Hot-Water & Steam Boiler Repair
Boiler Repair in Elgin & the Fox Valley
Cold radiators, a boiler that keeps locking out, or water on the basement floor? We diagnose and repair every brand of residential hot-water and steam boiler, day or night. You get a clear flat-rate price before we touch a part.
- 24/7 no-heat emergency service
- Hot-water and steam boilers, all brands
- Price approved before work starts
- Licensed, insured and bonded
Signs Your Boiler Needs Repair
A boiler rarely quits without warning. In a Fox Valley winter, with design temperatures near 0°F and the boiler running most of the day from November to March, small problems turn into no-heat calls fast. Call us if you notice any of these.
- Cold radiators or baseboards. Some rooms heat and others never do. Trapped air, a dead circulator or a stuck zone valve are the usual reasons.
- Uneven heat. The first radiator on the loop is hot and the last one is lukewarm. Flow, pump speed or a boiler short cycling on its limit.
- Kettling, banging or gurgling. Rumbling from the boiler is scale on the heat exchanger. Gurgling in the pipes is air. Banging in a steam system is water hammer from condensate that cannot drain.
- Pressure climbing or dropping. A hot-water boiler should sit near 12 to 15 psi cold. Climbing pressure points to the expansion tank or fill valve; falling pressure means a leak.
- Water under the boiler. A relief valve that weeps, a pump flange gasket, a leaking section or a corroded fitting. None of it gets better on its own.
- Pilot or burner will not stay lit. A thermocouple, flame sensor, gas valve or a draft problem pulling the flame off the burner.
- Repeated lockouts. The control shuts the burner down and shows a code. Each safety it trips is telling you something specific.
- The boiler runs but the house never reaches setpoint. Low flow, scale, a stage stuck low or a boiler that was never sized for the load.
- Gas bills climbing with no change in use. A boiler cycling constantly, a fouled burner or a scaled heat exchanger is burning gas without delivering the heat.
- Soot, a yellow flame or a hot flue collar. Combustion or venting trouble. Shut it down and call.
Smell gas? Leave the house right away, call 911 from outside, and call your gas utility’s emergency line from outside before calling us.
Carbon monoxide alarm going off? Get everyone outside, call 911 or your gas utility, and do not run the boiler again until it has been inspected.
The Most Common Boiler Failures We See
Hot-water and steam boilers in the older housing stock of Elgin, St. Charles, Sycamore and East Dundee fail in predictable ways. Here is what goes wrong, how you can tell, and what we do about it.
Most common
Circulator pump
The circulator moves hot water from the boiler through the radiators or baseboard and back. When the motor or the cartridge seizes, the boiler heats up and shuts off on its limit while the house stays cold. A leaking flange gasket is the other common failure. We check for voltage at the pump, confirm the impeller is turning, and replace the cartridge or the whole pump with the right size for your loop.
Pressure related
Expansion tank and fill valve
Water expands as it heats, and the expansion tank absorbs that growth. When its bladder fails or it waterlogs, pressure spikes and the relief valve dumps water on the floor every cycle. A fill valve stuck open does the same thing. We check tank charge against system pressure, test the fill valve, and replace what failed.
Safety
Relief valve
The relief valve opens at 30 psi on a residential hot-water boiler to protect the system. A valve that drips constantly has either been fouled by debris or is doing its job because pressure really is too high. We find out which before replacing it, because a new valve on an over-pressurized system will drip too.
Zoned homes
Zone valves and relays
Homes with more than one heating zone use motorized zone valves or separate circulators controlled by a relay. A zone valve with a stripped gear or burned motor leaves that zone cold while the others heat. A stuck-open valve overheats a room. We test each end switch and motor, and replace the head or the body as needed.
Ignition
Burners, thermocouple and flame sensor
Older standing-pilot boilers rely on a thermocouple; newer ones use a hot surface igniter or spark and a flame sensor. Dirty burners, a weak thermocouple or an oxidized flame sensor all produce the same symptom: the burner lights and drops out, or will not light at all. We clean and test, then replace only what fails the test.
