Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The JX150 and JX200 are the two largest Mini-Therm JX boilers and the JX200 closes the non-condensing line at the 200 size — the top of the 50-200 MBTU/h range in Document 1478C — while the JX150 is the step below it.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Laars JX150 | Laars JX200 |
|---|---|---|
| Maximum input (as printed) | 150 MBH | 200 MBH |
| Fuel | Natural gas or propane | Natural gas or propane |
| Domestic hot water | None built in — a DHW relay kit and DHW panel assembly are listed in the manual's replacement-parts sections | None built in — a DHW relay kit and DHW panel assembly are listed in the manual's replacement-parts sections |
| Error reporting | No digital display or numeric codes — Section 11.C troubleshooting table and Section 11.D flow charts use the control LEDs (TEMP ACTIVE, LOW WATER, HI TEMP, TARGET) | No digital display or numeric codes — Section 11.C troubleshooting table and Section 11.D flow charts use the control LEDs (TEMP ACTIVE, LOW WATER, HI TEMP, TARGET) |
The JX200 is the ceiling of the Mini-Therm JX line — the largest size column in the parts tables of Document 1478C — and the JX150 is the step directly beneath it. Both are non-condensing, gas-fired hydronic boilers with natural-gas and propane parts sets and altitude groupings, diagnosed by LED and flow chart because neither has a digital display.
The manual's service content is shared across the steps: Section 11.C's numbered symptoms, the gas-pressure checks (5.5-10.5 in WC natural gas and 10-13 in WC propane inlet; 4.0/9.0 in WC NG/LP manifold) and Section 11.D's flow charts apply to both models.
Homes that genuinely need the JX200's full ceiling are at the top of what the residential non-condensing JX range can do — beyond it, larger loads move to Laars' condensing FT or commercial lines. Below that load, the JX150 delivers the same behaviour at the lower size column.
Laars Heating Systems
The Laars JX150 is the second-largest Mini-Therm JX boiler: a non-condensing gas-fired residential hydronic boiler at the 150 size step of the 50-200 MBTU/h range, with LED-based analog diagnostics and no digital display.
Laars Heating Systems
The Laars JX200 is the largest Mini-Therm JX boiler: a non-condensing gas-fired residential hydronic boiler at the 200 size top of the 50-200 MBTU/h range, with LED-based analog diagnostics and no digital display.
The JX200 at the 200 size — the manual's parts tables end at that column and the cover states sizes 50-200 MBTU/h.
Only when the heat-loss calculation genuinely approaches the 200 size. Both boilers are the same design with the same diagnostics; extra size without a matching load is not an advantage.
Above the non-condensing JX ceiling, larger residential or commercial loads are served by Laars' condensing FT, NeoTherm and commercial products, which are documented separately from the Mini-Therm JX manual.
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.