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RIRED Member Posts: 4
I have 2  forty gal gas fired water heaters with smoke pipe going into unlined chimney along with a gas fired burnahm boiler with 5" flue going into the same chimney and I am wondering if I can add one more small gas fired boiler`s pipe into same chimney. This would be a total of two boilers and two water heaters.If it has to be lined how do you conncect all those pipes to the liner .I would think that would be difficult. Maybe my best option is a powered vent boiler but they are more money and I think the flue for those is expensive as well. I am trying to add a zone of heat for a second floor apartment building so any advice or information regarding this would be appreciated! PS current boiler is not big enough to cover btu`s for zone upstairs! Another option that was mentioned to me was rinnai gas fired heaters but I think those would be difficult to install in an old house and how does the heat get to all the rooms evenly?


  • unclejohn
    unclejohn Member Posts: 1,751
    Some where

    Theres a chart for that. Max BTU's for chimney area sq. ".
  • Tim McElwain
    Tim McElwain Member Posts: 4,487
    Give us the total

    BTU's of all the equipment you want to install into the chimney? You will find that information on the plate on the equipment, we are looking for input.

    How high is the chimney?

    Is it a straight run to the roof or does it have offsets?

    Does it at least have a clay tile liner?

    You can connect all the equipment outside the chimney with a vent connector when using a liner that is how it is done.

    What is heating the second area now? You may have to run baseboard heating to that area.
    RIRED Member Posts: 4

    Hi first thanks for the response I have been looking at some of the items you mentioned. The chimney is straight and about 30 feet high its in a 2 story house with a gable roof. The chimney doesn`t not have a clay liner. The boilers are 45000 and 85000 btu I think off hand I don`t know what the hot water heaters are but they are standard 40 gas fired whirlpool water heaters sold at lowes so we can probably assign a nummber to those that is close to there rating. Next time I go to the house I will try to gather more information. I am getting a price difference of about 500 dolllars more for a direct vent with 200 dollars worth of stainless flue and fittings etc. I think adding a liner for the natural vent boiler will bring me close to the cost of the indirect so why not go that route? As far as your question on what they used for heat on second floor it was gas fired wall heaters that look very old and in rough shape and they had one steam radiator that  they extended from the first floor steam system. The steam system boiler cannot supply enough btu`s to heat second floor. This is an old house with no insulation in walls and because of the way it is built you can`t even blow in insulation there is no wall cavity because it has planks going vertical etc. Yes I plan on using about 100 ft of hydronic baseboard for 2nd floor at 580 btu per hour approx.. well mclain has a nice direct vent boiler with a input rating of 60000 mbh model # cgi-3 85 % efficient
  • Tim McElwain
    Tim McElwain Member Posts: 4,487
    edited March 2013
    By any chance

    with the RI Red are you in Rhode Island?

    Also is the chimney an inside or outside (three sides exposed) chimney?

    What are the interior measurements of the existing chimney?
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