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Ensure that the maximum BTU/H rating on the
pressure relief valve is equal to or greater than the
maximum input BTU/H rating of the combination boiler.
Pressure Relief Valve must be installed on the provided
CH Pressure Relief valve tapping at the top of the
Combi (CH supply line: maximum 30 psi, DHW outlet
line : maximum 150 psi). No other valves should be
placed between the pressure relief valve and the
appliance.
Place a 150 psi PRV on DHW outlet piping as close to
the unit as possible.
This appliance has a high-temperature shut o switch
built in as a standard safety feature. Therefore a
“pressure only” relief valve is required.
External pressure relief valves must be installed.
Observe the following. Failure to comply with the
guidelines on installing the pressure relief valve and
discharge piping can result in personal injury, death
or substantial property damage.
A special brass adaptor, air eliminator and relief valve
are supplied in an accessory box. Install this tting on
the right front connection as shown here.
This safety relief valve (30 psi) is shipped loose for eld
installation.
Install the air eliminator and relief valve as shown.
For safety, the relief valve(s) must be installed into its
designated location and not be removed or plugged.
Failure to comply with the guidelines on installing the
pressure relief valves and discharge piping can result
in personal injury, death or substantial property
damage.
Direct the discharge piping of the pressure relief valve
to a nearby oor drain so that hot water will not splash
on anyone or any nearby equipment. Attach the hard
piped copper discharge line to the pressure relief valve
and run the end of the line within 6-12″ (150 - 300mm)
of the oor.
A separate extenal LWCO can be installed by removing
the 3/4” cap on the brass adaptor to install the LWCO.
Test the operation of the valve after lling and
pressurizing system by lifting the lever. Make sure the
valve discharges freely. If the valve fails to operate
correctly, replace it with a new relief valve. Ensure that
the discharge capacity of the pressure relief valve is
equal to or greater than the maximum input rating of
the combination boiler.
3/4” 30 psi Relief Valve
Do not operate this appliance before the pressure
relief valve supplied is installed with sucient
relieving capacity in accordance with the ASME
Rating Plate on the boiler.
DO NOT install a CH pipe line relief valve with a
pressure higher than 30 psi and a DHW pressure
relief valve with a pressure rating above 150 psi.
This is the maximum allowable relief valve setting
for the combination boiler.
WARNING
WARNING
4.18 Pressure Relief Valve
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