Navien Water quality limits (DHW and system fill)
Navien Water quality limits (DHW and system fill): reference table for the combi boiler (Navien NFC-H series): a quick-reference table with notes.
Navien Water quality limits (DHW and system fill) table
| Contaminant | Max allowed |
|---|---|
| Total hardness | 200 mg/l (12 grains/gallon) |
| Aluminum | 0.05 to 0.2 mg/l |
| Chloride | 250 mg/l |
| Copper | 1.0 mg/l |
| Iron | 0.3 mg/l |
| Manganese | 0.05 mg/l |
| pH | 6.5 to 8.5 |
| Sulfate | 250 mg/l (DHW table); 205 mg/l (fill table) |
| Total dissolved solids | 500 mg/l |
| Zinc | 5 mg/l |
| Chlorine (fill water) | 4 mg/l |
How to use the Navien Water quality limits (DHW and system fill) table
Find your exact model in the first column and read across the row. Values in the Navien Water quality limits (DHW and system fill) table are a summary for quick reference; the rating plate on the unit and the manufacturer's manual for your model always decide. If your model is not listed, or a value looks different from what you see on the unit, check the manual before changing anything.
Notes
- Manual shows sulfate 250 mg/l on p.26 and 205 mg/l on p.33.
Applies to: NFC-250/175H, NFC-250/200H
Navien models this applies to
Navien Combi Boiler error codes →
Source: Navien NFC-H Installation Manual, 3.2 DHW water quality p.26 and 3.4 fill water p.33. Written in our own words as a summary; always check the original manual.
General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.