Hayward H150FDP, H200FDP, H150FDPASME, H150FDNASME, H200FDN Troubleshooting Manual

HxxxFD(N/P)ASME

Universal H S eries Heaters

T roubles hooting Guide

HxxxFD(N/P)

TSG-UHS16b

Copyright 2017 Hayward Industries Inc.

High Voltage Electrocution Hazard

Hazardous voltage can shock, burn, cause serious injury

and or death. To reduce the risk of electrocution and or

electric shock hazards:

• Only qualified technicians should remove the panel

• Replace damaged wiring immediately

• Insure panel is properly grounded and bonded

2

!

Warning

Safety Precautions

3

Table of Contents

ICB and Fuse Board Layout 4-6
UHS Sequence of Operation:

Normal/Failure to Light

7-8

UHS Gas and Electrical Connections

9-11

How To:

Pg.

12-17

Program Heater Bypass &
Temperature Lockout

13-15

Test/Adjust Gas Pressure 16-17

Troubleshooting:

Pg.

18-64

Diagnostic Codes and Part Numbers

19-20

1. Heater not powering up

21-26

2. Open FC1&/FC2 Fuse

27-28

3. Open FC3&/F1 Fuse

29-31

4. Open FC4 Fuse

32-33

5. “BD” Code

34-35

6. “EE” or “CE” Code

36-37

Troubleshooting (cont.):

Pg. 18

-64

7. “IO” or “SB” Code

38

-39

8. “SF” or “HS” Code

40

-41

9. “PF” Code

42

-43

10. “HF” Code

44

-45

11. “LO” Code

46

-51

12. “IF” Code

52

-55

13. “AC” Code

56

-57

14. “AO” Code

58

-60

Heat Exchanger:

Flow requirements

61

Heat Exchanger: Inspection

62

Heat Exchanger: Potential Failure Causes

63

UHS Wiring Schematic

64

UHS

Wiring Diagram

65

4

A

Remote Control: 24VAC (E1)

B

Flame Sensor (E4)

C

Temperature Sensor (E2)

D

Display Output: 24VAC (E7)

E

3A Fuse (F1)

F

Low Voltage R & C: 24VAC (E12,
E13)

G

Gas Valve & Safety Switches:
24VAC (E11)

H

High Voltage: 120VAC (E10)

I

Blower/Inducer (E6)

J

Ignitor (E3)

C

H

G

F

D

E

J

I

B

A

Integrated Control Board Layout (ICB)

5

A

Power connection for junction boxes:
120/240VAC (P1) After Aug 08

B

Terminal block for field wiring
connections: 120/240VAC (TB1) Before
Aug 08 Input

C

Voltage Selector 240 OR 120VAC
determined by plug (P2): NOTE: 240VAC

plug factory installed

D

Fuse: 3A protect primary input voltage,

will fail with excessive voltage, improper

wiring, shorted transformer or fuse
board (FC1 & FC2)

E

Transformer Primary: 120/240VAC (P3)

F

Transformer Secondary: 24 (left) &
120VAC (right) (P4)

G

Fuse: 1.5A protects transformer
secondary, will fail if short occurs
between fuse & ICB (FC3)

H

Fuse: 2.5A protects transformer high
voltage secondary, will fail with blower,
ignitor or ICB failure (FC4)

I

Low Voltage Output: 24VAC (P5)

J

High Voltage Output: 120VAC (P6)

Fuse Circuit Board Layout

A

B

C

E

F

G

H

J

I

Fuse board configuration Prior to November 2010 (Older Style)

D

6

Fuse Circuit Board Layout

H

Fuse board configuration as of November 2010 (Newer Style)

Changes compared to older style fuse board:

G

Fuse: (FC3) has been removed, since the

F1 fuse was added to the ICB

H

Fuse: (FC4) is now a 3A fuse, matching
the FC1 & FC2

NOTE: Fuses located on THIS board are all 250v SLO-BLO 5 x 20 mm.

Hayward Part # FDXLFSK19F30 (Qty. 10)

G

The control continually compares the set temp to the actual water temp. When

the water temp is 1º below the set point the following sequence starts:

1. The control checks for open blower vacuum switch

2. Blower starts pre-purge cycle as the ignitor heats up (20 Sec).

3. The control checks for a closed blower vacuum switch.

4. At proper ignitor temp, a 4 second trial begins. Gas valve opens and
monitors flame sense. The blower will turn off for one second. The ignitor
is de-energized at flame sense or at completion of 4 sec trial. If the flame is
sensed, The blower vacuum switch, control loop, temp sensor & flame
sensor are constantly monitored during call for heat.

5. When set temp is reached, the control ends the call for heat. The gas valve
is de-energized, and the flame is extinguished.

6. The blower will operate for a 30 second post purge.

7

UHS Sequence of Operation: Normal

NOTE: If during step four, the heater fails to fire, please procced to the next page for
more details outlining failure to light operations.

If trial fails:

1. Gas valve de-energizes (for 30 second, blower post purge).

2. Starts over at #2 of heating mode sequence.

3. Retries 3 times until lockout (IF code).

4. Waits 60 minutes then retries 3 more times.

5. Will continue to retry every 60 minutes, until demand for heat is
stopped.

NOTE: When making keypad entries of any type there may be a 5-10 sec delay for
certain situations.

