Hot-Water Gas Boiler Not Heating? Common Repairs for Kokomo Homes

Hot-water boiler heat is quiet, even and comfortable. When it works, most people forget it is there. When it stops, the house cools down slowly at first and then all at once. Some homes around Kokomo, Greentown, Russiaville and Tipton heat with hot-water (hydronic) gas boilers and radiators or baseboard, and these systems tend to run into the same handful of problems.

This post covers what those problems look like, what you can safely check, and when to call for gas boiler repair.

Safety first: if you smell gas, leave the house now. Call your gas utility and 911 once you are outside. Do not flip switches or try to find the leak.

Signs your gas boiler needs repair

Boilers usually give some warning before they quit completely. Watch for:

Some radiators warm, others cold
The house never reaches the thermostat setting
Water on the floor around the boiler or under a radiator
The pressure gauge reading much higher or lower than usual
Banging, gurgling or kettle-like rumbling
The boiler firing and shutting off over and over

Any one of these is worth a call before the next cold night. Boilers that limp along tend to fail at the worst time, and a small fix now usually beats a no-heat call in January.

It also helps to know your normal. Take a quick look at the pressure gauge and listen to the boiler on a day it is working fine. When something changes later, you will notice it sooner, and you can tell the tech exactly what is different.

Cold radiators and uneven heat

If the boiler is running but a few radiators stay cold, especially upstairs, there is often air trapped in the system. Air rises, so it collects in the highest radiators and blocks hot water from getting in.

Many hot water radiators have a small bleed valve at the top corner. With the system cool, a homeowner can open it a little with a radiator key and close it as soon as water appears. Keep a cloth handy. If bleeding does not help, or every radiator is cold, the problem is likely the circulator pump, a zone valve, or the boiler itself.

If you are not comfortable opening a bleed valve, or you are not sure where they are, call us and we will take care of it.

Pressure that will not stay put

Hot water boilers run at a set pressure. Your gauge, usually on the front or side of the boiler, shows where it is. Low pressure can mean a leak somewhere in the system or a problem with the fill valve. High pressure can point to a failing expansion tank or a fill valve that will not shut off.

If the pressure relief valve is dripping or the gauge keeps creeping up, do not cap it or tie it off. That valve is there to protect the boiler. Turn the thermostat down and call for repair.

Leaks around the boiler or pipes

Small drips at fittings or valves are common on older systems and are often a simple fix. A steady leak from the boiler body is more serious. Either way, water on the floor is a sign to have it looked at soon. Leaks also pull fresh water into the system, which can speed up corrosion inside.

Pilot and ignition problems

Older boilers may have a standing pilot light. Newer ones use an electronic igniter. If the boiler will not fire, check that the thermostat is calling for heat, the boiler power switch is on, and the breaker has not tripped.

Past that, leave the burner alone. Relighting a pilot is in the owner’s manual for some models, but if it goes out again, or you are not comfortable with it, that is a job for a tech. Never try to relight anything if you smell gas.

Noises that mean something

Some sounds are normal. A soft click when the burner lights, or a little ticking as pipes warm up, is just metal expanding. Others are worth a call:

Banging or hammering

This can mean air in the system, a sticking valve, or mineral buildup.

Rumbling like a kettle

Often scale or sludge on the heat exchanger. The boiler has to work harder and heat less.

Whining or grinding

Usually the circulator pump motor or bearings wearing out.

What we do on a Kokomo boiler repair call

We repair hot-water (hydronic) gas boilers, getting the system you already have heating again. A tech will typically check the burner and ignition, pressure, expansion tank, circulator, zone valves and controls, then explain what failed and what the fix is before any work starts.

If your home uses a furnace instead, see our furnace repair page. We have been serving Kokomo since 1969.

Schedule furnace service or call us at 765-236-1212.

Frequently asked questions

Why are some of my radiators cold?

Trapped air is a common cause, especially in upstairs radiators. If bleeding the radiators does not help, the circulator pump, a zone valve or the boiler may need repair.