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    BadgerBoiler MN's Avatar
    BadgerBoiler MN Posts: 10, Reputation: 1
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    #21

    Oct 29, 2012, 04:10 AM
    Quote Originally Posted by hvac1000 View Post
    As soon as I read Glowcore I thought of Heat Transfer Products Company which made them. That is what happens when I got older since I have forgot more manufactures names than I remember.
    Sorry, Heat Transfer Products did not make GlowCore boilers. In fact we bought some of the first indirect-fired-water heaters from HTP to make the first condensing boiler/indirect package in the country. HTP did not come out with the Munchkin until 2000 or so. GlowCore made condensing boilers from 1985 to 1995 or so. But I can relate to memory loss...
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    hvac1000 Posts: 14,540, Reputation: 435
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    #22

    Oct 29, 2012, 07:08 AM
    Quote Originally Posted by BadgerBoiler MN View Post
    Almost perfect.

    Except, the by-pass, or primary/secondary (P/S) pumping is required to keep minimum flow through the low-mass heat exchanger used by most condensing boiler manufacturers. The addition of a by-pass or two pump, primary-secondary pumping can be a detriment to high efficiency potential, since they may increase return water temperature to the boiler and always add the parasitic cost of the second pump, without adding anything to the performance of the boiler or system.

    When replacing boilers in older homes with one thermostat (zone) here in the Twin Cities, we use IBC, Lochinvar, Triangle Tube, Viessmann, and HTP products, as they appreciate the fact that every boiler system is a custom design. By contrast, Buderus, Burnham, SlantFin and Weil McLain specifically mandate the use of P/S pumping in all application new and retrofit, voiding the warranty if P/S is not used. The simple majority of the condensing boiler manufacturers do require P/S pumping to protect their boilers from overheating and only those familiar with the technology should deviate from this "idiot proof" policy.

    The high efficiency condensing boilers are a perfect match for almost any old gravity cast iron radiation system, as they were originally designed for relatively low operating temperatures and often may operate well below the original design water temperature with the reduced heat loads often found in older homes with upgraded windows and insulation. Our best fuel savings matching a "then new" Lochinvar Knight to the cast iron radiators of a 1921 bungalow in St.Paul, MN. The local gas supplier came out three times to check their gas meter as the fuel bill had gone down over 60%.

    Had I been an expert witness for the contractor in the "Ohio" case, I doubt the outcome would have been the same. Regardless of application, a properly installed condensing boiler will typically operate at 88.6% combustion efficiency in the coldest weather, delivering 180°F water to the system and not condensing at all. In cold climates the design condition (coldest week of the year) is so short that the bulk of the year much lower temperatures can be used to heat the space. It is in the shoulder months that the condensing boiler saves the most on fuel in non-typical applications such as fin-tube baseboard, fan coils and cast iron radiator.

    There is much confusion over the savings available from condensing boilers. For instance it is the "return" water temperature that lowers the flue gasses to dew point and recovers the energy. So any system designed to operate with a return below 140°F will likely condense a good part of any heating season. All condensing boiler available in the US and Canada today feature weather sensitive controls, which modulate the flame and consequently the output and average water temperature of the system.

    Those who downplay the inherently superior performance of condensing boilers willingly the ignore the obvious advantages and real-world saving of this superior technology including, sealed combustion (shutting down the drafty chimney), weather sensitive control (lower operating temperatures on all but the coldest days and reduce flue temperatures (from 400°F to less than 150°F).

    When choosing a high efficiency condensing boiler one should seek out the local expert, whom you will recognize by his certificate of competency, issued by any condensing boiler manufacturer and the sample heat load he provides since sizing any boiler is the first critical step in any hydronic heating design.
    The Ohio case was interesting. What it came down to was the fact that there was not enough radiation surface available to heat the structure without running the condensing boiler at 180 degrees. It was a fan coil system and that added to the problem. The original contractor that installed the condensing boiler did not take the lack of heat radiation surface into consideration since it had always done the job before with the old boiler. He had told the customer and put in writing that the system would work as advertised which was 92 or 93 % efficiency but when operated at a higher temperature it was less than you mentioned at 82% or so efficient. The customer felt he was cheated since his utility bills were still quite high. In other words the court ruled that the customer did not get what he paid for and that brings me to the root cause of the problems around here with high efficiency boilers.

    Not many HVAC company's around here really have a pro on staff that knows how to sell condensing boilers properly and after they are sold no one to properly service them. I am sure there are a few but not many since this is not real boiler country at my location.

    The next item I see time after time. Lack of proper design on replacement type installs. Almost all the systems are short on heat radiation. Since there is not much cast iron here it is mostly copper baseboard and some fan coil systems originally designed to run at 165 to 180 degrees. If you do not have enough feet of copper baseboard you have to run a higher temp water to maintain the temp in the structure when it gets real cold outside. You and I know there are controls that can vary the boiler temp and most if not all mod-con condensing boilers have this control as part of the package from the factory but years ago this was not included in some of them so most of the company's did not install a good old Tekmar 256 or similar to help eliminate part of the problem.

