Advice on converting from Oil to Gas


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Old 09-03-13, 08:12 PM
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Advice on converting from Oil to Gas

Hello,

I am interested in converting my pretty new Weil-Mclain Oil burner to a gas one. I live in New England and have a steam system with radiators. I have a gas line already running into my house for a tankless water heater and a gas range. I've had 4 different companies come to my house and give me estimates, 2 of them have said that I can just replace the gun on the Weil-Mclain with a gas burner and run a gas line to it. One of them also recommended that I have a vent installed to pipe in fresh air to the boiler to help with any Co2 problems. My chimney is already lined so that's not an issue.

The other two companies wanted me to get ride of my Weil-Mclain and just get a gas boiler. One said that replacing the gun wasn't as efficient use of the gas because the chamber is much larger and it's a better investment to get a new boiler. The other said that I wouldn't be able to replace the gun on the Weil-Mclain at all and my only option is to get a new boiler.

Does anyone have any opinions on this? I really would like to get away from oil as I live in a cold climate and have a large 1800 sq ft. 5 bed room house. It was recently gutted to the studs and remodeled, but the heart of it is still from 1920. The difference between replacing the gun and replacing the entire boiler is roughly $4,000 give or take from the estimates, so i'm leaning towards just replacing the gun, but would like to know if anyone else has had any experience with this situation or could offer any other kind of insight.

Thank you,

Sam
 
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Old 09-03-13, 08:38 PM
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You would want to change the boiler. The oil boiler chamber is over sized for gas and changing just the burner would make it inefficient. I would go with the company's that recommend boiler replacement.

Next what size boiler are they installing? A house of your size should weigh in at aroung 45k btu or so,,,, make sure a heat loss calc is done. 90% of old boilers are oversized...

Last..... heat emitters? They are keeping the rads???? Converting them to hot water? Keeping steam?
 
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Old 09-03-13, 10:28 PM
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Some boilers cannot accept a gas conversion burner. That you had three contractors tell you they could I suspect that your boiler CAN be so converted.

However, it IS true that a boiler designed for gas from the start will be more efficient than an oil fired boiler with a gas conversion burner. The real question is how much will this lower efficiency cost over the life of the equipment or the time you live in the house? Four thousand dollars will buy a lot of gas.

And since this is a steam system there is probably going to be even less difference between the converted boiler and boiler designed for gas in a hot water system. If it were me I would go with the conversion burner. I might also go for a slightly smaller combustion chamber but that is optional.
 
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Old 09-04-13, 05:43 AM
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They are keeping the radiators and keeping the steam system, just want to change the boiler to a gas burner. I think they said an IN5? Not sure if that's a thing, but both companies that wanted to change my boiler took stock of all of the radiators in the house so they seemed to know what size I needed. Is the efficiency issue is marginal one? Enough to really justify another $4,000 on a new boiler?

Thank you for your input, it's much appreciated!
 
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Old 09-04-13, 10:40 AM
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Not a steam guy but you size the boiler to the amount of radiation in the home...

Is the efficiency issue is marginal one? Enough to really justify another $4,000 on a new boiler?
Furd answered best here...

And since this is a steam system there is probably going to be even less difference between the converted boiler and boiler designed for gas in a hot water system. If it were me I would go with the conversion burner. I might also go for a slightly smaller combustion chamber but that is optional.
Ignore my first answer. I assumed they were changing to a water system...I did not think anyone keeps steam systems anymore, but probably a money thing...
 
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Old 09-04-13, 11:22 AM
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I honestly don't know why anyone would want a steam system in their house other than the huge cost of converting a steam system to hot water.

Be that as it may, steam systems are totally different animals from hot water systems. With a steam system the heat loss of the house is used to size the radiators and then the area of the radiators is used to size the boiler, just the opposite of a hot water system. Making significant improvements to the building's "envelope" such as air sealing or increased insulation will NOT change the required size of the boiler but it may mean that some areas will require less radiation. Since steam systems are not zoned it often just means a lesser amount of time that the boiler is fired.

Because ALL steam systems have to create steam to operate there is very little room for savings using things like outside temperature setback or optimized run time based upon the thermostat "on" time. A steam system will never be as efficient as a hot water system and trying to make it so is a futile waste of money. The one possible exception to this rule is a "vapor" system where the system is often running in a vacuum but these systems are even rarer than a straight steam system and have their own problems.

So, if you cannot afford to convert your system to hot water, and you probably can't, then the minimal savings in efficiency by going to a new boiler will take many years to realize. I would go with the conversion burner.
 
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Old 09-04-13, 06:25 PM
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Thank you both for your input, it is extremely helpful. I guess my last question would be, with such an inefficient system would there still be enough money saved in the long run by doing the conversion that it would be worth it for the cost? Or is it money poorly invested because its not a good sytem to begin with and I'd be better off just dealing with my oil burner?
 
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Old 09-04-13, 07:08 PM
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It looks like I have lead you down the wrong path. Steam systems are not inherently inefficient, just less efficient than the best hot water systems. Properly maintained, your steam system can be nearly as efficient as the average hot water system. Changing to a hot water system makes no sense unless you have an unlimited budget AND are going to do a total gut and rebuild inside your home.

Changing the system to hot water, with all the bells and whistles to make it the most efficient it can be would cost a large pile of Krugerrands. There would be little to no economic gain in anything under several decades although there could be some comfort gains. Changing the boiler would also be a payback measured in decades in my opinion vs. just changing the burner PROVIDED that the existing boiler is in fairly decent condition.

