Laars Heating Systems · Error codes
Laars NeoTherm Residential 221 — Unconfigured DHW (domestic Hot Water) High Limit Setpoint Setting
221
Unconfigured DHW (Domestic Hot Water) high limit setpoint setting. The DHW high limit setpoint is unconfigured, so recheck the selected parameters and reverify and reset the module, verifying the electrical grounding if the fault repeats. The table classifies it as L.
Applies to
This overheating code is displayed by the NeoTherm residential control (hold/lockout codes) on NeoTherm Residential models (NTH 080–285), as documented in NeoTherm Residential Installation and Operation Instructions, Document 1252K (service manual 1291 adds codes 152/153) (1252K). Codes can differ between controller generations, so always check the manual that matches your unit.
- Laars Heating Systems NeoTherm Residential
- Laars NTH080
- Laars NTH105
- Laars NTH150
- Laars NTH210
- Laars NTH285
Controller: NeoTherm residential control (hold/lockout codes). Source manual: 1252K.
Why a code is not a diagnosis
An over-temperature code protects the heat exchanger or venting; it does not reveal whether the cause is low water flow, a failed pump, trapped air, fouling or a sensor fault.
Safe things to observe
- Note the code and whether rooms or hot water are still working.
- If you see steam, melted wiring or smell burning, switch the appliance off at its service switch and call a technician.
Do not
- Do not reset the appliance repeatedly while the cause is unknown.
- Do not remove covers or bypass any high-limit device.
How professional service helps
- A technician checks pump operation, flow, system pressure and the cleanliness of the heat exchanger.
- Combustion and safety devices are verified with an analyser and the manufacturer's procedure after any repair.
Where ROMA provides on-site service
On-site service is currently offered in Greater Vancouver, BC, including Vancouver, Burnaby, Richmond, Surrey, Coquitlam, North Vancouver, West Vancouver, New Westminster, Port Coquitlam, Port Moody, Delta, Langley, Maple Ridge, Abbotsford, Chilliwack, White Rock, Pitt Meadows, Tsawwassen, Anmore, Lions Bay, Belcarra, Bowen Island, Mission. Everything else on this site is reference information you can use anywhere in Canada.
Parts and service
Parts commonly involved
These parts appear in the documented text for this alert. A code reports a condition, not a failed part — a technician confirms the cause by testing before anything is replaced.
High-limit switch
A high-limit switch shuts the burner off when boiler water gets hotter than it should, protecting the heat exchanger and the system from overheating.
What a technician checks →
Service for this alert
- Gas Boiler Repair
Licensed gas technicians from ROMA Heating & Cooling diagnose and repair residential and light-commercial gas boilers across…
Every boiler part explained — what it does, how it fails and what a technician checks.
Documented for Laars Heating Systems NeoTherm Residential.
Frequently asked questions
Can I clear this code myself?
Clearing a code without fixing its cause usually just brings it back. Note the code, check the safe items on this page, then call a licensed technician. If your appliance manual describes a user reset for this exact code and it stays away, no call may be needed.
Boiler locked out? Call with the alert text ready.
The brand, model and this alert are passed along when you request service online, so the technician arrives prepared.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
- NeoTherm Residential Installation and Operation Instructions, Document 1252K (service manual 1291 adds codes 152/153) · 1252K · accessed September 7, 2026
Facts checked September 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.