    You see and service many more boilers in your area as I mentioned before and that gives you an edge on knowledge much more so that the locals here. I have been retired for many years but still enjoy talking about it and every once in a while fixing a problem.

    I still run my dependable Paloma style system here. I test it every year with my old dependable UEI KM900CO/P Combustion Efficiency Analyzer and it is at 80% during high fire every year. I also send the meter back to UEI every year to have it calibrated. I know it is old but at one time it was the cats meow. That Paloma has been in since 1980 or 1981 and so far my design for this 2600 sq. ft. house has worked well. My gas bills are real cheap as compared to others in this area of similar size homes. In 30 plus years the Paloma has only needed 8 real services when a part went south and usually that is the diaphragm in the water valve used for gas safety and to prevent dry fire. One expansion tank (internal rubber duck went bad) and one Grundfos pump. It has been a great unit and I have enough spares to keep it running long after I am gone if anyone knows how to work on this simple machine. Note: I have always kept the gas pressure a bit low and that has kept the heat exchanger it in like new condition and no signs of burn out. I might loose a bit of BTU's but did not need them all to start with.

    Thanks for posting back on some of this stuff since I always find it interesting to read other peoples perspective on equipment and gain some additional knowledge. I have never met a man or a woman in the heating business that new it all. It is impossible in today's world when something new is developed every few months. ( I will be learning till the day I die). Thanks again.
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    BadgerBoiler MN Posts: 10, Reputation: 1
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    #23

    Oct 29, 2012, 07:35 AM
    I appreciate your knowledge and experience. It is true that many of the early fin-tube systems (then trying unsuccessfully to compete with emerging forced air, were short of radiation.

    One point must be considered further.

    "when operated at a higher temperature it was less than you mentioned at 82% or so efficient."

    We design and install many high efficiency condensing boilers and all will produce combustion efficiency at 86%+ regardless of the operating water temperature if the burner is tuned properly, most of them out-of-the-box on NG. Further, the lack of chimney and built-in outdoor reset will save another 5% on the typical fuel bill, so unless the fin-tube was inadequate to heat the space at any temperature a minimum 10% fuel savings should be automatic.

    It is good to remember that it never pays to oversell but this one smells bad to me. I fear it was the contractor that didn't get what he bargained for and the category that suffers most.
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    BadgerBoiler MN Posts: 10, Reputation: 1
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    #24

    Oct 29, 2012, 08:30 AM
    Quote Originally Posted by hvac1000 View Post
    As soon as I read Glowcore I thought of Heat Transfer Products Company which made them. That is what happens when I got older since I have forgot more manufactures names than I remember.
    Sorry, Heat Transfer Products did not make GlowCore boilers. In fact we bought some of the first indirect-fired-water heaters from HTP to make the first condensing boiler/indirect package in the country. HTP did not come out with the Munchkin until 2000 or so. GlowCore made condensing boilers from 1985 to 1995 or so. But I can relate to memory loss...
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    hvac1000 Posts: 14,540, Reputation: 435
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    #25

    Oct 29, 2012, 09:19 AM
    Quote Originally Posted by BadgerBoiler MN View Post
    I appreciate your knowledge and experience. It is true that many of the early fin-tube systems (then trying unsuccessfully to compete with emerging forced air, were short of radiation.

    One point must be considered further.

    "when operated at a higher temperature it was less than you mentioned at 82% or so efficient."

    We design and install many high efficiency condensing boilers and all will produce combustion efficiency at 86%+ regardless of the operating water temperature if the burner is tuned properly, most of them out-of-the-box on NG. Further, the lack of chimney and built-in outdoor reset will save another 5% on the typical fuel bill, so unless the fin-tube was inadequate to heat the space at any temperature a minimum 10% fuel savings should be automatic.

    It is good to remember that it never pays to oversell but this one smells bad to me. I fear it was the contractor that didn't get what he bargained for and the category that suffers most.
    The contractor did bit the bullet on that deal but I am sure he learned a valuable lesson also. Do not do any job if you do not have the skill level to complete it properly. Lets face it there are good and bad contractors. I always thought I was one of the good guys but I am sure someone somewhere was not happy with my service usually because of price. Somewhere around here there is a big book of thank you letters etc. from customers. My wife made the book to remind me of my past and when I give a class (which is vary rare now) to show the students that you do not have to rip people off to make a good living and have a successful business. If you treat people right they will always call you back when they need something else fixed.
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    BadgerBoiler MN Posts: 10, Reputation: 1
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    #26

    Oct 29, 2012, 06:39 PM
    "not happy with my service usually because of price"

    If they got what they paid for, the price was right. I would let you do my work.

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