8

UHS Sequence of Operation: Failure to Light

9

UHS Electrical & Gas Connection

Connections located on both the left & right side of heater cabinet

Low Voltage

High Voltage

Gas Supply

Bonding Lug

Electrical & Gas connections as of September of 2008 (Newer Style)

10

Electrical & Control Connections (cont.)

Fig. 1

Ground connection

Two Wire Remote

Connection:

Orange (Pool) and

White (Common)

Three Wire Remote

Connection:

Orange (Pool),

White (24V), & Red

(Spa).

120VAC or 240VAC

Connection

Electrical connections as of September of 2008 (Newer Style)

NOTE: Control hookup located outside control box.

11

Orange (Pool) & White (24VAC,

Common)

Orange (Pool), White (24VAC,

Common), & Red (Spa)

Three wire hook-up

Two wire hook-up

Electrical & Control Connections (cont.)

Electrical connections prior to September of 2008 (Older Style)

Universal H Series Heaters®

How To:

13

How To: Program Heater Bypass Operation

Follow the included steps to place the heater in bypass mode for external control.

NOTE: the maximum temperature set point is 104° F.

Press the ‘MENU ICON’ button to place the

heater in ‘STANDBY’.

Press and hold the minus button and ‘MENU

ICON’ button for 3 seconds.

‘bo’ should appear on the display when the

heater has successfully entered bypass mode.

Once in bypass, press the ‘MENU ICON ’

button until ‘POOL’ or ‘SPA’ is illuminated.

Step 2

Step 3

Step 4

Step 1

14

How To: Program Temperature Lock-Out

NOTE: The default Max temp lock-out set points are 90ºF (Pool) 104ºF (Spa).

Press the ‘MENU ICON’ button to place the

heater in ‘STANDBY’ mode.

Press and hold the minus & plus buttons for 3

seconds.

The ‘SPA’ indicator should illuminate & the

display should show the Max Temp set point.

Raise or lower the temperature displayed

using the minus or plus button.

Step 2 Step 1

Step 3

Step 4

Follow the included steps to place the heater in bypass mode for external control.

15

How To: Program Temperature Lock-Out (cont.)

NOTE: When setting the max temp lock-out set point, the LEDs & display

should flash rapidly.

Press the ‘MENU ICON’ button to toggle to the

‘POOL’ now that the ‘SPA’ is set.

Raise or lower the temperature displayed

using the minus or plus button.

To finalize, press the ‘MENU ICON’ button

until the heater goes back into ‘STANDBY’.

Step 6 Step 5

Step 7

This feature is available on heaters manufactured after February 25th 2011.

16

Measure the inlet static pressure

(valve off) & load pressure (valve

on / energized).

Measure the outlet manifold

pressure (valve on / energized), as

shown below.

The static & load values should be

within the levels listed on the data

plate, example on Page 17.

Manifold reading should be

between 1.8”- 2.0” w.c for natural

Gas or 6.8”- 7.0” w.c for propane.

NOTE: Please refer to Installation Manual for proper gas line sizing.

Step 1

Step 2

How To: Test/Adjust Gas Pressure

IF inlet pressures are correct AND the

manifold pressure is high or low, go to

step 4.

*NOTE: Before any adjustment occurs, verify inlet gas pressure meets the requirement
set forth by the data plate on the heater. IF it does, continue to step 4. IF NOT, refer to

installation manual and/or contact installer.

Verify heater specifications off the heater

plate (bottom front inside heater)

17

How To: Test/Adjust Gas Pressure (cont.)

Step 3

*Adjust the manifold pressure

(at the gas valve)

Remove plug. Once removed, increase

pressure by rotating valve clockwise,

(counter clockwise to reduce pressure).

Step 4

NOTE: IF incoming gas pressure is within range, then your manifold pressure

should be correct per factory settings.

Universal H Series Heaters®

Troubleshooting:

Below is a list of all Diagnostic Codes for the UHS Heater. Troubleshooting Steps for

each Code are covered on the following pages.

Diagnostic

Code

Description

AC Blower Vacuum Switch closed
AO Blower Vacuum Switch open
BD Bad board or secondary high voltage fault
CE Communication Error Between Control Module and Display Interface Assembly
EE Bad board
HF Flame present with Gas Valve not energized.
HS

Maximum return water temperature exceeded and / or rapid water temperature rise.

IF Ignition Failure

IO Ignitor Circuit Open

LO Water Pressure Switch, Vent Pressure Switch, or Temperature Limit Switch Fault

PF Voltage polarity reversed, low voltage detected

SB Keypad failure

SF Temperature Sensor (thermistor) input failure

19

Diagnostic Codes

The following outlines the various replacement parts required for this

troubleshooting guide.

Part Number:

(H150-H400)

Part Number:

(H500)

Description

IDXL2TRF1930 IDXL2TRF1930 Transformer

FDXLFWP1930 FDXLFWP1930 Fuse Board (field wiring panel)

FDXLWHA1930 FDXLWHA1930 Wiring Harness Kit (complete)

FDXLICB1930 FDXLICB1930 ICB (integrated control board)
IDXL2DB1930 IDXL2DB1930 Prio r 07 /16-Display Board (only)

FDXLBKP1930 FDXLBKP1930 Prior 07/16-Bezel/Keypad Assy.

*FDXLBKP1932 *FDXLBKP1932 Display/Bezel/Keypad Assy.

