Harsco Industrial P-K THERMIFIC N700 Installation & Owners Manual page 32

3.7.3.4 Drain Valve and Piping
An external drain connection is not supplied with the boiler. A drain valve must be provided and
installed, by the installing contractor, near the inlet (system return) connection to the boiler and piped to a
suitable floor drain. If necessary, the boiler can be completely drained through the bottom header by
removing the flush plug in the front of the bottom header.
This plug may also be used to flush accumulated sediment from the bottom of the boiler.
3.7.4 Flushing and Filling
3.7.4.1 Flushing the System
Before filling the boiler, flush the system to remove the debris. Clean and flush old piping thoroughly
before installing the boiler.
Under no circumstances should the hydronic system be flushed while the boiler is attached to the system
since the debris or corrosion products could accumulate in the boiler and plug the boiler heat exchanger.
If the piping system attached to this unit will be chemically cleaned, the boiler must be disconnected from
the system and a bypass installed so that the chemical cleaning solution does not circulate through the
boiler.
3.7.4.2 Filling
To be sure that the boiler is not air-bound, open the pressure-relief valve located at the rear of the boiler.
Leave the relief valve open until a steady flow of water is observed at the floor drain. Close the valve
and finish filling the system.
3.7.5 Water Quality
3.7.5.1 Heating Boiler Applications (N-Series)
A heating boiler is designed to operate in a closed-loop system. As such, the system should be tight and
not require make-up water. A high percentage of untreated make-up water can cause premature failure
due to buildup of scale; such failure is not covered by warranty.
Scale can also reduce efficiency. For example, a scale thickness of 1/16" will result in a 12.5% loss of
efficiency.
The water quality should be within the guidelines established by the American Boiler Manufacturers
Association, as follows:
Total solids: ............................ 2,500 ppm
Total alkalinity: .......................... 500 ppm
Total hardness: ......................... 150 ppm
The amount of oils, fats, grease, and other organic matter should be limited to 10 ppm.
Consult your water conditioning or chemical treatment supplier for analysis and recommendations.
Never install a valve that can isolate the flow switch (low water cut-off) from the boiler.
Burn hazard! Hot fluids! Use caution when servicing or draining the boiler.
P-K THERMIFIC
32
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Gas-Fired Boiler