The controls
Aquastat, low-water cutoff and control board
The aquastat sets the boiler’s operating and high-limit temperature. The low-water cutoff shuts the burner off if the water level drops. On modern condensing boilers, a control board manages all of it and reports fault codes. We verify inputs and outputs before condemning a control, because a bad reading is often a bad sensor, not a bad board.
Venting
Draft, vent and combustion
Atmospheric boilers need a clear chimney and good draft. Condensing boilers vent through PVC and need clean intake and exhaust plus a working condensate trap. A blocked vent, a stuck pressure switch or a plugged trap will lock the boiler out. We check the vent path first, because replacing a switch that is doing its job does not fix anything.
Cracked section or heat exchanger? That one is different. A cast-iron boiler leaking between sections, or a condensing boiler with a leaking heat exchanger, is usually not worth repairing. We shut it down, show you what we found, and walk you through boiler replacement with the Nicor Gas discount already figured in.
What to Expect on a Boiler Repair Visit
You should know exactly what is happening at each step. Here is how a boiler repair call with us goes.
1. Booking. Call (847) 224-2420 or book online any time. Tell us whether the boiler is hot-water or steam, what it is doing, and if the control shows a code, what the code is. No-heat calls get priority, and we run 24/7 for emergencies.
2. Diagnosis. The technician starts at the thermostat and follows the sequence the boiler itself runs: the call for heat, the relay or control, the circulator or zone valve, the ignition and flame proof, then the safeties. We check system pressure, look at the expansion tank and relief valve, bleed a radiator to check for air, inspect the burners and venting, and on steam boilers check the water level, the low-water cutoff and the main vents. This takes 30 to 60 minutes on most boilers.
3. Findings and price. We show you the failed part and explain what caused it, because a failed circulator or relief valve usually has a reason behind it. Then you get a flat-rate price for the repair, in writing, before any work begins. A second, non-urgent issue gets mentioned, not pushed. The repair is quoted flat-rate, and you approve that price before any work.
4. The repair. Our vans carry circulator cartridges, zone valve heads, relief valves, expansion tanks, thermocouples, igniters and common controls, so most repairs are finished the same visit. A brand-specific gas valve or board may need to be ordered, and where it is safe we leave the boiler running until it arrives.
5. Testing. A repair is not done when the part is in. We fill and purge the loop, set the pressure, run a full heat cycle, check flame signal and combustion, confirm each zone gets hot, and on condensing boilers make sure the trap is draining. Then we clean up and leave the area the way we found it.
6. Follow-through. You get an invoice that lists the part, the readings and any recommendations. If the boiler is at an age where the next repair might not be worth it, we say so and can put together a free written replacement quote.
What Boiler Repair Costs in the Fox Valley
Flat-rate pricing, approved in writing before work starts. No hourly meter running while we look for parts.
Every repair visit starts with a flat diagnostic fee. During office hours (9 a.m. to 5 p.m., Monday through Friday) the service call is $130; weekday evenings after 5 p.m. it is $180, and nights, weekends and holidays are $260. Each includes 30 minutes of travel and 30 minutes of diagnostics, and parts are extra. That covers the trip and the time it takes to find the actual problem. The repair is quoted separately, flat-rate, for you to approve before any work. If you decide not to repair, the diagnostic fee is all you owe, and you keep the written findings.
Boiler repairs range widely because the parts do. A thermocouple, radiator vent or relief valve is a small, quick job. A zone valve, expansion tank or aquastat sits in the middle. A circulator, gas valve or condensing-boiler control board is at the top, and a leaking section or heat exchanger usually means replacement rather than repair. You see the number for your exact repair before you say yes.
| Repair | Typical symptom | Where it usually falls |
|---|---|---|
| Thermocouple or flame sensor | Pilot or burner drops out | Lower end |
| Radiator or main air vent | One cold radiator, hissing | Lower end |
| Relief valve | Dripping at the discharge pipe | Lower end |
| Expansion tank | Pressure climbs, relief valve dumps | Lower to middle |
| Zone valve head or body | One zone never heats | Lower to middle |
| Aquastat or relay | Boiler will not fire or runs pump nonstop | Middle |
| Circulator pump | Boiler hot, radiators cold | Middle to upper |
| Gas valve or control board | Lockouts, no ignition | Upper end |
| Cracked section or heat exchanger | Leaking from the boiler body | Usually replacement |
Maintenance plan members get 5% off repairs, priority scheduling during the first cold snap, and one free business-hours service call each year. If the repair is large enough that financing helps, you can prequalify in about 2 minutes with no impact to your credit score.
