Would you buy your combi boiler at "The Wholesale Warehouse"?

[Nanker Phelge]

I am getting close to the point when I want to purchase a Bosch 151 combi for our home and like many others find myself on a tight budget. So being as thrifty as I can I am trying to check as many avenues for savings possible before plunking down my cash. I wonder what others opinions might be, and experience would be even better if there is any out there, about buying my boiler at "The Wholesale Warehouse" ?

http://www.thewholesalewarehouse.ne...-mounted-natural-gas-boiler-model-zwb42-3-ng/

I could save $500+ buying my boiler at "The Wholesale Warehouse" compared to the supplier I have been planning to purchase the boiler from online. The other supplier, although they appear to be a shop more dedicated to the HVAC world, in reality they refer all questions relating to the Bosch to Bosch, so it does not appear they will be a source for information after the purchase is complete.

So I am figuring that if "The Wholesale Warehouse" can get the boiler to me in tact, any questions and warranty issues that crop up will surely be directed to Bosch anyway and not the seller. Perhaps then, the HVAC competence level of the seller matters little?

 

[Leon82]

when I bought my bosch tankless water heater from the plumbing store I got the pro model. it turned out that they used to sell an aquastar 2700 model at home depot. they were the same unit. I emailed their parts distributor and he said the pro model had a longer warranty and a different customer service number to call.

 

[Sponsor]

 

[Dana]

The minimum input on the 151 is 36,000 BTU/hr, which at ~95% combustion efficiency would yield an output of about 34,000 BTU/hr. If you're installing cheap baseboard rather than radiators, the smallest amount of baseboard that balances at condensing temps (the only way to get condensing efficiency) would be about 135 feet PER ZONE. Also, regulating the domestic hot water temperature at low flow will be a problem at 34,000 BTU/hr of min-fire output. The 151 is almost never a "right" solution.

From your heat load calculation thread, it looks like your heat load at -25F will be under 60,000 BTU/hr even after corrections (especially if you tighten up the place.) Your average whole-house load in mid winter will only a bit higher than 34,000 BTU/hr, which means the thing would cycle on/off a lot rather than modulate, putting unnecessary wear & tear on the boiler and cutting into efficiency a bit.

A better solution would be to use an ~80,000 BTU/hr mod-con with a 10:1 turn down ratio, which can balance on zones as short as 30' of baseboard, and use a tank type indirect hot water heater sized for the biggest tub you have to fill. (Most do just fine with a ~40 gallon version.) Some boilers that fill the bill are:

HTP UFT-080w (== Westinghouse WBRUNG 080W)

Navien NHB-080

The UFT (or WBRUNG) 080W has a secondary port plumbed in designed for supporting an indirect hot water tank. The fire tube heat exchanger also means that in most cases you would not need to plumb it primary/secondary, making it a bit easier & cheaper to install than the Navien. Both the UFT and NHB are Korean imports, but HTP is a US boiler manufacturer with a reputation for good support on any of their products (home-grown or imported) in most locations. If Navien has better support than HTP near you it might be a better choice, but it's somewhat more sensitive to the system design particulars than the UFT.

With a min-fire output of about 7500BTU/hr you'll get at LOT more condensing efficiency out of these mini-mod-cons than the Bosch 151 combi, and an indirect would give you much better hot water delivery than the 151 as well, at both high flow and low flow. The combi heater will either flame out or scald at low flow, and will have a burner-constrained upper limit on maximum flow. An indirect tank's flow is limited only by the plumbing.

BTW: If you're in Ontario you're not exactly in International Falls MN. What is your actual location (Fort Frances)?