Efficiency of condensing water heater VS cupronickle fin type w/ mixing valve
Efficiency of condensing water heater VS cupronickle fin type w/ mixing valve
(OP)
So I'm trying to choose the proper water heater for our application and make sure I'm not being taken in by boiler salesmen trying to sell me a condensing boiler...
My question is pretty simple...Will a standard cupronickle fin sealed combustion boiler (looking at an RBI Dominator) with a mixing valve to maintain higher inlet temperatures be a long-lasting substitute for a condensing boiler? Our current water heater has run without a mixing valve, and was of the copper-fin, non-sealed combustion type, and has twice had an extremely corroded heat exchanger replaced.
Our system is 100% makeup, once through process. Makeup water replenishes the 500 gallon storage tank which we set at 140 degrees. We use 1000-2000 gallons per hour. I'm looking at a 2MBH unit which should be more than enough.
Would the efficiency losses be negligable if we used a mixing valve to bring inlet temp up to 150 degrees or so to minimize condensation?
Thanks for the advice guys. Let me know if more information is needed.
My question is pretty simple...Will a standard cupronickle fin sealed combustion boiler (looking at an RBI Dominator) with a mixing valve to maintain higher inlet temperatures be a long-lasting substitute for a condensing boiler? Our current water heater has run without a mixing valve, and was of the copper-fin, non-sealed combustion type, and has twice had an extremely corroded heat exchanger replaced.
Our system is 100% makeup, once through process. Makeup water replenishes the 500 gallon storage tank which we set at 140 degrees. We use 1000-2000 gallons per hour. I'm looking at a 2MBH unit which should be more than enough.
Would the efficiency losses be negligable if we used a mixing valve to bring inlet temp up to 150 degrees or so to minimize condensation?
Thanks for the advice guys. Let me know if more information is needed.





RE: Efficiency of condensing water heater VS cupronickle fin type w/ mixing valve
Generally speaking 95% of the cost of a boiler over its lifetime is in fuel. you can quickly calculate the fuel savings based on run-time (full fire equivalent), efficiency and gas cost to see if it makes sense financially.
Caveat: I'm a condensing boiler salesman.
Regards
Sean
RE: Efficiency of condensing water heater VS cupronickle fin type w/ mixing valve
RE: Efficiency of condensing water heater VS cupronickle fin type w/ mixing valve
Sean
RE: Efficiency of condensing water heater VS cupronickle fin type w/ mixing valve
Is 120 too low to try using a bypass or mixing valve to keep inlet temp up high enough for a non-condensing model?
RE: Efficiency of condensing water heater VS cupronickle fin type w/ mixing valve
You said the inlet water to the boiler was 100% makeup. To me that implies cold water, not 120F water.
If your make-up water is 120F and you only want 2000 GPH your boiler at 2,000,000 btu boiler is grossly oversized. At 100 degree delta T our 1.5 Million condensing boiler can supply you with 1812 GPH. I dare say most other mfg's should be similar.
Double check your parameters and size according to the load rather than the old boiler.
Regards
Sean
RE: Efficiency of condensing water heater VS cupronickle fin type w/ mixing valve
I might have used the terminology wrong. The water used in our process never returns, and the makeup water feeds into the 500 gallon storage tank. Delta T is about 90 degrees for our 1-2000 GPH, but there may be spikes in usage.
I think if I decide to go with a condensing boiler however, makeup water would not be piped into the storage tank, but rather into the boiler intake before the bypass valve....at least that is what I have seen in plumbing drawings.
RE: Efficiency of condensing water heater VS cupronickle fin type w/ mixing valve
Based on your delta T of 90 degrees We would quote you a 1.5 million btu boiler which would give you 2016 GPH. I'm sure other manufacturers would be similar.
Our 2 million would give you 2688 GPH, hugely over sized based on your post.
Regards
Sean