Kenmore 153.33443, 153.33453 owner manual Start Up Conditions, Thermal Expansion

Start Up Conditions

Thermal Expansion

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 fl ow 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 or device 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
153.331020	2	8 (203 mm)	12-3/4 (323 mm)		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 (Gallons)
	Water
	Pressure	30	40	50	66	80
Expansion	40psi	2	2	2	5	5
Tank	50psi	2	2	2	5	5
Capacity	60psi	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.

FIGURE 26.

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 fi ring. If the flame is not drawn toward the draft hood, shut off water heater and make necessary air supply changes to correct.

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