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74,000 BTU Output Cast Iron Oil Boiler (No Burner)

Brand:
Buderus
SKU:
G115WS3-NO-BURNER
Rating:
(10)
Q&A:
(6)
74,000 BTU Output Cast Iron Oil Boiler (No Burner)
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G115WS3-NO-BURNER has been discontinued
Discontinued May 4, 2026
This product was discontinued by the manufacturer.
BTU Input
105000
105000
Burner Brand
None

This item replaces: G115WS3-KNOCKDOWN

Schematic Feature!
Replacement Parts

Product Highlights

Product Highlight: Fuel Type
Oil
Product Highlight: System Type
Hydronic (Water)
Product Highlight: BTU Input
105000 BTUs
Product Highlight: Supply Size
1-1/4"
Product Highlight: Height (Inches)
34.5" Height
Product Highlight: Width (Inches)
23-1/2" Width

Description

Heating equipment must be installed, commissioned, and serviced by a licensed and qualified professional in accordance with manufacturer instructions, applicable codes, and industry standards. Manufacturers do not accept warranty or technical support requests from homeowners or unlicensed individuals. All warranty and technical inquiries must be initiated by the licensed professional responsible for the installation.

This product title reflects the boiler's IBR Net Output Rating when using a chimney vent burner. No burner is included.
  • Choosing burner 7738000097 for this boiler produces a 85,000 BTU DOE Rating and 74,000 BTU IBR Rating.
  • Choosing burner 7738000095 for this boiler produces a 74,000 BTU DOE Rating and 64,000 BTU IBR Rating.

Aquastat is not included. We recommend the Honeywell L7224U1002 Aquastat for this boiler.

The R2107 Logamatic Control is not included and can be purchased separately.

The Buderus G115WS boiler is based on the highly successful G115, the World's best selling boiler. The G115WS has been redesigned and reengineered to extract and deliver more heat from every fuel dollar, and now has higher outputs at less cost per BTU. Acknowledged as the leader in high-efficiency, low emission hydronic heating, Buderus offers innovative design and quality manufacturing with exceptional efficiency and performance.

Features:
  • Redesigned for Higher Outputs and Efficiency
  • High Efficiency - AFUEs Above 86%
  • Flexible, Corrosion Resistant GL-180M Cast Iron
  • Full Swing Burner Door for Excellent Serviceability
  • Chimney Vent from 85,000 to 136,000 BTU/Hr Output
  • Direct Vent from 74,000 to 120,000 BTU/Hr Output


Specs

Burner Brand:

None

BTU Input:

105000

Fuel Type:

Oil

Capacity (Boiler):

8.7 Gal

DOE Rating:

85000 (Chimney)

74000 (Direct)

IBR Rating:

74000 (Chimney)

64000 (Direct)

Efficiency:

86.7% (Chimney)

86.5% (Direct)

Supply Size:

1-1/4"

Return Size:

1"

Vent Size:

5"

Height (Inches):

34.5"

Width (Inches):

23-1/2"

Length (Inches):

23-5/8"

System Type:

Hydronic (Water)

Weight (lbs):

330 lbs

Contact

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You May Also Need

Box

G115WS3

Replacement Parts

SKU: G115WS3-NO-BURNER

Brand: Buderus

Search Parts:
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Product Image of no image
Boiler block G115 WS
63036027
Sorry, we don't currently sell this item. Request This Item
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Countersunk bolt DIN 7991 -M 8 x 16 -Ms
N/A
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Gasket D 41.7x55x1.5mm Afm 34, Left, 86159710
86159710
Buderus
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Gasket D33x44x2mm
63005462
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Plug G 1
05317712
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Stud bolt, M10x65 5.6 as per drawing
05555070
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Hexagon nut ISO4032-M10-8-A3K
N/A
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Washer DIN115-A10.5-A3K
N/A
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Reducing Nipple G1"Xg3/4, 63027607
63027607
Buderus
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Sensor sleeve PMW -3 SEE (4 1/2")"US"
7747022364
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Anchor bolt set, M8x310mm
05127574
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Flue connection complete
05354074
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Feed Unit G115 24Sect 1 1/4Npt1 Cpl"Us, 63028062
63028062
Bosch
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Seal 55x41.7x1.5 mm
05752540
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Heat exchanger baffle
05347085
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Flue baffle
63028999
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Washer DIN126-9
N/A
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Hexagon bolt ISO 4017 -M8x25-8.8
N/A
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Hexagon nut DIN 6923-M8-8.8-A3K
N/A
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Hinge bracket G105/G115
05327033
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Product Image of no image
Washer DIN125-A10.5-A3K
N/A
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Product Image of no image
Hexagon bolt ISO4017-M10x25-8.8
N/A
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Hexagon bolt ISO4014-M10x65-8.8
N/A
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Washer DIN125-A10.5-A3K
N/A
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Boiler feet M10x51mm complete
05236440
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Flue pipe sealing collarDN130 complete
05354010
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Flue silencer DN130 complete, without condensate drain; higher sound absorption
05074020
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Flue silencer D130 with an adaptor of 100mm length, with condensate drain; lower sound absorption
05074022
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Flue pipe sealing collar assy. DN130 (stepped)
05354030
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Spacer sleeve R3/8"x39
N/A
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Product Reviews

