No heat in one unit: thermostat and leaking air bleeder replaced
Last updated Reviewed by Waseem Shahzad, Lead Technician
Islip, NYBoiler RepairTechnician: ShabbyNovember 2025
No heat in one unit of a multi-unit home. We replaced a failed thermostat and a leaking air bleeder and tuned up the four-zone boiler.
What the homeowner reported
There was no heat in one of the units in a multi-unit home heated by a single boiler.
What we found
The thermostat for that unit had failed, and an air bleeder on the heating system was leaking.
What we did
Shabby replaced the thermostat and the leaking air bleeder, then performed a boiler tune-up covering all four zones.
The result
The heating system was working well at the end of the visit.
Job details are from our November 2025 service record for this Islip home. Customer details are left out.
General information, not details from this job
About air bleeders and zone thermostats
On a hot-water boiler, automatic air bleeders let trapped air out of the piping so water can circulate. When one sticks or leaks, it can drip water or let air build up, and rooms on that loop go cold. In a building with several zones, each thermostat tells the boiler and its zone valve or circulator when to send heat, so one failed thermostat can leave a single apartment cold while the rest of the building is fine. Checking both the controls and the water side finds the real cause.
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