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Oil to gas conversion for a steam system

Herb G
Herb G Member Posts: 2
In getting bids/proposals for a gas fired boiler for a steam system several have been for a Peerless oil fired EC04 system to be fired with a Riello gas burner.  Why don't they just propose a Peerless Series 63 gas-fired steam boiler?  What am I missing - what are the advantages/disadvantages of this conversion approach rather than going with the gas-fired Peerless Series 63?

Herb G


  • JStar
    JStar Member Posts: 2,752

    A wet base boiler with a power burner is much more efficient and a lot safer than a regular atmospheric boiler. We fully endorse it here!
  • Steamhead
    Steamhead Member Posts: 15,874
    edited July 2013

    not only the Peerless EC, but also the Smith 8, Slant/Fin Intrepid, Utica SFE/Columbia CSFE, Weil-McLain Gold Oil- all are wet-base boilers, normally sold with oil burners but run well with power gas burners too. They extract more heat from the flame than an atmospheric type like the Peerless 63. That's the way to go.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • Herb G
    Herb G Member Posts: 2
    Looking at the numbers

    I've tried to assess the claim of increased efficiency to be

    obtained by going with the Peerless wet-base (EC/ECT) rather than the

    dry-base (Series 63).  If we look at the efficiency ratings for the

    Peerless EC/ECT boiler we see that the AFUE efficiency is between

    83-85% for steam, depending on the particular model.  This is for

    oil-firing since it is an oil-fired boiler.  If we fire it with a

    gas burner I estimate we can expect about a 2-3% loss in efficiency

    giving us at best 81-83% efficiency.  I get this loss estimate by

    looking at the Peerless TCII boiler which, albeit is a large

    commercial boiler, is wet-base and designed to fire with both oil

    and gas.  This boiler shows about a 2-3% decrease in thermal

    efficiency when going from oil to gas.  Given this, I expect we will

    see a gas fired EC/ECT boiler giving as AFUE of about 81-83%, at


    Checking out the Peerless Series 63 we see that for spark ignition

    with a steam system AFUE's between 82-83%,  It looks that installing

    a conversion system instead of the Series 63 is at best a wash when

    it comes to AFUE efficiency.  It might even be worse than a wash

    since the EC/ECT boiler was not designed for gas-firing.

    If I had a EC/ECT I would probably do the conversion but for a new

    installation it seems to be a problematic choice.  Going the

    conversion route would at best give me the same efficiency, I may

    also be voiding my boiler warranty and the system may be more

    difficult to tune since it would be more complex by having both the

    boiler with a separate burner as opposed to having an integrated

    Herb G
  • JStar
    JStar Member Posts: 2,752

    We more often see an INCREASE in efficiency with gas. NOT the other way around.

    If a contractor finds it too difficult to install...find a new contractor.
  • Steamhead
    Steamhead Member Posts: 15,874
    Don't get obsessed with AFUE

    it's not the whole story.

    An atmospheric boiler like the 63 loses a noticeable amount of heat out of its base, since the flame is completely below the cast-iron sections. The AFUE test procedure does not take this into account- that's your tax dollars at work >:(  .

    You'll see the difference in thermal efficiency when you calculate the DOE output as a percentage of the Input rating. On the 63 series this is 83% give or take, on the EC it's 86%. That might not sound like much, but after the fracking lawsuits are settled and they finish converting coal-fired power plants to gas, the cost of gas will rise again. So the EC with power burner will make a difference in how much you pay for fuel- the higher the cost-per-BTU, the better off you'll be.

    When we talked to Peerless some time ago, they didn't care whether we converted an EC or not. Their position was, we make the boiler, someone else makes the burner.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • SWEI
    SWEI Member Posts: 7,356
    We make the boiler, someone else makes the burner

    How refreshing!

    US Boiler, are you listening?
This discussion has been closed.