FDXLBCP1150 Kit-Bezel Control Panel 150
FDXLBCP1200 Kit-Bezel Control Panel 200
FDXLBCP1250 Kit-Bezel Control Panel 250
FDXLBCP1300 Kit-Bezel Control Panel 300
FDXLBCP1350 Kit-Bezel Control Panel 350
FDXLBCP1400 Kit-Bezel Control Panel 400

FDXLBCP1500 Kit-Bezel Control Panel 500

20

Troubleshooting Part Numbers

Part Number:

(H150-H400)

Part Number:

(H500)

Description

FDXLBWR1930 FDXLBWR1500 Blower

FDXLIGN1930 FDXLIGN1930 Ignitor

FDXLTER1930 FDXLTER1930 Thermistor (temperature sensor)
IDXL2SNT1930 IDXL2SNT1930 Combustion Blower Tube Kit
FDXLEGL1931 FDXLEGL1931 Exhaust Gas Limit Switch

FDXLHLI1930 FDXLHLI1930 High Limit Kit (temperature limits)
IDXLFLS1930 IDXLFLS1930 Flame Sensor (3” & 5”)

FDXLFSK1930 FDXLFSK1930 Fuse Kit

FDXLWPS1930 FDXLWPS1930 Water Pressure Switch

FDXLBVS1930 FDXLBVS1930 Blower Vacuum Switch
FDXLBRN1930 FDXLBRN1930 Burner Kit

*FDXLGSV0001 FDXLGSV1500N Gas Valve (Natural Gas)

FDXLGSV002

FDXLGSV1500P Gas Valve (Propane)

FDXLVPS1930 FDXLVPS1930 Vent Pressure Switch

* Heaters made prior to 07/16 that want the new display/bezel/keypad, will need to replace

the old display with the Kit-Bezel Control Panel specific to their model heater.

1. Heater Not Powering Up

Heater not

powering up

Correct source

power issue

YES

NO

Correct voltage

selector plug?

NO

Inspect wires &

connections,
are they OK?

YES

Test FC1 &

FC2 fuses

Is incoming

power correct?

Is either

fuse blown?

Go to:

Section 2

Test 22-28VAC

between R & C on

P5 (fuse board)

Test

transformer

output for 22-

28VAC

Is voltage

correct?

NO

Replace fuse

board:

FDXLFWP1930

NO

Install correct

plug and

retest

Replace harness

and/or reseat

connection:

FDXLWHA1930

YES

YES

NO

Test transformer input

for 110-125VAC

YES

Is voltage

correct?

Replace

transformer:

IDXL2TRF1930

YES

NO

Is voltage

correct?

YES

Go to section B

(next page)

NO

Replace fuse

board:

FDXLFWP1930

21

1. Heater Not Powering Up (cont.)

YES

NO

Inspect wires &

connections,
are they OK?

Disconnect and

test the red &

grey wires on ICB

for 22-28VAC.

YES

Replace wire

harness:

FDXLWHA1930

Section B

(continued from

previous page)

Secure

wiring/plugs

and retest

Is voltage

correct?

NO

On ICB, test 3A

fuse for

continuity

Is fuse

blown?

NO

YES

On the ICB, verify

22-28VAC

between AC &

COM (pins 1&4)

Replace fuse:

FDXLFSK1930

then go to

section 3.

Is voltage

correct?

Replace the ICB:

FDXLICB1930

Replace display/

bezel/keypad:

(See Pg. 20)

NO

YES

For models manufactured prior to August of 2008,

proceed to step 1B. IF model is later, go to 1C.

Verify input power

Verify 110-125 or 220-245VAC off fuse board (TB1).

IF correct, go to 1D. IF NOT, correct source power.

Verify heater manufacture date

Step 1A Step 1B

IF voltage is present, go to step 1D. IF voltage is

incorrect, correct source power.

Models after August 2008

Step 1C

23

Verify selector plug matches incoming line power.

IF it does not, power OFF & correct. IF OK, go to 1E.

Voltage selector plug

Step 1D

1. Heater Not Powering Up

Inspect Fuse Board wiring, ensuring all plugs are

securely fastened. IF correct, proceed to step 1F.

Test Fuses

Verify that FC1 & FC2 fuses aren’t open. Replace all

open fuses & go to section 2. IF correct, go to 1G.

Inspect connections

Step 1E

Step 1F

Disconnect the P3 plug from the fuse board. Test

110-125VAC between pins 1&2 and 3&4 on the

board. IF good, go to 1H. IF NOT, replace the Fuse

board (pg. 20).

Test transformer input

Step 1G

24

Disconnect P4 plug from fuse board. Verify 22-

28VAC between pins 1 & 2 (red wires), then 110-

125VAC between pins 4-6 (grey wires). IF correct,

go to 1I. IF incorrect replace transformer (pg.20).

Test transformer output

Step 1H

1. Heater Not Powering Up (cont.)

NOTE: Step 1I – Heaters older
than 11/2010 – If no voltage
across R & C, remove
FC3 fuse and test for
continuity. IF open go to page

24. IF OK go to Step 1J

Disconnect the plug from P5 (on fuse board). Test

22-28VAC between R & C. IF no voltage, replace

Fuse Board (pg. 20). If correct, go to step 1J.

Inspect wiring

Inspect ICB wiring, ensuring all plugs are securely

fastened. IF wiring is OK go to Step 1K. IF NOT,

secure wiring/plugs then retest.

