Noritz NR501-OD Service Manual page 24

<NRC661 (-DV, -OD), NRC711 (-DV, -OD)>
Freeze prevention control
Freeze prevention heater
8
NO
301, 302 / 30
351, 352 / 35
Heaters turn ON
7
NO
Thermistor-Exhaust
Thermistor-Exhaust
less than 37
Heaters turn ON
Thermistor-Exhaust
Has 50 min passed
Heaters turn OFF
Fan motor operation flow ( -DV model )
Thermistor-Exhaust
normal
YES
NO
Thermistor-Exhaust
18
YES
No error code
611, 612, 614 / 61
YES
Fan Turn ON
< 1,200 rpm >
3 minutes
YES
Fan Turn OFF
NO
Thermistor-Exhaust
46 or more
YES
Thermistor-Air
normal
YES
-DV
NO
or
SV conversion
YES
normal
YES
NO
(3 )
YES
NO
(8 ) or more
YES
NO
YES
NO
Thermistor-Exhaust
less than 37 F (3 )
YES
NO
351, 532 / 35
NO
NO
NO
Fan speed
1,200 500rpm
YES
611 / 61 Thermistor-Exhaust
26 F or more
YES
Fan Turn OFF
Thermistor-Air
less than 37
YES
Thermistor-Air
less than 28
YES
Heaters turn ON
YES
Has 50 min passed
YES
Heaters turn OFF
Thermistor-Air
more than 14
YES
Has 5 min passed
YES
7
Thermistor-Exhaust
NO
Thermistor-Exhaust
NO
Fan motor stopped
NO
8
more than 32
NO
Thermistor-Exhaust
more than 14
* 4
NO
Thermistor-Exhaust
24
NO
NO
C
Heaters turn ON
NO NO
YES
NO
Has 20 min passed
YES
Heaters turn OFF
NO
C Thermistor-Air
more than 14
YES
NO NO
Has 15 min passed
YES
Fan motor operation flow ( SV conversion )
NO
normal
351, 352 / 35
YES
32
YES
No error code
611, 612, 614 / 61
YES
NO
YES
Thermistor-Air
normal
Thermistor-Air
YES
normal
YES
Thermistor-Air
more than 32
NO
Thermistor-Air
YES
YES
YES
Fan Turn ON Fan Turn ON Fan speed
< 2,400 rpm > < 1,200 rpm > set 2,400 rpm
NO
Fan Turn OFF
YES
NO
Fan speed
Target 500rpm
Thermistor-Exhaust
YES
46
YES
611 / 61
X or more
YES
Fan Turn OFF
* 4 When fan speed is 1,200rpm, X = 46 F
* 2 When fan speed is 2,400rpm, X = 59 F
NO
NO
C
NO
NO
NO
NO
Thermistor-Air
32
YES
Fan speed
set 1,200 rpm
NO