TXV Devices

Safety Review Lock Out/Tagout Equipment Disconnect Switch Read and Follow Specific Instructions in Manufacturer’s Service Literature HVAC Technician Wearing Safety Glasses and Gloves Remove Watches and Other Jewelry Before Servicing Equipment

The Compressor METERING DEVICE EVAPORATOR CONDENSER COMPRESSOR

Heat Absorption & Rejection METERING DEVICE CONDENSER (HEAT REJECTED) EVAPORATOR (HEAT ABSORBED) Heat Absorption & Rejection COMPRESSOR

The Metering Device COMPRESSOR METERING DEVICE EVAPORATOR CONDENSER VARIES REFRIGERANT AS LOAD CHANGES METERING DEVICE CONDENSER (HEAT REJECTED) EVAPORATOR (HEAT ABSORBED) COMPRESSOR

Compressor Failure COMPRESSOR STARVED METERING DEVICE EVAPORATOR TOO LITTLE REFRIGERANT STARVED EVAPORATOR CONDENSER COMPRESSOR

Refrigerant Floodback METERING DEVICE TOO MUCH REFRIGERANT FLOODED EVAPORATOR CONDENSER COMPRESSOR

DOE Efficiency Mandate January 23, 2006 Residential, single phase  65,000 Btuh cooling Minimum SEER = 13, up 30% from 10% SEER Minimum HSPF – 7.7, up 13% from 6.8% HSPF Applies to split system cooling and heat pumps Applies to packaged cooling and heat pumps No new standards for other products

Bi-Flow TXV Hard Shutoff Balanced Port Extended Inlet Connection Thermostatic Element “Power-head” External Equalizer 3/8-in. SAE Outlet Connection Thermostatic Sensing Bulb “Balanced” Pushrod/Pin Superheat Spring Check Valve

Forces Within a TXV Force Description Opening Force: Closing Force: Pressure exerted on top of diaphragm and created by the temperature of the bulb and refrigerant in the charge. Closing Force: Suction pressure exerted under diaphragm. Closing Force Factory preset superheat spring. Opening Force Liquid pressure acting on pin area. This force is eliminated in the balanced port construction. Sensing Bulb Diaphragm Orifice Rules of Movement 1 + 4 > 2 + 3 Valve will move open 1 + 4 < 2 + 3 Valve will move close 1 + 4 = 2 + 3 Valve will stay in position

Increased Load Higher pressure in sensing bulb Diaphragm Higher pressure in sensing bulb Higher liquid line pressure Valve forced open More refrigerant to evaporator Evaporator Coil Orifice

Decreased Load Lower pressure in sensing bulb Diaphragm Lower pressure in sensing bulb Lower liquid line pressure Valve forced closed Less refrigerant to evaporator Evaporator Coil Orifice

“Balanced” Pushrod/Pin Balanced Port TXV “Balanced” Pushrod/Pin Force created by high pressure liquid is “balanced”, and does not act as an opening force on the pin. High Pressure Liquid at Valve Inlet High Pressure Liquid at Valve Inlet Spring Force With a conventional pin, high pressure liquid acts as an opening force pushing against the spring. As high side pressure changes, valve opening SH changes. Conventional Pin Spring Force

Typical Example Indoor Coil 3 psi p Airflow Liquid Line from Equalizer Line Typical Example Evaporator Suction Header Distributor 25 psi P Indoor Coil 3 psi p Airflow Liquid Line from Condenser Circuit Feeder Tubes Bulb TXV Feeler Bulb From this slide we see how a direct expansion system is connected to a typical coil. The distributor assembly provides a connection point for the feeder tubes and also houses the nozzle. Suction Line External Equalizer Line

Bi-Flow Operation (Cooling) Check Valve Closed (Cooling) TXV controls liquid feed to evaporator Seat Valve CLOSED High Pressure Liquid at Valve Inlet Low Pressure Liquid with Flash Gas at Valve Outlet

