Downstairs HVAC System Replacement in Frisco, TX 75034

Goodman 4-Ton Air Conditioner & 80,000 BTU Gas Furnace | Engineering-Driven Installation

Greentech Engineering Heating & Air Conditioning recently completed a full downstairs HVAC system replacement for a single-family home in Frisco 75034, upgrading an aging York system to a new Goodman split air conditioner and gas furnace.

This long-form case study is written for homeowners who want to understand what a proper HVAC replacement actually includes, beyond brand names and advertised SEER ratings. It documents the equipment selection, installation process, safety upgrades, and engineering standards used.

In Frisco and the greater DFW area, many two-story homes were built with builder-grade HVAC systems designed to meet minimum code at the time of construction. After 10–20 years of operation, these systems often develop predictable issues:

• Reduced cooling capacity during peak summer heat
• Longer runtimes and uneven temperatures between floors
• Aging compressors, coils, and furnaces approaching failure
• Lower efficiency compared to modern SEER2 standards

In this home, the downstairs York system had reached the point where continued repairs would no longer be cost-effective or reliable. The homeowner chose a full system replacement to restore comfort, improve efficiency, and reduce long-term risk.

New Downstairs HVAC System Installed

Air Conditioning System

• 48,000 BTU (4-Ton) Goodman Split Air Conditioner
• 14.3 SEER2 performance (meets current DOE efficiency standards)
• Factory-installed filter drier
• Factory-charged for 15 ft of refrigerant line set

Condenser Design Highlights

• Energy-efficient compressor
• Copper tube / enhanced aluminum fin coil
• 5mm diameter tubing (1.5–4.0 ton range)
• Designed for durability under Texas heat loads

Warranty

• 10-year factory limited parts warranty (with homeowner registration)

Evaporator Coil

• ADP 60,000 BTU horizontal evaporator coil
• Factory-installed thermal expansion valve (TXV)
• All-aluminum coil construction
• Low water-retention, rust-resistant thermoplastic drain pan
• Rifled aluminum tubing with corrugated aluminum fins

Warranty

• 10-year factory limited parts warranty
• 10-year unit replacement plan (with registration)

Gas Furnace

• Goodman 80,000 BTU gas furnace
• 80% AFUE, single-stage heating
• ECM blower motor for efficient and quiet airflow
• Multi-position installation capability

Furnace Features

• Heavy-duty aluminized-steel tubular heat exchanger
• Durable silicon nitride igniter
• Self-diagnostic control board with constant memory
• Consistent, energy-efficient air circulation

Warranty

• 10-year factory limited parts warranty
• 20-year limited warranty on the heat exchanger (with registration)

Controls

• New thermostat installed and configured to match airflow and system capacity

Engineering-Based Scope of Work (Detailed)

At Greentech Engineering Heating & Air Conditioning, every system replacement follows documented engineering procedures—not shortcuts. Below is the full scope used for this Frisco project.

1. System Removal & Refrigerant Recovery

• Existing York system safely removed and disposed
• Refrigerant fully pumped down and recovered in compliance with EPA regulations

2. Safety, Drainage & Equipment Base Upgrades

• New gas sediment trap installed (current mechanical code requirement)
• New auxiliary drain pan installed
• Safe-T float switch added for overflow protection
• Drain line insulation installed
• New concrete condenser pad installed and leveled

3. Condensate Drain Line Rebuild

• Existing drain line cleared using pressurized dry nitrogen
• New drain trap and vent installed
• All necessary drain modifications included to reduce future clog risk

4. Mechanical Mounting & Structural Support

• New evaporator coil and furnace connected to supply and return plenums
• Secured with hex washer head HVAC screws
• Balanced and supported with appropriate hanging and structural materials

5. Air Sealing & Efficiency Measures

• All cabinet and duct connections sealed using:
  • HVAC-rated metal tape
  • Professional duct sealant (mastic)

This step minimizes air leakage and ensures conditioned air reaches living spaces.

6. Gas Line & Exhaust Modifications

• All required gas line changes completed
• Furnace exhaust flue pipe modified as needed for safe combustion and code compliance

7. Refrigerant Line Set Preparation

• Existing copper line sets flushed with RX-11
• Dry nitrogen used to remove residual oil and contaminants

8. Brazing & Line Connections

• Line sets brazed using 15% silver brazing rod
• Nitrogen purging during brazing to prevent internal oxidation
• Work performed by certified HVAC technicians

9. Nitrogen Pressure Test

• System pressurized to 250 PSI using dry nitrogen
• Pressure held for a minimum of 15 minutes
• Leak integrity confirmed prior to evacuation

10. Deep Vacuum Procedure

• System evacuated to below 500 microns
• Confirms removal of moisture and non-condensables
• Critical for compressor reliability and system efficiency

11. Startup, Testing & Verification

• Refrigerant charged to manufacturer specifications
• Full heating and cooling operation tested
• Safety controls, airflow, temperature split, and gas operation verified

Why Proper Installation Matters in Frisco, TX

Frisco homes experience:

• Long cooling seasons
• High attic temperatures
• Extended system runtimes

A correctly installed HVAC system:

• Delivers consistent downstairs comfort
• Protects the compressor and heat exchanger
• Reduces water damage risk from drain failures
• Preserves manufacturer warranty coverage

Equipment quality matters—but installation quality determines performance.

Service Area

Greentech Engineering Heating & Air Conditioning proudly serves:

• Frisco
• Plano
• McKinney
• Allen
• Prosper
• Greater Dallas–Fort Worth metroplex

We specialize in residential HVAC replacements, airflow optimization, and engineering-based diagnostics for single-family homes.

Frequently Asked Questions (Q&A )

Is a 14.3 SEER2 air conditioner sufficient for Frisco, TX?
Yes. A 14.3 SEER2 system meets current DOE standards and is a reliable, cost-effective choice for many Frisco homes when properly sized and installed.

What does an ECM blower motor do?
An ECM motor adjusts airflow more precisely than traditional motors, resulting in quieter operation, improved comfort, and lower electrical consumption.

Why is nitrogen pressure testing important?
Pressure testing at 250 PSI confirms there are no leaks before refrigerant is added, protecting the compressor and ensuring long-term reliability.

How long does a full HVAC replacement take?
Most full system replacements are completed in one day, depending on ductwork condition and required code upgrades.

Is flushing existing line sets necessary?
Yes. Flushing with RX-11 and nitrogen removes old oil and contaminants, reducing the risk of premature compressor failure.

Schedule HVAC Replacement in Frisco, TX

If you are considering HVAC system replacement in Frisco, TX 75034, choose a contractor that prioritizes engineering standards, documentation, and long-term performance—not just price.

Greentech Engineering Heating & Air Conditioning
Licensed • Insured • Residential HVAC Specialists

Availability may vary based on scheduling and system conditions. Contact us.

Author

Siwei (Lucas) Chen
CTO | Greentech Engineering Heating & Air Conditioning
B.S. Mechanical Engineering – Virginia Tech
ACCA Certified (Manual J, S, D)
NCI Certified – Air Balancing & Duct Optimization
10+ Years Residential HVAC Engineering Experience in Dallas–Fort Worth

This article was reviewed and approved by Lucas Chen to ensure technical accuracy, code compliance, and alignment with HVAC industry best practices.

About ACCA.

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