Weil-Mclain Boilers: Ultra
Re: Status & Fault Codes
The Ultra Series 1 & Series 2 boilers have a 4-digit display for monitoring operating status & fault codes.
OPERATING STATUS
After the display shows "Stby" for a brief period, the first character shows boiler status, followed by boiler outlet water temperature.
| 1st Digit | Boiler Status |
| 0 | Standby - no call for heat |
| 1 | Pre-purge (10 sec) or Post-purge (15 sec) |
| 2 | Ignition |
| 3 | Burner on for space heating |
| 4 | Burner on for Domestic Hot Water |
| 5 | Checking airflow before pre-purge |
| 6* | Burner off because temperature setting has been reached |
| 7 | Pump off-delay after space heating cycle (10 sec) |
| 8 | Pump off-delay after DHW heating cycle (30 sec) |
| H | Test mode - manual high-fire |
| L | Test mode - manual low-fire |
* First digit = 6 - Also shown if control module loses flame signal during run mode.
SOFT LOCKOUTS
If the burner is being held off due to a soft lockout, the display alternates between showing "9" followed by boiler outlet temperature and "b" followed by the 2-digit codes below.
* All soft lockouts will automatically reset once the condition returns to normal or has timed-out.
| Code | Description |
| _18 | Outlet temperature too high (over 203 deg). Burner off until outlet water temperature drops 9 deg below target temperature. |
| _19 | Return temperature too high (over 203 deg). Burner off until both outlet temperature and return temperature drop 9 deg below target temperature. |
| _24 | Return temperature higher than outlet temperature. Burner off until corrected. |
| _25 | Outlet temperature rose too quickly. Burner off 10 to 15 min. |
| _26 | External limit open. Burner off for 150 sec. |
| _29 | Blower signal not zero when it should be. Burner off until condition corrected. |
| _30 | Temperature rise more than 58 deg. Burner off for 150 sec up to 22 min. (each failed cycle adds 1 min.) |
| _35 | Shorted flue temperature sensor. Burner off until corrected. |
| _40 | Open flue temperature sensor. Burner off until corrected. |
| _52 | Flue temperature exceeded 216 deg but did not exceed 225 deg. (hard lockout at 225 deg.) Burner off for 150 sec. |
| _65 | Waiting for blower to restart. |
HARD LOCKOUTS
First digit = "E" - Hard Lockout. Boiler in hard lockout requires manual RESET.
| Code | Description |
| 00 | Flame detected on startup |
| 02 | Ignition failed after 5 tries |
| 03 | Internal control failure |
| 04 | Power lost after lockout |
| 12 | External limit open (wired in hard lockout circuit) |
| 18 | Outlet water temperature was higher than 210 deg. |
| 19 | Return water temperature was higher than 210 deg. |
| 25 | Temperature rise greater than 58 deg |
| 28 | No signal from blower |
| 29 | Blower signal not zero when it should be |
| 31 | Outlet temperature sensor shorted |
| 32 | Return temperature sensor shorted |
| 36 | Outlet temperature sensor open |
| 37 | Return temperature sensor open |
| 44 | Internal control failure |
| 52 | Flue temperature was higher than 225 deg. |
| 60 | Internal error reading parameters |
| 61 | Airflow circuit failure |
| 65 | not enough blower driving force |
INFORMATION MODE
| Param | Description |
| 1 | Measured outlet water temperature |
| 2 | Measures return water temperature |
| 3 | Not used |
| 4 | Outside air temperature (if connected) |
| 5 | Flue temperature |
| 6 | Target outlet water temperature |
| 7 | Outlet water temperature rate of change (deg/sec) |
| 8 | Return water temperature rate of change (deg/sec) |
| 9 | Not used |