8 | Appliance details
1) To measure Gas Pressure, see Measuring Gas Pressure, chapter 8.6, page 23.
2) Activation varies with inlet water temperatures from 0.5 - 1.6 gallon/minute (1.9
- 6.1 l/m).
3) Protection against water drops.
If appliance is installed at elevations above 2000ft, refer
to chapter 10.8.1 Fan speed adjustment.
• Flame failure device (ionization flame rod sensor)
• Overheat prevention (temperature limiter)
• Inlet temperature sensor
• Outlet temperature sensor
• Back flow temperature sensor
Unpacking the heater
Before installing the unit, be certain you have the correct heater for
your type of Gas - Propane or Natural Gas. Identification labels are
found on the shipping box, and on the rating plate which is located on the
right side panel of the cover.
Type of gas
6 720 644 956 (2016/05)
45 - 65
The box includes
• 940 ESO
• Bracket for wall hanging the heater
• Exhaust vent adaptor (with 4 screws and gasket provided)
• Combustion air inlet adaptor (with 3 screws and gasket provided)
• Installation manual (manual can be downloaded at www.bosch-
• Product registration card
Please complete and return the enclosed product registration card.
The 940 ESO is not approved or designed for:
• Manufactured (mobile) homes, boats or any mobile installation.
(Modular homes are acceptable for installation).
• Use above 8000 ft A.S.L. altitude (see page 28).
• Outdoor installation without installation of Outdoor kit (BTOK).
• Applications where inlet water temperature is higher than 140°F
(60°C). A 3-way valve or mixing valve must be installed before
the appliance if inlet water temperature exceeds this limit.
Remove front cover
▶ Loosen the two Phillips head screws located on bottom rear of cover.
Loosen the two screws