What are the specs for this Piston?

The correct replacement for Goodman model WGHP4348AAA Heat Pump — B1789878 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 WGHP4348AAA Heat Pump — B1789878.

What symptoms indicate I need a new piston?

Common symptoms that indicate you need a new piston 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 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 WGHP4348AAA Heat Pump — B1789878

Name: OEM Goodman Piston Kit for WGHP4348AAA Heat Pump — B1789878
Brand: Goodman
SKU: GOODMAN-899
Price: 12.95 USD
Availability: InStock

SKU: GOODMAN-899 Brand: Goodman

$12.95 $17.48

OEM Guaranteed

Same-Day Ship

30-Day Returns

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Texas CMBL #19328542014

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Govt POs Accepted

The Goodman B1789878 Piston Kit is a genuine OEM refrigerant metering device for WGHP4348AAA heat pump systems. The piston — a fixed-orifice flowrator — sets refrigerant flow into the coil to maintain correct superheat and rated capacity. The larger-capacity WGHP4348AAA requires its specific orifice size, so using the matched B1789878 ensures the system meets its factory efficiency and cooling specs.

Specifications

OEM Part Number: B1789878
Compatible Model: WGHP4348AAA
Type: Fixed-orifice piston / flowrator metering device
Brand: Goodman
Application: Heat pump refrigerant control
Fit: Direct OEM exact-fit replacement

OEM vs. Generic

Our OEM B1789878 is bored to the exact factory orifice for the WGHP4348AAA, guaranteeing proper metering for this unit's tonnage. Generic universal pistons require manual orifice selection and can mis-meter refrigerant, risking floodback or starvation. For matched-system and warranty work, the OEM piston is the reliable choice.

Installation Difficulty

Moderate — requires refrigerant recovery, opening the coil or line set, and EPA 608 certification. Recommended for licensed HVAC technicians.

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

OEM Goodman Piston Kit for WGHP4...

$12.95

Frequently Asked Questions

Does this Piston fit my Goodman WGHP4348AAA Heat Pump — B1789878?

Yes. This is the factory-specified OEM piston for the Goodman WGHP4348AAA Heat Pump — B1789878. 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 on my Goodman WGHP4348AAA Heat Pump — B1789878?

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?

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

Is this piston 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?

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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