Welcome! Here are the website rules, as well as some tips for using this forum.

# Oil to Gas Conversion Formula

Member Posts: 113
Hi all,

I am thinking of converting from oil fired burner to a dual fuel burner (oil and gas). The idea is to operate on whichever is cheapest. Everyone tells me that gas is cheaper now, but no one seems to know the formula to convert gallons of oil to therms of natural gas.

I use about 5000 gallons of oil each year for a multi-tenant building. How can I figure out how many therms would be needed to provide the same amount of fuel to heat the building and what is the approximate price per therm used (I realize it may vary from area to area - I'm located in Boston)

Any help would be much appreciated.

Thanks,

Jeremy

• Member Posts: 16,255
A gallon of oil contains 140,000 BTU

and a therm of gas contains 100,000 BTU.

So take the gallons of oil per hour, multiply that by 140,000 and then divide by 100,000. That will give you the number of therms you will need.

For example, if you are burning 8 gallons of oil per hour, 8 x 140,000 = 1,120,000.

1,120,000 / 100,000 = 11.2 therms per hour.
All Steamed Up, Inc.
Towson, MD, USA
Steam, Vapor & Hot-Water Heating Specialists
Oil & Gas Burner Service
Consulting
• Member Posts: 113
Any idea of price per therm?

Even a rough ballpark would be helpful.
• Member Posts: 4,593
The cost per therm

today is \$1.431. You can track the cost at www.bls.gov/ro1/cpibosap.htm for Boston area.

What kind of boiler are you converting and for a duel fuel burner which have you chosen?
• Member Posts: 113
edited July 2011
Thanks for the website

It's always hard to figure it out the price per therm because gas companies have distribution charges, delivery charges, supply charges etc. Does the \$1.431 include all of those in the average?

Anyway, we have two properties we are thinking of converting. One has a Weil McLain 880 and the other has a Weil McLain 680. I haven't committed to any type of burner yet, but I think my contractor recommended a power flame dual fuel burner. I have to check to make sure. I'll post back after I ask him. I first just wanted to figure out if I would be saving enough money to justify the expense.

Do you recommend any particular burner for dual fuel? Are there any special considerations I should be thinking of?

Thanks so much for the help.

-Jeremy
• Member Posts: 4,593
To the best of my knowledge

the cost per therm does not include surcharges - double check that with your local utility.

Power Flame Duel Fuel are good burners. The most important consideration is the contractor and his qualifications as to installing conversions. If you are not satisfied with his expertise then shop around. I am in the Rhode Island area and we have one very qualified installer down here who is presently working with me on converting a 2,500,000 BTU Duel Fuel application
• Member Posts: 5,409
gas in Boston

The cost of gas last winter was about \$1.92 per therm, including delivery and any other charges the gas company foists on us; that works out to \$2.70 for the equivalent of one gallon of heating oil.

Bob
Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
Vaporstat with a 12oz cut-out and 4oz cut-in
3PSI gauge
• Member Posts: 113
Dual Fuel Burner

Thanks to all for the pricing info. It turns out I was incorrect that the contractor had suggested powerflame. We've been talking about converting for a while and that was the name I had remembered being floated around.

However, it appears the dual fuel burner would be bought from a company called Industrial Combustion: http://www.ind-comb.com/

I don't know the exact model we would get yet, but does anyone here know if they make good burners? Any impressions?

Thanks,

Jeremy
• Member Posts: 4,284
Firing gas in a weil boiler

They list natural gas as being a few points less efficient than firing oil. So your gross required therms of gas could be as high as 4% more than with oil. Tuning of both fuels to meet the load would help trim this difference as opposed to simply firing to the factory specs.
Cost is what you spend , value is what you get.

cell # 413-841-6726
https://heatinghelp.com/find-a-contractor/detail/charles-garrity-plumbing-and-heating
• Member Posts: 212
Com oil & gas

Be careful with burners that make claims that they can burn gas or oil. It could be like the amphibious vehicle, it will go on land & water, but doesnt do either very well. If you truly are looking for a peice of equip to burn both fuels, look at a good quality 3 pass c/i boiler, that can be used with either gas or oil, then buy the burner that you would want to switch to as your optional burner should you want to change fuels. Then, you will get the higher efficiency from each.
• Member Posts: 4,593
What size boiler

are we talking about here. As for dual fuel Power Flame has an excellent reputation for such application.

It is best to get the make of your boiler and then look it up to see what the boiler manufacturer recommends for their boiler as to dual fuel.

I am working on a project right now for dual fuel 2,500,000 BTU's using a Power Flame Burner. We are converting an HB Smith 8 section boiler over from oil to dual fuel.
• Member Posts: 212
Oil to gas

Before switching fuels, consider this. Look into the new Honeywell AQ251 controller with outdoor reset, zone monitoring capabilities, and lockout, when combined with the AQ1000 tstats. That would be a huge fuel savings even before you switch. Then set your heating curve appropriatly, so on a jan night, you will have the 180 degrees you need, but on an april morning, you may only need 130- 140. Then, when the temp gets to about 60, the heat would go off completely.

