Reliance Water Heaters Comprehensive Guide to Expansion Tank Features and Importance in Water Heating Systems

Reliance Water Heaters

500 Tennessee Waltz Parkway

Ashland City, TN 37015

Reliance Hotline: 1-800-365-4054

www.reliancewaterheaters.com

© 2007 November 2007R RPMCP00107

EXPANSION & PUMP TANKS

WHY EXPANSION TANKS ARE IMPORTANT

Thermal expansion occurs when water is heated during non-use periods. The installation of a Pressure Reducing Valve (PRV), Check Valve or Back Flow Preventer ˝closes˝ the water system, leaving water with no room for expansion. National Standard Plumbing code: 10.5.7 requires backflow prevention, to prevent backflow into the water main.

Thermal expansion in a closed plumbing system can be damaging, dangerous and costly. Its effects include damage to water heater connections, gas water heater flue tubes, pumps serving washers and dishwashers, leaking faucets, ˝weeping˝ of water through the water heater T&P Safety Valve, and noisy water hammer in the pipes.

A properly sized Expansion Tank eliminates these problems, by giving water a place to go when thermal expansion occurs. When a water heating cycle ends, or when any fixture is opened

within the system, the impact of thermal expansion is reduced, and water drains out of the expansion tank back into the system.

RELIANCE EXPANSION

TANK FEATURES

nProtection against dangerous thermal expansion in closed systems

nSteel shell with polyurethane coating for maximum corrosion resistance

nDrawn-steel tank with 2-coat bonded polymer inner lining

nButyl diaphragm, for permanent separation of air and water, with no waterlogging

nIn-line design, with 3⁄4˝ NPTM Connection: installs in cold water line of water heater

nMaximum Working Pressure 150 PSI

nMaximum Temperature: 140°F Residential 180°F Commercial

nIAPMO Approved

n5-Year Limited Warranty

TYPICAL EXPANSION TANK

INSTALLATION

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.

Expansion Tank Sizing Chart For Residential Water Heaters

Inlet Water		Water Heater Capacity in Gallons
Pressure*	30	40	50	66	82	100
40 PSI	ETC-2X	ETC-2X	ETC-2X	ETC-5X	ETC-5X	ETC-5X
50 PSI	ETC-2X	ETC-2X	ETC-2X	ETC-5X	ETC-5X	ETC-5X
60 PSI	ETC-2X	ETC-2X	ETC-5X	ETC-5X	ETC-5X	ETC-5X
70 PSI	ETC-2X	ETC-2X	ETC-5X	ETC-5X	ETC-5X	ETC-5X
80 PSI	ETC-2X	ETC-5X	ETC-5X	ETC-5X	ETC-5X	ETC-5X

*Highest recorded inlet water pressure in a 24-hour period of regulated water pressure.

A

B

Water Heater Expansion Tanks

		Maximum Acceptable		Dimensions
		Volume (Gallons)		in Inches		Shipping
	Gallon					Weight
Model Number	Capacity	40 PSI	60 PSI	A	B	(Lbs.)
ETC-2X	1.96	1.27	1.03	83⁄8	121⁄2	5
ETC-5X	4.55	3.05	2.19	113⁄8	143⁄4	8
ETC-10X	9.21	6.55	5.25	153⁄8	153⁄4	20

All models: 150 PSIG Maximum Working Pressure