On a York ZF 3 to 6 ton rooftop unit (J03ZF and similar), the Simplicity Lite unit control board shows a slow heartbeat in normal operation and flashes a number code for each fault: 2 = anti-short-cycle delay, 3 = high pressure switch lockout, 5 = low pressure switch lockout, 7 = freeze switch lockout and 9 = ignition control problem. York installation manual 697890-YIM-C-0213 (ZF036–072, 60 Hz) lists the full set in Table 29, and the later 5188244-YIM-B-1016 titles the same table "Simplicity Lite Unit Control Board Flash Codes".
What does each Simplicity Lite flash code mean?
York notes that these flash codes do not represent alarms on their own. They tell you what the board is doing or why it locked a function out.
| LED / flashes | Meaning (697890-YIM-C-0213 Table 29; same list in 5725848-XIM-A-0319 Table 26) |
|---|---|
| Off | No power or control failure |
| Steady on | Control failure; replace the control |
| Heartbeat | Normal operation |
| 1 flash | Not used, to avoid confusion with the heartbeat |
| 2 flashes | Control waiting on the anti-short-cycle delay (ASCD) |
| 3 flashes | Compressor locked out on the high pressure switch (HPS1) |
| 5 flashes | Compressor locked out on the low pressure switch (LPS1) |
| 7 flashes | Compressor locked out on the freeze switch (FS1) |
| 9 flashes | Ignition control locked out, failed, tripped on its limit switch, or heat section jumper plug missing |
| 10 flashes | Compressors locked out on low outdoor air temperature |
| 11 flashes | Compressors locked out because the economizer is providing free cooling |
| 13 flashes | Compressor held off on low voltage |
| 14 flashes | EEPROM storage failure (control failure) |
A 9-flash code sends you to the ignition control board (ICB), which has its own LED and its own codes (Table 30 of the same manual). See York ZF ignition control flash codes for those, and York ZF rollout switch and limit trips for the limit and rollout checks.
How do you read the fault history and reset a lockout?
York's ZF manual 5725848-XIM-A-0319, which covers the Simplicity Lite board, describes the board's three buttons and the flash timing:
- Flash timing: error codes flash about 200 ms on and 200 ms off. The normal heartbeat is a 1-second on/off pulse and is not an error code.
- LAST ERROR: one press shows the last five flash codes, newest first. Two presses within five seconds clear the fault history.
- TEST RESET: one press bypasses any anti-short-cycle delay for one cycle. Two presses reset active lockouts.
- COMM SET UP: sets the network address when units are networked.
- ICB history: active ignition alarms flash on the ICB LED, but the ICB stores no history.
For heating faults, the 60 Hz manual 697890-YIM-C-0213 says to remove the call for heat by setting the thermostat below the space temperature. That clears the flash codes.
Our practical advice: press LAST ERROR before you reset anything. A history of repeated 3 or 5 codes points to a refrigerant-side problem, and clearing it first throws away your best clue.
How are the fan on and off delays set?
The same board sets the indoor fan delays. York lists three button combinations in 697890-YIM-C-0213:
| Setting | Buttons pressed together | Board flashes | Fan ON delay | Fan OFF delay |
|---|---|---|---|---|
| Gas heat option #1 | LAST ERROR + TEST RESET | 3 times | 30 s | 90 s |
| Gas heat option #2 | COMM SETUP + TEST RESET | 4 times | 30 s | 180 s |
| Electric heat | COMM SETUP + LAST ERROR | 2 times | 0 s | 30 s |
If a replacement board is installed on a gas unit, check that the fan delays match the heat type before you leave.
S1-03102993000 or S1-03102995000: which board is in your unit?
Our catalog lists two Simplicity Lite boards for J03ZF units. The live titles describe S1-03102993000 as "Gas/Electric, 4S" and S1-03102995000 as "Gas/Electric, 2S". On our J03ZF page, S1-03102993000 is listed for most models and S1-03102995000 for a smaller group. York's manuals do not explain the 4S and 2S labels, so do not choose by the label. Read the part number on the board you are replacing, or send us the model and serial number.
