Originally Posted by BadgerBoiler MN
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.