Test P5 (low voltage)

Step 1I

25

Step 1J

1. Heater Not Powering Up (cont.)

Disconnect and test the red and grey wires from

the ICB. IF 22-28VAC is present go to step 1L. IF

NOT, replace wire harness (pg. 20).

Test ICB input (low voltage)

Step 1K

Test F1 (3AMP) fuse

On the ICB, locate and test the 3A fuse for

continuity. IF fuse is blown, replace it and go to

section 3. IF Ok, go to step 1M.

On the ICB, verify 22–28VAC between AC & COM

terminals (pins 1 & 4). IF voltage is present, replace

display/bezel/keypad. IF no voltage, replace ICB

(pg. 20).

Test ICB’s display output

26

1. Heater Not Powering Up (cont.)

Step 1L

Step 1M

27

2. Open FC1 &/or F2 Fuse

Open FC1

&/or F2 Fuse

YES

Correct voltage

selector plug?

NO

Install correct

plug and

replace fuse

Did this

correct the

problem?

YES

NO

Is transformer

wiring damaged,

pinched, or worn?

Problem

solved

Test

transformer

resistance

Correct/repair

transformer

wiring

YES

NO

Is resistance

correct?

NO

YES

Replace

transformer:

IDXL2TRF1930

Contact
Support

[phone]

IF voltage selector plug matches voltage, go to step
2B. IF not, power down, replace FC1 & FC2 fuses, &

switch plug to proper voltage.

Inspect transformer wiring

Inspect transformer wiring, ensuring the insulation

on the wiring is not damaged. IF damaged replace

transformer (pg. 20). IF OK go to 2C.

Verify voltage selector plug

Step 2A

With power off, remove the P3 & P4 plugs. On the P3 plug measure resistance between the

orange & yellow wires for 1.9 – 2.9 Ohms, then do the same between the black and brown

wires. IF resistance is out-of-range, replace transformer (pg. 20). IF OK and problem still

persists, contact technical support: [phone].

Test transformer resistance

28

Step 2B

2. Open FC1 &/or F2 Fuse

Step 2C

29

3. Open FC3 &/or F1 Fuse

Open FC3

&/or F1 Fuse

Check the remote

connection/high

limits

Is low voltage

wiring damaged,

pinched, or worn?

Is water pressure

switch wiring

damaged, pinched,

or worn?

Replace wire harness:

FDXLWHA1930

OR high limit if damaged:

FDXLHLI1930

YES

NO

YES

Are any wires

showing

continuity?

NO

Is blower vacuum

switch wiring

damaged, pinched,

or worn?

YES

Is gas valve wiring

damaged, pinched,

or worn?

NO

NO

YES

Test gas valve

wires for

continuity against

ground

Replace gas

valve:

(pg. 20)

YES

Inspect ICB

wiring, any wires

compromised?

YES

Replace wiring

harness:

FDXLWHA1930

Replace ICB:

FDXLICB1930

NO

Replace wire harness:

FDXLWHA1930

OR pressure switch if

damaged:

FDXLWPS1930

Replace wire harness:

FDXLWHA1930

OR vacuum switch if

damaged:

FDXLBVS1930

Replace wire harness:

FDXLWHA1930

OR Replace gas valve:

Please refer to (pg. 20)

NO

Power down and inspect all remote connections

and high limit wiring for damage. IF damaged,

repair/replace (pg. 20). IF OK, go to step 3B.

Inspect water pressure switch

With power off, inspect the water pressure switch

wiring for damage. IF damaged, replace the wire

harness (pg. 20). IF OK, go to step 3C.

Inspect connections/high limits

Step 3A

With power off, inspect the blower vacuum switch

wiring for damage. IF damaged, replace the wire

harness (pg. 20). IF OK, go to step 3D.

Inspect blower vacuum switch

Step 3C

30

With power off, inspect the gas valve wiring for

damage. IF damaged, replace the wire harness (pg.

20). IF OK, go to step 3E.

Inspect gas valve wiring

Step 3D

Step 3B

3. Open FC3 &/or F1 Fuse

With power off, measure resistance, comparing

each terminal to ground. IF any terminal shows

continuity, replace the gas valve (pg. 20). IF OK, go

to step 3F.

ICB wiring

Inspect ICB wiring. IF wiring is damaged, replace

the wire harness with a new wire harness kit (pg.

20). IF OK and the problem still exists, replace the

ICB (pg. 20)

Verify gas valve is not shorted

Step 3E

31

Step 3F

3. Open FC3 &/or F1 Fuse (cont.)

When testing the gas valve, if continuity appears between any wires and ground, then

this implies a short has occurred and the gas valve will need to be replaced (refer to

pg. 20 for part number).

32

4. Open FC4 Fuse

Open FC4

Fuse

Inspect ignitor

wiring for

damage

Is ignitor wiring

damaged, pinched,

or worn?

Is blower wiring

damaged, pinched,

or worn?

Replace ignitor:

FDXLIGN1930

YES

NO

YES

NO

Is the resistance

incorrect?

NO

YES

Ohm out blower for 8-

9ohms (before Sept.

2010) OR for 4-5ohms
(after Sept. 2010), is

resistance correct?

YES

NO

Replace blower:

Please refer to (pg. 20)

Replace ignitor:

FDXLIGN1930

Ohm out the

ignitor verifying:

8-25ohms

Contact

Support

[phone]

Replace blower:

Please refer to (pg. 20)

Inspect the Ignitor & Blower wiring. Verify

insulation is not damaged. IF wires are damaged,

replace the damaged part (pg. 20). IF OK, go to 4B.

