September 7th, 2007, 03:39 PM
Bosch DW and tankless water heater
I have a Bosch diswasher (SHE58C05UC/40) purchased in July 2007. I am having an issue relating to incoming hot water. We have a Nortiz tankless water heater in our house, which requires a minimum flow of 0.7 gallons/min before it will activate. This minimum flow threshold is typical of tankless water heaters. Our dishwasher appears to draw water quite slowly, below this minimum flow rate and as a result, our tankless water heater does not turn on when using the dishwasher. So the dishwasher operates using 40-50 F incoming water. Granted, the DW has its own heater to heat this water, but I suspect this will put undue use on the internal DW water heater or that it will be unable to provide the 100-120 F degree temperature rise to bring the water to the proper temp. My main question is: At what rate (gal/min) should I expect the dishwasher to request water? Since ours is clearly drawing water slowly, does this indicate a problem with the pump, inlet valve, etc ?? I did speak with someone over the telephone at bosch customer service and after much questioning and time on hold they quoted me a rate of over 2 gal/min, but seemed unfamiliar with the issue (even though bosch makes it own line of tankless water heaters). I'm not sure how much merit to put on her answer. Does anyone have any experience with using this or similar DW in combination with a tankless water heater? I plan on running the hot water before turning on the DW in order to enusre that the pipes are filled with hot water, but the issue will remain that the DW does not activate the tankless water heater. Some possibly related issues that we are having are very long cycle times (170+ minutes for AutoWash with the extended dry option, or 140+ minutes for Autowash w/o the extended dry option). With hotter incoming water, will this cycle time be shorter? Secondly, we do notice quite a sour odor from the dishwasher after just a day of not running it. Bosch's answer was to run the DW everyday, which seems a waste to me. We bought the new DW in part to save energy and water. It takes us 3-4 days to fill it with dirty dishes. I wonder if the lack of incoming hot water (due to the low flow request from the DW) would cause or contribute to the odor? Lastly, I have considered using an undersink point of use Ariston 2.5 gal mini-tank water heater placed next to the dishwasher in order to provide instant hot water to the dishwasher. Would this Arsiton 2.5 gal tank heater be sufficient for the dishwasher's hot water demand, or would I need a larger 4 gal or 6 gal model? Thank you for reading this post. I look forward to any suggestions.
September 7th, 2007, 04:21 PM
Believe you will be good to install another one just for the sink/dishwasher...you will be having lots of problems otherwise, dishwashers do fill slow and you will need the instant hot water for any brand of dishwasher for it to clean properly...I run the rinse only cycle on my Whirlpool tall tub to rinse them off and prevent the odors you are referring to, might do this after loading dishes every time, since I just have just me I normally just run mine for a load only once a week or so...
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