lp-83 Rev. 006 Rel. 005 Date 12.18.17
9
D. Temperature and Pressure Relief Valve
On SSU-80 and SSU-119 residential models, as well as all commercial
models, a 3/4” temperature and pressure (T&P) port and relief valve
are provided. On all other models, an appropriate T&P valve must
be supplied and installed as detailed in the piping diagrams in this
installation manual.
Use both thread tape and pipe dope to install an NPT brass T&P
relief valve for hot water heaters, as required by local codes but
not less than valves certified as meeting the requirements for relief
valves for hot water heaters (ANSI Z21.22 / CSA 4.4) by a nationally
recognized lab that maintains periodic inspection of production
listed equipment. Make sure the relief valve is sized to the BTU/Hour
capacity of the water heater. The T&P valve must be plumbed down
so discharge can exit at least 6” above the structural floor. The relief
line cannot be in contact with any live electrical parts. If the relief
valve constantly weeps install an expansion tank. See expansion
tank manufacturer’s instructions for suggestions.
To avoid water damage or scalding due to relief valve operation:
•
Discharge line must be connected to relief valve outlet and
run to a safe place of disposal. Terminate the discharge line
in a manner that will prevent possibility of severe burns or
property damage should the relief valve discharge.
•
Discharge line must be as short as possible and the same
size as the valve discharge connection throughout its
entire length.
•
Discharge line must pitch downward from the valve
and terminate at least 6” above the floor drain, making
discharge clearly visible.
•
The discharge line shall terminate plain, not threaded, with
a material serviceable for temperatures of 375
o
F or greater.
•
Do not pipe discharge to any location where freezing could
occur.
•
No valve may be installed between the relief valve and
heater or in the discharge line. Do not plug or place any
obstruction in the discharge line.
•
Test the operation of the relief valve after filling and
pressurizing the system by lifting the lever. Make sure the
valve discharges freely. If the valve fails to operate correctly,
immediately replace with a new properly rated relief valve.
•
Test T&P valve at least once annually to ensure the waterway
is clear. If valve does not operate, turn the heater “off” and
call a plumber immediately.
•
Take care whenever operating relief valve to avoid scalding
injury or property damage.
FAILURE TO COMPLY WITH THE ABOVE GUIDELINES COULD
RESULT IN FAILURE OF RELIEF VALVE OPERATION, RESULTING
IN POSSIBILITY OF SUBSTANTIAL PROPERTY DAMAGE, SEVERE
PERSONAL INJURY, OR DEATH.
Do not thread a cap or plug into the relief valve or relief valve line
under any circumstances! Explosion and property damage, serious
injury, or death may result.
RE-INSPECTION OF T&P RELIEF VALVES: T&P valves should be
inspected AT LEAST ONCE EVERY THREE YEARS, and replaced if
necessary,
by a licensed plumbing contractor or qualified service
technician to ensure that the product has not been affected by
corrosive water conditions and to ensure that the valve and
discharged line have not been altered or tampered with illegally.
Certain naturally occuring conditions may corrode the valve and
its components over time, rendering the valve inoperative. Such
conditions can only be detected if the valve and its components
are physically removed and inspected.
Do not attempt to
conduct an inspection on your own.
Contact your plumbing
contractor for a re-inspection to assure continued safety.
FAILURE TO RE-INSPECT THE T&P VALVE AS DIRECTED COULD
RESULT IN UNSAFE TEMPERATURE AND/OR PRESSURE BUILD-UP
WHICH CAN RESULT IN PROPERTY DAMAGE, SERIOUS PERSONAL
INJURY, OR DEATH.
E. Scalding
An ASSE 1017 or ASSE 1070 temperature limiting or mixing valve is
recommended in installations servicing disabled or elderly persons,
or children. Mixing valves do not eliminate the risk of scalding.
To avoid scalding:
•
Set the water heater set point temperature as low as possible.
•
Feel water before bathing or showering.
•
If thermostatic valves are required, use devices specifically
designed for such purpose. Install these devices in accordance
with instructions provided by the manufacturer.
Failure to install a temperature limiting or mixing valve and follow
these instructions could result in property damage, severe personal
injury, or death due to scalds.
This water heater can
deliver scalding water. Be
careful whenever using
hot water to avoid scalding
injury. Certain appliances
such as dishwashers and
automatic clothes washers
may require increased water
temperatures. By setting the
thermostat on this heater to
obtain the increased water
temperature required by
these appliances you may
create the potential for scald
injury.
To protect against injury,
install a mixing valve in the
water system. This valve
will reduce point of use
discharge temperatures by
mixing cold and hot water
in branch supply lines. Such
valves are available from your local plumbing supplier.
The following table details the relationship of water temperature
and time with regard to scald injury and may be used as a guide in
determining the safest water temperature for your applications.
Approximate Time / Temperature Relationships in Scalds
120
o
F
More than 5 minutes
125
o
F
1 1/2 to 2 minutes
130
o
F
About 30 seconds
135
o
F
About 10 seconds
140
o
F
Less than 5 seconds
145
o
F
Less than 3 seconds
150
o
F
About 1 1/2 seconds
155
o
F
About 1 second
Table 6 - Approximate Time / Temperature Relationships in Scalds
the tank and valve. If the tank is replacing a tankless coil in the
boiler, disconnect coil plumbing and use the cold inlet pipe and hot
water outlet pipes for the water heater.