Weil McLain WM97+ Boiler Parts

Weil-McLain WM97+ boiler parts are OEM replacement components engineered specifically for the WM97+ CT Wall Mount Gas Boiler series, a condensing residential gas boiler produced in 70, 110, and 155 MBH input configurations. The WM97+ runs as a Category IV appliance, which means it requires specific Category IV-rated venting, and parts must meet that same standard to keep the system operating correctly. Weil-McLain WM97+ boiler parts span the full assembly, from heat exchanger and combustion components to controls, piping, jacket, and venting, so technicians can restore the unit to factory spec rather than chasing generic substitutes. For a wall-mount condensing boiler that's already in the field and running hard, having the right part on hand is what separates a one-trip fix from a callback.

Heat Exchanger and Combustion Components

The heat exchanger assembly is the core of the WM97+ and the part category that sees the most wear in condensing operation. Weil-McLain lists a complete heat exchanger assembly (part 383-700-101) that includes the condensate dish, cover plate, burner, igniter, sight glass, refractory, water sensors, gaskets, silicone, and hardware as a single reference kit. Technicians who need to address one specific failure point can order individual sub-components: the heat exchanger body alone (383-700-254), the condensate dish with gaskets and hardware (383-700-102), the cover plate assembly with refractory and silicone (383-700-108), or the igniter kit with gasket and screws (383-700-113). The burner, gasket, and hardware come as a standalone assembly (383-700-106), and the heat exchanger water temperature sensor (511-724-296) fits either the inlet or outlet position.

Controls and Electrical Assemblies

The WM97+ control system handles ignition, modulation, circulator speed, and system protection from a single integrated assembly. The complete control assembly (383-700-240) includes the ignition control, user display, circulator speed control, wire harnesses, plastic components, gaskets, and label, making it the appropriate replacement when the control system fails as a unit. Individual electrical components support targeted repairs: the flue temperature sensor (511-724-292) with its gasket (590-318-011), the outdoor temperature sensor (510-312-218), the control transformer rated at 120/24 volt and 50 VA (511-802-015), and the on/off power switch (511-624-645). Wire harnesses are broken out by circuit, with separate high-voltage and low-voltage assemblies for the left side of the pod and a dedicated low-voltage harness for the right side.

Piping, Circulator, and Pressure Components

The internal piping and hydronic components keep water moving through the heat exchanger and into the system loop. Upper and lower pipe assemblies with gaskets (383-700-144 and 383-700-145) connect the heat exchanger to the system connections, and the Taco 007 wet-rotor circulator with gaskets (383-700-152) drives flow through the boiler. The replacement cartridge for the 007 circulator (511-405-142) handles service without requiring removal of the full pump body. The expansion tank (383-700-148) is pre-charged to 12 PSI with a 3.2-gallon capacity, and the pressure and temperature gauge (380-000-000) reads 0 to 75 PSIG and 60 to 320 degrees F on a 3-inch dial. The low water cut-off (383-600-069) serves as a critical safety component, shutting down the burner if system water level drops below a safe operating threshold.

Jacket and Structural Parts

Jacket parts cover the outer cabinet, mounting hardware, and the internal flue and air adapter connections that route combustion air and exhaust through the boiler casing. The front door assembly (383-700-250) includes seals, logo, and labels, and the door latch and hardware (383-700-251) come as a separate component. The wall-mount bracket assembly is split between a wall-side kit (383-700-118) and a boiler-side bracket with hardware (383-700-119), giving technicians the option to replace just the component that's damaged. Flue pipe adapters (560-907-719), boiler flue pipe (560-907-720), and air inlet adapters (560-907-718) handle the Category IV vent connections at the cabinet, and individual cabinet-to-pipe gaskets are cataloged separately for those connections.

