Internal Circulation Pump; And Dhw Pressure Relief Valves - NTI TRX II Series Installation Start-Up Maintenance

Part 4 - Water Piping
E. Internal Circulation Pump
To calculate the size of the heating installation refer to the graph below.
Graph Representing the Available Circulation Pump Head
Available Head vs. Flow Rate
25
20
15
10
5
0
0 2 4
Table 11 - Internal Circulation Head Curve
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.
WARNING
The pressure relief valve provided with the boiler must be installed as
detailed in Figure 1 1. 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.
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 installing the relief valve. Use one wrench
to prevent the fitting from turning. Failure to prevent the fitting from
turning could cause damage to boiler components.
Figure 12 - Installing the CH Pressure Relief Valve
24
6 8 10
Flow Rate [US GPM]
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.
WARNING
12
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 375oF 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.
RE-INSPECTION OF RELIEF VALVES: Relief valves should be
inspected AT LEAST ONCE EVERY THREE YEARS, and replaced if
necessary, by a licensed plumbing contractor or qualified service
technician to ensure that the product has not been affected by
corrosive water conditions and to ensure that the valve and discharge
line have not been altered or tampered with illegally. Certain naturally
occuring conditions may corrode the valve and its components over
time, rendering the valve inoperative. Such conditions can only be
detected if the valve and its components are physically removed
and inspected. Do not attempt to conduct an inspection on your
own. Contact your plumbing contractor for a re-inspection to assure
continued safety.
420012001300 - Rev. 04 - 031524