Patterson-Kelley MACH C-1500H Installation & Owner's Manual page 46

Low Water Cut-Off
The boiler is furnished with a probe-type low water cut-off; no field piping is required. If the water level in
the boiler drops below the probe, the boiler will shut down and LOCKOUT LOW WATER LEVEL will be
displayed on the control panel. The low water cutoff circuit will automatically reset when the low water
condition clears; however, the boiler controls will retain the lockout condition until the reset button on the
display is depressed. Installation of external limit controls may be required by certain codes or in certain
installations. Review applicable local codes for
NOTICE! Some local jurisdictions may require an auxiliary low water cut-off device installed in the
external piping. The auxiliary low water cutoff device only prevents operation when the water level
in the appliance is insufficient. It does not detect low water conditions in other parts of the system.
Installation of automatic air vents in the "high points" of the piping or additional low water safety
devices should be considered to protect the system.
Drain Valve and Piping
boilers feature a ¾" drain connection. Prior to draining the boiler, electrical power and
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The P-K MACH
gas supply must be turned off to the boiler, and the boiler must be isolated from the system at the supply
and return connections.
NOTICE! The 3/4" manual drain is for draining the water inside the heat exchanger only, not the
entire hydronic or domestic system. Draining the entire system through the boiler or water heater's
drain valve will deposit sediment and debris from the system inside the heat exchanger. This will
result in poor heat transfer and premature failure. Refer to
& Retrofit Systems for more information on best piping practices.
Condensate Drain
The condensate is acidic (pH between 3.0 and 5.0) and may be corrosive to some building drain systems.
A condensate neutralization system may be required and is available from Patterson-Kelley. If the
condensate drainage system is exposed to freezing temperatures, it must be field heat traced. The boiler
could generate up to one gallon of condensate per 100,000 BTU input. For example, a C-4000 boiler at
full fire can produce 40 gallons per hour of
state and local codes.
Piping with Refrigeration Systems
When installed in a two-pipe system that provides both chilled and hot water, the control system should
be configured so as to limit the time rate of change of temperature at the boiler. Consult your
authorized Patterson-Kelley boiler representative for application guidance.
Piping with air handling units
The boiler piping system of a hot water heating boiler connected to heating coils located in air handling
units, where they may be exposed to refrigerated air circulation, must be equipped with flow control
valves or other automatic means to prevent gravity circulation of the boiler water during the cooling
cycle.
Revised: January 3, 2020
Released: January 3, 2020
details.
condensate. Disposal of condensate must comply with all
 Patterson-Kelley 2020
All Rights Reserved.
P-K MACH
Technical Service 1.877.728.5351
Appendix D – Best Practices For New
1004905981 P-K MACH C1500H-C4000 Installation and
Owners Manual (Rev F Jan-2020).docx
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Gas Fired Boiler
Page 41