06-10-2007, 07:20 AM
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.
" 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?"
----------------------
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.
Larry