Bradley CNA Serie Installation page 18

CNA-Series Tankless Heater
Troubleshooting using the Flow Limit Control Board (FLCB)
Problem
The heater does not work or works intermittently .
High Temp .
Limit Sensor
Input
High Flow
Status
Low Flow
Status
Bank 2 Over
Temp . (OT)
Bank 1 Over
Temp . (OT)
Purge/Dump
(SNA Models
Only)
Element Load Bank 1–2 or 3–4 is not energized .
If the above steps do not solve the problem, some additional checks may be performed. Follow the
schematic to perform the following continuity checks:
 Emergency stop switch .
 Door guard .
 High temperature bimetals (Manual Reset Safeties) .
 Optional ground fault breaker must be in the closed position for the unit to work .
 All internal breakers must be in the ON position for the unit to work .
For additional information on Troubleshooting or other information, please call Bradley technical support at
1-800-999-4320 . Please have Model No . and Serial No . available when seeking technical assistance . Serial No .
tag is located in the enclosure on the upper left hand corner of the back plate . Please record and maintain this
information at all times:
CNA- Model No.
Serial No.
18
Solution
Check that the flow sensor located at the inlet is
spinning with water running . Check if in Low flow
(> 1 .5 gpm/5 .7 Lpm) that the FLCB light is on . If in High
flow (> 15 gpm/56 .8 Lpm) both the low flow light and high
flow lights will be illuminated .
Check that water flow through the heater is adequate to
activate the flow sensor at 1 .5 gpm (5 .7 Lpm) .
Check that the heater is wired with the proper breaker and
wire size . Refer to Electrical Specifications table for proper
requirements .
Check that the unit is receiving voltage from all 3 phases
of the power source . A load voltage reading is also helpful .
Check FLCB with corresponding light indicated:
Bank 1–2 on the front bezel = Bank 1 on the FLCB
Bank 3–4 on the front bezel = Bank 2 on the FLCB .
If the light is off and there is power on . Check if water
temperature is greater than 175˚F (79°C) . Decrease water
temperatures and restart .
8/1/2021
Installation
Bradley • 215-1814 Rev. G