When the boiler dies on a cold night in Simsbury, CT, the house starts losing heat right away, and the 24/7 line is open for it. While you wait, check that the thermostat is set to heat, confirm the boiler's service switch is on, and look at the breaker. Open cabinet doors under sinks and let a faucet drip on exterior walls to protect the pipes. If you smell gas or a carbon monoxide alarm sounds, leave the house now.
Boiler repair is the diagnosis and fix of the appliance that heats water or makes steam, plus the pumps, valves, controls and piping that carry it to radiators or baseboards. DOE describes a boiler as heating water to provide hot water or steam for heating, distributed through pipes. When one fails, the cause is usually a single part, and a plumber's job is to tell which one.
Same-day visits are offered when the schedule allows. Evening, weekend and holiday calls go to the same dispatcher.
No heat tonight: what to do before anyone arrives
Safe checks you can make
Do only what is listed here. Do not open the boiler's cover, bypass a safety control or force the relief valve.
- Turn the thermostat to heat and set it a few degrees above room temperature.
- Make sure the boiler's red service switch is on and that its breaker has not tripped. Reset a breaker once only.
- Look at the pressure gauge and note the reading for the dispatcher, along with any blinking light or code.
- Open cabinet doors on exterior walls and let a faucet drip. The National Weather Service advises both to protect pipes.
Gas smell or carbon monoxide: leave first
If you smell gas, go outside and call Connecticut Natural Gas at 866-924-5325 or 911 before anyone calls a plumber. Do not flip switches or use a phone near the odor. EPA lists worn or poorly maintained boilers and blocked, disconnected or leaking flues among carbon monoxide sources, and says the gas is colorless and practically odorless. Headache, dizziness, nausea or flu-like symptoms that ease when you leave the building are a warning.
Why a Simsbury winter is hard on a boiler
NWS Boston climate data for Hartford (Bradley) lists a 1991 to 2020 normal January average low of 18.8 degrees F. A boiler in this region runs for months at that load, so a weak circulator or a tired igniter fails on the coldest night, not in October. If the boiler has not been looked at in a while, book a check before the first hard freeze.
Power matters as well as fuel. Even a gas boiler needs electricity for its controls and pump. The state's 2012 storm response report says about 830,000 customers lost power after the October 2011 snowstorm, and some stayed out nearly two weeks. If your house sits cold for a long outage, NWS advises keeping the heat at 55 degrees or higher when you are away and knowing where your main water shutoff is.
No heat right now?
Check the thermostat and breaker, then call the 24/7 line. Same-day visits when available.
Hot water versus steam: why the repair differs
DOE describes steam heat as one of the oldest systems, using radiators, and hot water or hydronic heat as moving hot water to baseboard units. The two fail in different ways.
| System | How it heats | Common faults |
|---|---|---|
| Hot water baseboard | A pump moves hot water through zones | Failed circulator, stuck zone valve, trapped air, low pressure |
| Hot water radiators | Same loop, cast iron radiators | Air pockets that leave top floors cold, leaking radiator valves |
| Steam | Boiler makes steam that rises to radiators | Low water cutoff, stuck air vents, water hammer, wrong water level |
| Combination or indirect | Boiler also supplies a hot water tank | Heat works but showers do not, or the reverse. See water heater repair if the tank is separate. |
Banging, low pressure, leaks and cold radiators
No heat at all
Thermostat, power, a safety lockout, a failed igniter or a low-water cutoff is the usual cause. Repeated resets of a lockout can mask a real fault, so stop after one.
Low pressure
Pressure that creeps down means water is leaving the loop through a leak, a stuck relief valve or a failed expansion tank. A fill valve can hide a leak by topping up silently. If you cannot see where the water goes, leak detection can trace it.
Banging and knocking
Steam systems bang when condensate gets trapped in a sagging pipe. Hot water systems clank from trapped air or scale on the heat exchanger.
Leaking boiler
A drip from a pump flange or valve packing is often a small repair. Water seeping from the boiler body usually means the unit is nearing the end.
Pilot or ignition faults
A dirty flame sensor, a weak igniter or a blocked vent can lock out the burner. Relighting a gas appliance repeatedly is not a fix.
Cold radiators
Trapped air on a hot water system leaves the top of a radiator cool. Bleeding it is a reasonable homeowner job, but not on steam.
