LP-719 Rev. 000 Rel. 000 Date 6.25.20
21
E. Internal Circulation Pump
Table 10 - Internal Circulation Pump Head Curve
To calculate the size of the heating installation refer to the graph below.
Graph Representing the Available Circulation Pump Head
0
5
10
15
20
25
0
2
4
6
8
10
12
He
ad
[
�]
Flow Rate [US GPM
]
Available Head vs. Flow Rate
F. CH and DHW Pressure Relief Valves
This boiler has a high-temperature shut-off switch built in as a standard
safety feature. Therefore, a “pressure only” relief valve is required.
DO NOT operate this appliance before the supplied pressure relief
valve is installed with sufficient relieving capacity in accordance
with the ASME rating plate on the appliance.
The pressure relief valve must be installed as detailed in Figure 11.
No other valves should be placed between the pressure relief valve
and the appliance. Failure to comply with these guidelines can
result in substantial property damage, personal injury, or death.
WARNING
!
CH Loop
This boiler is provided with a CH pressure relief valve that complies
with the ANSI/ASME Boiler and Pressure Vessel Code, Section IV
(Heating Boilers). The included 30 psi CH Pressure Relief Valve must
be installed at the top of the boiler as illustrated below.
DO NOT install a relief valve with a pressure rating in excess of 50 psi
- the maximum allowable operating pressure of the boiler. The relief
valve capacity must exceed the BTU/H input capacity of the boiler. To
install the pressure relief valve proceed as follows:
CAUTION
Use two wrenches when tightening the pressure relief valve into
the pipe. Use one wrench to prevent the pipe. Failure to prevent
piping connections from turning could cause damage to boiler
components.
Figure 11 - Installing the CH Pressure Relief Valve
DHW Loop (Combi Models)
The DHW piping must be provided with a DHW pressure relief valve
that complies with local codes, but not less than valves certified
as meeting the requirements of Relief Valves for Hot Water Supply
Systems, ANSI Z21.22 / CSA4.4 by a nationally recognized lab that
maintains periodic inspection of production listed equipment.
A DHW pressure relief valve is not included with the boiler, and is
to be field supplied and installed in the DHW piping. DO NOT install
a DHW relief valve with a pressure rating greater than 150 psi - the
maximum allowable operating pressure of the boiler’s DHW circuit.
After installing the relief valves and filling and pressurizing the
system, test the operation of the valves by lifting the levers.
Make sure the valves discharge freely. If a valve fails to operate
correctly, replace it with a new relief valve.
The relief valve capacity must exceed the BTU/H input capacity of
the boiler.
Radiant heating
For appliances with underfloor heating, it is possible but not
necessary to fit a safety thermostat onto the radiant heating outlet.
If the thermostat cannot be installed, the radiant heating equipment
must be protected by a thermostatic valve, or by a by-pass to prevent
the floor from reaching too high a temperature.
WARNING
!
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
boiler 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 relief valve at least once annually to ensure the
waterway is clear. If valve does not operate, turn the boiler
“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.
