Pennco Insufficient Heat Output

Boiler runs but house never reaches set temperature

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Undersized boiler, Incorrect aquastat settings, Air in system reducing output, Fouled heat exchanger reducing efficiency

Safety first: Use caution around hot surfaces.

Check boiler temperature: Ensure the high limit setting is appropriate (often 180–200°F for baseboard systems). Adjust per Pennco manual if set too low.
Bleed system: Remove air from radiators and high points to restore full heat transfer.
Inspect heat exchanger: Have a technician clean the combustion side and check for scale on the water side.
Load vs. capacity: If the home has been added onto or insulation is poor, a heat loss calculation may show the boiler is undersized.

Medium 3/5

High Limit Aquastat

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