Laars Heating Systems · Rheos (discontinued)
Laars Rheos 1200
The Laars Rheos 1200 is a discontinued commercial modulating boiler at 1,200,000 BTU/h input, with a 6 in vent outlet, 6 in air inlet, 2-1/2" NPT water connections and a 20°F-rise flow of 104 gpm.
Key figures
- Max input
- 1,200,000 BTU/h
- Max CSA output
- —
- AFUE
- —
- Min input
- —
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Laars Rheos 1200 in practice
The Rheos 1200 is the 1,200,000 BTU/h input size of Laars' discontinued commercial modulating boiler and volume water heater line, documented in Document 1170F. The Figure 1 dimensional table lists a 6 in vent outlet, a 6 in air inlet, 2-1/2" NPT water inlet and outlet connections and a 1" NPT standard gas connection, and Table 8 gives a 20°F-rise flow of 104 gpm at 18 ft of head for the RHCH boiler.
The model structure reads RH for the Rheos mid-sized commercial series, C or H for mid-efficiency (non-condensing) or high-efficiency (condensing), H or V for hydronic or volume water, and the size digits; Document 1185B covers the condensing Rheos+ RHHH boiler and RHHV water heater at the same four sizes. The line installs up to 10,000 ft without high-altitude modification and Laars' discontinued-documents index lists both the Rheos and Rheos+ manuals and parts lists.
Best suited to
- Commercial hydronic loads near 1,200,000 BTU/h input
- Buildings replacing a Rheos or Rheos+ boiler or volume water heater
- Plants needing the manual's printed flow and head-loss data for pump sizing
Applicability and support
- Model number
- RHCH1200
- 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 | The 1170F model nomenclature prints 1,200,000 / 1,600,000 / 2,000,000 / 2,400,000 BTU/hr input for the four sizes. |
| Venting and air | ||
| Vent outlet | 6 in | Per the Figure 1 dimensional table. |
| Air inlet connection | 6 in | Per the Figure 1 dimensional table. |
| Physical and connections | ||
| Water inlet / outlet | 2-1/2" NPT | Per the Figure 1 dimensional table. |
| Gas connection (standard pack A) | 1" NPT | Per the Figure 1 dimensional table; control packages B and E use a larger gas connection on some sizes. |
| Operating limits and other | ||
| Flow at 20°F rise (RHCH boiler) | 104 GPM | With 18 ft of head loss per Table 8; maximum temperature rise is 30°F. |
| Altitude | To 10,000 ft without high-altitude modification | Per the manual's gas-supply notes; maximum inlet pressure 13 in WC, minimum 4 in WC natural gas and 6 in WC propane. |
| Fuel | Natural gas or propane | Natural gas or propane; the manual prints standard gas connections for both fuels. |
Manuals
Alerts documented for this model
None documented yet.
Frequently asked questions
What are the Rheos 1200's connections?
A 6 in vent outlet, 6 in air inlet, 2-1/2" NPT water connections and a 1" NPT standard gas connection, per the Figure 1 dimensional table in Document 1170F.
What flow does the Rheos require?
Table 8 lists 104 gpm at a 20°F rise with 18 ft of head loss for the RHCH boiler at this size; the maximum temperature rise is 30°F.
Is the Rheos discontinued?
Yes. Laars files the 1170 Rheos and 1185 Rheos+ documents under Discontinued Documents and lists the manuals and parts lists on its discontinued-documents index.
Questions about the Laars Rheos 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 Rheos 1200 vs Laars Rheos+ RHHH 1200Comparison
- Laars Rheos 1600Same series
- Laars Rheos 2000Same series
- Laars Rheos 2400Same series
- Laars Rheos+ RHHH 1200Same series
- Laars Rheos+ RHHH 1600Same series
- Laars Rheos+ RHHH 2000Same series
- Laars Rheos+ RHHH 2400Same series
- Rheos (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 — Rheos+ product page · accessed September 9, 2026
- Laars — Rheos Installation and Operation Instructions, Document 1170F · 1170F · accessed September 9, 2026
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.