Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The NTH105 and NTH150 are the second and third steps of the NeoTherm Residential ladder — the 105 and 150 columns of Document 1252K — on the same modulating condensing platform with the same Hold/Lockout code system. The NTH150 is also the smallest size at which Laars lists the companion NTV water heaters.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Laars NTH105 | Laars NTH150 |
|---|---|---|
| Maximum input (as printed) | 105 MBH | 150 MBH |
| Fuel | Natural gas or propane | Natural gas or propane |
| Domestic hot water | Boiler model — the control's error table includes DHW high-limit (80) and DHW sensor (93) entries per Appendix B | Boiler model — the control's error table includes DHW high-limit (80) and DHW sensor (93) entries per Appendix B |
| Error reporting | Numeric codes reported as Hold (H) or Lockout (L) — Appendix B of the I&O manual (Document 1252K) and Appendix 1 of the service manual (Document 1291) | Numeric codes reported as Hold (H) or Lockout (L) — Appendix B of the I&O manual (Document 1252K) and Appendix 1 of the service manual (Document 1291) |
Both boilers belong to the Model NTH 080-285 family in Document 1252K, differing only in the parts-list size column: 105 versus 150. The operator interface, the 11.G diagnostics menus, the lockout-and-alarm history and the Appendix B Hold/Lockout tables are the same across the line.
The NTH150 is a notable threshold in Laars' residential documentation: the service manual (Document 1291) pairs the NTH boiler range with the NTV water heaters at sizes 150-285, so the 150 column is where the documented NTH-plus-NTV combinations begin.
Choosing between the two follows the load calculation: homes and light commercial spaces whose design-day demand stays within the 105 column are served by the NTH105, while a load that approaches it steps up to the NTH150 — the middle size of the residential range and the start of the NTV pairing range.
Laars Heating Systems
The Laars NTH105 is the second NeoTherm Residential boiler size: a floor-standing modulating condensing unit at the 105 step between NTH080 and NTH150, on the numeric Hold/Lockout code system of Document 1252K.
Laars Heating Systems
The Laars NTH150 is the mid-size NeoTherm Residential boiler: a floor-standing modulating condensing unit at the 150 step of the 080-285 MBTU/h range, on the numeric Hold/Lockout code system of Document 1252K.
The size step: 150 against 105 in the parts list of Document 1252K. Design, operator interface and the Hold/Lockout code tables are shared.
The service manual (Document 1291) covers the NTH boiler at 080-285 together with NTV water heaters at 150-285, so the 150 column is the entry point of the documented NTV pairing range.
Both use Appendix B of Document 1252K (page 72) and Appendix 1 of Document 1291, where every code is classified as a Hold (retry) or Lockout (stop) with its corrective procedure.
A consultation includes a heat-loss review so the size is right the first time.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
Facts checked September 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.