Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
Boilers.ca is a brand of ROMA Heating & Cooling · Licensed gas contractor LGA0202903
Comparison
Verdict in brief
The FTXL FTX1000 is the Series 110 flagship at 999,000 BTU/hr: against the FTX850 it fires 100 to 1000 MBH at 98.3% submittal thermal efficiency (the line's best) with 10:1 turndown, stepping the gas connection to 1-1/4", the air intake to 6" and the water content to 19 gallons.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Lochinvar FTXL FTX850 | Lochinvar FTXL FTX1000 |
|---|---|---|
| Heating input, minimum | 121.4 MBH | 100 MBH |
| Heating input, maximum | 850 MBH | 1,000 MBH |
| Gross output | 825 MBH | 982 MBH |
| Net AHRI water rating | 717 MBH | 854 MBH |
| Efficiency (thermal) | 97 % | 98.3 % |
| Water content | 15.9 gal | 19 gal |
| Space-heating water connections | 2-1/2" | 2-1/2" |
| Gas connection | 1" | 1-1/4" |
| Air inlet size | 4" | 6" |
| Vent size | 6" | 6" |
| Shipping weight | 604 lb | 670 lb |
The FTX850 is a Series 120 unit and the FTX1000 is the Series 110 "FTXL 1.0" — the I&O covers them in separate series groups, and they behave differently at part load: the submittal rates the 850 at 7:1 turndown and the 1000 at 10:1.
The 1000 prints the best efficiency in the line — 98.3% submittal thermal efficiency against the 850's 97.0% — and lifts capacity from 850 to 1000 MBH of input with gross output from 825 to 982 MBH and the AHRI net rating from 717 to 854 MBH.
The plant steps too: the gas connection grows from 1" to 1-1/4", the air intake from 4" to 6", water content from 15.9 to 19 gallons and shipping weight from 604 to 670 lb per the submittal; the vent stays 6".
Lochinvar
The FTXL FTX850 fires 121.4 to 850 MBH with 825 MBH gross output and a 717 MBH AHRI net rating at 97.0% submittal thermal efficiency, on 2-1/2" water connections with 6" venting.
Lochinvar
The FTXL FTX1000 tops the FTXL line at 100 to 1000 MBH input with 982 MBH gross output and an 854 MBH AHRI net rating at 98.3% submittal thermal efficiency — the "FTXL 1.0" 999,000 model.
The FTXL I&O covers "Models 400-850 Series 120 & 1000 Series 110" — the FTX1000 is the Series 110 unit while the 400-850 sizes are Series 120.
The FTX1000 at 98.3% thermal efficiency per the submittal — higher than the Series 120 sizes, which run from 98.0% (FTX400) down to 97.0% (FTX850).
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 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.