21
• The NH199-DV / NH150-DV is a boiler to be
used for space heating or indirect water heating
only. Do not use the hot water supplied by the
boiler for drinking purposes.
• This boiler has a pressure rating of up to 150
psi, but it is designed to be used in a low pres-
sure (15 psi) closed loop heating system. Use a
30 psi safety relief valve.
• The required heating load should not exceed the
following ratings:
NH199-DV: 135,000 Btu or below
NH150-DV: 100,000 Btu or below
The above values include a 15% allowance to
provide for piping losses and pick up.
* The boiler will stop automatically if the load
surpasses these values greatly.
• When using anti-freeze, use Noritz approved anti-freeze only.
• The total flow rate of the heating circuit should be no less than 4 gpm (15 L/min.) and no greater
than 17 gpm (65 L/min.).
• The return temperature should be 80
°
F (25
°
C) or greater.
Flow rate (GPM)
0 3.8 7.6 11.4 15.2 19.0 22.8 26.6 30.4 34.2 38.0 41.8 45.6 49.4 53.2 57.0 60.8 64.6
T-T connection
Contact for Lamp
Circulator outputs,
Air inlet thermistor
Controller
SC
Controller
Rotational
frequency sensor
Fan motor
Air supply
120VAC
Transformer
Gas solenoid valve-2
Gas solenoid valve-1
Gas solenoid valve-3
Water supply thermistor
Drain plug
Supply
Gas
Return
Inlet filter
Water drain plug
Water flow
switch
Primary gas
valve
Gas proportioning
valve
Burner
Flame rod
Ignition plug
Igniter
Over heat prevention
device (Thermal fuse)
Water return thermistor
Heat exchanger
thermistor
Exhaust
High limit switch
Safety relief
valve
NH199-DV, NH150-DV Friction loss
Flow rate (L/min)
