What are the specs for this Piston Kit?

The correct replacement for Goodman model GMP125-4 — B1789876 is this exact part. It is the factory-specified replacement with exact OEM specifications. Using a part with different specifications can cause equipment damage or void your warranty. You can verify this by checking the data plate on your Goodman equipment which lists the model number GMP125-4 — B1789876.

What symptoms indicate I need a new piston kit?

Common symptoms that indicate you need a new piston kit include unusual noises, intermittent operation, complete failure to operate, or visible damage. For specific diagnostic guidance, visit nationalhvacparts.com/pages/hvac-diagnostic.

Is this piston kit compatible with Bryant or Payne systems too?

Many Goodman parts are cross-compatible with Bryant and Payne systems since all three brands are manufactured by Carrier Global Corporation. The same physical part is often used across multiple brand labels with different model numbers. To verify cross-compatibility, check your Bryant or Payne equipment service manual for cross-compatible part numbers, or contact info@nationalhvacparts.com with your model number for confirmation.

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Goodman

OEM Goodman Piston Kit for GMP125-4 — B1789876

Name: OEM Goodman Piston Kit for GMP125-4 — B1789876
Brand: Goodman
SKU: GOODMAN-11902
Price: 7.95 USD
Availability: InStock

SKU: GOODMAN-11902 Brand: Goodman

$7.95 $10.95

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Texas CMBL #19328542014

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The Goodman B1789876 Piston Kit is the genuine OEM metering piston set for GMP125-4 gas furnaces. The piston controls precise fuel metering at the burner, ensuring a clean, correctly sized flame and safe, efficient combustion. Using the factory-specified piston is important for proper heat output and to avoid sooting or nuisance limit trips caused by an incorrect orifice size.

Specifications

OEM Part Number: B1789876
Type: Furnace piston / metering kit
Compatibility: Goodman GMP125-4 gas furnace
Function: Meters gas flow to the burner assembly
Brand: Goodman (Genuine OEM)

OEM vs. Generic

The OEM B1789876 kit is bored to Goodman's exact specification for the GMP125-4. Because even a small change in orifice diameter alters the firing rate, using a genuine OEM piston is strongly recommended over a generic substitute to keep the appliance within its rated input and combustion tolerances.

Installation Difficulty

Moderate (3/5). Requires shutting off gas and power, accessing the burner/manifold assembly, and swapping the piston. Combustion and gas work should be performed or verified by a qualified HVAC technician.

Shipping Information

Orders placed before 3PM CST ship same business day
Standard delivery: 2-5 business days
Express shipping available at checkout
Free shipping on orders over $75
Tracking number emailed upon shipment

Return Policy

30-day returns on unused parts in original packaging
Electrical parts (capacitors, contactors, control boards) are final sale once installed
Email info@nationalhvacparts.com to initiate a return
Refunds processed within 5-7 business days

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Frequently Asked Questions

Does this Piston Kit fit my Goodman GMP125-4 — B1789876?

Yes. This is the factory-specified OEM piston kit for the Goodman GMP125-4 — B1789876. It is a direct drop-in replacement that fits without modification. Always verify the model number on your equipment nameplate before ordering.

How do I replace the piston kit on my Goodman GMP125-4 — B1789876?

Refer to your equipment service manual for model-specific steps. General approach: turn off power, photograph connections, remove old part, install new part, restore power and test. For gas components, hire a licensed technician. Email info@nationalhvacparts.com for guidance.

What symptoms mean I need a new piston kit?

Common symptoms: unusual noises, intermittent operation, complete failure, or visible damage. Visit our diagnostic hub for symptom-based troubleshooting.

Is this piston kit compatible with Bryant or Payne too?

Many Goodman parts are cross-compatible with Bryant and Payne since all three brands are manufactured by Carrier Global Corporation. The same physical part is often used across brand labels with different model numbers. To verify: check your Bryant or Payne equipment service manual for cross-compatible part numbers, or email info@nationalhvacparts.com with your model number.

Should I use OEM or aftermarket for my Goodman piston kit?

OEM recommended for reliability and warranty compatibility. OEM parts match exact factory specifications for proper fit, performance, and safety. While aftermarket alternatives cost less upfront, the risk of improper fit and reduced lifespan usually makes OEM the better value long-term.

How fast does National HVAC Parts ship?

Orders placed before 3:00 PM CST ship the same business day. Standard delivery is 2–5 business days anywhere in the continental United States. Express shipping available at checkout. We ship from Houston, TX to all 50 states. 30-day return policy on all parts.

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