Hot water runs out very quickly compared to heater capacity.

Safety: Turn off power before opening any plumbing connections.

Steps:

• Increase set temperature: If safe, raise the thermostat setting to increase stored energy (do not exceed manufacturer limits).
• Check dip tube: On some Eldom models, the cold inlet dip tube directs incoming cold water to the bottom. If broken, cold water mixes at the top, reducing usable hot water. Inspect and replace if accessible.
• Check mixing valve: If a thermostatic mixing valve is installed, verify its setting and operation; a faulty valve may mix too much cold water.