Bosch has the best warranty in the industry for its line of AquaStar Tankless Water Heaters!
Bosch provides a 12 year warranty on the heat exchangers for all gas and propance tankless water heaters (2 years for parts).
Here is the warrantly as listed on bosch-climate.us:
AquaStar water heaters are warranted by the Bosch will furnish a replacement heat exchanger and will furnish a replacement of any other part which fails in normal use and service within the applicable periods specified below, in accordance with the terms of this warranty. The Bosch Water Heating replacement will be warranted for the unexpired portion of the original warranty. This warranty will be valid only for water heaters in possession of the original purchaser as recorded on the warranty card.
The Heat Exchanger
If the heat exchanger fails within twelve (12) years after the original installation and operation, Bosch Water Heating will furnish a replacement heat exchanger. However, if the water heater is installed in other than a single family dwelling, or is used as a circulating heater in any application, this heat exchanger warranty is limited to two (2) years from date of original installation and operation.
All Other Parts
If any other part fails within two (2) years after original installation and operation, Bosch Water Heating will furnish a replacement part free of charge.
In addition to supplying the replacement part(s), Bosch Water Heating will provide ground service delivery for these parts.Expedited or upgraded shipping will be charged to the customer.
This warranty does not cover any labor costs associated with service, removal or re-installation of part(s). All such costs must be borne by the Purchaser.
This warranty will not apply:
1. to defects or malfunctions resulting from failure to properly install, operate or maintain the unit in accordance with the printed instructions provided;
2. to damage or abuse, accident, neglect or freezing and other acts of nature;
3. to damage resulting from operation with either the thermocouple or overheat sensor removed;
4. to failure of the heat exchanger resulting from the operation of the water heater in a corrosive atmosphere or at water temperatures exceeding the maximum rating, or if the water heater is not supplied with potable water.
5. to defects or damage cause by any attachment or modification, including any energy-saving device.
Note: The water heater must be free of damaging scale deposits and not subject to gas pressures greater than those shown on the rating plate, which must not be altered, defaced or removed.
It has come to our attention that products from Bosch Water Heating are being sold through on-line auctions and other unauthorized distribution channels. We believe that in some cases there are legitimate consumers trying to sell product that they have purchased through legitimate distribution channels. However, we are finding that some of the merchandise has actually been stolen from our customers. Please be advised that our product warranty is void with respect to stolen goods. Further, we reserve the right to require a legitimate sales receipt showing that the product was purchased from one of our customers in order to provide warranty coverage.
How to Make a Claim
1. The Owner should contact the dealer who sold the water heater covered by this warranty or
2. Owner should submit the warranty claim directly to Bosch Water Heating at the address listed below, and they will arrange for the handling of the claim.
3. Whenever any inquiry or service request is made, be sure to include the water heater model number, the date of manufacture, date of installation, Dealer's name and the watts and voltage.
4. When returning the water heater or component part(s), they must be individually tagged and identified with the Returned Goods Authorization # issued by Bosch Water Heating and shipped prepaid to Bosch Water Heating at the address below.
No one is authorized to make any other warranties on behalf of Bosch Water Heating. It is expressly understood that the replacement warranty of Bosch Water Heating shall be in lieu of any and all other warranties, express or implied, including warranties of merchantability or fitness for a particular use or purpose, and further that Bosch Water Heating shall not be liable for any loss or damage directly or indirectly arising from the use of the hot water heater, or for any consequential damages arising from such use (including damages from water leakage). Bosch Water Heating's sole liability with respect to any defect shall be for the replacement of defective part(s). Some states do not allow such limitations and exclusions, so the above may not apply to you. This warranty gives specific legal rights. You may also have other rights which vary from state to state. In the event that warranty service is required, reasonable proof of the effective date of installation and operation must be provided; otherwise it may not be possible to honor warranty.
Note: Specifications and product information subject to change without notice.