Boiler Replacement With an Indirect Water Heater in Acton

The boiler in an Acton home was the original unit, and the homeowner called us about replacing it. The conversation quickly turned to hot water too. The house had a separate water heater that was seven or eight years old, and the question was whether to keep it or let a new boiler make the hot water through an indirect tank. If you have an aging boiler and a water heater that isn't new either, you're facing the same decision.

Gas and boiler work isn't DIY

Boiler replacement involves gas piping, venting and combustion, and in Massachusetts it's licensed, permitted work. If you smell gas or a carbon monoxide alarm sounds, leave the building and call 911 from outside; we can help once the fire department or gas utility says it's safe. Soot around the boiler, or a boiler that stops heating, calls for a licensed technician, so don't adjust or take apart anything yourself.

What the homeowner wanted

The homeowner, an engineer, had done the research before we arrived. Their priorities were reliability, low maintenance and something close to a drop-in replacement. They pointed to Weil-McLain as a brand with decades of history, widely available parts and technicians who know it well. The home is on well water, and the homeowner preferred a simpler system to an on-demand (tankless) setup, citing the added complexity with well water.

They also liked the idea of pairing the new boiler with an indirect water heater instead of keeping a separate hot water tank.

How an indirect water heater works

An indirect water heater is an insulated storage tank with a coil inside. Hot boiler water circulates through the coil and heats the household water around it, so the tank has no burner of its own. The boiler handles both jobs, and there's one fewer water-heating appliance to maintain.

The trade-off is that your hot water now depends on the boiler. A boiler problem affects both heat and hot water, which is one reason serviceable equipment and annual maintenance matter so much with this setup.

When the existing water heater is also getting older, planning the hot water tank replacement together with the boiler means one plan covers the piping, the controls and removal of the old heater, instead of two separate projects.

The existing system

The house had a two-zone forced hot water system, one zone per floor, running through fin-tube baseboard (copper pipe with metal fins) across about 1,800 square feet. The zone layout and the home's heat loss matter for sizing, which is why we size a replacement from the house's actual heating needs instead of copying the old boiler's output.

The boiler was original to the house, which the homeowner bought in 1996, so it had been running for decades. Its gas valve had failed and been replaced more than once, and parts for older boilers get harder to find over time. Age alone doesn't decide replacement. Repeat failures of major parts and shrinking parts availability are what made replacement the sensible conversation here.

Venting out the side instead of the chimney

The plan vented the new boiler through the side of the house rather than up the existing chimney. That meant checking the required distances between the vent termination and openable windows and other openings, which the gas code and the manufacturer's instructions set. Our check found enough clearance on the side of the house near the gas meter to route the PVC exhaust. The homeowner had looked into sleeving the chimney but agreed new PVC venting was the simpler, more reliable path.

Installing only what we can service

We only install systems we're equipped to service ourselves, because we want to be the ones you call years from now. The Weil-McLain model discussed here is largely serviceable by any experienced technician, with a handful of parts specific to that boiler; everything else on the system is standard and widely available. Jeneral Plumbing is owner-operated by a Licensed Master Plumber (MA #9628831-PL-M) who is factory trained by Weil-McLain. Annual boiler service belongs in any new installation plan. Our Home Guardian service plan includes an annual heating-system visual inspection, which is not the same as the manufacturer's annual maintenance procedure.

Flush the old system first

Whatever boiler goes in, we flush and treat the existing baseboard loops before connecting it. Sediment and buildup from decades of service don't leave with the old boiler, and cleaning the loops protects the new equipment from the start.

How much does a new boiler cost with an indirect tank?

We didn't set a final price during this consultation, and we don't publish a range, because the answer depends on the house. These are the main cost drivers:

• the boiler type and size, based on the home's heating needs;
• the venting route, whether a new sidewall vent or chimney work by a chimney contractor;
• the indirect tank's size and how it's piped and controlled as its own zone;
• zoning, circulators and the piping near the boiler;
• flushing and treating the existing system;
• any gas piping changes, permits and inspections;
• removing the old boiler and water heater.

After seeing the house, we give you a written flat-rate price for approval before work begins.

Planning your own replacement

Jeneral Plumbing is based in Westford, MA, and serves Acton and other Middlesex County towns, confirming the address, the work and availability before booking. A regular-hours visit carries an $80 dispatch fee — the cost of the visit, waived when you hire us for the work. Our boiler installation and water heating pages cover the equipment options.

Call (978) 392-7789 with your boiler's age, the number of zones, how you heat water now, and whether you're on a well or town water.