Pentair 250K BTU/HR - Manual (Page 18)

18
PRESSURE RELIEF VALVE
Canadian code requires and some U.S. local codes may
require installation of a pressure relief valve. Purchase
separately and install a 3/4" pressure relief valve comply-
ing with the ANSI/ASME Boiler and Pressure Vessel Code,
having a capacity equal to the Btu/hr rating of the heater.
The relief pressure of the valve MUST NOT EXCEED 50
PSI.
A 3/4" NPT connection is provided in the manifold for
installing a pressure relief valve. The relief valve must be
installed vertically. To install the valve, use a 3/4" brass
nipple and elbow (user supplied), as illustrated in Figure
19. No valve is allowed to be placed between the mani-
fold adapter and the relief valve.
To avoid water damage or scalding from operation of the
relief valve, install a drain pipe in the outlet of the pres-
sure relief valve that will direct water discharging from
the valve to a safe place for disposal. Do not install any
reducing couplings or valves in the drain pipe. The drain
pipe must be installed so as to allow complete drainage
from the valve and drain line. The relief valve should be
tested at least once a year by lifting the valve lever.
Explosion hazard. Any heater installed with
restrictive devices in the piping system downstream from
the heater (including check valves, isolation valves, flow
nozzles, or therapeutic pool valving) must have a relief
valve installed as described above.
WARNING
Pipe relief valve discharge
to a drain or other safe
disposal site.
2681 1096
Relief Valve Installed
User
supplied
pipe
fittings
Turn star wheel to raise pressure set
point if pressure switch is more than
2 feet (0.6M) below water level
FIGURE 19: Relief Valve
FIGURE 18: Water Pressure Switch Adjustment
Turn star wheel to lower pressure
set point if pressure switch is more
than 5 feet (1.5M) above water level
Raise Pressure
Lower Pressure
A reference scale is on the
back of pressure switch
Star wheel
Star wheel