Boilers and Radiator Heat in Older West Michigan Homes

A cast iron radiator makes a sound nothing else in a house makes. A tick, then another, then a slow rolling series of them as the one under the front window comes up to temperature for the first time since April.

Plenty of houses around here still heat that way. Grand Rapids has neighborhoods full of homes built well before forced air was the default, and East Grand Rapids, the older streets in Wyoming, and pockets of Grandville are the same story. People buy these houses, fall in love with the woodwork, and then discover in their first fall that the heating system is nothing like what they grew up with and nobody ever explained it to them.

Two Completely Different Systems

Before you touch anything, figure out which one you have. The maintenance is different and so is the safety.

Hot water, also called hydronic. A boiler heats water to somewhere around 160 to 180 degrees and a circulator pump pushes it out to the radiators and back. Tell-tale signs: a pressure gauge reading in the low teens, a pump mounted on the piping near the boiler, and an expansion tank — either a cylinder hanging from the ceiling joists or a smaller pressurized can near the boiler. The vast majority of systems I work on in this area are this type.

Steam. Older, simpler, and built on a different principle entirely. The boiler actually boils water, steam rises through the pipes on its own pressure with no pump involved, gives up its heat in the radiators, condenses back to water, and drains back down by gravity. Tell-tale signs: a glass tube on the side of the boiler with a water line visible in it, a gauge reading in ounces or single-digit pounds, and little silver air vents on the side of each radiator that hiss when the system is coming up.

Get this right before you start, because the single most common piece of homeowner advice on the internet — bleed your radiators every fall — is correct for one of these and actively dangerous on the other.

Hot Water: The Fall Startup

Maybe forty-five minutes, and most of it is walking around with a small key.

Read the pressure gauge cold. Twelve to fifteen psi is normal for a two-story house, a little more for three stories. If it's at eight, the upper-floor radiators won't fill and those rooms will be cold no matter what the thermostat says. If it's climbing toward thirty, something's wrong and the relief valve is eventually going to open and put water on your basement floor.

Bleed the radiators. This is the one that fixes the most complaints. Air works its way to the top of a radiator over the summer, and hot water can't displace it, so the top stays cold while the bottom gets hot. Fire the system up, let it run twenty minutes, then work your way through the house with a radiator key and a cup. Start on the lowest floor closest to the boiler and work outward and upward. Open each bleeder valve slowly. You'll hear air hiss out, and when it turns to a steady dribble of water, close it.

Bleeding pushes pressure down, so check the gauge again when you're done and top it off if needed. Then re-check it the next day.

Look at the expansion tank. The older style is a big horizontal cylinder up in the joists. The newer style is a football-sized can with an air valve on the bottom. Either way, if it's waterlogged the system pressure will spike every time the boiler runs and the relief valve will weep. Tap a modern one. The top half should sound hollow. If the whole thing sounds solid and feels heavy, it's failed.

Walk the whole system looking for white crust. Dried mineral deposits at a valve, a fitting, or under a radiator mean water has been leaking there, slowly, probably for a while. Small leaks in a hot water system are worth catching because the makeup water they pull in brings fresh oxygen, and oxygen is what eats cast iron from the inside.

Move the furniture. A radiator behind a couch or under a full-length curtain is heating upholstery. Give them room.

Steam: A Different List

Steam systems want less from you, but what they do want, they want done right.

Check the sight glass. The water level should sit around the middle. Too low and the low-water cutoff shuts the burner down, which is the safety doing its job, because a steam boiler fired dry is genuinely dangerous. Too high and you'll get water carrying over into the steam lines, which causes banging.

Flush the low-water cutoff. There's a blowdown valve underneath it. Open it with a bucket under it until the water runs clear, then let it refill. Sediment collects in that device and a clogged one can fail to protect the boiler. Do it monthly through the season, not just in the fall.

Do not bleed anything. Those air vents on the radiators are automatic. They let air escape ahead of the incoming steam and close when steam reaches them. Opening one by hand on a hot system will burn you. If a radiator stays cold, the vent is probably clogged and needs replacing — they're inexpensive.

Watch how the radiators fill. A steam radiator should get hot most of the way across. One that's hot at the inlet and cold at the far end usually has a bad vent. One that's banging usually has condensate trapped in it because it's lost its pitch back toward the return, and sometimes a shim under the far legs is the entire fix.

Leave the radiator valves all the way open or all the way closed. On a one-pipe steam system, a partly open valve is the classic recipe for water hammer, because steam is trying to go in the same opening condensate is trying to come out of.

What Needs Somebody With Tools

Boilers last a long time, and they punish neglect quietly.

Annual service on one means a combustion analysis at the burner, an inspection of the flue and the chimney connection, testing the low-water cutoff and the relief valve, checking expansion tank charge, looking at the circulator and its bearings, and inspecting the sections themselves for leaks and scale. On a steam system it also means skimming the boiler if there's oil in the water from previous work. A skipped skim causes surging and hammering that people chase for years.

The chimney deserves extra attention in these houses. Many were built for coal, converted to oil, then converted to gas, and each conversion left the flue oversized for what it's now venting. Old liners shed tile into themselves. A blocked or deteriorated flue on a boiler is the same problem as on a furnace, with the same consequences.

I got called to a house on the east side of Grand Rapids a few Octobers ago — 1920s place, hot water system, and the second floor had been cold for two winters. Previous company had quoted them a whole new boiler. The boiler was fine. System pressure was sitting at nine psi because a fill valve had failed years earlier and nobody had looked at the gauge, so the water simply wasn't reaching the upstairs radiators. We replaced the fill valve, brought the pressure up, bled the system floor by floor, and the upstairs was warm that afternoon.

Nothing clever about that. Somebody just read a gauge before writing a quote.

Why I'd Keep It

I get asked a lot about ripping out the radiators and putting in forced air. I almost always argue against it.

The retrofit is brutal. Houses built for radiators have no chases for ductwork. Getting supply and return where they need to go means soffits dropped through finished rooms, closets sacrificed, and plaster opened up. It's a renovation, not an HVAC job, and it's priced like one.

Radiant heat is genuinely more comfortable. Cast iron warms the room and the objects in it and holds temperature steadily instead of cycling. There's no blower noise and nothing blowing dust around. Once people live with it a while, most don't want to trade it.

The distribution side outlasts everything. Those radiators and most of that piping will be there long after several boilers have come and gone. If the boiler is shot, replace the boiler — modern condensing units get real efficiency out of a hydronic system, particularly when they can run at lower water temperatures. The expensive part of your system is already installed and paid for.

The legitimate complaint is air conditioning, and it's a fair one — there's no ductwork to put it in. That's exactly the problem ductless mini-splits solve, and pairing a good boiler with a ductless system for summer is a common answer in these neighborhoods. You keep the heat that works and add cooling without tearing into the walls.

If your boiler needs attention, that's work we do: boiler repair in Grand Rapids and across the surrounding communities, on systems a lot older than I am.