4.6 out of 10 reviews
89% would recommend this product
4.6
out of 10 Reviews
89% would recommend this product
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5 star
90%
4 star
0%
3 star
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2 star
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Customer Images

Most Liked Positive Review

The Cadillac of boilers!

In October 2009 I installed the Buderous G115-3 74,000 BTU boiler on top of a Buderus L160 indirect fired domestic hot water heater. I also purchased the Logamatic 2107 controller with outdoor temp sensor. This setup replaced an old 136,000 BTU Atlas boiler with internal DHW coil. So more than 2 years later all I can say is that this is a fantastic combo that is very efficient and provides lots of hot water too. The Logamatic controller took awhile to tweak (with helpful telephone instructions from Buderous customer service) and now provides perfect setback based on our lifestyle and outdoor temperature. I have averaged better than 20% fuel savings over the last 2 years and we never run out of hot water like the old system. I can clean the hemispherical combustion chamber myself (It still isn't sooty after 2 heating seasons!) and it will never need a liner or target replacement like other boilers. This thing burns CLEAN. The only down side is the chosen AFG burner is a lot noisier than the old AF burner we had before. The German Buderus products are so well made I do not understand why anyone would want a Weil McLain or similar when you can have a MUCH higher quality Buderus for virtually the same price. If you appreciate great engineering and use of latest marerials and technology, you will really like the Buderous stuff.
VS

Most Liked Negative Review

Failed in under 20 months

My Buderus g115ws3 ran problem-free for 18 months, with reduced oil consumption compared to the 22-year-old boiler it replaced. Then it stopped working. The tech from my service company found that section seal had failed and was weeping water into the combustion chamber. Buderus required the tech to come out a second time to verify what he had already found and made him wait onsite for a callback -- an unnecessary $500 expense on top of $1100 already spent to diagnose the problem. Now it has been almost three weeks and Buderus has not yet responded to the warranty paperwork. The $1600 I have already spent plus the labor I will have to spend to install a replacement plus the cost of running emergency electric heat will far exceed any fuel savings. So far my experience with Buderus has been low quality, high cost, poor/nonexistent service -- plus two months of no heat/hot water.
Showing 1-10 of 10 reviews

3 years later I've been very happy

Installed myself. Been getting 88% efficiency when I check with the analyzer. At this point the very low maintenance and price of oil have been great. I've changed the nozzle yearly and opened the door once. Very clean inside after 3 tanks of oil.
Rivian
NH
6 months ago
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Exceeded my expectations

Just starting into my first winter with it and so far it's been great. Install went perfect and paired with the reillo f3 it's super quiet and efficient
Chris
New England
4 years ago
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Failed in under 20 months

My Buderus g115ws3 ran problem-free for 18 months, with reduced oil consumption compared to the 22-year-old boiler it replaced. Then it stopped working. The tech from my service company found that section seal had failed and was weeping water into the combustion chamber. Buderus required the tech to come out a second time to verify what he had already found and made him wait onsite for a callback -- an unnecessary $500 expense on top of $1100 already spent to diagnose the problem. Now it has been almost three weeks and Buderus has not yet responded to the warranty paperwork. The $1600 I have already spent plus the labor I will have to spend to install a replacement plus the cost of running emergency electric heat will far exceed any fuel savings. So far my experience with Buderus has been low quality, high cost, poor/nonexistent service -- plus two months of no heat/hot water.
Mountain biker
Central Connecticut
4 years ago
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Happy Customer

Received my boiler early than expected and it was packed very well! Haven't installed it yet and if it doesn't leak I will be a very satisfied customer.
DanDew
Kennebunkport Maine
5 years ago
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Buderus G115

Replaced cracked Weil McLain chamber back in 2012 with the Buderus and a Beckett burner and beckett Aquasmart control. Definitely see the difference in efficiency after two years use. Use a separate tankless water heater, but the Buderus is still running clean
Freddy j
Westchester county NY
11 years ago
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Efficient but LOUD