Verify ignitor resistance

Disconnect ignitor from ICB & measure resistance

of ignitor. Verify 8-25 ohms between 20°-140°F. IF

correct, go to 4C. IF NOT, replace ignitor (pg. 20).

Ignitor and blower wiring

Step 4A

33

Step 4B

4. Open FC4 Fuse

With power off, disconnect blower plug from ICB. Models manufactured before Sept. 2010:

measure across pins 1-2 (black & red), then 3-4 (white & blue) for 8-9 ohms. Models after Sept.

2010: measure for 4-5 ohms across the two terminal with wires. IF out-of-range, replace

blower (pg. 20). IF correct, contact technical support [phone].

Measure blower resistance

Step 4C

Before Sept. 2010

34

5. Service LED ON: ‘BD’ Code

‘BD’ Code

Power down and

check the FC4

fuse

Is fuse blown?

Disconnect P6 and

test for 110 -

125VAC between

pins 3-5.

Proceed to:

Section 4

YES

NO

YES

NO

On P4, verify 110-

125VAC between

4-6 (grey wires)

YES

Is voltage

correct?

Is voltage

correct?

Replace fuse

board:

FDXLFWP1930

NO

Replace

transformer:

IDXL2TRF1930

Verify E10 for 110-

125VAC between

1-3 (white & black)

Is voltage

correct?

YES

NO

Replace

transformer:

IDXL2TRF1930

Replace wire

harness:

FDXLWHA1930

With power off, verify the FC4 fuse has continuity.

IF fuse is good, go to 5B. IF fuse is blown, go to

Section 4.

Verify ICB output

Disconnect the P6 connector and test voltage for

110-125VAC between pins 3-5. IF no/low voltage,

go to step 5D. IF correct, go to 5C.

Test the FC4 fuse (continuity)

Step 5A

Disconnect the E10 connector from ICB. Verify 110-

125VAC between 1-3 (white & black). IF present,

replace ICB. IF NOT, replace wire harness (pg. 20).

Verify ICB input

Step 5C

35

Disconnect P4 from fuse board. Verify 110-125VAC

between 4-6 (grey wires). IF OK, replace fuse

board. IF NOT, replace transformer (pg. 20).

Verify transformer output

Step 5D

Step 5B

5. Service LED ON: ‘BD’ Code

36

“EE” OR

“CE” Code

Check display for

“EE” code

Is “EE” code

present?

The “CE” code may

clear with a reset of

power, power cycle

the heater

YES

NO

Are

connections

secure?

Check display

ribbon cable

connection

6. Service LED ON: “EE” OR “CE” Code

Replace ICB:

FDXLICB1930

Did the “CE”

code clear?

YES

NO

Secure

connections

& retest

NO

YES

Did “CE” code

clear?

YES

Problem

solved

NO

Replace

display/bezel/

keypad:

(See Pg. 20)

Replace ICB:

FDXLICB1930

Go to

section B

Section B

Did the “CE”

code clear?

Problem

solved

YES

Contact

Support

[phone]

NO

“EE” error indicates the you have a defective ICB

board. IF this error appears, replace ICB (pg. 20). IF

no EE error, go to 6B.

Check display for “CE”

“CE” (communication error) indicates a problem

between the ICB & display board. Cycle power

OFF/ON. IF error persists, go to 6C.

Check display for “EE”

Step 6A

Verify ribbon cable is secure. IF cable is secure,

replace display/bezel/keypad assy. (pg. 20) then go

to 6D. IF NOT secured, reconnect.

Inspect display connections

Step 6C

37

IF after replacing display/bezel/keypad, “CE” error

persists, replace ICB (pg. 20). IF replacing ICB fails

to solve problem, contact support [phone].

Verify “CE” has cleared

Step 6D

Step 6B

6. Service LED ON: “EE” OR “CE” Code

“IO” OR

“SB” Code

Check display for

“IO” code

Is “IO” code

present?

The “SB” code may

clear with a reset of

power, power cycle

the heater

YES

NO

Verify ignitor wiring is

not damaged and

plugged in securely

7. Service LED ON: “IO” OR “SB” Code

38

Is ignitor wire

damaged?

Replace ignitor:

FDXLIGN1930

YES

NO

Ohm ignitor, verify

8-25 ohms (20°-

140°F), reading out

of range?

YES

NO

Replace ICB:

FDXLICB1930

Replace

display/bezel/

keypad:

(See Pg. 20)

“IO” error stand for ignitor Open. IF this error

appears, go to step 7B. IF “IO” does not appear, go

to step 7D.

Inspect ignitor wires

Power down and inspect ignitor wiring, ensuring

ignitor plug is securely attached to the ICB. IF OK,

go to step 7C. IF not, secure plug.

Check display for “IO”

Step 7A

With power off, verify ignitor ohm resistance ( 8-25

ohms between 20°- 140°F). IF correct, replace ICB.

IF out-of-range, replace ignitor (pg. 20).

Ohm out ignitor

Step 7C

39

“Stuck Button” indicates display board is acting as

if the button is being pressed and held. Replace

display/bezel/key pad (pg. 20). Go to pg. 66 to test.

Check display for “SB”

Step 7D

Step 7B

7. Service LED ON: “IO” OR “SB” Code

“SF” OR

“HS” Code

Check display for

“SF” code

Is “SF” code

present?

