On a York ZF 3 to 6 ton gas/electric rooftop (J03ZF, J04ZF, J05ZF), three heat safeties can stop the burner: the primary limit (automatic reset), the auxiliary limit (manual reset) and the rollout switch, which latches the ignition control until power is removed for 20 seconds. York installation manual 697890-YIM-C-0213 shows limit trips as 6 flashes and rollout as 7 flashes on the ignition control board, and points first to airflow, gas input, temperature rise and the flue.
What does each heat safety do?
| Device | What it senses | What the unit does | Reset |
|---|---|---|---|
| Primary limit | Heat exchanger tube temperature. Mounted just above the heat exchanger tube inlet on the right side. | ICB flashes the limit code. The UCB runs the indoor blower and the ICB runs the draft motor while it is open. When it closes and the call is still there, ignition restarts. | Automatic |
| Auxiliary limit | Backup temperature limit, wired in series with the primary limit. Mounted in the upper right hand corner of the panel, between the burner manifold and the flue gas collector box, just behind the draft motor. | ICB flashes the primary limit code. The furnace will not retry ignition during that call for heat. | Manual |
| Rollout switch | Flame spilling out into the burner manifold area. Located in the burner vestibule just above the right hand side of the burner assembly. | ICB closes the main and pilot gas valves and flashes the rollout code. It will not retry during that call for heat. | Remove power for 20 seconds to reset the ICB |
York adds two warnings about the auxiliary limit. If it has opened, the primary limit may also be faulty. And repeated primary limit trips from a complete blower failure can heat the unit enough to trip the auxiliary.
The ICB treats a primary limit trip as a temporary lockout. An auxiliary limit or rollout trip needs someone to reset it (697890-YIM-C-0213, gas heat operation errors).
What does York say to check for a limit trip (6 flashes)?
York says excess heat from low or no airflow opens a limit. The ICB shuts the gas valve, flashes 6, and the UCB runs the indoor blower. The checks in 697890-YIM-C-0213 are:
- Check airflow. If it is absent or weak, repair the air circulation system, then reset the auxiliary limit and verify operation.
- Verify the circulating air system, gas input rate and air temperature rise against the unit data plate.
- If the code persists, York gives a test at the 9-pin ICB connector, with the gas valve off, to tell a failed ICB from a limit that is really opening. If the limit is opening, replace that limit.
Our practical advice: a dirty filter, a slipping belt or a failed blower motor causes more limit trips than a bad limit. Fix airflow before you replace the switch.
What does York say to check for a rollout trip (7 flashes)?
Remove power for 20 seconds to reset the ICB. Then York lists four common causes:
| Cause | Check |
|---|---|
| Blocked flue outlet | Look for debris and clear it |
| Loose blower wheel on the draft motor | Confirm the wheel is secure on the shaft |
| Air temperature rise outside the data plate range | Check for low airflow or too much gas input |
| Cracked heat exchanger tube(s) | Compare the burner flame with and without the indoor blower running. If the flame changes, inspect the tubes. |
If all four check out, York's next step is a similar test at the 9-pin ICB connector, with the gas valve off, to decide between the ICB and the rollout switch. A rollout switch that trips again after a reset is telling you about the burner or flue, not about itself.
What limit setting does my unit need?
York's ZF manual gives limit control settings by tonnage, heat input and drive type (Tables 21 and 22 in 697890-YIM-C-0213). The copies we could read did not line the temperatures up with their rows, so we do not repeat them here. Read the setting printed on the old switch or the unit's data plate, and order by the part number on the old switch. Do not swap in a limit with a different setting.
Parts involved
| Component | Role in this issue | Where to find it |
|---|---|---|
| Rollout switch | Opens on flame rollout; 7 flashes | York S1-02526392011 Rollout Control |
| Temperature (limit) control | Listed for many ZF and DH/DM/DJ 5-ton models; confirm it is your primary limit by part number | York S1-02532606000 Temperature Control |
| Auxiliary limit | Manual-reset limit listed for DH, DM and DJ 5-ton units | York S1-02532655000 Control, Auxiliary/Limit, Manual Close |
| Limit control | Listed for many DH060 and DM060 models | York S1-02531830000 Limit Control |
| Ignition control board | Shows codes 6 and 7; latches on rollout | York S1-03109161000 Spark Ignition Control Board, UT, 24V | OEM Source 1 Part |
| Draft motor | Loose wheel is a rollout cause | York S1-02435322000 Venter Draft Inducer Motor 1/40 HP, 3200 RPM, CW, 208/230V 1-Phase 60 Hz | OEM Source 1 Part |
| More switches | Browse | York S1 Pressure & Limit Switches | Source 1 OEM |
Which York units this applies to
- York J05ZF parts: 5-ton ZF rooftop; rollout and temperature control listed.
- York J04ZF parts: 4-ton ZF rooftop; rollout listed.
- York J03ZF parts: 3-ton ZF rooftop; rollout listed.
- York DH060 parts: rollout, auxiliary and limit controls listed. York's DH manual was not used here.
- York DM060 parts: same controls listed; confirm by part number.
- York DJ060 parts: same controls listed; confirm by part number.
Scope: Behavior and checks are from York installation manual 697890-YIM-C-0213 (ZF036 to ZF072, R-410A, 60 Hz). DH, DM and DJ units have their own York manuals. For the other ignition control codes (2, 3, 5, 8, 9, 10), see York ZF ignition control flash codes.
Before you order
Note which code the ICB flashed and read the part number and setting printed on the switch. Send the unit model and serial number with it. To confirm fit, contact us at help@totalhvacparts.com or 610-487-7999.
Frequently Asked Questions
How do you reset the rollout switch on a York ZF rooftop?
York manual 697890-YIM-C-0213 says to remove power for 20 seconds to reset the ignition control board after a rollout. Find the cause first: blocked flue, loose draft motor wheel, wrong temperature rise or cracked tubes.
Is the auxiliary limit on a York ZF unit manual reset?
Yes. York says the auxiliary limit is manual reset, sits in the upper right hand corner of the panel and is wired in series with the primary limit.
What does 6 flashes mean on a York ZF ignition control?
A primary or auxiliary high temperature limit is open. York says the usual cause is low or no airflow, so check filters, belt and blower before the limit.
Why does my York rooftop keep tripping the rollout switch?
York lists a blocked flue outlet, a loose blower wheel on the draft motor, temperature rise outside the data plate range, and cracked heat exchanger tubes. Repeated trips call for those checks, not a new switch.
Sources
- York form 697890-YIM-C-0213, Installation Manual, ZF Series R-410A, ZF036–072, 60 Hz (gas heat operation errors and temperature limits, page 54; rollout switch and auxiliary limit, page 55; flash code 6 and 7 troubleshooting, pages 63–64; Table 30, page 66)
- Live product titles and series page part lists, as shown on each product page
Gas heat service involves line voltage, fuel gas and combustion products. Service should be performed only by qualified personnel, following York's manual for your unit and your facility's lockout/tagout procedures.