Indirect Water Tank Hot-Water Problems
Indirect water tanks use your boiler to heat water stored in a separate cylinder. When hot water stops working, the problem could be in the boiler, the tank, or the connection between them.
How Indirect Systems Work
Your boiler heats water that circulates through a coil inside the indirect tank. This transfers heat to the domestic water stored in the tank. A tank sensor tells the boiler when to fire, and a circulator pump moves the boiler water through the coil.
Common Indirect Tank Failures
Faulty tank temperature sensor (boiler does not fire for hot water), zone valve or circulator failure (hot boiler water does not reach the tank), coil leak (boiler water mixing with domestic water), or tank thermostat miscalibration.
Diagnosing Indirect System Problems
We check the tank sensor operation, verify the zone valve or circulator is working, inspect the coil for leaks, and confirm the boiler is responding to hot-water calls.
Safety Reminder
If you smell gas, suspect carbon monoxide or believe there is an immediate danger, leave the property and contact emergency services or the appropriate gas emergency authority. Do not remain inside — exit the building immediately and call for help from outside.