No heat in cold weather
A house with no heat in a New Hampshire January can freeze pipes within a day or two. Check that the thermostat is calling for heat, that the boiler has power and fuel, and that the emergency switch has not been flipped. If those are fine and the boiler still will not run, call our 24/7 line.
If you smell gas or heating oil, leave the house and call 911 or the fuel supplier from outside. Never reset a boiler repeatedly, because each failed start can flood the combustion chamber on an oil unit. Tell the dispatcher what lights or error codes show on the boiler.
- The boiler does not start and the thermostat is calling for heat.
- Water leaking from the boiler or from a pipe near it.
- The pressure gauge reads very high or near zero.
- Banging, kettling or gurgling noises from the system.
- Cold radiators or baseboards while the boiler runs.
Symptoms and likely causes
These are typical matches, and the plumber verifies each with tests.
| Symptom | Likely cause | Typical fix |
|---|---|---|
| No heat, boiler silent | Tripped switch, failed control board, no fuel | Check power, reset safely, replace the failed control |
| Low pressure | Leak in the system or a failed expansion tank | Find the leak, refill and test |
| High pressure and a dripping relief valve | Waterlogged expansion tank | Replace the tank, check the relief valve |
| Kettling noise | Mineral scale in the heat exchanger | Flush or descale |
| Radiators cold at the top | Air in the system | Bleed the radiators and purge the zones |
Heat out and the house is cooling?
Call the 24/7 line and tell the dispatcher what the boiler shows.
What a boiler visit covers
The plumber begins by listening to the description and checking the simple items first, such as power, thermostat settings, pressure and water level. Then the plumber tests the circulator pumps, zone valves, control board and burner or igniter. Most no-heat calls come down to one failed component.
Boiler work often overlaps with the heating trade, and the plumber tells you plainly when a job belongs to a heating contractor, such as a furnace or an oil burner service. For the plumbing side of a hydronic system, including leaks, pressure, expansion tanks and zone valves, we handle the repair.
Older systems in older Derry houses
Many older homes around Derry Village and East Derry heat with cast iron radiators or baseboard loops that have been in place for generations. These systems can be reliable, but valves seize, pipes corrode and air collects. Insulating pipes in unheated cellars and bleeding air each season keeps them running smoothly.
If your boiler has a tankless coil for domestic hot water, a boiler failure also means no hot water. In that case read our water heater repair page, and tell the dispatcher that both heat and hot water are out.
Seasonal care for hydronic systems
Maintenance before the cold arrives is cheaper than a no-heat call in January.
- Schedule a service visit each fall before the first cold snap.
- Bleed radiators that feel cold at the top.
- Check the pressure gauge and note the normal reading.
- Keep the area around the boiler clear.
- Insulate exposed pipes in the cellar and crawlspace.
Protecting the house while you wait
If the heat will be off for hours, open cabinet doors under sinks on exterior walls and let a faucet drip on the coldest lines. Use space heaters with care and never run a gas oven for heat. The plumber also checks for frozen sections once heat returns, and the burst pipe repair page covers what to do if a pipe has already split.
Boiler Repair questions in Derry
Yes. The line is open 24/7. If the boiler is out in cold weather, call (603) 815-9179, describe what the boiler shows and open cabinet doors on exterior walls while you wait.
Low pressure usually means a leak or a failed fill valve. High pressure often points to a waterlogged expansion tank. The plumber reads the gauge, checks the relief valve and finds the cause.
We handle the plumbing side of hydronic systems. Burner service on oil units and furnace repair are separate trades, and the plumber will say so if your problem belongs to one of them.
Noise often comes from air in the lines or scale on the heat exchanger. Bleeding the system or flushing the boiler usually helps. Persistent banging deserves a visit.
It depends on the age, the part that failed and the condition of the heat exchanger. The plumber explains repair costs against replacement so you can decide.
References: manufacturer instructions for your boiler. Derry code enforcement, 603-432-6148, for replacement permits. call 911 or the fuel supplier first for any gas or oil smell.
Boiler repair in Derry, any hour
Call now. The plumber diagnoses and gives you a clear price before work starts.