We bought this boiler with a separate hot water heater, to replace our aging 27 year old Weil Mclain with separate Hot Water heater (which was working) with the external temperature sensor. It works very well, heating our 4600 sq foot, 6 zone home. It took some getting used to due to the temperature sensor. We appear to be saving fuel, however, the weather has been milder than usual, and with prices down, and not having the records for fuel use from last year, I can't speak to the efficiency. The biggest problem is that it is installed under our family room, and the flue shares a chimney with our fireplace. It is very loud. My husband insulated the floor above it, which helped some, but it is still very loud. Much of the noise is the air flow going up the flue. If it could have been installed at the other side of the house, it might not be so noticible, but the builder had installed the furnace flue in the same chimney as the family room fireplace, so there was no option. The noise is bothering my husband so much he is considering replacing it.
CT homeowner
East Lyme, CT
12 years ago
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Best Boiler on the Market

I installed a Buderus G115 with a Riello 40-F3 in my 5000 sf house 17 years ago. I live in Alaska and my boiler has over 31,000 hours on it. I clean the boiler and replace the nozzle once a year. I have never even had a boiler technician look at it. Absolutely runs like a champ with minimal maintenance. Would not consider another brand.
Chris Johansen
Fairbanks, Alaska
12 years ago
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The Cadillac of boilers!

In October 2009 I installed the Buderous G115-3 74,000 BTU boiler on top of a Buderus L160 indirect fired domestic hot water heater. I also purchased the Logamatic 2107 controller with outdoor temp sensor. This setup replaced an old 136,000 BTU Atlas boiler with internal DHW coil. So more than 2 years later all I can say is that this is a fantastic combo that is very efficient and provides lots of hot water too. The Logamatic controller took awhile to tweak (with helpful telephone instructions from Buderous customer service) and now provides perfect setback based on our lifestyle and outdoor temperature. I have averaged better than 20% fuel savings over the last 2 years and we never run out of hot water like the old system. I can clean the hemispherical combustion chamber myself (It still isn't sooty after 2 heating seasons!) and it will never need a liner or target replacement like other boilers. This thing burns CLEAN. The only down side is the chosen AFG burner is a lot noisier than the old AF burner we had before. The German Buderus products are so well made I do not understand why anyone would want a Weil McLain or similar when you can have a MUCH higher quality Buderus for virtually the same price. If you appreciate great engineering and use of latest marerials and technology, you will really like the Buderous stuff.
Cozy in Vermont
VT
15 years ago
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Top of the line boiler

Great boiler but beware it does not heat your hot water, only the heating system.
jeff
bucks county , pa
15 years ago
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Very nice boiler

What's to say... Its small and quiet. After a few seasons of heating I might have a more complete opinion...
Ehutch
Plainfield VT
16 years ago
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Product Q&A

6 Questions
6 Questions
ASK A QUESTION

Q: Will the 74,000 BTU Output cast iron chimney vent oil boiler heat my 1800 sq ft home, that was built in 1875, the house has blown in insulation and storm windows. I also plan on adding a indirect hot water heater.

Asked by Jerry 13 years ago

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Verified Author and ReplyVerified Reply- PexSupply Staff

This boiler would be able to provide approximately 41 BTUs per square foot in an 1,800 square foot house. This could be a bit low for for a house as old as yours. We would recommend an on-site heat loss analysis.

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-

I installed this unit in my house 2 years ago. and it heats the house really well & efficiently-1800 sq ft farmhouse built in 1860's w/ blown in insulation,storm windows and 60 gallon indirect hot water. I am in upstate NY and it gets cold here! - Jeff

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Q: Can i cold start this boiler once a year?

Asked by Billy 15 years ago

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Verified Author and ReplyVerified Reply- PexSupply Staff

Yes, you can.

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Q: How much does it weight and how difficult is it to get through doorways and down the basement stairs?

Asked by 15 years ago

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Verified Author and ReplyVerified Reply- PexSupply Staff

The dry weight of this boiler is 330 lbs. Please view this manual for the dimensions of the product--that will help you determine how difficult it will be to navigate through your doorways and stairs: http://s3.pexsupply.com/manuals/1249544647674/17212_PROD_FILE.pdf

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Q: it is enough to heat up my 1066 sqft house

Asked by 16 years ago

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Verified Author and ReplyVerified Reply- PexSupply Staff

This unit will work for you as long as your heat load is not over 69.4 BTUs per square foot. We suggest using our simple and quick BTU calculator which will help you chose the correct size boiler: http://www.pexsupply.com/pex/control/BTUCalculator

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Q: is 74,000 btu enough for a 2400 sq. foot house

Asked by lenny 16 years ago

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Verified Author and ReplyVerified Reply- PexSupply Staff

It is not. To heat an application this large you will need around 118,000 BTU.

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Q: Does boiler come pre-assembled or is it "knocked down"? Thanks

Asked by 16 years ago

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Verified Author and ReplyVerified Reply- PexSupply Staff

This comes with sections, and insulation already installed under the the jacket

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