AHRI K2WT, Installation, Operating And Service Instructions

Page: 75 / 164

75
107110-01 - 6/16
C. Standard Piping Installation Requirements
Observe the following requirements when installing the boiler piping:
1) Relief Valve (Required) – The relief valve is shipped loose and must be installed in the location shown in Figure
9.9, using the side outlet Tee and other fittings provided. ASME Section IV currently requires that this relief
valve be installed above the heat exchanger as shown. Pipe the outlet of the relief valve to a location where water
or stream will not create a hazard or cause property damage if the valve opens. The end of the discharge pipe must
terminate in unthreaded pipe. If the relief valve discharge is not piped to a drain, it must terminate at least 6” above
the floor. Do not run the discharge piping through an area that is prone to freezing. The termination of the relief
valve must be in an area where it is not likely to become plugged by debris.
The relief valve supplied with the boiler is set to open at 30 psi. If it is replaced, the replacement must have
a setting less than or equal to the maximum allowable working pressure (MAWP) shown on the ASME data plate
located on the left side of the heat exchanger behind the service access panel (Figure 9.9).
2) Gauge (Required) - Indicates supply water pressure and temperature. This gauge is shipped loose. Install it as shown
in Figure 9.9.
3) Circulator (required) – The boiler loop circulator is factory installed inside the boiler cabinet. Usually at least
one addition circulator (not supplied) will be required for the system to work properly. See the previous section for
more information.
4) Expansion Tank (required) – If this boiler is replacing an existing boiler with no other changes in the system,
the old expansion tank can generally be reused. If the expansion tank must be replaced, consult the expansion tank
manufacturer’s literature for proper sizing.
5) Fill Valve (required) – Either a manual or automatic fill valve may be used, but a manual valve is preferred because
it eliminates unmonitored additions of make-up water to the system. The ideal location for the fill valve is at the
expansion tank.
6) Automatic Air Vent (required) – At least one automatic air vent is required. Manual air vents will usually be required
in other parts of the system to remove air during initial fill.
7) Manual Reset High Limit (required by some codes) - This control is required by ASME CSD-1 and some
other codes. Install the high limit in the boiler supply piping just above the boiler with no intervening valves. Set
the manual reset high limit to 200°F. Wire the limit per Figure 10.3 in the Wiring section.
8) Isolation Valves (recommended) - Isolation valves are useful when the boiler must be drained, as they will eliminate
having to drain and refill the entire system.
9) Strainer (recommended) – Install a Y Strainer, or other suitable strainer, to prevent any system debris from entering
the boiler and fouling the water passages. Note that some strainers have a significant pressure drop, which may
impact the ability of the boiler pump to obtain the required flow. See Paragraph B of this section for additional
information.
IX. System Piping
(continued)
DangEr
Explosion / Scald Hazard.
Pipe relief valve discharge to a location where the potential of severe burns is eliminated.
Do not install a relief valve having a setting greater than the MAWP shown on the rating plate.
Do not install a valve in the relief valve discharge line.
Do not install relief valve in a location other than that specified by the factory.
Do not plug the relief valve discharge.