Version 1.4
124 NCB-E Service Manual
5.2.19 439Error
Error occurrence conditions and check items
Error
Description
E439
Flow sensor error
As one or more units are operating in the cascade system, if no flow is detected during DHW
using, the system considers it as a defective flow sensor. The system displays 439E (cleared
manually) on the front panel and switches the unit operation into the Lock-Out mode (gas
valve and ignition transformer locked).
Check items
1. Check the supply of cold water while the cascade system is disabled. (frozen/locked valve).
2. Defective flow sensor.
3. Defective PCB.
Is there water flow?
Check flow sensor connector
(CN5)
Clean water flow sensor
Disable cascade operation and
open faucet
Check cold water supply
NO
Yes
Check method
Fault
Possible Causes
Check method
No hot water flow
Cold water supply error
1. Check if the cold water line is frozen.
2. Check if the cold water filter is clogged.
Содержание NCB-150E
Страница 3: ......
Страница 147: ...Version 1 4 146 NCB E Service Manual 7 2 Burner Assembly 1 2 9 10 11 12 13 14 21 18 17 4 20 13 19 12 10 16 15 3 6 5 7 8...
Страница 153: ...Version 1 4 152 NCB E Service Manual 7 5 Fan Gas Assembly 2 4 7 5 6 11 14 12 11 10 9 13 11 15 1 3 8...
Страница 156: ...Memo...
Страница 157: ...Memo...