Installation Guide
 14 • Residen al Standard Gas Water Heater Use and Care Guide
INSTALLATION
 14 • Residen al Standard Gas Water Heater Use and Care Guide
INSTALLATION
Step 1:
✓
Verify that your 
home is equipped 
and up-to-date for 
proper opera on 
Installing a new water heater is the 
perfect  me to examine your home’s 
plumbing system and make sure the 
system is up to current code stan-
dards. There have likely been plumb-
ing code changes since the old water 
heater was installed. We recommend 
installing the following accessories 
and any other needed changes to 
bring your home up to the latest code 
requirements. Upda ng your plumb-
ing system can help extend the life of 
your water heater, avoid damage to 
your home and property, and reduce 
the risk of serious injuries or death. 
Inspect your home and install any de-
vices you need to comply with current 
codes and assure that your new water 
heater performs at its best. Check 
with your local plumbing offi cial for 
more informa on.
✓
Water pressure
Most codes allow a maximum 
incoming water pressure of 80 psi 
(we recommend a working pressure 
no higher than 50-60 psi). Check your 
home’s water pressure with a pressure 
gauge and adjust if necessary. High 
water pressure can damage the water 
heater, piping, and other appliances.
HOW: Purchase an inexpensive water 
pressure gauge from Lowe’s®.   Con-
nect the water pressure gauge to 
an outside faucet and measure the 
maximum water pressure experienced 
throughout a 24-hour period (highest 
water pressures o en occur at night). 
Figure 12 - Use a Water Pressure Gauge to make 
sure your home’s water pressure is not too 
high.
To adjust your home’s water pressure: 
Locate your home’s Pressure Reduc-
ing Valve (PRV) on the main incoming 
(cold) water supply line and adjust the 
water pressure control to between 
50 and 60 psi. If your home does not 
have a Pressure Reducing Valve, install 
a PRV on the home’s main water sup-
ply line and set it to between 50 and 
60 psi. Pressure Reducing Valves are 
available at Lowe’s®. 
BACKGROUND: Over the years, many 
u li es have increased water supply 
pressures so they can serve more 
homes. In some homes today, 
pressures can exceed 100 psi. High 
water pressures can damage water 
heaters, causing premature leaks. If 
you have replaced toilet valves, had a 
water heater leak, or had to repair 
appliances connected to the plumbing 
system, pay par cular a en on to 
your home’s water pressure. When 
purchasing a PRV, make sure the PRV 
has a built-in bypass.
✓
Wa-
ter pressure  in-
crease caused by ther-
mal expansion
Verify that you have a properly sized 
Thermal Expansion Tank. We recom-
mend installing an expansion tank if 
your home does not have one. Plumb-
ing codes require a properly pressur-
ized, properly sized Thermal Expan-
sion Tank in almost all homes.
Figure 13 - A Thermal Expansion Tank helps 
protect the home’s plumbing system from pres-
sure spikes.
HOW: Connect the Thermal Expansion 
Tank (available from Lowe’s® .) to the 
cold water supply line near the water 
heater. The expansion tank contains 
a bladder and an air charge. To work 
properly, the Thermal Expansion Tank 
must be sized according to the water 
heater’s tank capacity and pressurized 
to match the home’s incoming water 
pressure. Refer to the instruc ons 
provided with the Thermal Expansion 
Tank for installa on details.
BACKGROUND: Water expands when 
heated, and the increased volume 
of water must have a place to go, or 
thermal expansion will cause large 
increases in water pressure (despite 
the use of a Pressure Reducing Valve 
in the home’s main water supply line). 
The Safe Drinking Water Act of 1974 










