Tankless boiler efficiency? - Page 2
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  1. #14
    Join Date
    Sep 2004
    Posts
    654
    Running a boiler with cold start may save a few dollars a month, BUT you'll give all of that back and then some once the boiler gets loaded with scale from being left cold for long periods of time. A dirty boiler consumes lots of fuel. The cost of a quality indirect HWH will change your mind, trust me.


  2. #15
    Join Date
    Aug 2001
    Location
    Central MA
    Posts
    572
    Ok,

    I work for an oil company and we install Direct Vent Buderus boilers. On a chimney they aren't so bad, direct vent they tend to be problems. A Buderus boiler can only have an Indirect WH they have no provision for Tankless. Direct vent is the most quiet.

    The Weil McLaine Gold likes warmth but if you got an indirect you could have it turned down to about 120 degrees as someone else said. Today's indirects have very low losses. Power Venters fail every three to five years, they are a mechanical device working under high temperatures and affected by the products of combustion.

    My opinion is any fuel has products of combustion and a chimney gets them away.

    Hope this helps,
    Leo

  3. #16
    Join Date
    Jan 2002
    Posts
    1,196
    Go indirect w/ cold start. The boiler will fire enough to keep it dry. Your Gold is poor insulated compared to an indirect's 2-3" of R.

    Why have the thing maintain temp, and lose it, when it's not needed? Like having your car idling in the driveway all night in case you MAY want to drive it?

  4. #17
    Join Date
    Aug 2001
    Location
    Central MA
    Posts
    572
    Weil Golds tend to get dirty on Cold Start. What's cheaper, spending extra to get it cleaned and using extra oil heating a dirty heat exchanger or using a little more oil keeping it warm and having less of a maintenance issue. He stated it is he and his wife so in warm weather that indirect won't call often hence the boiler gets much colder. I base my statements on doing service and annual tune ups and seeing what is cleaner and what isn't.
    If this guy were to use more oil I wouldn't benefit from the sale so I am not trying to sell oil. I am an advocate of conservation.
    Leo

  5. #18
    Join Date
    Jul 2006
    Posts
    72
    There is a reason why Buderus is one of the only boilers sold in the U.S that does not have a tankless boiler.

    Tankless heaters will not keep up with the hot water demand of the house, period.


  6. #19
    Join Date
    Aug 2006
    Posts
    42
    Not true for me on tankless providing enough hot water. We had never had an issue on running out of hot water yet. Not only between me and my wife, but with 4 others staying in the home and all showering at roughly the same time.

    Anybody know what the rough percetage of fuel I would save running cold start and an indirect WH?

  7. #20
    Join Date
    Feb 2003
    Posts
    1,996
    Your savings would mostly be in the non-heating months. So I'd guess 5-10% of your total yearly bill. Now do you
    burn 700 or 2000 gals a year? Are you in Alaska or Virginia with a 10 month winter or a 5 month winter?

    If your boiler is oversized, you'll be wasting fuel all the time. I'd only put an indirect on a boiler replacement
    or if there was a shortage of hot water. I don't see the payback in your situation. Might make more sense to lower the min temp of the aquastat to 120 and high limit to 140
    during the summer.

  8. #21
    Join Date
    Jul 2006
    Posts
    72
    Originally posted by dbuck50
    Not true for me on tankless providing enough hot water. We had never had an issue on running out of hot water yet. Not only between me and my wife, but with 4 others staying in the home and all showering at roughly the same time.

    Anybody know what the rough percetage of fuel I would save running cold start and an indirect WH?
    Lucky for you. I've come across many homeowners who were dissatisfied with the output of a tankless boiler for domestic needs.

    Keep in mind, particular boilers need not be running "at maximum output" depending on what the outdoor temp. is.

    Why run a boiler at the same firing rate if its 60 degrees outside compared to 30 degrees? Lots of wasted energy.

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