Weil-McLain Simplicity 150-C
The Simplicity 150-C is the mid-size Simplicity: 150 MBH input, 139 MBH DOE heating capacity and 95% AFUE with 4.0 GPM of DHW at a 70°F rise in the same 16-inch cabinet.
Key figures
- Max input
- 150 MBH
- Max CSA output
- 139 MBH
- AFUE
- 95 %
- Min input
- —
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Weil-McLain Simplicity 150-C in practice
The Simplicity 150-C fires at 150 MBH input for 139 MBH of DOE heating capacity and a 121 MBH net AHRI rating at 95% AFUE, with 10:1 turndown and the combi-or-heat-only flexibility shared by every Simplicity size. Its brazed plate DHW section delivers 4.0 GPM at a 70°F rise per the brochure.
The 150-C keeps the compact 16 x 20 x 34 inch cabinet of the 110-C but steps up to 3.1 gallons of water content and 105 lb, with the same 3/4" heating connections, 1/2" DHW connections and 2"-or-3" venting to 100 ft. It vents as a Category IV appliance with a ULC S636-compliant kit in Canada.
Best suited to
- Homes whose heat-loss calculation lands in the 110-150 MBH band
- Households wanting noticeably more hot water than the 110-C
- Combi replacements in a 16-inch cabinet footprint
Applicability and support
- Model number
- Simplicity 150-C
- Canadian availability
- available
- Production status
- current
- ROMA supplies
- Confirmed at consultation
- ROMA services
- Confirmed at consultation
- Warranty
- Series terms
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 Weil-McLain. Units are shown with every value; notes flag conflicting sources or missing figures.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| Input, maximum | 150 MBH | CSA input (maximum). |
| Output | ||
| DOE heating capacity | 139 MBH | DOE heating capacity at maximum input; the manuals also call this CSA Output. |
| Net AHRI water rating | 121 MBH | Net AHRI rating per the boiler manual ratings table. |
| Efficiency | ||
| Efficiency (AFUE) | 95 % | 95% AFUE per the boiler manual, brochure and CA page. |
| Domestic hot water | ||
| DHW flow at 70°F rise | 4 GPM | Per the Simplicity brochure ratings table. |
| Domestic hot water | Integrated combi: built-in DHW module with brazed plate heat exchanger | |
| Venting and air | ||
| Venting | 2" or 3" PVC, CPVC, polypropylene or stainless steel (Category IV) | Canada: install per CAN/CSA B149.1 or B149.2 with a ULC S636-compliant vent kit. |
| Max. equivalent vent/air length | 100 ft in 2" or 3" (vent and air each) | |
| Physical and connections | ||
| Weight | 105 lb | Boiler weight per the brochure and product spec table. |
| Dimensions (L x W x H) | 16" x 20" x 34" | |
| Gas connection | 1/2" NPT male | |
| Heating water connections | 3/4" NPT male | Boiler out and boiler in are 3/4" male NPT on the 150; DHW connections are 1/2" male NPT. |
| Operating limits and other | ||
| Turndown | 10:1 | 10:1 turndown ratio per the brochure and submittal. |
| Boiler water content | 3.1 gal | |
| Altitude rating | 2,000 ft | No modifications from sea level to 2,000 ft; the boiler auto-derates about 4% per 1,000 ft above sea level. |
| Fuel | Natural gas or propane | Propane requires a conversion kit per the CA product page. |
Manuals
- Simplicity Boiler Manual, 550-143-073/0125550-143-073/0125 · 2025-01
Alerts documented for this model
- Nothing shown on display screen and boiler will not respond to call for heat
- Nothing is shown in display screen and no other boiler components are operating
- Nothing is shown on display screen, but boiler is operating
- TEMP RISE
- COMM ERR
- CTRL FAULT
- LWCO OPEN
- RETURN > SUPPLY or BLR IN > BLR OUT
- BOILER OUT SNSR or FLUE SENSOR
- FLUE TOO HIGH
- MANUAL LIMIT or AUTO LIMIT
- HIGH TEMP LIMIT
- FALSE FLAME
- GAS RELAY 1-4
- IGN FAULT 1
- IGN FAULT 2
- FLAME LOSS
- AIR P-SW OPEN
- CLOSURE SWITCH
- CONFIG FAULT
- DHW OUT > BLR OUT
- CHIP FAULT
- 60F > RETURN
- FLUE 1 OPEN
- FLUE 1 SHORT
- FLUE 2 OPEN
- FLUE 2 SHORT
- BOILER OUT1 OPEN
- BOILER OUT1 SHRT
- BOILER OUT2 OPEN
- BOILER OUT2 SHRT
- BOILER IN OPEN
- BOILER IN SHORT
- BLOWER FAULT 1
- BLOWER FAULT 2
- BLOWER FAULT 3
- BLOWER FAULT 4
- WRONG J6
- A2D FAULT
- FLAME CIRCUIT
- SUPPLY SENSOR
- RETURN SENSOR
- DHW OUT SNSR
- OUTDOOR SENSOR
- EXCEEDED FLOW RATE
- REDUCED TGT - FLUE
- REDUCED TGT - BLR
- REDUCED TGT - FLOW
- CLOCK FAULT
- WRONG SOFTWARE
- LOW FLAME SHUTDOWN
- INTL DISPL COMM ERR
- PREHEAT ACTIVE
- CALIBRATE NEEDED
- CALIBRATE IS ACTIVE
Frequently asked questions
How does the 150-C differ from the 110-C?
Input rises from 110 to 150 MBH, DOE heating capacity from 100 to 139 MBH, DHW flow from 2.9 to 4.0 GPM at a 70°F rise, and weight from 96 to 105 lb. The cabinet stays 16 x 20 x 34 inches.
What are the 150-C's connections?
3/4" NPT male heating connections, 1/2" NPT male DHW connections and a 1/2" NPT gas connection, like the 110-C.
Can the 150-C run heat-only?
Yes — Simplicity units can be configured as combi or heat-only boilers, so a future hot-water heater replacement can switch the same appliance to combi duty.
Questions about the Weil-McLain Simplicity 150-C?
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.
Sources and verification
- Weil-McLain Canada — Simplicity · accessed September 7, 2026
- Simplicity Boiler Manual 550-143-073/0125 · 550-143-073/0125 · accessed September 7, 2026
Facts checked September 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.