Condo has no heat? A 10-minute emergency diagnostic for PMs.

Confirm whether it's building-wide or zone-specific

Call back two of the complaining residents and ask them to confirm: are all their radiators cold, or just some? Are they on the same floor or different floors?

Different floors with full no-heat = building-wide. Same floor or same stack only = zone-specific. This determines whether you're chasing a central plant issue or a distribution issue, and where you walk first.

Walk into the mechanical room and look at the boilers

Each boiler will have a display panel showing one of four states: STANDBY (sitting idle waiting for a call), FIRING (currently running), LOCKOUT (faulted and refusing to fire), or a numerical fault code.

If all boilers show LOCKOUT or a fault code — you have a central plant problem. Continue to Step 3.

If boilers are firing but heat isn't reaching units — skip to Step 4 (circulator pumps).

Photograph every fault code

Take a clear photo of each boiler's display showing the fault code. Common codes you'll see:

• E04 / F32 / "Low water" — make-up water failure or system leak (go to Step 5)
• E22 / F22 / "Ignition lockout" — flame failed to establish; usually gas supply or igniter
• E33 / "Flue gas" — exhaust path blocked (snow on rooftop intake/vent is common in winter)
• "Sensor fault" — failed temperature sensor; tech needs to attend

Photograph everything before resetting. You'll need the codes for the tech.

Confirm circulator pumps are running

Put your hand on each circulator pump housing. A running pump vibrates and is warm. A failed pump is silent and cold to the touch.

If pumps are off but should be running: check the pump breakers in the electrical room. A tripped breaker is common.

If pumps are running but flow isn't reaching units: probable cause is an air-locked loop or closed isolation valve. Tech required.

Check system pressure on the boiler gauge

Each boiler has a pressure gauge on the front (psi). Normal cold operating pressure: 12–25 psi.

If pressure reads below 10 psi — your make-up water has failed. The boiler will lock out on low water as a safety measure. Continue to Step 6.

If pressure reads above 30 psi — the expansion tank has likely failed (waterlogged). Tech required, but the boiler will run safely on the relief valve in the short term.

Check the make-up water valve

The make-up water valve is the brass valve on a small pipe coming off the cold-water main into the boiler loop. It should be partially open (handle parallel to pipe = open; perpendicular = closed).

If the valve is closed: open it. System pressure will start to rise within 2–3 minutes. Once pressure reaches 15 psi, you can reset the boilers.

If the valve is open but pressure isn't rising: there's a leak somewhere in the system. Tech required.

For zone-specific issues, check zone valves and aquastat

If only certain stacks or floors are cold, the issue is usually in distribution. Locate the zone valve panel (often in a sub-mechanical closet near the affected stack). Each zone valve should be opening when the thermostat calls for heat.

Listen for the valve motor clicking and the actuator turning. A stuck or failed zone valve will require tech replacement, but you've now isolated the problem.

Check the Building Automation System (BAS)

Log into your BAS (Honeywell, Siemens, Delta, Distech, etc.) and check:

• Is the heating schedule active? (Sometimes a schedule gets accidentally overridden to "off")
• Are setpoints reasonable? (A staff member may have set them to 50°F for "energy saving")
• Are there any active alarms?
• Is any mode override active? ("Manual", "Off", "Holiday")

Clear any incorrect overrides. Many no-heat calls turn out to be BAS schedule issues, not equipment failures.

For penthouse-fed buildings, confirm MAU operation

If your high-rise uses a penthouse-mounted Make-Up Air Unit (MAU) for corridor pressurization, walk up and confirm it's running. A failed MAU often presents as "no heat in upper floors" because the heating coil inside the MAU isn't transferring heat to incoming air.

Document everything and call dispatch

You should now have:

• Photo of every boiler fault code
• Reading of current system pressure
• Confirmation of which pumps are running / not running
• Status of make-up water valve
• BAS schedule / setpoint status

When you call your contractor's emergency line, lead with this information. A tech who arrives knowing the fault code, pressure reading, and confirmed pump status can often have heat restored in 30–60 minutes instead of 2–3 hours.