Repair or Replace? How We Decide
We will fix almost any boiler. The question is whether you should pay to fix this one.
Start with the 50% rule. If the repair costs more than half of what a new boiler would cost, replacement almost always wins, because you are putting real money into a unit that is still old everywhere else. Under that line, age and condition decide it.
- Under 15 years old: repair it. Parts are available, and many are still under the manufacturer’s parts warranty if the boiler was registered.
- 15 to 20 years old: repair the inexpensive things. Weigh a circulator, gas valve or board against the boiler’s overall condition and whether it has needed other work recently.
- 20 years or older: get a replacement quote alongside the repair price. A cast-iron boiler can run a long time, but a 20-year-old atmospheric unit is also giving up a lot of efficiency compared with a 95% condensing or combi boiler, and the Nicor Gas discount narrows the gap.
- Any age with a cracked section or leaking heat exchanger: replace.
- Repeated repairs: two or three service calls in a couple of winters means the boiler is wearing out as a whole, not failing one part at a time.
When replacement is the better call, we give you a free written quote the same visit. Read more on our boiler replacement and boiler installation pages, or see our overall boiler services. A fall boiler tune-up is the best way to avoid most of the repairs on this page in the first place.
Why Fox Valley Homeowners Call Rest Assured for Boiler Repair
We are a local Elgin company, not a call center. The person who answers can tell you when a technician will be there.
Laars boilers, installed by our team. We repair every brand.
- Hot-water and steam boilers, radiators and baseboard, all brands repaired
- Owner Jeff Kerley is EPA 608 Universal and NATE certified in gas heating installation
- Licensed, insured and bonded; municipally licensed in Elgin, Aurora, Bartlett, Huntley and Streamwood
- BBB of Chicago & Northern Illinois Complaint Free Award, 2024 and 2025
- Housecall Pro Superpro 2024 through 2026, with online booking any time
- Nicor Gas Contractor Circle Installing Member for when replacement makes sense
- Stocked vans, so most repairs are done in one visit
Boiler home with no cooling? Most have no ductwork, and a Daikin ductless mini-split is the usual answer. We handle furnaces and heat pumps too.
If Repair Turns Into Replacement, Nicor Gas Helps
As a Nicor Gas Contractor Circle Installing Member, we take the instant discount right off your invoice: $350 on a qualifying 95% AFUE heating boiler, or $500 on a qualifying combination boiler that also heats your domestic hot water. See Nicor Gas instant discounts.
Want to keep the boiler you have running? Our semi-annual maintenance plan is $240 a year and includes the fall heating tune-up, one free business-hours service call, priority scheduling and 5% off services.
Boiler Repair Across the Fox Valley
Based in Elgin, we serve homes throughout Kane, McHenry, DuPage and DeKalb counties.
- Elgin
- South Elgin
- St. Charles
- Aurora
- Bartlett
- Streamwood
- Huntley
- Plato Center
- Sycamore
- Carpentersville
- West Dundee
- East Dundee
- Algonquin
- Gilberts
- Hampshire
- Pingree Grove
- Campton Hills
- Geneva
- Batavia
- Barrington
- Hoffman Estates
- Schaumburg
- Burlington
- Marengo
- Wayne
- Sleepy Hollow
Don’t see your town? Call (847) 224-2420. View all service areas.
Boiler Repair FAQs
Do you offer emergency boiler repair in Elgin?
Yes. No-heat boiler calls are answered 24/7 at (847) 224-2420. We serve Elgin and the Fox Valley towns across Kane, McHenry, DuPage and DeKalb counties, and we have a dedicated emergency boiler repair page for after-hours situations.
How much does boiler repair cost?
Every visit starts with a flat diagnostic fee. Once we find the fault, you get a flat-rate price in writing to approve before any work. Parts range from a simple relief valve or zone valve up to a circulator or gas valve, and we quote each one before touching it.
Why are my radiators cold when the boiler is running?
