Navien NFC-175, Installation & Operation Manual

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23 Installing the System Piping
3.2 Installing a Domestic Hot Water (DHW)
System
The Navien NFC boiler provides domestic hot water continuously
when water flow is detected by the flow sensor. This method is
the most efficient means of heating water by allowing the boiler
to operate at a lower return water temperature by minimizing
standby losses, thus increasing combustion efficiency.
3.2.1 Guidelines for the DHW System
With its multi-purpose design, the Navien NFC boiler provides hot
water on demand. This means that the boiler produces DHW only
when the user demands it. The boiler recognizes a DHW demand
when the flow sensor detects a DHW flow of approximately 0.5
GPM or greater. Once the flow sensor detects the flow, the boiler
immediately goes into DHW mode regardless of the status of the
space heating system. Read and follow the guidelines listed below
to ensure safe and proper installation of a boiler heating system.
Scald Hazard
Hotter water increases the risk of scald injury. There is a hot water
scald potential if the DHW temperature is set too high. Be sure
to follow the adjustment instructions in the boiler’s operation
manual.
About the DHW Quality
Proper maintenance of the boiler is required when water quality
does not meet EPA standards. Damage caused by poor water
quality is not covered under warranty. The following table shows
the maximum contaminant levels allowed, based on the EPA
National Secondary Drinking Water Regulations (40 CFR Part
143.3). If you suspect that your water is contaminated in any way,
discontinue use of the DHW and contact an authorized technician
or licensed professional.
Contaminant Maximum Allowable Level
Total Hardness Up to 200 mg/l (12 grains/gallon)
Aluminum 0.05 to 0.2 mg/l
Chloride Up to 250 mg/l
Copper Up to 1.0 mg/l
Iron Up to 0.3 mg/l
Manganese Up to 0.05 mg/l
pH 6.5 to 8.5
Sulfate Up to 250 mg/l
Total Dissolved Solids (TDS) Up to 500 mg/l
Zinc Up to 5 mg/l
3.1.3 Space Heating System Piping
When connecting the space heating system, follow these
guidelines:
●
Tighten the connection valves with care to avoid damage.
●
After installing the boiler, clean the strainer for space heating
return. Then, test the boiler for proper space heating flow and
inspect for leaks. Instruct the boiler owner that the strainer must
be cleaned periodically to maintain proper space heating water
flow.
The Navien manifold system allows for easy separation of the
Boiler-Primary loop from the System-Secondary loop(s). Refer to
the following illustration for a typical water piping example with a
Navien manifold system.
Space
Heating
Supply
Space
Heating
Return
Note
Refer to the following illustration for details on
installing the NFC-175/200 Manifold System (Part
Number: 30021988A) to the valve kits.
Valve Kit
Manifold Kit
(Pipe, Union, Gasket)
Gasket
Also. check that a pipe, unions, gaskets, and valves are all included
in the Manifold kit box and the Valve kit box. After installing the
manifold and valve kits, ensure that the fittings, such as the unions
and gaskets, are properly sealed with the pipe.