GLOW T180 - Operation and Maintenance

Glow T180
Tankless Condensing Water Heater
35
3.6.3 Pressure Relief Valve Installation,
Operation and Maintenance
DO NOT PLUG THE PRESSURE
RELIEF VALVE!
When tightening the pressure relief valve into
the hot water isolation valve, make sure to place
the wrench’s jaws on the relief valve’s wrench ats.
Applying force on any other part of the valve’s body
may cause irreparable damage.
Δ Do not install any manually operated shutoff
valves between the relief valve’s inlet or outlet
connections and associated water heater or
discharge piping connections. Install the relief
valve’s inlet connection directly into the tankless
hot water heater isolation valve’s designated
connection only. An unobstructed ow path
must exist between the pressure relief valve
and water heater in order for the relief valve to
function properly.
Δ The outlet connection of the pressure relief
valve must face downward, requiring a vertical
discharge pipe. In accordance with IPC code
requirement 504.6, install a suitable-length
nipple as a discharge pipe, into the female NPT
outlet of the pressure relief valve.
Δ Do not reduce the 3/4” nominal pipe size (NPS)
at any length of the piping. The end of the
discharge pipe must not be threaded and must
remain open and unobstructed.
Δ The discharge piping must not contain low
points, which may trap water. The piping must
allow complete drainage.
Δ The discharge piping must discharge into a
suitable open drain and must not be allowed to
freeze.
Operation
In the event that the tankless water heater and its
piping system exceed designed pressure limits,
the pressure relief valve will automatically open,
discharging large amounts of very hot water. Correct
installation of the discharge piping and drainage
are critical in avoiding a scalding danger or water
damage.
Maintenance
Annually inspect the end of the discharge piping for
signs of relief valve leakage. Carefully lift the spring-
loaded lever and center it horizontally against the
identication disc, allowing hot water to ow from the
end of the discharge pipe, into the drain. CAUTION!
Discharged water is extremely hot and can scald!
Avoid contact with the water. After a few seconds,
ip the lever back down, closing the valve. If the
pressure relief valve fails to ow water when opened
or fails to re-seat when closed, contact a qualied
installer for valve replacement.
For safe operation of the water heater, ensure that:
Δ The pressure rating of the relief valve must not
exceed 150psi.
Δ The BTUH rating on the relief valve must equal
or exceed the BTUH input of the water heater.
Δ No valve of any type should be installed between
the relief valve and the water heater.
Δ Discharge from the relief valve should be piped
to a suitable drain. Piping used should be of a
type approved for the distribution of hot water.
Δ The discharge line must be no smaller that the
outlet of the relief valve. The drain line must
pitch downward to allow for complete drainage of
the line.
Δ The end of the discharge line should not be
threaded or concealed and should be protected
from freezing. No valve of any type, restriction,
or reducer coupling should be installed in the
discharge line.
Δ To prevent vibration and noise coming from the
system, do not use pipes of reduced diameter,
short radius elbows or severe reductions in the
cross sections of the water passages.
Δ The water owing out of the pressure relief
valve during its operation may be extremely hot.
Before operating relief valve, make sure drain
line is installed to direct discharge to a safe
location such as an open drain. Avoid scalding
and/or water damage.
A pressure relief valve is to be installed on the hot
water supply outlet line below water heater that
is rated in accordance and complying with The
Standard for Relief Valves and Automatic Shutoff
Devices for Hot Water Supply Systems, ANSI Z21.22
or CSA 4.4 Code.
The pressure relief valve must be installed on the
hot water supply line and in such a manner that
the discharge is to be piped to a suitable drain for
disposal should relief occur. No reducing coupling
or other restrictive device is to be installed on the
discharge line. The discharge line must be installed
to allow complete drainage of both the service valve
if installed and the line itself.