Navien NP Condensing Tankless Gas Water Heater - Service Manual

5.20. 36Error
Error occurrence conditions and check items.
Error
36E
Communication
Error
Check items
Description
If a master/slave communication error occurs under the cascade system, the system
displays the 36E (cleared automatically) error message.
1. All other water heaters except the water heaters where the communication error
has occurred operate normally. (The water heaters with the communication error
maintain the Cascade ON mode, and operate normally when the flowmeter works.)
2. If a communication error occurs in the master water heater, all the slave water
heaters operate individually.
1. Check the communication cable.
2. Check the external power supply (187~254V).
3. Check the communication switch on the PCB.
4. Check if the PCB works normally.
Check method
Error
Communication
error
Other trouble
Cause
Defective power
supply
Defective
communication
cable
Setting error
Check method
Check the power supply to the water heater.
Check the connection of the communication cable,
and if the cable is disconnected.
In the Cascade system, the controller communication switch
(DIP S/W No. 6) must be set to ON for the first and the last systems,
and OFF for the remaining systems.
< Communication switch (DIP S/W No. 6)>
Other trouble
Defective
PCB
If the trouble continues despite the checking of above items,
the PCB is defective.
©Navien America Inc. 2010
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NR/NP series service Manual
Version 2.0