AC Service Tech LLC HVAC Quick Reference Cards — 3 Durable Polystyrene Cards for Refrigerant Charging, Superheat/Subcooling & Delt

Three double-sided polystyrene HVAC quick-reference cards that let technicians quickly determine target subcooling, target superheat, delta T, refrigerant P/T values, and charging weights for common refrigerants.

These compact HVAC Quick Reference Cards from AC Service Tech LLC condense the most-used field calculations and charts into three durable, pocket-sized polystyrene cards. Designed for service technicians working on air conditioners and heat pumps, the set helps you assess refrigerant charge, troubleshoot cooling performance, and weigh refrigerant accurately without flipping through manuals or apps. Each card is double-sided and engineered to withstand jobsite conditions, from cold startups to sunny rooftops.

How do these cards tell me if a system is charged correctly?

The cards present both target subcooling (for TXV/expansion valve systems) and target superheat (for fixed-orifice systems), plus total superheat guidance so you can compare calculated values to manufacturer expectations. By measuring suction and liquid line temperatures and pressures, a technician can quickly decide whether a system is undercharged, correctly charged, or overcharged.

• Target Subcooling table for TXV-equipped systems
• Target Superheat chart for fixed-orifice systems
• Total Superheat guide for field verification
• Quick checks to distinguish undercharge vs. overcharge scenarios

What measurements do I need to use the charging and troubleshooting guides?

Use common field readings: liquid-line temperature, suction-line temperature, and gauge pressures. The cards include a P/T (pressure-temperature) chart for five common refrigerants, plus instructions to find bubble and dew saturated temperatures for blends. Combine the temperature readings with the P/T chart and the card’s formulas to determine target superheat/subcooling and whether to add or remove refrigerant.

• Liquid and suction line temps for superheat/subcooling
• Gauge pressures matched to P/T chart for refrigerant saturation temps
• Instructions for blend refrigerant bubble/dew point lookup
• Step-by-step weighing guidance for full or partial charges

How do these cards help with heat transfer and system performance checks?

The cards include a Delta T reference so you can verify the system’s air-side heat transfer is within expected ranges. Measuring the temperature drop across the evaporator and comparing it to the card’s suggested Delta T range points toward airflow or coil issues rather than refrigerant problems, helping you narrow diagnostics faster.

• Delta T chart for quick evaporator performance checks
• Guidance to separate airflow issues from refrigerant faults
• Troubleshooting prompts based on measured temperature splits
• Compact format suited to field inspections

What charging and weighing tools do the cards support on the job?

The set contains a refrigerant weight-per-foot chart to estimate additional refrigerant needed for line sets and clear instructions to weigh full or partial charges into an evacuated unit. These practical helpers reduce guesswork when adding refrigerant by weight rather than relying only on pressure or time-in methods.

• Refrigerant weight chart per foot of tubing for several refrigerants
• Weigh-in procedure steps for empty, vacuumed systems
• Quick tips for partial-charge calculations and hose-volume considerations
• Durable card material suitable on the tool belt while working

Who is this for: HVAC technicians, service contractors, field supervisors, and apprentices who need a fast, reliable reference when charging and diagnosing air conditioners and heat pumps. The three double-sided cards are weather- and UV-resistant, rated for jobsite temperatures from 0°F to 130°F, and offer practical tables and step-by-step prompts to speed up accurate diagnostics and charging on the roof, in basements, or at remote job sites.

Features:

• Flexible
• Weather and UV Resistant
• Polystyrene Card Material Tested 0°F-130°F
• Three Cards Double Sided per Pack
• HVAC Technician Resource