The “HS” code

stands for High

Sense (water

temperature).

YES

NO

Ohm thermistor,

checking each red to

black, do the readings

differ by more than 1°?

40

Replace

thermistor:

FDXLTER1930

YES

NO

8. Service LED ON: “SF” OR “HS” Code

Replace ICB:

FDXLICB1930

Make sure water

inlet & outlet are

plumbed correctly,

are they reversed?

YES

Plumb correctly in

compliance with

installation manual

NO

Ohm thermistor,

checking each red to

black, do the readings

differ by more than 1°?

NO

Replace ICB:

FDXLICB1930

Replace

thermistor:

FDXLTER1930

YES

The “SF” (Sensor Failure) indicates that the

thermistor (or temp sensor) is reading out of range.

Ohm temp sensor, checking each red to black. IF

the two readings differ more than 1°, replace

thermistor. IF NOT, replace ICB (pg. 20).

“HS”, are inlet/outlet reversed?

Check display for “SF”

Step 8A

41

Step 8B

The “HS” (High Sense (water temperature)) will appear if the water sensor is reading

above 105° OR if the sensor detects an increase of more than 6° with-in 60 seconds.

8. Service LED ON: “SF” OR “HS” Code

Verify the water inlet & outlet are not reversed;

reversing these will often cause frequent

occurrences of the “HS” error code. Follow the

steps outlined in 8A. IF the thermistor checks-out,

replace the ICB (pg. 20).

Is the incoming

power within 10%

of required voltage?

“PF” Code

Verify incoming

power is within 10%

+ or – of required

voltage.

YES

42

NO

Replace ICB:

FDXLICB1930

Correct source

power issue

9. Service LED ON: “PF” Code

Inspect ground

and neutral

connections, are

they clean and

secured?

YES

NO

Clear dirt/debris and

secure ground and

neutral wires and

retest

Ensure voltage is within 10% + or – of required

voltage. IF voltage is correct, go to step 9B. IF NOT,

then the problem is related to source power and

must be corrected before error will clear.

Inspect ground & neutral

Verify incoming power

Step 9A

43

Step 9B

“Polarity Failure” This code will display if low voltage is detected, if the ground path is

not sufficient, or the ICB is defective. Reset is immediate after error is corrected.

Verify both neutral and ground connections (both

internal and external) are clean and secured. IF

ground and neutral connections check-out, then

replace the ICB (pg. 20).

9. Service LED ON: “PF” Code

Does heater

fire?

“HF” Code

Power cycle the

heater at the

breaker

YES

44

NO

Verify error code &

jump to section that

best describes error

Reduce the

temperature set

point until heater

stop firing

10. Service LED ON: “HF” Code

Did the “HF”

code reappear?

YES

NO

Did the “HF”

code reappear?

YES

NO

Problem

solved

Toggle the

mode button

and call for heat

Test for 24VAC

off the gas valve

Is 24VAC
present?

Do you have
manifold gas

pressure?

YES

NO

Replace ICB:

FDXLICB1930

YES

NO

Replace gas valve:

Please refer to (pg. 20)

Power cycle the heater, in an attempt to clear an

erroneous “HF” code. IF power cycling clears to the

“HF” message and the heater fires, drop the

temperature to suspend heating. IF “HF”

reappears, go to step 10B.

Call for heat and test gas valve

Power cycle heater

Step 10A

45

“HF” (heat or flame sensed) will occur if flame is sensed when the gas valve is off, the

control will go into lockout. The blower will continuously run until corrected. When

corrected, control will run blower for 5 seconds then restart heater after 2 minutes.

Press the mode button to toggle the heater and

call for heat. IF 24VAC is still present at gas valve

AND manifold pressure is not present, gas valve is

defective and needs to be replaced. Otherwise,

replace the ICB (pg. 20).

10. Service LED ON: “HF” Code (cont.)

OFF

ON

Step 10B

“LO” Code

Verify adequate

water flow, is

flow sufficient?

Is water pressure

switch wiring free of

damage?

YES

NO

46

Increase flow

rate/clean filter

11. Service LED ON: “LO” Code

YES

Replace wire

harness:

FDXLWHA1930

NO

Check continuity of

water pressure

switch, is continuity

present?

NO

Replace water

pressure switch:

FDXLWPS1930

YES

Adjust switch

if necessary

Did error

clear?

Problem

solved

YES

Verify high

limit wires

are free of

damage

NO

Are wires free

of damage?

Replace high

limits kit:

FDXLHLI1930

NO

YES

Is this heater

installed
indoors?

YES

Go to

section B

(next page)

NO

Heater made

after Feb.

2016?

YES

NO

Contact

Support

[phone]

YES

Does exhaust

gas limit have

continuity?

Replace exhaust
gas limit switch:

FDXLEGL1930

NO

Inspect vent

pressure switch

tube & connections

47

11. Service LED ON: “LO” Code

Repair or replace

tube kit:

IDXL2SNT1930

Section B

(continued from

previous page)

Is tube

damaged?

YES

NO

Inspect flue and

vent sizing

Is flue dirty?

YES

Clean flue

and retest

NO

YES

NO

Vent sized

correctly?

Refer to

installation/

indoor vent
instructions

Test vent

pressure switch

continuity

Continuity

present?

YES

NO

Replace vent

pressure switch:

FDXLVPS1930

Heater made

after Feb.

2016?

YES

NO

Contact

Support

[phone]

Does exhaust

gas limit have

continuity?

