATER HEATER
COLD WATER
;ITTtNG
0)
PRESSURE
REDUCING
VALVEWITH
BY-PASS
(z)
PRESSUREGAUGE
WATER
SHUTOFF
RECOHHENDED INSTALLATION
(VERTICAL HOUNTING)
WATER HEATER
COLD WATER
INLET FITTING
|
HOT _ COLD
FLOOR, CEILING
JOIST,ETC.
STRAPHNG
I|1 I 0)
Ill | PRESSURE
I Ii / REDUCINGINLETCOLD
VALVE WITH WATER
(I) BY-PASS SHUTOFF
EXPANSION '_ !
TANK
(2)
PRESSUREGAUGE
ALTERNATE RECOHHENDED
iNSTALLATiON
(HORIZONTAL HOUNTING)
STRANGE SOUNDS
Possible noises due to expansion and contraction of some metal
parts during periods of heat-up and cool-down do not represent
harmfiil or dangerous conditions.
21