I own a Navien NHB-110 which has a dip switch that dictates the max water temp depending on whether PVC or CPVC is used for exhaust venting.
The confusion arises for me as Navien speaks of the exhaust temp and water temp interchangeably.
The manual states
If you require that return water hotter than 140°F (60°C) to circulate
back to boiler, the DIP switch must be configured
(Dip Switch 2,
switch #8 to ON position). (Mine is off as I have PVC)
Otherwise, the boiler will control and
maintain the flue and DHW temperature below 150°F (65°C) and
140°F (60°C) respectively
And
In high temperature applications, the exhaust temperature
can exceed 149°F (65°C). In that case, you must use Schedule
40 or 80 CPVC or Approved Polypropylene in the USA
or Type BH Special Gas Vent Class IIB (CPCV) or Class IC
(Polypropylene) that conforms to ULC-S636 in Canada.
http://us.navien.com/__DATA/ProductDocument/2014/12/11/[2]_NHB_Installation_Operation_Manual_Eng_141105.pdf
Likewise with the dip switch off for use of PVC, my water temp only reaches 150 by default.
What’s the relation between the water temp and exhaust temp, a 150 water temp can translate to 80 degree exhaust. Yet Navien is limiting the water temp to 150 to satisfy the PVC exhaust limitation of also 150 degrees.
Perhaps I am misunderstanding something.
Thanks for any clarification.
Cheers
The confusion arises for me as Navien speaks of the exhaust temp and water temp interchangeably.
The manual states
If you require that return water hotter than 140°F (60°C) to circulate
back to boiler, the DIP switch must be configured
(Dip Switch 2,
switch #8 to ON position). (Mine is off as I have PVC)
Otherwise, the boiler will control and
maintain the flue and DHW temperature below 150°F (65°C) and
140°F (60°C) respectively
And
In high temperature applications, the exhaust temperature
can exceed 149°F (65°C). In that case, you must use Schedule
40 or 80 CPVC or Approved Polypropylene in the USA
or Type BH Special Gas Vent Class IIB (CPCV) or Class IC
(Polypropylene) that conforms to ULC-S636 in Canada.
http://us.navien.com/__DATA/ProductDocument/2014/12/11/[2]_NHB_Installation_Operation_Manual_Eng_141105.pdf
Likewise with the dip switch off for use of PVC, my water temp only reaches 150 by default.
What’s the relation between the water temp and exhaust temp, a 150 water temp can translate to 80 degree exhaust. Yet Navien is limiting the water temp to 150 to satisfy the PVC exhaust limitation of also 150 degrees.
Perhaps I am misunderstanding something.
Thanks for any clarification.
Cheers
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