Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The JX075 and JX100 are adjacent Mini-Therm JX size steps — 75 and 100 in the 50-200 MBTU/h range of Document 1478C — on the same non-condensing platform with LED-based analog diagnostics and no numeric codes on either.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Laars JX075 | Laars JX100 |
|---|---|---|
| Maximum input (as printed) | 75 MBH | 100 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) |
Both models are covered by the single Mini-Therm JX manual, Document 1478C: a non-condensing gas-fired hydronic design with natural-gas and propane parts sets, altitude groupings, and the twelve-symptom troubleshooting table (11.C) and LED flow charts (11.D) instead of any numeric error display.
The difference between the models is the size column: the JX075 carries the 75 parts column and the JX100 the 100 column. Neither produces domestic hot water internally — the DHW relay kit and panel assembly listed in the parts sections are the accessories for hot-water-demand applications on both.
For a typical detached home the JX100 is the more common landing point of the two, while the JX075 suits smaller houses, suites and low heat-loss buildings. Sizing follows the heat-loss calculation; the manual's service procedures are identical across the steps.
Laars Heating Systems
The Laars JX075 is the second Mini-Therm JX size: a non-condensing gas-fired residential hydronic boiler at the 75 step of the 50-200 MBTU/h range, with LED-based analog diagnostics and no digital display.
Laars Heating Systems
The Laars JX100 is the mid-range Mini-Therm JX boiler: a non-condensing gas-fired residential hydronic boiler at the 100 size step of the 50-200 MBTU/h range, with LED-based analog diagnostics and no digital display.
The size step only: 75 versus 100 in the parts tables of Document 1478C. The non-condensing design, fuels, LED diagnostics and service guidance are shared.
Document 1478C covers the whole 50-200 MBTU/h Mini-Therm JX line, so one manual serves the JX075, the JX100 and the rest of the series.
No. The JX has no digital display; diagnosis uses the numbered troubleshooting table and the TEMP ACTIVE, LOW WATER, HI TEMP and TARGET LEDs in the flow charts.
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.