Great landlord setup
• Member Posts: 16,255
These

are W-M 80-series steam boilers.
All Steamed Up, Inc.
Towson, MD, USA
Steam, Vapor & Hot-Water Heating Specialists
Oil & Gas Burner Service
Consulting
• Member Posts: 113
Thanks for all of the info/posts

1. Charlie: I didn't know that Natural Gas was less efficient than oil, but it seems that with the cost of natural gas so much cheaper it still makes sense to burn Natural Gas. The burner will definitely be tuned after the install.

2. Greg Maxwell: I've talked to a few people since Friday and they've all said good things about Industrial Combustion's burners. Our boilers are only a few years old so we will not be changing them now. I thought about the option of putting on a strictly gas burner and then saving the oil burner, but I didn't want to have to hire someone to come back and switch the burners. I'd rather be able to change between the two without a contractor. The cost for a dual fuel burner was only slightly higher.

3. Tim: One boiler is a Weil McLain 880 and the other is a Weil McLain 680. See Chart attached for ratings. We are planning on installing FP series Industrial Combustion Dual Fuel Burners on each boiler. See webpage for ratings etc.: http://www.ind-comb.com/fpseries.htm. The 680 will get the FPLG 8 and the 880 will get the FPLG 11. It looks like each burner can fire at the max rate for the boiler using either gas or oil. Is there anything else I should be looking at? What is your opinion on Industrial Combustion's burners?

4. Greg Maxwell: Our system is steam heat, not forced hot water. If I read your post correctly it seems the control you recommended is for hot water systems. Regardless, we just spent a great deal of money on a new Heat Timer Platinum system about a year or two ago. It has saved a lot of money so far. We also utilize indoor temperature sensors.

5. Steamhead: are you familiar with Industrial Combustion's burners? Do the ones I mentioned above seem like a good match?

Thanks for all of the help and advice everyone.

-Jeremy
• Member Posts: 4,593
The match for burners is great

The WM 680 uses 787,000 BTU's so the FPLG8 will give you 800,000 BTU's. The WM 880 uses 1,062,000 so the FPLG11 will give a 1,100,000.

Industrial Combustion's burners are great burners and have been around since back in the 1940's if memory serves me correctly. There is an outfit in Mass called Interstate HVAC Controls who handle that burner line. I have known them for sometime. I am sure they could give you the pros and cons of the burners if you contact them. They have been in business for over 70 years and have a great reputation. They install and service which is vital with commercial burners. They came out of Cambridge Mass originally but now are in Brighton. Contact info www.interstatecontrols.com or e-mail [email protected]

Make sure you check with the local gas company to ensure they can provide you gas and guarantee pressure needed for burners even with zero degree temperatures. You are looking at around 2,000,000 BTU's so the size of the gas service is critical along with the size of tap hole drilled in the gas main in the street.

The installer should give a proposal which includes a complete refurbishing and other things for the boilers. I will compile a list and post it later today.
• Member Posts: 4,593
Important stuff to make sure

the job is done correctly.

This is what we specify as an example of a job for a dual fuel burner.

1.     Remove existing oil burner, leave with customer.

2.     Wire brush and vacuum boiler.

3.     Have chimney cleaned by licensed professional sub-contracted to contractor installing burner.

4.     Open and clean water side controls.

5.     Drain and flush boiler.

6.     Notify customer of any hidden defects.

7.     Supply and install one new Power Flame CR2-G-20A gas burner, UL, CSD-l, low/high/low, 2" gas train, 208/1/60, with burner mounted control cabinet to include:

·        One Honeywell RM7897 A (UV) Control

·        One Control Switch

·        One low fire hold switch.

·        Five indicating lights

8.     Supply and install new 3" threaded gas line from meter to boiler room, this will require cutting new access hole through wall near meter, thereof this is to be a dedicated line.

9.     Supply and install all necessary hangers on ceiling to support pipe.

10.  All wall penetrations to be sleeved with plastic and sealed with expanding foam.

11. Supply and install gas train vent to terminate outdoors.

12.  Supply and install secondary pressuretrol to operate high fire.

13. As per code, Supply and install one manual reset McDonnell Miller low water switch on existing control.

14.  Supply and install all necessary wiring as per NEC Code, utilizing #14 THHN stranded wiring.

15. Supply and install new insulation block on existing burner mounting plate.

16.   Pipe in 2" gas train to new burner.

17.  Supply and install one new Tjernlund PAI-6 fan powered ceiling mounted air intake system with fan proving kit interlocked to all fossil fuel burning appliances in the space.

18.  Supply and install Honeywell 845 relay wired in series with burner to operate air intake system.

19. Cut 10" access hole through wall of boiler room.

20.  Supply and install intake hood over penetration and run duct to ceiling suspended air intake system.

21 Start up and computer tune new burner. Issue customer copy of printout as per RI Clean Air Act.

22.  Pressure test new gas line.

23.  Contractor to engage local permit, not to exceed \$ 150.00.

24.   Notify customer of any hidden defects.

25. Install Carbon Monoxide detectors as required throughout the dwelling.

• Member Posts: 113
Tim, Thanks for all of the information!