Source: Notarized Certificate of Business, Wabash Co. Partnership & Firm Record Book 1, p. 56, February 29, 1924:

David F. Priser  being duly affirmed says that he is one of the owners and proprietors of the business of the Instant Water Heater Company, having its principal place of business in the Town of North Manchester, in Wabash county, State of Indiana. That said Instant Water Heater Company is a co-partnership composed of himself and one, Levi D. Ikenberry, and as such they are engaged in the manufacturing and selling of the Instanto Steam Water Heater.

 He further says that there are no other persons connected with him in the conducting of said business who have a financial interest therein, and that he and said Levi D. Ikenberry are the only persons having an interest in said business, and the only persons connected directly or indirectly with the ownership of the same are David F. Priser and Levi D. Ikenberry, both residents of the town of North Manchester, Wabash County, State of Indiana, and none others.

Source: Aurora (1930) Ad:

will cool milk to desired shipping temperature.
Manufactured by INSTANT WATER HEATER CO., Inc.
North Manchester, Indiana
Write for price.  (Patent Applied For)