Converting a Megasteam from oil to propane

The Wire Nut

Hi all,

I have Burnham Megasteam MST513 steam boiler (7 years old) with a Beckett AFG oil burner. Given that heating oil is north of $5/gallon up here in NE PA, and propane is just under $2/gallon, and I have a 1000 gallon propane tank buried about 10' outside from my boiler I think it makes sense to convert to propane and just have just 1 fuel to deal with.

Steamhead told me years ago that oil packs more BTUs per gallon than propane, and since oil was around $2/gallon at the time, I didn't pursue changing it. But now, less BTU per gallon should still be a lot cheaper!

The Megasteam heats my old stonehouse, and I have a Lochinvar Cadet burning propane to heat our 7 year old addition using radiant and the DHW indirect for the addition. The propane also runs my backup generator and eventually a stove.

Beckett make the CG4 gas burner that seems to be a direct replacement for the AFG and it costs far less than my last 150 gallon oil fill! I may need a new air tube (AFG70MLASN per Supplyhouse support), but that's not very expensive, though I think the existing AFG air tube can be repurposed.

I'm also thinking that it might also mean less annual cleaning of the boiler too.

So, does anybody have experience with this burner? Anything I should be aware of? Is there a better option?

Alex
The WireNut (aka Stonehouse)

Steamhead

Burnham/US Boiler has a hissy fit when we talk about converting MegaSteam boilers to gas, even though there is no safety or technical reason it won't work well (if done right, that is). Also, I don't think Beckett will sell a CG4 for one of these boilers.

I'd suggest using a Carlin EZ-Gas.

random12345

Homeowner with Megasteam MST288 here in the Boston area. I have wanted to convert to natural gas for a while now. Here is what I have found after many hours of investigation...Burnham prohibits this, and you will for sure void your warranty (what's left of it). I know converting to natural gas is doable and safe, and has been done. I'm not sure about propane. Your town's plumbing/gas inspector may or may not approve it. Mine didn't. He won't do it without some kind of documentation from Burnham saying it's ok. So for me, it's not possible. If your inspector approves it, your home insurance company may or may not give you grief about it. Such is life. Good luck to you whatever you decide. This is an unfortunate situation, and I have not received a satisfactory explanation from Burnham as to their rationale for this despite multiple emails. I also just sent you a message.

The Wire Nut

Thanks Steamhead (how have you been, it's been a while!), and Random. I'll investigate the Carlin and also chat with my building inspector who is pretty friendly and flexible. It never occurred to me that I would need to get this approved, but I guess it's plumbing of a sort!

Now the fun begins...

EBEBRATT-Ed

@The Wire Nut

oil is 1400000btu/gallon
propane is 95000 btu/gallon

so you need 1,48 gallons of propane to =1gallon of oil

STEVEusaPA

EBEBRATT-Ed said:

@The Wire Nut

oil is 1400000btu/gallon
propane is 95000 btu/gallon

so you need 1,48 gallons of propane to =1gallon of oil

Oil will be less if it’s bio. Propane may be less efficient.
You’ll also have to change the baro to dual acting.

The Wire Nut

STEVEusaPA said:

EBEBRATT-Ed said:

@EBEBRATT-Ed

oil is 1400000btu/gallon
propane is 95000 btu/gallon

@EBEBRATT-Ed you had one too many zeros in your oil btus, it's 140,000, not 1,400,000! Oil therefore has about 1.5 times the BTUs per gallon as propane. But here in NEPA, oil is $5+ gallon and propane is $2+ per gallon. So it would take $3 worth of propane to provide the same BTUs as a gallon of oil. Now as prices change that equation will change. And it would take a fair bit of usage to make up the difference once you pay for the propane burner and the gas line install charges, but over the long run, it might be worth it. I would hope it burned cleaner than oil and would make the yearly cleaning less dusty!

random12345

EBEBRATT-Ed said:

@The Wire Nut

oil is 1400000btu/gallon
propane is 95000 btu/gallon

so you need 1,48 gallons of propane to =1gallon of oil

That is seriously wrong. Huge mistake. I believe it is actually closer to 1.5127382124494037851438573460234 since he's using ultra low sulfur heating oil with 2% biodiesel.

https://greet.es.anl.gov/greet_excel_model.models

EricBaisch

“The Wire Nut”
I also have a Mega Steam MST512. I had it installed new with a Carlin EZ Gas five years ago. It’s been running great. I run natural gas, not propane. This installer marked that tag on tube leading into the boiler “Diffuser Plate Style: D, Orifice Size: 9/32, Natural Gas”. The installer was originally going to install a Riello burner, but the shipment was delayed longer than we wanted to wait.
Eric

random12345

@EBEBRATT-Ed

I was only being half-serious when I made that comment. No offense intended. If you haven't looked at the GREET model, you might appreciate using it.

random12345

@EricBaisch

Did your town plumbing/gas inspector approve it? How about your home insurance?

The Wire Nut

Thank you Eric. Looks neat and clean. Given all the feedback I'm wondering if it really pays to move to propane. It would almost be nice to have a dual fuel burner like some commercial systems have. Then you just burn what's cheaper.

I also wonder why Burnham doesn't want you to convert to an alternate fuel. As long as it's a proper burner and setup and adjusted properly who cares what type of fuel you're burning?

Jamie Hall

For what it's worth, here in northwestern CT Propane and bulk buy oil are almost exactly the same price per BTU. Spot price on oil is higher today, but both it and spot propane prices go up and down like demented yo-yos, so check back tomorrow...