Questions and Answers for Bosch Tronic 3000 US4-2R 4kW 2.5 GPM Point-of-Use Electric Tankless Water Heater

A:  Mary, No overflow tank is required. This is a completely tankless appliance with no reservoir. So there is no possibility of overflow as there is nothing to flow over.

A:  Hello Songbird, While the model US9 has many great applications in the home from vanities to showers, the US9 is probably not the best choice for your specific tub application. This is due to the unit's water temperature rise being tied into the rate of flow through the unit and the volume of water you need to have at a desired temperature before enjoying your tub. The greater the flow rate, the less temperature rise in the output water. In a tub application you will want to fill the tub as quickly as possible with a water temp at your maximum comfort level upon getting in. If you apply the full potential flow rate of your faucet into the tub, the US9 will not heat the water to its maximum potential. If you reduce the flow rate to gain temperature output, you increase the amount of time to fill the tub and allow more time for the initial water entering the tub to lose temperature. You can overcome this dilemma by moving to a unit with a greater kW rating. In this case, the model US12 is more likely to suit your needs. If you believe the unit will have additional simultaneous draws, in addition to your tub fill, you may want to increase that kW rating further to a whole house unit like our model WH17 (17 kW).

A:  Danno, Unfortunately, as a manufacturer we are not in the position to specify the wire size. There are other factors that can come into consideration for wire size besides the unit's specified load. We recommend consulting a professional electrician that will take into account all the variables, including apllicable code requirements.

A:  I would recommend 8/3 or 6/3, if you want to go lower like 10/3, you should double it with two 30 amp breakers. I got 8/3 with a 40 amp breaker

A:  You will want one of our other more powerful units for your whole house needs. The model US9 is considered a Point of Use tankless water heater and is intended for single use applications, like a dual vanity. We suggest you explore our Whole House models WH17 and WH27 for your application. If you will only have one shower operating at a time, the WH17 should cover your needs. Search "Bosch WH17" on this web site. These are commonly stocked items.

A:  The model US9 "may" be sufficient for this purpose. It is highly dependent on your ground water temperature - which is usually a function of geography. In general, if you are in a Southern or Southwest climate then the US9 may be sufficient for a shower and bathroom. In such an instance, you may need to avoid both the shower being active at the same time the Hot on the sink is active. If you are in a Mid-Atlantic, Mid-West, or Northern climate, the US9 will likely be insufficient for your shower needs. In which case, we suggest moving up to a 12 kW or greater product. Our model US12 should be sufficient for your needs regardless of geography. Keep in mind that the electrical requirements will be different from the US9 to the US12.

A:  This question is better suited for the vendor, Bosch. Their contact number is: 1 (917) 421-7209. Thank you for choosing The Home Depot.

A:  The wattage is 3.4 watts.

A:  Use a simple heat transfer formula to get a better idea of what this is likely to consume Q (in joules second) = Mass (in gr) multiplied by Delta T (degrees centigrade rise) multiplied by C (specific heat of H2O) and divided by T (Time in seconds) I will not input the conversions and calculations here -You will have to take my word for it. To heat up 0.75gal of water in 60 seconds, one need to transfer 3.2kw of energy to the water. Considering a rated efficiency of 0.8 (or 80%), it will take +-4kw of juice to do the job. Fun Fact: With the average home's energy rate at $0.12/kw, this heater will cost you about $0.48 per minute of use. The cost of using it for 20 minute equals the cost to heat water with a 40gal Hybrid Heat Pump water heater for the whole house, PER MONTH!

A:  Do you mean 3.4 kilowatts?

A:  The model US7 has a 5 yr. warranty. The quality of the Tronic 3000 tankless series allows for them to all be warranted for use in commercial / light industrial applications , as well as residential. The lifespan will be greatly influenced by the hardness of your water, your usage, and maintenance. Due to it being an industrial grade product, you can expect a much longer lifespan than what is common in this product category.

A:  1/2

A:  1/2 IP size, make sure you have sufficient electrical power to get proper heating more voltage the better

A:  The model US7 is designed to be hard wired. Please do not attach an extension cord. Using an extension cord can pose extreme risk, will be in opposition to electrical code, and will void the warranty. Please note that the US7 requires a 240 V service at 30 A.