Start Up Conditions

Thermal Expansion

Property Damage Hazard

Avoid water heater damage

h_tall thermal e×paneion tank if necessary

Co_ltact ql_a_ifiedinstaller or sewice agency

Water supply system may, because of such events as high line pressure, frequent cut-offs, and the effects of water hammer 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 by-pass, and no other measures are taken, the devices cause the water system to be closed. As water is heated, it expands (thermal expansion} and closed systems do not allow for the expansion 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 water heater's temperature-pressure relief valve is

reached, the valve will relief 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 corrected,

It is recommended that any devices installed which could create a closed system have a by-pass and/or the system have an expansion 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, see Figure 26.

Thermal Expansion Tank Specifications

 

Tank

Dimensions

Pipe

Model

Capacity

in Inches

Fitting

Number

In Gallons

Diameter

Length

On Tank

153.331929

2

8(293rnm)

12-3/4(323mm)

3/4"Male

153.331050

5

11 (279 mm)

14-3/4 (375 mm)

3/4" Male

 

Expansion

Tank Sizing

Chart

 

 

 

Inlet*

Water

Heater

Capacity

(Ganons]

 

Water

 

 

 

 

 

 

Pressure

30

40

50

66

80

Expansion

40psi

2

2

2

5

5

Tank

50psi

2

2

2

5

5

Capacity

6Opsi

2

2

5

5

5

Needed

70psi

2

2

5

5

5

 

80psi

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.

 

 

WATER

HEATER

{3)

 

/

COLD

WATER

PRESSURE

HOT

SOLD

iNLET

FITTING

REDUCING

 

 

 

 

VALVE WITH

 

 

 

 

BY-PASS

 

 

 

WATER SHUT-OFF

 

PRESSURE

GAUGE

INLET

COLD

 

_ECOMMENDED

 

iNSTALLATION

 

 

{VERTICAL

MOUNTING)

 

WATER HEATER

 

 

 

 

COLD WATER

 

 

 

 

INLET

FITTING

 

FLOOR, CEILING JOIST, ETC.

NOT

COLD

_

STRAPPING

 

 

 

 

 

PR g dg2

 

 

 

 

VALVE WITH

/

II

 

_%111

 

BY-PASS

 

EXPANSION

 

 

 

/

 

 

/

 

 

 

t

 

 

 

 

WATER

SHUT-OFF

 

PRESSURE

GAUGE

INLET

COLD

 

ALTERNATE RECOMMENDED

iNSTALLATiON

 

{N ORIZONTAL MOUN37NG)

 

FIGURE26.

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.

Condensation causes sizzling and popping within the burner

area during heating and cooling periods and should be considered normal. See Condensation section.

Draft Hood Operation

Check draft hood operation by performing a worst case depressurization of the building. With all doors and windows closed, and with all air handling equipment and exhaust fans operating such as furnaces, clothes dryers, range hoods and bathroom fans, a match flame should still be drawn into the draft hood of the water heater with its burner firing. If the flame

23

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Kenmore 153.33616 owner manual Start Up Conditions, Chart, By-Pass