HVACopediaAll brands · Boiler troubleshooting
Poor heat / circulation
What is going on
Air-bound sections, cavitating pump, failed circulator, closed zone valve, waterlogged tank.
Check in this order
- At operating temp supply−return ≥20 °F
- Bleed/purge
- Check vents, scoops
- Pump amp/noise
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Source: General HVAC service practice — verify per model. Written in our own words; check the manual for your exact model.
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.