Laars Heating Systems · Mighty Therm (discontinued)
Laars Mighty Therm 1200
The Laars Mighty Therm 1200 is a discontinued 1,200,000 BTU/h commercial hydronic boiler (Model HH without a pump or PH pump-mounted) with 972,000 BTU/h output, a 856 MBTU/h IBR net rating and a 995 lb shipping weight per submittal 1053K.
Key figures
- Max input
- 1,200,000 BTU/h
- Max CSA output
- 972,000 BTU/h
- AFUE
- —
- Min input
- —
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Laars Mighty Therm 1200 in practice
The Mighty Therm 1200 is one of the nine indoor sizes in the 500-1825 group of Laars' discontinued atmospheric commercial boiler line, documented in the 1053K submittal and the 1049F installation manual. The submittal lists it at 1,200,000 BTU/h input with 972,000 BTU/h output and a 856 MBTU/h IBR net rating, a 995 lb shipping weight (plus 55 lb with a mounted pump) and a 25°F-rise flow of 75 gpm at 4.8 ft of head.
Model HH ships without a pump and Model PH is pump-mounted; the submittal lists a 1/2 HP pump drawing 5.2 A for this size. The boiler connects on a 1-1/4" NPT natural-gas connection and 2-1/2" NPT water connections, runs on natural gas or propane, uses Category I draft-hood venting, and must be derated 4% per 1,000 ft above 2,000 ft. Laars' discontinued-documents index lists the 500-1825 manual and the 175-400 and 2000-5000 manuals, and the Document Library files the 1064/1065 manuals under Manuals, Discontinued Documents.
Best suited to
- Commercial hydronic loads near 1,200,000 BTU/h input
- Buildings replacing a legacy atmospheric Mighty Therm HH or PH boiler
- Plants that want the 500-1825 submittal's IBR net rating for sizing
Applicability and support
- Model number
- HH/PH 1200
- Canadian availability
- historical
- Production status
- discontinued
- ROMA supplies
- Confirmed at consultation
- ROMA services
- Confirmed at consultation
- Warranty
- Not verified
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.
Specifications
Published specifications
Values as published by Laars Heating Systems. Units are shown with every value; notes flag conflicting sources or missing figures.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| Input | 1,200,000 BTU/h | Per the Mighty Therm 500 to 1825 Indoor Hydronic Boiler Submittal Data (Document 1053K). |
| Output | ||
| Output | 972,000 BTU/h | Per the submittal's sizing table. |
| IBR net rating | 856 MBTU/h | Per the submittal; the note prints IBR net = output / 150. |
| Physical and connections | ||
| Shipping weight | 995 lb | Per the submittal; units with pumps add 55 lb. |
| Gas connection (natural) | 1-1/4" NPT | Per the submittal's dimensional data; propane sizes are printed separately and some optional gas trains use a larger connection. |
| Water connection | 2-1/2" NPT | Per the submittal's dimensional data. |
| Electrical | ||
| Pump (PH models) | 1/2 HP, 5.2 A | Per the submittal's pump data; Model HH is supplied without a pump. |
| Electrical | 115 V single phase, less than 12 A | Per the submittal's electrical data. |
| Operating limits and other | ||
| Flow at 25°F rise | 75 GPM | With 4.8 ft of head loss per the submittal's rate-of-flow table. |
| Altitude | De-rate 4% per 1,000 ft above 2,000 ft | Per the submittal's notes. |
| Fuel | Natural gas or propane | Natural gas or propane; the submittal prints natural-gas and propane connection sizes and the model structure uses N and P fuel codes. |
Manuals
Alerts documented for this model
None documented yet.
Frequently asked questions
What are the Mighty Therm 1200's ratings?
Submittal 1053K lists 1,200,000 BTU/h input, 972,000 BTU/h output and a 856 MBTU/h IBR net rating, with a 995 lb shipping weight.
What is the difference between Model HH and PH?
Model HH is the boiler without a pump and Model PH is the pump-mounted version; the submittal lists a ${o.pump} pump drawing ${o.amps} for this size and adds 55 lb to the shipping weight when pumps are included.
Is the legacy Mighty Therm discontinued?
Yes. Laars' discontinued-documents index lists the Mighty Therm 175-400, 500-1825 and 2000-5000 manuals, and the Document Library files the 1064/1065 manuals under Manuals, Discontinued Documents.
Questions about the Laars Mighty Therm 1200?
Describe what the boiler is doing and get a straight answer about the next step.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Compare and explore
- Laars Mighty Therm 500Same series
- Laars Mighty Therm 600Same series
- Laars Mighty Therm 715Same series
- Laars Mighty Therm 850Same series
- Laars Mighty Therm 1010Same series
- Laars Mighty Therm 1430Same series
- Laars Mighty Therm 1670Same series
- Laars Mighty Therm 1825Same series
- Mighty Therm (discontinued) series hub
- Buying guide
Sources and verification
- Laars Heating Systems — official site · accessed September 7, 2026
- Laars — contact (Laars Canada, 9 Brigden Gate, Halton Hills, Ontario) · accessed September 7, 2026
- Laars — Document Library (Discontinued Documents category) · accessed September 9, 2026
- Laars — Discontinued Documents · accessed September 9, 2026
- Laars — Mighty Therm product page · accessed September 9, 2026
- Laars — Mighty Therm 500 to 1825 Indoor Hydronic Boiler Submittal Data, Document 1053K · 1053K · accessed September 9, 2026
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.