Oil to Gas Boiler Conversion Run-Around

[jadnashua]

Do you currently have a thermometer on the return line you can check out? If so, what temps are you seeing there verses the outlet temps? If you don't have one, if you have a reasonably accurate instant read meat thermometer or oven thermometer, you could put it on the return pipe and wrap something around it to help keep it in contact.

[Tom Sawyer]

Lot of talk about mod con boilers. Low mass, high efficiency. The Europeans were the first ones to put these things into regular use. Funny thing is though that 30 years later they are going back to high mass cast iron boilers. Seems the mod cons are not quite as efficient as everyone thought. Here is a situation where because of the system mass a mod con could be used but not without having to make piping modifications at additional expense when in reality, when you do a cost/payback analysis the most prudent thing to do is to replace the boiler with a more efficient one. My choice would be the Buderus Logano oil fired series. Probably a BE115 wich is non condensing but still runs at close to 92%

[danboston]

Tom:

I may be able to go to gas. If so, my contractor recommended that I switch to a Burnham ES-2. It is an 85% AFUE cast-iron gas-fired boiler with outdoor atmospheric controls that adjust the boiler temp up or down based upon the outdoor temp - it is not a mod-con. My contractor says that with the outdoor control it will get to about 90% efficiency. Is there a Boderus equivalent?

[jadnashua]

http://www.buderus.us/products/gashe...ganog124x.html is one model that would seem to be sized right. THere are other versions, floor mounted verses hung. I chose Buderus partly because of recommendations, but also because the US headquarters is nearby in Londonderry, NH. It's handy to have them so very close. A quick read seems that this may use a SS heat exchanger, which might allow cooler returns, and improve efficiency.

You'd have to read the spec sheet to see if either would be damaged by lowering the return temp too far (a function of outside temps/load, and desired supply temps). A conventional CI burner just can't benefit as much as a mod-con as condensation in a CI burner/heat exchanger will typically ruin it. The Buderus might, as at least some parts are SS.

As I said before, turning the water temp down just means the burner runs less time, but when oversized, could make it cycle even more. Some of that is controlled by the smarts in the computer, but, put a blowtorch on a teacup, and you don't need to run it as long as you would with a match. The best way to match needs with output is a mod-con. There are ways to help a conventional boiler by increasing the load (buffer tank). If you're going to use the boiler for an indirect, the ability to cold start with a mod-con will save you for the 5-6 months of the year when you don't need any space heating as well.

[danboston]

I had a contractor provide me a price quote to remove the old boiler and replace it with a Burnham MPO-IQ 3-pass oil boiler and a 50-gallon stone-lined Burnham indirect water heater. Burnham claims 87% efficiency for the oil boiler with an outdoor temperature control that adjusts boiler water temperature based on the outdoor temperature. Based upon information that I passed along to the contractor, he had his vendor calculate a heat loss for the house to be about 90,000 btu/hr. Burnham offers a 98,000 btu boiler (MPO-IQ115) that seems to be the right size. I was going to look into Buderus, but heard that they can be up to 20% higher in cost than Burnham? Also, my oil tank is about 50 years old and am wondering if I should replace that ? Finally, what is the noise factor? Is the Buderus quieter than the Burnham?

[BadgerBoilerMN]

The type of radiation and the mode of distribution have little to do with the boiler choice or size (unless the system is steam). Your "veteran" (a term a reserve for those who have actually served) gave the predictable response. It is a sad fact that those who have been in the business longest often are the same ones who haven't changed their minds since the first day, a good way to make money perhaps but an attitude that serves the customer poorly. Note that oil boilers must be serviced every year and oil is an unstable commodity tied to the world market, whereas natural gas is domestic, secure and is cleaner by half than fuel oil.


First, a heat load must be done, this is the only way to properly size a boiler, be it replacement or new construction. If you insist on a computer generated heat load analysis, you will thin the field to one or two.

Once the heat load is secured available fuel should be considered, if there is an up charge for gas line it is factored into the 20-year life of the boiler (not how long you will be living there, as you can sell a good fuel bill).

Finally, radiation and to a lesser degree, distribution can be factored in. If the contractor can tell you how much radiation you have, its potential output and the relative load, he can crack wise about condensing boilers. Ask him, how many condensing boilers he has installed in the last say, 40 years.

http://www.badgerboilerservice.com/contractor.html

He may be right about your situation, but I doubt he knows why.

[danboston]

I have decided between three different gas-fired mod-con boilers: Burnham Alpine 80, HTP Elite 80 and the Prestige Solo 60. These units all have the same lowest min (16 K btu/hr). My heat loss rate is between 25 to 35 K btu/hr. Am I better off going with the lowest max available (e.g., the Solo 60) or does it not really matter?

Alpine 80 output (min/max) = 16/80

HTP Elite 80 output (min/max) = 16/80

Solo 60 output (min/max) = 16/60

Also, if properly sized, do I really need a buffer tank?

[mike02563]

Dan, what system did you end up with and how has it been performing? I'm looking to make a decision on a new furnace in an oil to gas conversion myself. The cheapest is the Burnham Alpine being offered from National Grid for around $1K after rebate. The HTP Elite had seemed like a better furnace and with a higher rebate may not be that much more then the Alpine. I haven't been able to read many reviews on the Elite that is until I read some reviews on the Munchkin and from my understanding made from the same company and are built similarily? I had heard that was a solid furnace but after reading the reviews on this site her, I am no sure I should go with either.

http://www.furnacecompare.com/furnaces/munchkin/reviews
http://www.furnacecompare.com/furnaces/burnham/reviews



I'm just looking for some advice on what furnace to get and will be making a decision soon. Any help anyone can give me would be greatly appreciated.

Thanks!

[Dana]

IIRC he ended up with something completely different.

BTW: "Furnace" usually refers to a ducted hot air heating system, whereas hydronic (pumped hot water) boilers were danboston's quest. Which are you looking for?