Lots of older apartment buildings, duplexes, fourplexes and mixed-use buildings in Missoula and around Western Montana are heated by one central boiler. When that system works, nobody thinks about it. When it doesn't, it's a mid-January phone call from a dozen cold tenants at once. If you own or manage one of these buildings, here's what I'd want you to know heading into winter.
Why one boiler raises the stakes
In a single-family home, a heating problem affects one household. In a multi-unit building, one bad circulator pump, a failed zone valve or a boiler that's locked out can leave every unit cold. Shared systems also tend to be bigger and more complex. They often have several zones, multiple pumps, an expansion tank sized for the whole building, and sometimes an indirect water heater supplying hot water to every tenant. More parts means more places for something to go wrong. It also means a little planning goes a long way.
A pre-winter checklist for shared boiler systems
Before the real cold settles in, a professional service visit should cover:
Burner and combustion. Clean the burner, check the flame, and test combustion so the boiler burns safely and efficiently, whether it runs on natural gas or propane.
Safety controls. Test the high-limit, the low-water cutoff and the pressure relief valve. These are what keep a boiler from becoming dangerous.
Venting and flue. Inspect for blockages, corrosion or poor draft. With several households in one building, carbon monoxide safety isn't optional.
Pressure and expansion tank. Make sure the system holds proper pressure and that the expansion tank is doing its job.
Pumps and zone valves. Confirm each circulator and zone valve opens, closes and moves water the way it should, so the top-floor units get heat too.
Air in the lines. Bleed trapped air that causes cold radiators, gurgling and uneven heat between units.
Domestic hot water. If an indirect water heater is tied into the boiler, check that it's keeping up with the building's demand.
Signs your building's boiler needs attention now
Tenant complaints are often your first warning. Pay attention if you hear about:
Some units too hot and others too cold
Banging, knocking or gurgling in the pipes
Radiators or baseboards that stay cold at the top
Hot water running out faster than it used to
Water around the boiler or relief valve
The boiler short-cycling, or locking out and needing a reset
Any one of these is worth a call before it turns into a no-heat emergency on the coldest night of the year.
Plan ahead for emergencies
A little preparation makes a winter breakdown much easier to handle:
Know where the boiler's emergency shutoff, gas or propane shutoff, and water shutoff are, and make sure on-site staff know too.
Keep the mechanical room clear, unlocked for service, and free of storage that blocks airflow.
Have an HVAC contact who answers at night and on weekends. ProCare Climate is open 24/7, so you can call at 2 a.m. in January and reach a person.
Keep basic records of past service, parts replaced and the boiler's age. It speeds up any repair.
Repair, upgrade or replace?
Older boilers in multi-unit buildings can often keep running reliably with good maintenance and the right repairs. Eventually, though, it can make more sense to upgrade controls, replace worn pumps, or replace the boiler itself. Bigger jobs like a boiler replacement usually need a permit and an inspection, and I handle pulling permits and scheduling inspections so you don't have to. Install estimates are free, and I'll give you an honest look at whether repair or replacement makes more sense for your building.
Local, hands-on boiler experience
ProCare Climate started in July 2026, but I've been working on HVAC systems in Western Montana for more than 10 years, including boilers in homes, apartment buildings and commercial spaces. I work on all brands. I serve Missoula, Lolo, Frenchtown, Stevensville, Hamilton, Polson and the surrounding areas. Learn more about our boiler service in Missoula, or see the areas we cover in Hamilton and Polson.
Get your building ready for winter
Don't wait for the first tenant call. Call ProCare Climate any time, 24/7, at 406-546-1289 to schedule boiler service for your building, or request a free install estimate right here on the site.