Replace exhaust
gas limit switch:

FDXLEGL1931

NO

YES

Inspect the water pressure switch wiring, ensuring

wire harness terminals are securely fastened. IF

damaged, replace wire harness (pg. 20). IF secure

and free of damage, go to step 11B.

Continuity test

Inspect water pressure switch

48

“LO” Code (Limit Open) may relate to water flow. Verify the pump is running &

adequate water is flowing through heater.

“LO” is NORMAL when the pump is turned off.

Remove wires from water pressure switch &

measure continuity across terminals (while pump

is running). IF open, replace water pressure switch.

IF OK, go to Step 11C.

11. Service LED ON: “LO” Code

Step 11A

Step 11B

Some sites may require a pressure switch

adjustment. IF adjustment does not correct or was

not required, go to 11D.

Inspect and test high limits

Inspect & test high limits. Verify continuity across

the temperature limit switches. IF open or wire is

damaged, replace (pg. 20). IF OK, go to 11E.

Pressure switch adjustment

Step 11C

IF this heater is installed in an indoor application,

proceed to step 11F. IF heater is installed in an

outdoor environment, go to step 11I.

Indoor application?

Step 11E

49

Applies To Indoor Installations ONLY: Inspect the

vent pressure switch tube connections. IF OK, go to

11G. IF NOT, repair/replace tubing (pg. 20).

Vent pressure switch/tubing

Step 11F

Step 11D

11. Service LED ON: “LO” Code (cont.)

Ensure that flue is not blocked or restricted. See

indoor vent sizing requirements in the heater’s

Installation Manual/Indoor Vent Instructions. IF

OK, go to step 11H. IF NOT, contact installer.

Vent pressure switch continuity

Inspect flue and vent sizing

Step 11G

50

Step 11H

Note: Please ensure that the vent size is sufficient for the heater model installed.

Failure to properly size venting may result in damage to heater OR COULD PUT

INHABITANTS AT SERIOUS RISK.

Disconnect wires from vent pressure switch and

measure continuity between VPS terminals. IF

open, replace the vent pressure switch (pg. 20). IF

OK, go to 11I.

11. Service LED ON: “LO” Code (cont.)

51

11. Service LED ON: “LO” Code (cont.)

Test continuity across the exhaust gas limit switch. IF open, replace switch (pg. 20). IF switch

does not exist AND problem still persists, contact support: [phone]

Indoor/Outdoor: Feb. 2016 and newer

Step 11I

Note: This switch is a one time safety. Once the switch has tripped then it NEEDS to be

replaced and the heat exchanger should be inspected for soot or damage.

“IF” Code

Turn on main

gas supply &

retest

YES

NO

Inspect gas

valve in heater

NO

Is heater’s gas

valve ON?

YES

Is main gas

supply ON?

Are

connections

secure?

Turn ON gas

valve and retest

YES

NO

52

12. Service LED ON: “IF” Code

On ICB, verify flame

sensor & gas valve

connections are

secure

Secure

connections

& retest

YES

YES

NO

Is inlet

pressure

correct?

Adjust

manifold gas

pressure

YES

Correct inlet
gas pressure

NO

Test 22-28VAC to

gas valve during

call for heat

(manometer

attached)

Is voltage

correct?

NO

Replace ICB:

FDXLICB1930

YES

Is there

manifold gas

pressure?

Replace gas

valve:

Please refer to

(pg. 20)

NO

YES

Is inlet and

manifold gas

pressure correct?

Go to

section B

(next page)

53

12. Service LED ON: “IF” Code

Section B

(continued from

previous page)

Is correct flame
sensor installed

OR damaged?

YES

Replace flame

sensor:

IDXLFLS1930

Check for damaged

OR wrong blower

air inlet plate

Is plate

damaged/

wrong?

NO NO

YES

NO

Contact tech

support:

[phone]

Inspect and/or

clean burner tubes

& orifices

Are burner tubes &

orifices damaged?

YES

NO

Replace with new burner kit:

FDXLBRN1930

OR Gas Valve

(includes orifices):

(pg. 20)

IF “Ignition Failure”, Ensure main gas supply is in

the ON position. IF ON, go to step 12B. IF NOT,

open gas supply.

Verify gas valve is ON

Verify that the gas valve, inside the heater, is in the

“ON” position. IF correct, go to step 12C. IF NOT,

rotate knob to ON position.

Inspect main gas supply

Step 12A

Ensure both flame sensor and gas valve are both

securely fastened to the ICB. IF correct, proceed to

step 12D.

Flame sensor & gas valve

54

Ensure gas static, load, and manifold pressures are

correct (See Page 16 & 17). IF OK, go to Step 12E. IF

NOT, go to Step 12F.

Verify gas pressure

Step 12D

Step 12B

12. Service LED ON: “IF” Code

Step 12C

Verify 22-28VAC off gas valve during ignition trial.

IF present & no pressure (manometer attached),

replace valve. Otherwise, replace ICB (pg. 20).

Verify correct flame sensor

Verify that the installed flame sensor is 5”. IF 3” is

installed OR IF sensor is damaged, replace it with
the 5” version (pg. 20). IF correct, go to step 12G.

Voltage/pressure off gas valve

Step 12E

Check for damaged/wrong blower air inlet plate. IF

wrong or damaged contact tech support (908) 355-

7995. IF OK, go to step 12H.

Verify blower air inlet plate

Step 12G

55

Inspect Gas Orifices & Burners for blockage. Clean

as required. IF damaged, replace (pg. 20). IF NOT

damaged, contact tech support [phone].

