Appliances in Nanawale

[sansei]

Les,

" So, I've learned some stuff that weeks of Internet research and talking to, supposedly, knowledgeable people didn't reveal. To sum up from this thread, it sounds like (and correct me if I'm wrong) Takagi, AquaStar (Bosch) and Paloma don't require electricity to function. Rinnai does need to be plugged in. Takagi and Rinnai use piezoelectric starters; AquaStar and Paloma have a constantly burning pilot, the kind you light manually. I would think that this is the case only on the older models. Newer models should be using the fuel saving piezoelectric starters. I've heard of the impeller/propeller-driven piezoelectric starter; it's a great idea.

It sounds like Takagi has what might be called a low-flow activation: it'll turn on and heat water at low water demand. Paloma and Rinnai seem to require higher demand to start heating. How does AquaStar rate in this respect?

The Rinnai seems to have a pump in it, we hear it humming when it's running. At first, this bothered me, but it lets me know that it's working before the hot water shows up. Initially, the noise WAS bothersome because the unit was having a problem and the loudness and erraticness of the humming was very bothersome. With a correctly functioning unit, the sound is very minimal. It could be lessened even more by mounting with sound dampening material between the unit and the wall. Sound output was not a spec that was very obvious when researching these heaters. Maybe only the Rinnai has an internal pump?"

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Most brands start with a basic gravity operated low flow rate model that will operate without electricity and have an efficiency of around 80%. The higher capacity units are more complicated to wring an extra 5-10% efficiency - makes sense because the fuel usage helps to justify the extra cost. The larger units have electronic controls, modulating burners, and blowers to force the exhaust gas through a larger heat exchanger. The blower is probably what you heard on the Rinnai. I don't think any of these units will work without electricity. I think units with blowers have a pressure sensor and will not ignite if the blower is not running.

Some units even use a concentric vent to extract the last bit of heat from the exhaust. The inner tube carries the exhaust and the outer ring brings in combustion air.

[sansei]

Les,
In regard to functionality of an on-demand water heater with a catchment system during a power outage, even if you have a Takagi, or other unit that doesn't need electricity to function, I would think that if your water system doesn't have pressure, water won't be pushed to your on-demand heater, and you won't get hot water delivered to your points of use. You can accommodate for this scenario if your tank level is high enough (water level in tank or the actual tank elevation) which would use gravity to supply pressure, or if you have an alternate form of electrical power (generator, photovoltaic, wind)."

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Systems that have a correctly installed pressure tank will continue to supply water in a power outage (mine does) up to the capacity of the tank. That is one of the reason there are advocates on this forum for a large pressure tank. The Gotcha is that the UV sterilizer, if you are using one, does need electricity to work so you need to use chlorine or boil the water during a power failure and after until the system is flushed.

[sansei]

Finally, on the subject of ovens.

I installed a gas cook top and an electric oven. I just don't use an oven often enough that the extra electricity use is a killer and I like the extra features (delayed cooking, timed cooking, etc.) on an electric oven. I think it is worth paying extra for a self-cleaning oven. Now, I have never used the cleaning feature so why pay for it? Self-cleaning ovens have extra insulation around them so the inside can get hot enough to carbonize the gunk without setting the house on fire. I can do dishes that require long moist cooking by starting it in the morning when it is cool, leave it in the oven the rest of the day to finish, and it will still be warm at dinner time.

[mella l]

Sansei, would you mention what type of gas cook top and electric oven you decided on? I have been looking into this for the very same reasons you mentioned, not used much and extra insulation. Thanks, Mella

mella l

[sansei]

First of all, my setup is about 7 years old so my reasons may no longer hold with units being sold today.

The cook top is a Viking because it was one of the few at the time with 15,000 BTU burners. Propane has about 15% less energy than natural gas, which is what the published heat output is based on, so you really end up with a 12,500 BTU burner when you do the propane conversion. I also liked the fact that all the burners are the same so I am not forced to use the high burner or the low burner where they place them.

The oven is a GE (not profile) because I did not need a big oven and GE for some reason was the only brand that would fit in a stock 27" wide cabinet. All the other brands for some reason were a smidge too wide. I think I just got the cheapest self cleaning model.