Guide
What to check before calling about your boiler
Five minutes of checks that can save a service call, or help the technician fix it faster.
Call Now Plumbing is a referral service. Your call is routed to an independent, locally run heating contractor who handles the visit.
The checklist
- Thermostat: mode, setpoint, batteries.
- Power: boiler service switch and breaker.
- Fuel: gas to other appliances, or oil tank level.
- Water: sight glass on steam, gauge on hot water.
- Codes and resets: write down any code. Press an oil reset once only.
Write these down
The boiler brand and model from the rating plate, its approximate age, steam or hot water, fuel, and exactly what you saw or heard. Angi suggests knowing the age, fuel type and model number so the technician can give a more accurate quote.[source]
About this guide. Written by Call Now Plumbing, a referral line operated by Get Called LLC, from the public sources listed on our sources page, checked Nov 3, 2026. It has not been reviewed by a licensed heating contractor. For advice on your system, ask the company you reach.
Related pages
Why a few minutes of checking helps
A heating company that knows what you have already ruled out can skip steps and bring the right part. Some problems also turn out to be things you can fix yourself, like a thermostat battery or a tripped breaker. And knowing the readings on your boiler helps the company judge how urgent the call is.
None of these checks involve opening the boiler, working on gas lines, or touching wiring. If anything looks unsafe, stop and call.
Thermostat details
Check that the thermostat is set to heat, that the set temperature is a few degrees above the room temperature, and that the display is on. Smart thermostats can lose Wi-Fi or have a schedule override; check the app. If you have multiple zones, check each zone's thermostat. If only one zone is cold, the problem is likely that zone's valve or circulator, not the boiler.
Power, fuel and water
Look for the boiler service switch, often at the top of the basement stairs or on the boiler, and confirm it is on. Check the breaker panel for a tripped breaker labeled boiler, burner or furnace. For gas, check whether the stove or water heater works. For oil, read the tank gauge. For a hot water boiler, read the pressure gauge. For steam, look at the sight glass.
Write all of it down. A short list like "thermostat calling, power on, gas stove works, pressure 8 psi, error code F4" is exactly what a technician wants to hear.
Outside the house
If your boiler vents through plastic pipes out a side wall, check that snow or ice is not covering them. After a heavy storm, this is one of the most common causes of a high efficiency boiler shutting down. Clear snow by hand gently; do not damage the pipe or its screens.
NOAA's 1991 to 2020 normals for the Utica Oneida County Airport station show January averaging a high of 30 degrees and a low of 14 degrees, with about 140 nights a year at or below freezing.[source]
Information about the house
Know your full address including any unit number, whether you own or rent, and how to get into the basement. Note the boiler brand and model from its label, and roughly how old it is if you know. If you have had recent work done, mention it. If anyone in the house is especially vulnerable to cold, say so.
When not to check, just leave
If you smell gas, leave the house and call 911 or your gas utility from outside. If a carbon monoxide alarm sounds, get everyone outside and call 911.[source] If water is pooling near the boiler's electrical parts, do not step into it. These are not situations for checklists.
A sample call
"Hi, I'm in Whitesboro, it is a single family house with a gas hot water boiler. The house is at 58 degrees. The thermostat is calling, the power switch is on, the gas stove works. The pressure gauge reads 5 psi cold, and the boiler shows error E2. I can be home all day." That takes thirty seconds and tells the company almost everything they need to plan the visit.
Frequently asked
Should I turn the boiler off and on? One reset is fine on most boilers if there is a lockout. If it fails again, leave it off and call. On oil boilers, repeated resets can be unsafe.Can I add water to my steam boiler? Only if the boiler is cold and you know where the fill valve is and how to watch the sight glass. Never add cold water to a hot steam boiler that has run dry; turn it off and let it cool, then call.The pressure on my hot water boiler is low. Should I open the fill valve? If you know your system and the pressure is only a little low, some owners do. If it keeps dropping, there is a leak, and adding water hides it. Call instead.The thermostat is blank even with new batteries. Some thermostats are powered by the boiler. A blank display can mean the boiler has lost power or its transformer has failed. Check the breaker and service switch.The heat works but the house is not getting warm. On a very cold night, an older or undersized boiler may run constantly and still fall behind. Note the indoor and outdoor temperatures and how long the boiler runs. That helps the company tell a failing boiler from a system that is simply at its limit.Information to keep by the boiler
Tape a card to the wall near the boiler with the brand, model, serial number, install date if known, fuel, the company that last serviced it, and the normal cold pressure or water level. Add the location of the main water shutoff and the gas shutoff. In a stressful moment, that card saves time.
If you rent
Tell your landlord before you call anyone, unless the landlord has told you to call directly. Many leases make the landlord responsible for heating repairs, and the landlord has to authorize the work. The state code requires 68 degrees in habitable rooms from September 15 to May 31 where the landlord furnishes heat.[source]
Safety first
If you smell gas, leave and call National Grid or 911 from outside. If a CO alarm sounds, leave and call 911. Do not troubleshoot the boiler in either case.
Write it down
Before you call, write the boiler brand, fuel, any codes and what you checked. Read it to the company.
Neighbors on the same street
If several homes lost heat at once, the cause may be a power or gas outage. Check with neighbors and the utility first.
Common questions
What if I find nothing wrong?
Call. Most boiler faults are inside the controls or burner.
Want a pro to look at it?
Call and get connected with a local heating company.
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