Inspect orifices & burner tubes

Step 12H

Step 12F

12. Service LED ON: “IF” Code (cont.)

“AC” Code

NO

56

Does the switch

have continuity?

YES

Is the blower

running?

NO

Replace blower
vacuum switch:

FDXLBVS1930

YES

13. Service LED ON: “AC” Code

Test for continuity

on the blower

vacuum switch

Put the

heater in

“Stand by”

Replace blower
vacuum switch:

FDXLBVS1930

Replace ICB:

FDXLICB1930

Isolate the blower vacuum switch. Measure

continuity between switch terminals. IF continuity

exist, replace switch (pg. 20). IF OK, go to 13B.

Verify blower operation

Test blower vacuum switch

Step 13A

57

Step 13B

“AC” Code stands for “Air Switch Closed”. The blower vacuum switch closed, when it

was expected to be open.

With the heater off (in “Stand By”), IF the blower
continues to run/operate, replace the ICB. IF not,

replace the blower vacuum switch (pg. 20).

13. Service LED ON: “AC” Code

YES

“AO” Code

58

Replace blower:

Please refer to

(pg. 20)

Is blower

damaged?

14. Service LED ON: “AO” Code

Are blower

vacuum switch

wires damaged?

YES

YES

Replace blower
vacuum switch:

FDXLBVS1930

NO

Is vacuum tube

damaged?

NO

Replace

vacuum tubing:

IDXL2SNT1930

YES

NO

YES

Correct voltage

selector plug?

NO

Install correct

plug and

replace fuse

Ohm out blower for 8-

9ohms (before Sept.

2010) OR for 4-5ohms
(after Sept. 2010), is

resistance correct?

Replace blower:

Please refer to

(pg. 20)

NO

Verify 110-125VAC on
Inducer off ICB between
pins 1-2 (left to right), is

voltage present?

YES

NO

Replace blower
vacuum switch:

FDXLBVS1930

Replace ICB:

FDXLICB1930

Go to

section B

section B

Check for bad blower and/or damaged blower

vacuum switch wiring. IF OK, go to step 14B. IF

damaged, replace compromised part (pg. 20).

Vacuum tube

Check for damaged vacuum tubing as well as its

connection to the blower. IF OK, go to 14C. IF NOT,

replace vacuum tubing (pg. 20).

Blower & vacuum switch wiring

Step 14A

IF voltage selector plug matches voltage, go to step

14D. IF not, power down, replace FC1 & FC2 fuses

(if open), & switch plug to proper voltage.

Verify voltage selector plug

Step 14C

59

Step 14B

14. Service LED ON: “AO” Code

60

14. Service LED ON: “AO” Code (cont.)

With power off, disconnect blower plug from ICB. Models manufactured before Sept. 2010:

measure across pins 1-2 (black & red), then 3-4 (white & blue) for 8-9 ohms. Models after Sept.

2010: measure for 4-5 ohms across the two terminal with wires. IF out-of-range, replace

blower (pg. 20). IF correct, go to step 14E.

Measure blower resistance

Before Sept. 2010

Step 14D

On the ICB (while calling for heat). Verify 110-125VAC across

Pins 1 & 2 of Inducer on ICB. IF OK, replace blower vacuum

switch (pg. 20). IF NOT present, replace ICB (pg. 20)

Blower plug on ICB

Step 14E

Internal By-Pass

Model Min GPM

H150FD
H200FD

20

H250FD
H300FD

25

H350FD
H400FD

30

H400FD

40

Maximum water flow 125 GPM

Flow requirements should be checked to insure proper operation.

Never allow heater to operate below minimum flow requirements or damage may

occur.

• Flow less than minimum could cause issues such as the heater dry firing or water to boil

causing high limits to trip and possible damage to heat exchanger.

• Flow exceeding maximum flow could cause issues such as damage to the heat

exchanger by thinning the tube walls.

Flow Requirements

NOTE: Internal by-pass

should be inspected
periodically as it could
be the cause of low or

high water flow through

the exchanger

61

Heat Exchanger: Flow Requirements

1. Remove black metal Trim Plate (around water manifold, 5 Black screws)

2. Remove water connection side Upper End Cap (Black Polymer- 4 screws in
rectangle holes marked with an arrow)

3. Disconnect Unions from plumbing (water connections, 1 inlet, 1 outlet.)

4. Remove (8) ½” hex head bolts ( 4 on each side-inlet and outlet)

5. Remove water manifold (also called the “Header”) and black polymer
“Mounting Blocks” to expose the ends of the heat exchanger tubes.

6. If there is any doubt as to whether or not there is damage from aggressive
water chemistry: take 3 pictures, 1 of each pair of tubes (inlet side and outlet
side), as well as the Model & Serial number decal, and send to your local
technical representative, or call [phone] for further instructions.

62

Heat Exchanger: Inspection

Heat Exchanger tubes should look like this picture

New, Clean Exchanger Low pH or High Water Flow High Sanitizer Levels

Annealed Fins – Low Water Flow

Freeze Damage

High pH, Alkalinity or Calcium

Hardness

Sooted – Improper Fuel

and Air Mixture.

High Sanitizer Levels Low pH

63

Heat Exchanger: Potential Failure Causes

64

Wiring Connection Diagram

65