Bi-Flow Operation (Heating) Check Valve Open (Heating) Flow from evaporator bypasses TXV OPEN High Pressure Liquid to the Outdoor Metering Device Liquid from the Indoor Coil

Feeler Bulb Locate the Feeler Bulb Properly

Subcooling Subcooling is heat removed from liquid refrigerant after it condenses from a gas to a liquid. Example: 110° F Condensing Temperature - 102° F Actual Liquid Temperature 8° F Subcooling

Subcooling Calculator

Checking and Adjusting Charge

Charge Procedure Service Valves Vapor/Suction Line Liquid Line Gauge Manifold Set Refrigerant Tank Liquid Line Digital Thermometer Sensor Flow Restrictor

R410A Subcooling Calculator 10° F 395 psig 106° F

R410A Subcooling Calculator MEASURED 10° F 395 psig 106° F

Liquid Line Temperature Correctly Charged Add Refrigerant Remove 109° F +3° F 106° F -3° F 103° F REQUIRED FROM CALCULATOR MEASURED-105 F DEGREES

Pressure/Temperature Card

System Diagnosis

COOLING MODE ONLY TXV Underfeeding Symptoms: Possible Causes: Frost on valve or indoor coil Low pressure reading at suction service valve High superheat HIGH liquid pressure at liquid line service valve Possible Causes: Clogged filter drier Liquid line restriction Clogged TXV port “Dead” TXV powerhead

COOLING MODE ONLY TXV Underfeeding Symptoms: Possible Causes: Frost on valve or indoor coil Low pressure reading at suction service valve High superheat LOW liquid pressure at liquid line service valve Possible Causes: Low refrigerant charge / no subcooling

End Result

COOLING MODE ONLY TXV Overfeeding Symptoms: Possible Causes: Too much refrigerant charge TXV bulb not attached to suction line Check valve blocked open Plugged external equalizer line TXV stuck open Symptoms: HIGH pressure reading at suction service valve Low superheat LOW or normal liquid pressure at liquid line service valve

COOLING MODE ONLY TXV Overfeeding Symptoms: Possible Causes: LOW pressure reading at suction service valve Low superheat HIGH or normal liquid pressure at liquid line service valve Possible Causes: Blocked return air Dirty air filter Dirty coil Indoor fan failure

End Result

TXV Hunting COOLING MODE ONLY Symptoms: Possible Causes: Pressure reading at suction service valve is swinging more than ± 3 psi (6 psi total) Superheat or suction temperature is swinging more than ± 4° (8° F total) Possible Causes: Blocked return air Dirty air filter Dirty coil Blower fan failure Low refrigerant charge

TXV Hunting

HEATING MODE ONLY TXV Restriction Symptoms: Possible Causes: High pressure reading at suction service valve Low pressure at liquid line service valve Unit runs for short time and trips on compressor overload Possible Causes: Check valve stuck closed

Compressor Discharge Gas Temp. 275 F Discharge Line Temperature Certain Failure 250 F Discharge Line Temperature Danger Level 225 F Discharge Line Temperature Maximum For Desirable Life

KEY FACTS ABOUT OIL TEMPERATURES BREAKS DOWN AT 350 F Creates Contaminates and Accelerated Wear VAPORIZES AT 310 - 320 F Causing Rings and Cylinder Wear

ARE THERE ANY QUESTIONS?

Carrier Equipment Donation Program

New Bargain List Process

Benefits of the New Process Reduces the process time from 2 months to 2 weeks Provides for real-time available inventory tracking

Program Highlights On-line site tracks current inventory Equipment is shipped direct to Vo-Tech School

Distributor Requirements Distributors will order via the on-line tool The distributor will still be responsible for signing off on the “In-Kind Donation Report” The distributor will forward the report with the “Thank You” letter

Example: In Kind Donation Report

Example: In Kind Thank You Letter

What I Need From You Your contact information What do you need? (be specific) Equipment information (space, electrical, etc) A promise that the equipment is only installed at your vocational institute

See Me After The Seminar For My Contact Information

Thank You For Your Time