Installation Manual

H-Series Demand Duo™ 2 Installation and Operation Manual 27
• An approved PRV (pre-installed on each
tankless water heater in the Demand Duo™ 2
system) is required by the American National
Standard (ANSI Z21.10.3) for all water heating
systems and shall be accessible for servicing.
• The PRV must comply with the standard for
Relief Valves and Automatic Gas Shutoff
Devices for Hot Water Supply Systems ANSI
Z21.22 and /or the standard Temperature,
Pressure, Temperature and Pressure Relief
Valves and Vacuum Relief Valves, CAN1-4.4.
• The PRV must be rated up to 150 psi and to at
least the maximum BTU/hr of the appliance.
• The discharge from the PRV should be piped
to the ground or into a drain system per local
codes.
• The PRV must be manually operated once a
year to check for correct operation.
• The PRV should be added to the hot water
outlet line and near the hot water outlet
according to the manufacturer’s instructions.
DO NOT place any other type valve or shut-off
device between the PRV and the water
heater.
• If a PRV discharges periodically, this may be
due to thermal expansion in a closed water
supply system. Contact the water supplier or
local plumbing inspector on how to correct this
situation. Do not plug the PRV.
• For safe operation, the relief valve(s) must not
be removed from its designated point of
installation or plugged.
• An approved T&P Relief Valve is required by
the American National Standard (ANSI
Z21.10.3) for all water heating systems and
shall be accessible for servicing.
• The T&P Relief Valve must comply with the
standard for Relief Valves and Automatic Gas
Shutoff Devices for Hot Water Supply
Systems ANSI Z21.22 and /or the standard
Temperature, Pressure, Temperature and
Pressure Relief Valves and Vacuum Relief
Valves, CAN1-4.4.
• The T&P Relief Valve must be rated up to 150
psi and to at least the maximum BTU/hr of the
appliance.
• The discharge from the T&P Relief Valve
should be piped to the ground or into a drain
system to prevent exposure or possible burn
hazards to humans or other plant or animal
life. Follow local codes. Water discharged
from the relief valve could cause severe burns
instantly, scalds, or death.
• The T&P Relief Valve must be manually
operated once a year to check for correct
operation.
WARNING
• Water discharged from the PRV could cause
severe burns instantly or death from scalds.
• DO NOT plug the PRV and do not install
any reducing fittings or other restrictions in
the relief line. The relief line should allow for
complete drainage of the valve and the line.
• DO NOT place any other type valve or shut-
off device between the PRV and the water
heater.
• DO NOT pipe the T&P Relief Valve, PRV,
and/or condensate drain together into a
common pipe.
WARNING
• DO NOT plug the T&P Relief Valve and do
not install any reducing fittings or other
restrictions in the relief line. The relief line
should allow for complete drainage of the
T&P Relief Valve and the line.
• DO NOT place any other type valve or shut
off device between the T&P Relief Valve and
the water heater.
• DO NOT pipe the T&P Relief Valve, PRV,
and/or condensate drain together into a
common pipe.