Right now gas enjoys a sizable advantage over oil as far as cost and it also has the feature that it doesn't need to be stored. Speaking of storage, is your oil tank buried and if so how old is it? ANY fuel oil tank that is buried should be dug up ASAP and replaced with an above-ground tank. Again, I think a conversion burner DOES make sense. We have a member (Luckydriver) that had a conversion burner installed a year or so ago and he has realized at least a fifty percent reduction in his fuel costs. Obviously you need to balance that saving against the capital cost of the conversion but I really think that you will pay for the conversion in the first year and from then on it is pure savings, even if it isn't the absolute most efficient system on the planet.
 
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Old 09-05-13, 05:48 AM
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Excellent insight once again, thank you. Ya I have no interest at all in changing my steam system to hot water, we just bought this house and while I don't know why the contractor didn't do that, like you suggested it was probably because it was to expensive. Our Oil tank is above ground right now, but is showing some signs of wear because it's really old so I do want to avoid having to by a new tank and would rather just invest in the gas conversion for the boiler instead.

Since we just moved in I have not gone through an entire winter with the system we have in place so I don't know what the costs are. So i'm somewhat at a crossroads right now, do I wait a winter with the oil burner and see what the actual price is and than use that figure as a comparable for the gas savings? Or just suck up the costs for the conversion burner now and hope for the best.
 
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Old 09-05-13, 02:47 PM
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How much oil do you have? There is little market for old residential fuel oil so you will likely have to pay to get rid of it. If the tank is near empty then I would suggest doing the conversion now. If the tank is near full then I would burn it off before conversion.

Gas conversion burners cost in the neighborhood of $600 the last time I checked, which was about a year or so ago. The boiler really should have the firesides cleaned when you install the conversion burner and the cost of cleaning will run somewhere around $150 depending on the boiler and the prevailing rates in your area. Add in the cost of extending the gas line to the burner and including all permit and inspection fees and you are probably looking at $1,000 to $1,500 total cost not including removal and disposal of the oil tank. Again, your local prices could be a bit lower to significantly higher.

Here is the thread started by luckydriver when he asked about installing a conversion burner in his system. http://www.doityourself.com/forum/bo...ck-math-2.html It is long but it has a wealth of information. The order of the posts may be messed up from my link.

Here is another of luckydriver's threads concerning an incorrect conversion burner first being installed. http://www.doityourself.com/forum/ga...cceptable.html
 

Last edited by Furd; 09-05-13 at 03:28 PM.
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Old 09-05-13, 06:56 PM
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I agree with Furd's suggestion of doing the conversion burner, especially with a steam boiler.

I believe the 400 ppm of CO refered to in Luckydriver's thread was the maximum allowed in the exhaust, certainly not in the house.
 
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Old 09-06-13, 05:59 AM
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Thank you for the link to the thread it is very helpful.

The tank is currently empty which is why I wanted to try to move on this now. Unfortunately the two quotes i've gotten to do the conversion have both been $4,000. That includes a new burner, running the pipes to the new burner, all the electrical wiring and permits, cleaning out the boiler inspecting my chimney (which i'm pretty sure is already lined) as well as removing the oil tank. If it were only $1,500 i would jump on it, but $4,000 has give me pause if it this is the right move right now.

Unfortunately I'm not sure what i should do. I'm thinking I should just go through a winter with my oil burner and at least see how much money i'm going to spend so that I can actually calculate my savings by switching over to gas, but I loath the idea of filling up the tank with oil. It is a quandary.
 
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Old 09-06-13, 06:10 AM
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I would call tech support here and tell them what you got and what you want to do....This way you will know for sure if you can actually convert...

Also they will suggest reps in your area so you can get an additional quote....

Technical Support
 
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Old 09-06-13, 06:14 AM
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Additionally what did the installers say the burner they were using? The carlin EZ burner is what I see most in the field...

http://www.carlincombustion.com/down...gas-053008.pdf
 
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Old 09-06-13, 09:13 AM
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Do you want to do-it-yourself? It is a pretty straightforward job but it does require a fair amount of tools and techniques. You might be able to DIY parts of the job and then sub out that which is beyond your skills. We would need ten thousand pictures of your current installation to guide you. Okay, that's a slight exaggeration but numerous well-lit and in focus pictures will help. We don't need any close-ups but instead pictures from far enough away to see how everything is set up and what kind of clearances exist. Also need to see the gas meter and piping.
 
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Old 09-08-13, 06:56 PM
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Ya they wanted to install the carlin burner
 
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Old 09-08-13, 07:05 PM
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Ya I have no interest in doing this myself but thank you for the offer to help. I may reach out to someone else for an additional quote, but I suspect that it will be similar in price since I've had two quotes that were basically the same. I just talked to my sister in law and she has an oil burner with a forced hot water system and she pays 2400 a year for heating (roughly three tank fill ups running $800 each). Her house is a little smaller than mine and has older insulation. I suspect that with my system I'm looking at more than that a year? Question is how much would the gas conversion burner run me a year, I suspect it would be less than that? Even with a $1000 saving it would pay for itself in 4yrs. Still very undecided on this....
 
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Old 09-08-13, 07:17 PM
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Old 09-08-13, 07:24 PM
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With energy prices the way they are, converting to gas is a no-brainer even if the thing runs at 50-60% efficiency.
 
 

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