Platform & Control Notes
NeoTherm (Honeywell SOLA touchscreen) shows numeric codes plus plain-text in an orange status bar. Codes 1–62 are mostly internal/sensor self-checks; everyday lockouts (ignition failed, flame lost, high-limit) appear as TEXT in the status bar. Mascot FT and older Mighty Therm use different schemes — call us.
Model Families & Platforms
- NeoTherm (NTH high-efficiency condensing)
- Mascot FT (Wall-hung fire-tube)
- Mighty Therm (Volume commercial water heater / boiler)
Diagnostic Characteristics & Common Service Topics
Laars boilers utilize specific display codes and safety lockouts to protect the heat exchanger, combustion system, and hydronic loop. Everyday issues like pressure loss, flame sensing errors, or circulator faults trigger specific responses depending on the controller generation.
| Code | Meaning | Action Required |
|---|---|---|
| 63 (Safety chain / rollout) | A device in the safety chain opened: flow switch, extra high-limit, low-water cutoff, low/high gas-pressure switch, or condensate level switch. | Call a pro to identify which safety device opened and correct the root cause. Gas-pressure and low-water trips are not homeowner resets. |
| 61 (Anti short cycle) | Normal protective hold — the burner is held off to prevent rapid on/off cycling. Not a fault. | No action usually needed — it clears itself. If the boiler short-cycles constantly, have a pro review sizing/controls. |
| 62 (Fan speed not proved) | The combustion fan didn't reach the required speed during start. | If it persists, call a pro to check or replace the combustion fan. Not a homeowner repair. |
| 51 (Pump fault) | Control detected a problem with the boiler pump/circulator subsystem. | Have a pro check the circulator and flow. A boiler that can't move water shouldn't be run hard. |
| 49 (24 VAC voltage low/high) | The control's 24 VAC supply is outside the acceptable range. | Pro task — check the transformer, connections, and incoming power. |
| 53 (AC input phases reversed) | Line and neutral reversed / wiring polarity problem on the AC input; lockout. | Call a pro/electrician — incorrect AC polarity must be corrected by a qualified person. |
| 3–31 (Internal fault) | Family of internal control-module faults (hardware, safety-relay, flame-bias, spark-voltage self-checks). | Try one reset. If an internal-fault code repeats, the control module typically must be replaced by a technician. |
| 1 / 2 (Safety data not verified) | The control needs its safety parameters verified — usually after a control/module replacement or a safety-parameter change. | Installer/technician task — complete the device configuration and safety verification. Not a homeowner step. |
Complete Error Code Library
For the complete searchable error-code lookup table for Laars equipment (including all 8 codes, exact lockout causes, and technician actions), visit the Phillips Hydronics Error Code Library.
Related Symptom & Diagnostic Guides
Sources & Documentation
- error-codes.json — https://www.manualslib.com/manual/3192527/Laars-Neotherm-Nth.html?page=88