Hot Water Boiler Repair for Radiator, Baseboard and Radiant Heat
A hot-water boiler heats water and pumps it through radiators, baseboard or radiant floor tubing in closed loops. Unlike steam, the system stays full of water under modest pressure, and it depends on a circulator, an expansion tank, a fill valve, a relief valve and often several zone valves or pumps. When one of those parts fails, the symptoms can look like a boiler failure even when the boiler itself is fine.
In plain language: if the boiler runs but a zone stays cold, the pressure gauge keeps dropping or climbing, or the pipes gurgle, we test each part in order and tell you what failed before we replace anything.
Tell us what the system is doing when you call — that decides which truck and which parts head to your address.
Common hot water boiler problems we repair
The calls we take most often are a single zone that will not heat, a pressure gauge that drops and needs refilling, a relief valve dripping onto the floor, gurgling or rushing sounds in the pipes, and a boiler that runs constantly without satisfying the thermostat. Each one points to a different part, so we test rather than guess.
- Failed or seized circulator pumps
- Zone valves that stick open or closed
- Waterlogged or undersized expansion tanks
- Fill valves that overfeed or fail to feed
- Air trapped at high points or radiators
- Leaks at fittings, flanges and baseboard elements
Pressure that drops or climbs
A hot-water system that keeps losing pressure is losing water somewhere — a weeping relief valve, a leaking fitting or a pinhole in old piping. Topping it off repeatedly brings fresh oxygen and minerals into the boiler, which corrodes and scales it from the inside. A system whose pressure climbs when it heats usually has an expansion tank that has lost its air charge, which in turn makes the relief valve open.
We explain this in detail in why boiler pressure rises and the relief valve drips.
Boiler not heating? Check the order
When a hot-water boiler is not heating, we work through it in sequence: thermostat and zone call, power and switches, system pressure, the circulator, gas valve and ignition, flame sensing, venting and condensate on modern units, then the distribution piping. A boiler that fires but a house that stays cold is usually a circulation or air problem, not a burner problem.
Modern condensing and combi boilers add electronic controls, a condensate trap and PVC venting. Error codes help, but they point to a category, not a part. We confirm the actual fault before ordering anything.
Radiant floors and mixed systems
Radiant floor heat runs at lower water temperatures and often uses a mixing valve or injection pump between the boiler and the floor loops. Homes in the suburbs frequently combine baseboard upstairs, radiant in a basement or addition and an indirect water heater on the same boiler. We trace which zone is calling and which pump or valve is responding so one fix does not cause a new problem elsewhere.
Repair or replace?
Most hot-water boiler repairs are part replacements on a sound boiler. Replacement makes sense when the heat exchanger leaks, the boiler is near the end of its expected life and failures are stacking up, or parts are no longer available. We price both options when replacement is on the table.
Planning ahead? See boiler replacement and installation.
Where we do this work
We work from 2093 Rand Rd, Des Plaines, IL 60016 and cover Cook and DuPage county communities plus Chicago. Every community is listed on our service areas page, or start with one of these:
Questions we are asked about this service
Why does my boiler pressure keep dropping?
The system is losing water through a leak, a weeping relief valve or a failed component. Repeated refilling corrodes the boiler, so the leak should be found and repaired.
Why is one zone cold while the rest of the house heats?
Usually a zone valve or circulator for that zone has failed, the thermostat is not calling, or air is trapped in that loop. We test each in order.
What causes gurgling in hot-water heating pipes?
Air in the system. It can be purged, but if it keeps returning, something is letting air in — often low pressure, a failed vent or a leak.
Do you repair combi boilers?
Yes. We repair wall-hung combi and condensing boilers, and Right Away is a certified Navien installer for combi boilers, boilers, tankless water heaters and furnaces.
Is a dripping relief valve dangerous?
It is doing its job by releasing excess pressure, which is a sign something else is wrong — usually the expansion tank or fill valve. Do not cap or plug it. Call for service.
Related services
Guides worth reading
- Boiler pressure rises and the relief valve drips
- Boiler running but radiators cold
- No heat in a Chicago winter? What to check first
Every article is on our plumbing and HVAC guides page.
Schedule this service
Call 847-550-3322 for Des Plaines and the suburbs, or 773-250-6060 in Chicago. You can also request service online.