On a hot-water system, the usual reasons are air trapped in the radiator, a circulator that is not moving water, a stuck zone valve or a boiler that is short cycling on its limit before the water gets around the loop. On a steam system, a clogged air vent keeps steam out of that radiator. We check the loop in order and fix the actual cause.
What is boiler kettling and is it dangerous?
Kettling is a rumbling or banging sound from the boiler itself, caused by scale on the heat exchanger making water boil locally. It is a warning sign, not an immediate danger, but it stresses the heat exchanger and shortens the boiler’s life. Call before it gets louder.
Why does my boiler pressure keep dropping?
Water is leaving the system somewhere. Common spots are a weeping relief valve, a leaking pump flange, a pinhole in old piping or a radiator valve packing. A failed automatic fill valve can also stop the system from making up small losses. We pressure-test and trace the leak.
Why is my boiler pressure too high?
Usually a waterlogged expansion tank or a fill valve that is stuck open. Either one lets pressure climb as the water heats until the relief valve dumps at 30 psi. Replacing the expansion tank or fill valve is a routine repair.
Why does my boiler keep locking out?
A lockout means a safety control stopped the burner: a flame sensor that cannot prove flame, a pressure switch that will not close, a low-water cutoff that sees no water, a blocked vent or a high limit that opened. We read the fault code, then test each safety rather than just resetting it.
Is water under my boiler an emergency?
It needs attention the same day. A small drip from the relief valve or a pump flange is common and repairable. A steady leak from the boiler body usually means the heat exchanger or a section is cracked, which is a replacement conversation. If it is running across the floor, close the boiler’s water feed valve and call.
Do you repair boilers you didn’t install?
Yes. We install Laars boilers and repair all brands of residential hot-water and steam boilers, including Weil-McLain, Burnham, Peerless, Utica, Navien, Lochinvar, Bosch and others, no matter who put them in.
Do you work on steam boilers?
Yes. Steam boilers in older Elgin, St. Charles and East Dundee homes have their own set of parts: low-water cutoffs, pressuretrols, sight glasses, main vents and radiator air vents. We service and repair all of them.
Can I reset my boiler myself?
Once. Check the thermostat, make sure the boiler’s power switch and gas valve are on, look at the pressure gauge (12 to 15 psi cold is typical on a hot-water system) and press the reset on the control. If it locks out again, stop and call. Repeated resets can hide a venting or safety problem.
What is an aquastat and why does it fail?
The aquastat is the temperature control on a hot-water boiler. It tells the burner when to fire and the circulator when to run. When it fails, the boiler either will not fire at all, overshoots its temperature or runs the pump nonstop. We test the well sensor and relay before replacing it.
How long does a boiler repair take?
Diagnosis takes 30 to 60 minutes on most boilers. Zone valves, relief valves, expansion tanks, thermocouples and common circulators are on the van, so many repairs are done the same visit. A brand-specific control board or gas valve may need to be ordered, and we tell you the lead time up front.
Should I repair or replace an old boiler?
Repair the inexpensive parts on any boiler that is sound. For a large repair on a boiler over 20 years old, or any boiler with a cracked section or heat exchanger, get a replacement quote alongside the repair price. We cover the math on our boiler replacement page.
Does the maintenance plan cover my boiler?
Yes. The semi-annual maintenance plan includes a fall heating tune-up, one free business-hours service call, priority scheduling and 5% off repairs. Boiler homes that also have a ductless system get the spring visit on that equipment.
My boiler home has no AC. What are my options?
Most boiler homes in the Fox Valley have no ductwork, so the practical answer is a ductless mini-split system. It cools in summer and can carry heat in the shoulder seasons so the boiler runs less.
Boiler Down? We’re On It.
Call any time for emergency boiler repair in Elgin and the Fox Valley, or book a repair online and we’ll confirm your arrival window.
Boiler on its last legs? Request a free replacement quote or see financing options.
Discount amounts reflect the 2026 Nicor Gas Energy Efficiency Program for qualifying equipment installed January 1 through December 31, 2026, and are subject to change or cancellation due to funding limits. Rest Assured HVAC LLC is an independent contractor and is not affiliated with or endorsed by Nicor Gas.
