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ULTRATEMP ETI™ Hybrid Heater Installation and User’s Guide
Problems or Symptoms
Possible Cause
Corrective Action
STACK FLUE HIGH:
Stack flue sensor
detects combustion gases above 185° F
[85° C].
1. Air flow restriction in combustion system
Clear obstruction from exhaust stack / vent.
2. High stack flue temperature without
LOW WATER FLOW, HI LIMIT SWITCH,
AGS LIMIT
Verify proper flow to heater. Ensure all isolation valves are open.
Refer to
LOW WATER FLOW
Alarm troubleshooting.
3. Poor heat transfer to water due to
excessive scaling or solids buildup in heat
exchanger
Call technical support. Correct pool / spa water chemistry.
4. Poor heat transfer to water due to
degraded insulation inside heat exchanger
Inspect chamber insulation for deterioration as evidenced by large
surface irregularities or missing pieces and replace if faulty.
STACK FLUE OPEN:
Stack flue sensor
circuit is open.
1. Faulty stack flue sensor or wiring
Disconnect stack flue sensor at connector and use 401k ohm
resistance test to verify wiring at sensor connection and at control
board connection. If control board indicates about 77° F [25° C]
replace sensor. If display indicates abnormally low value inspect and
replace wiring.
2. Faulty control board
Disconnect stack flue sensor connector at control board. Use 401k
ohm resistance test at control board connection to verify board
function. Display should indicate about 77° F [25° C]. If display
indicates abnormally high or low value replace control board.
STACK FLUE SHORT:
Stack flue sensor
short circuit.
Faulty stack flue sensor or wiring
Inspect stack flue sensor connector for excessive moisture.
Disconnect stack flue sensor at connector and on call for heat see
if alarm changes to
STACK FLUE OPEN
. Replace sensor. Refer to
STACK FLUE OPEN
Alarm troubleshooting for wiring.
CONDENSATE BLOCK:
Condensate float
switch detects water in exhaust stack.
CAUTION: High Voltage Present. Observe
extreme caution or call dealer or factory for
advice before attempting to Troubleshoot
Electrical Box.
1. Heater condensate drain hose restriction
Verify proper hose routing from heater base. Ensure there are no
loops, kinks or elevated portions between hose exit and heater base.
Correct as necessary.
2. Condensate drainage frozen due to
operation in freezing temperatures
Shut down and properly winterize heater.
3. Algae or solids buildup in float switch,
neutralizer cartridge or connected hose
Shake cartridge to breakup accumulation. Remove switch and verify
function. Clean or replace if necessary.
4. Faulty float switch
Disconnect switch at connector and check for continuity between
switch terminals while activating switch. Replace float switch if faulty.
5. Faulty float switch wiring
With mains power off, check continuity between gas relay terminal 4
and TB-GI-1 in low voltage box. Repair or replace wiring if faulty.
6. Faulty gas valve relay wiring
With mains power off, check continuity between ignition control
module terminal 24 VAC and gas relay terminal 2. Check continuity
between ignition control module B.GND and gas relay terminal 3.
Check continuity between gas relay terminal 1 and TB-O-5. Repair
or replace wiring if faulty.
7. Faulty gas valve relay
On call for heat, check for 24 VAC at gas relay terminal 1 to
determine if relay is being actuated. On call for heat, check for
continuity between relay terminals 2 and 4 to determine if relay is
functioning. Replace relay if faulty.
REPLACE CNC:
Condensate neutralizer
cartridge’s effective lifetime has expired.
Heater run time has met service interval for
condensate neutralizer cartridge
Check pH of gas heater condensate. Replace as necessary and
reset alarm / counter.
*
FREEZE WARNING:
Ambient air
temperature is too low for gas heater
operation.
Heater is attempting to run in below
freezing temperatures
Shut down and properly winterize heater.
Faulty stack flue sensor or wiring
If control board display indicates abnormally low stack flue
temperature value refer to
STACK FLUE OPEN
Alarm
troubleshooting.
*
To clear this alarm, press the DOWN arrow and MODE button simultaneously. The alarm may take a few moments to
clear after the buttons are pressed.
