26 Installing the System Piping
3.2.1 Guidelines for the DHW System
With its multi-purpose design, the Navien NFC-H
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 DHW 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
Note
Refer to the following illustration for
details on installing the NFC-H Manifold
System (Part Number: 30026576A) to the
valve kits.
Also, check that a pipe, unions, gaskets, and valves
are all included in the Manifold kit. After installing
the manifold, ensure that the fittings, such as the
unions and gaskets, are properly sealed with the
pipe.
WARNING
When installing the NFC-H boiler, the diameter
of the pipes must be equal to or greater than
the minimum pipe diameter (1.25 inches). The
boiler also must satisfy the minimum circulation
flow rate (8.0 GPM).
Model
Minimum
Pipe Diameter
Minimum
Flow (GPM)
NFC-250/175H
NFC-250/200H
1 1/4”
8.0
3.2 Installing a Domestic Hot
Water (DHW) System
The Navien NFC-H boiler provides domestic hot
water continuously when water flow is detected by
the flow sensor.
Summary of Contents for NFC-250/175H
Page 67: ...67 Venting for Combustion Air WARNING The vent installation detector Detectable Undetectable...
Page 149: ...Memo...
Page 150: ......