Parts involved
| Component | Role | Where to find it |
|---|---|---|
| Simplicity Lite unit control board (4S) | Runs cooling, heating calls and fan delays; shows the codes above | York S1-03102993000 Simplicity Lite Control Board, Gas/Electric, 4S | OEM Source 1 Part |
| Simplicity Lite unit control board (2S) | Listed for a smaller group of J03ZF models | York S1-03102995000 Simplicity Lite Control Board, Gas/Electric, 2S | OEM Source 1 Part |
| Ignition control board | Where a 9-flash code leads; has its own LED codes | York S1-03109161000 Spark Ignition Control Board, UT, 24V | OEM Source 1 Part |
| Pressure and freeze switches | Inputs behind codes 3, 5 and 7 | York S1 Pressure & Limit Switches | Source 1 OEM |
| Other boards | Browse all S1 boards | York S1 Control Boards | Source 1 OEM |
Which York units this applies to
- York J03ZF parts: 3-ton ZF rooftop, both Simplicity Lite boards listed.
- York J04ZF parts: 4-ton ZF rooftop, both boards listed.
- York J05ZF parts: 5-ton ZF rooftop, both boards listed.
- York DH060 parts: our page lists S1-03102993000 for some DH060 models; their own manual was not used here.
- York DJ060 parts: S1-03102993000 is listed for many DJ060 models; confirm by part number.
Scope: Flash codes and fan delays are from York installation manual 697890-YIM-C-0213 (ZF036 to ZF072, R-410A, 60 Hz). Button functions and flash timing are from 5725848-XIM-A-0319 (ZF036 to ZF076, 50 Hz), which covers the Simplicity Lite board. The board name is from 5188244-YIM-B-1016 (ZF036 to ZF072, 60 Hz). Smart Equipment and Simplicity SE controls are not covered here.
Before you order
Read the model and serial number from the unit nameplate and the part number printed on the old board. A steady-on or 14-flash code points to the board itself; most other codes point to a switch, sensor or the ignition control. To confirm fit, contact us at help@totalhvacparts.com or 610-487-7999.
Frequently Asked Questions
What does 9 flashes mean on a York Simplicity Lite board?
York manual 697890-YIM-C-0213 lists 9 flashes as the ignition control locked out, failed, tripped on its limit switch, or missing its heat section jumper plug. Check the ignition control board LED next.
What does 2 flashes mean on a York Simplicity Lite board?
On the ZF Simplicity Lite unit control board, 2 flashes means the control is waiting on the anti-short-cycle delay. York's ZF manual 5725848-XIM-A-0319 says one press of TEST RESET bypasses that delay for one cycle.
How do I see past fault codes on a York Simplicity Lite board?
Press LAST ERROR once to show the last five flash codes, newest first. Pressing it twice within five seconds clears the history, per York form 5725848-XIM-A-0319.
How do I reset a lockout on a York Simplicity Lite board?
York's ZF manual 5725848-XIM-A-0319 says two presses of TEST RESET reset active lockouts. Find the cause first, since a high or low pressure lockout will return if the problem is still there.
Sources
- York form 697890-YIM-C-0213, Installation Manual, ZF Series R-410A, ZF036–072, 60 Hz (Table 29 unit control board flash codes, Table 30 ignition control board flash codes, fan on/off delays, page 66; flash codes and resets, page 55)
- York form 5725848-XIM-A-0319, Installation Manual, ZF Series R-410A, 3–6.3 ton, 50 Hz (unit flash codes and button functions, page 50; Table 26 Simplicity Lite flash codes)
- York form 5188244-YIM-B-1016, Installation Manual, ZF036–072, 60 Hz (Table 31 title, "Simplicity Lite Unit Control Board Flash Codes")
- Live product titles and series page part lists, as shown on each product page
Rooftop units involve line voltage, gas and refrigerant under pressure. Service should be performed only by qualified personnel, following York's manual for your unit and your facility's lockout/tagout procedures.