Venting Kits and Miscellaneous Components

Weil-McLain produces a range of vent and air termination kits for the WM97+ to cover sidewall and vertical installations using PVC, AL29-4C stainless steel, or polypropylene pipe in 2-inch and 3-inch diameters. The PVC concentric vent kit for 2-inch pipe (383-700-167) and its 3-inch counterpart (383-500-350) handle horizontal or vertical terminations in a single-wall-penetration configuration. For separate-pipe sidewall terminations, kits come in PVC (383-500-100 for 3-inch) and stainless-plus-PVC combinations. The condensate trap kit (560-907-722), supplied with the boiler originally, is a cataloged replacement part, as is the condensate neutralizer kit (383-500-631) for installations where local codes require neutralization before drain discharge. Annual maintenance kits (383-700-165 for the 70 model) bundle the igniter, gaskets, venturi O-ring, refractory, silicone, and inhibitor test kit in a single order.

The first decision when ordering Weil-McLain WM97+ boiler parts is confirming which model size is installed: the WM97+ Series 2 comes in 70, 110, and 155 MBH input sizes, and some components differ between models. Burner assemblies, pipe assemblies, and maintenance kits are model-specific, so verifying the unit's rating plate before ordering is the fastest way to avoid a second trip.

For combustion-side failures, the question is usually whether a sub-component swap or a complete assembly replacement makes more sense. If the heat exchanger has failed mechanically, the complete assembly kit (383-700-101) covers everything in one order. If the failure is isolated, such as a fouled igniter or a cracked sight glass, individual components keep the repair targeted and the labor time reasonable. The igniter kit (383-700-113) is a common maintenance item and worth stocking proactively on WM97+ service routes.

On the controls side, the full control assembly (383-700-240) is the straightforward path when diagnostics point to the control system broadly. Sensor failures, which are among the more common field issues on condensing boilers, can often be addressed with just the flue temperature sensor (511-724-292) or the water temperature sensor (511-724-296), so checking fault codes before ordering the full assembly can save significant cost.

For venting, the WM97+ is a Category IV appliance, and vent pipe material selection matters. PVC is acceptable for lower flue temperatures, while AL29-4C stainless is specified for installations where flue temperatures may be higher or local codes require it. Vent and air pipe diameters are either 2-inch or 3-inch; 3-inch pipe supports longer runs, so installations with extended vent lengths should confirm pipe sizing against the WM97+ installation manual before ordering termination kits.

FAQs

What's the difference between the WM97+ 70, 110, and 155 parts?

The WM97+ Series 2 comes in three input sizes: 70, 110, and 155 MBH. Combustion components such as the burner assembly, maintenance kit, and certain pipe assemblies are model-specific and not interchangeable between sizes. Controls, sensors, and venting accessories may be shared across models, but confirming compatibility with the unit's rating plate and the Weil-McLain parts catalog is the right call before placing any order.

Which WM97+ parts need to be replaced during annual maintenance?

Annual maintenance on the WM97+ typically covers the igniter, combustion chamber gaskets, venturi O-ring, heat exchanger refractory, silicone sealant, and a system inhibitor test. Weil-McLain offers a model-specific maintenance kit (383-700-165 for the 70) that bundles these components together, which simplifies the annual service visit and reduces the risk of missing a worn part during inspection.

What type of venting is required for the Weil-McLain WM97+ boiler?

The WM97+ boiler requires Category IV venting, which is rated for positive-pressure, low-temperature, condensing flue gas. Approved vent materials include PVC, CPVC, AL29-4C stainless steel, and polypropylene pipe in either 2-inch or 3-inch diameters. Vent and air pipe lengths for 2-inch piping are more limited than for 3-inch, and all elbows must be sweep-type rather than short-radius. Weil-McLain vent termination kits cover both sidewall and vertical configurations.

How do I find the right WM97+ control assembly or sensor replacement?

Identifying the correct WM97+ control assembly or sensor starts with reading the active fault code from the boiler's user display. The complete control assembly (383-700-240) is the appropriate replacement when the fault points to the control system as a whole. Isolated sensor faults often indicate just the flue temperature sensor (511-724-292) or the supply/return water temperature sensor (511-724-296) needs replacement, which is a faster and more targeted repair.

Can the Taco 007 circulator in the WM97+ be serviced without replacing the full pump?

The WM97+ uses a Taco 007 wet-rotor circulator, and Weil-McLain catalogs the replacement cartridge (511-405-142) as a standalone component. Replacing the cartridge restores circulator performance without pulling the entire pump assembly from the piping, which reduces labor time and avoids disturbing the pipe connections at the boiler.