Bleeding a hot water radiator: safe limits
Bleeding applies to hot water systems only. Steam radiators use air vents instead, and opening the wrong valve can release scalding steam.
- Turn the heat down and let the radiator cool so you do not get burned.
- Hold a cloth and cup under the bleed valve, then turn it a quarter turn with a radiator key.
- Close the valve as soon as water spits instead of air.
- Check the boiler gauge afterward, since venting air can drop pressure and the system may need topping up by a plumber.
How the fault gets found
A technician starts with the controls and works toward the burner. Meters test voltage at the thermostat, pump and zone valves, a gauge confirms system pressure, and a sight glass on a steam boiler shows the water level. On a gas boiler, a combustion analyzer reads the exhaust and flags carbon monoxide at the flue.
The aquastat, relief valve and expansion tank are each tested in turn, and the flue and chimney are inspected for blockage. Any work on gas piping is done under a Connecticut plumbing license. Ask the Simsbury building department whether your repair or replacement needs a permit or inspection, because we do not state local rules we cannot verify.
Repair or replace: when a boiler is past saving
DOE puts boiler life expectancy at 15 to 30 years and efficiency at anywhere from 50 to 90 percent depending on age. Both numbers matter when a big part fails.
Repair when
- A circulator, zone valve, igniter, control or sensor has failed.
- The boiler body is dry and the heat exchanger tests sound.
- It is inside its 15 to 30 year range and has been serviced.
- A single fault explains the symptoms.
Past repair when
- The cast iron sections or heat exchanger are cracked or leaking.
- The unit gives off carbon monoxide that cannot be corrected.
- Repairs keep following one another and parts are scarce.
- Sludge and corrosion have spread through the system.
How an emergency no-heat visit runs
Check safety
The plumber checks for gas smell and carbon monoxide, then looks at the boiler, gauge and vents.
Find the fault
Testing runs from the thermostat through the controls, pump and burner to the heat distribution.
Get your price
You hear a clear price for the repair, and an honest word if the unit is near the end.
Fix and confirm
The part is replaced and the system is brought up to heat, with pressure, flame and vent confirmed before the plumber leaves.
What shapes the cost of boiler repair
A bleed valve and a failed control board are far apart in scope, so we do not publish prices. You will hear the number before work starts.
Insurance usually treats a worn-out boiler as maintenance. A sudden burst from a frozen pipe may be covered, as the Insurance Information Institute notes that standard policies generally cover frozen and burst pipes. Ask your insurer before repairs, and keep photos.
What boiler repair does not cover
Some heating jobs belong to a heating or electrical specialist, such as an oil burner problem or a damaged chimney. Tell the dispatcher what fuel your boiler uses so the right technician is sent. If a pipe has frozen and split, burst pipe repair is the next call. Old, leaking supply piping throughout the house may be a repiping question, not a boiler one.
We also dispatch to Avon, Bloomfield and Canton on cold nights.
Frequently Asked Questions
Yes. The 24/7 line takes no-heat calls overnight, on weekends and on holidays, and same-day visits are offered when the schedule allows. Tell the dispatcher your fuel, the gauge reading and any code or light. A gas smell or a carbon monoxide alarm goes to Connecticut Natural Gas or 911 before a plumber.
Confirm the thermostat is on heat and set above room temperature, the boiler's service switch is on, and the breaker is not tripped. Write down the pressure gauge reading and any blinking code. Do not open the boiler cover.
On a hot water system, usually yes, if you let it cool, use a cup and cloth and close the valve at the first spit of water. Never try it on steam. Check the boiler gauge afterward, because venting air can drop the pressure.
Water is leaving the system through a leak, a leaking relief valve or a failed expansion tank. Adding water without finding the cause hides the problem and brings in fresh minerals and oxygen. A plumber should trace it.
DOE gives a life expectancy of 15 to 30 years, and says efficiency runs from 50 to 90 percent depending on age. Condition and maintenance move you within that range. A cracked section ends the debate.
Ask the Simsbury building department. Rules differ by job, and we do not state local requirements we cannot verify. The department can tell you what applies to your repair or replacement.
- US DOE home heating fact sheet
- EPA what is carbon monoxide
- PURA what to do if you smell natural gas
- NWS Boston Hartford (Bradley) climate report
- NWS extreme cold advice
- CT Storm Response and Recovery Assessment Group report, 2012
- 2022 Connecticut State Building Code (2021 IPC plumbing edition), CT DAS Office of State Building Inspector