Typically powered by 8 AA alkaline batteries , providing about one year of life with standard use.
Bosch includes a pre-commissioning checklist in the manual to ensure the system operates silently. A common failure mode is "hydraulic noise" (gurgling or rushing water), which the manual states is usually caused by insufficient water volume in the secondary circuit. The solution (found on page 12 of the official manual) involves adjusting the balancing valves on the return legs while monitoring the El600's integral pressure gauge.
Once you download the manual, print pages 14–18 (the wiring diagrams and fault codes) and laminate them. Zip-tie this laminated card to the side of the El600. The next heating engineer who services your system will thank you.
located at the bottom of the external panel to provide temporary power from a power bank [4]. 4. Safety & Security System Lockout