Buderus, Bosch and what's still sold here
Buderus is one of the oldest names in heating. Johann Wilhelm Buderus founded the company in 1731, and it started casting sectional boilers in Lollar, Germany, in 1895. In 2004 Buderus's heating business merged with Bosch's, and since 2008 the German company has been Bosch Thermotechnik GmbH. In the US, Buderus sales and support run through Bosch Home Comfort.
What that means for you depends on which Buderus you have. Bosch's US site still lists two Buderus cast-iron oil boilers, the G115WS and the G215, plus SSB stainless boilers for commercial buildings. The Buderus gas boilers we run into in Twin Cities homes, the GB142, the G124X and the GC144, are on Bosch's discontinued Buderus list. Bosch still posts their manuals, parts lists and service instructions there, which helps a lot when we're working on one. Bosch's own current gas condensing boilers are the Greenstar and the Singular Combi; our Bosch service page covers the rest of that family.
What is a Buderus GB142 boiler?
The Logamax plus GB142 is the compact Buderus: a wall-hung, 95% AFUE gas condensing boiler in four sizes, for natural gas or propane. Buderus shipped it with the AM10 outdoor reset control, a sensor for an indirect water tank and a prefabricated low-loss header with its own circulator, which keeps flow through the boiler right no matter how the house piping was done. It vents in 3-inch PVC.
What we see on GB142 service calls:
- Condensate trouble. The trap and drain carry acidic condensate, and a clogged or frozen line shuts the boiler down. Bosch published a service kit that fits a new condensate trap and an internal bypass pipe.
- Vent terminations. A sidewall terminal behind a snowbank or coated in frost chokes the burner on a sub-zero night.
- Dirty system water. A GB142 feeding an old radiator loop collects sludge, and a boiler that kettles or overheats may need its heat exchanger cleaned and the loop flushed.
- Propane setup. Homes outside the gas lines run GB142s on propane, and Bosch's conversion and combustion settings have to be done right. Our post on propane heating costs covers the fuel side.
Cast-iron Logano boilers
Older Buderus installs are floor-standing Logano cast-iron boilers. The G124X is an atmospheric boiler that vents into a chimney, and its manual also covers the GA124, a sealed-combustion version. The GC144 is an atmospheric gas boiler for hot-water heat with a pilot you light by hand.
These are simple boilers, and most repairs are familiar: pilot and ignition trouble, a circulator or zone valve that quit, and an expansion tank that has lost its air and pushes the relief valve toward 30 psi. The part that needs respect is the flame roll-out switch. On both the G124X and the GC144 it trips when the flue or vent is blocked, and Buderus made it one-time use: the vent gets checked for blockage and the switch gets replaced, never bypassed. Bosch's GC144 manual also calls for inspecting the venting system every year, and we agree. Every fuel-burning boiler needs working CO alarms, and Minnesota law requires one within 10 feet of each sleeping room.
Should you repair or replace a Buderus boiler?
A cast-iron Logano with sound sections usually earns a repair. A GB142 becomes a closer call as it ages: if the heat exchanger leaks or the control board can't be sourced, a replacement makes more sense than chasing parts. We service and repair every Buderus we find, and when one is done we quote the boiler that fits your house and your radiation, whether that's a Bosch Greenstar or another brand such as Viessmann. Condensing boilers do their best work at low water temperatures, and our radiant floor vs baseboard guide explains why that matters when you pick the next one. Register any new boiler with its maker; many tie part of their warranty to registration, so check the current terms.
Booking Buderus service
Call 612-429-3465 from 7am to 9pm, seven days a week. Homes without heat get priority. A service call is a $79 trip charge, waived when you approve the repair, and you get a written, flat-rate price before we start. Completed repairs carry our 1-year parts-and-labor warranty, and installs carry a 2-year labor warranty on top of the manufacturer's parts warranty. A photo of the rating plate helps us bring the right parts, and our boiler and radiant heat page explains how we work on hydronic systems.
Buderus questions
Is Buderus still in business?
Yes, as a brand of the Bosch Group. Buderus dates back to 1731 and merged with Bosch's heating business in 2004. In the US, Bosch Home Comfort still offers the Buderus G115WS and G215 oil boilers and SSB commercial boilers, while the GB142, G124X and GC144 sit on its discontinued list. For gas condensing boilers, Bosch now sells its own Greenstar line.
Can you still get parts for a Buderus GB142?
Often, but confirm before you count on it. Bosch still posts the GB142's installation and service manuals, its propane conversion instructions and the instructions for a condensate trap service kit. Parts get harder to find as a model ages, so we look up your boiler by model and serial number and confirm the part before we quote. If a heat exchanger or control can't be sourced, we'll tell you and price a replacement.
Why does my GB142 shut down on the coldest nights?
Usually the exhaust or the drain. A condensing boiler vents cool, wet exhaust through PVC, and on a sub-zero night the wall terminal can frost over or disappear under a drift. The condensate line can freeze too, and a backed-up trap stops the burner. We check the vent run, the termination and the trap, and Bosch offers a revised trap and bypass kit for the GB142.
What replaces a Buderus GB142?
Usually another wall-hung condensing boiler. Bosch's current models are the Greenstar, in heating-only and combi versions, and the Singular Combi, both rated 95% AFUE. Viessmann, Lochinvar and Navien make comparable boilers. We size the new one to your home's heat loss, reuse piping and venting where the new manual allows, and give you the price in writing.
What does the AM10 on my Buderus do?
The AM10 is the outdoor reset control Buderus shipped with GB142 boilers. A sensor outside tells the boiler how cold it is, and the control lowers the water temperature on mild days and raises it as the weather turns. A condensing boiler saves the most when its water runs cooler, so a failed or missing outdoor sensor costs you efficiency.
Sources
- Buderus official site buderus.com