You're viewing our full library of technical Q&As. You can also view them broken down into the categories of Commercial HVACR, Residential HVACR, or General HVACR . You can also ask a question of your own.

Full Technical Q&A Library

Coil Cleaning Procedures
Advice for cleaning indoor and outdoor coils. Read it.

Cracked Heat Exchangers
What to do when a cracked heat exchanger is discovered, and why it matters. Read it.

Latest EPA Leakage Rates
Find and use the latest EPA leakage rates under Section 608. Read it.

Commercial Kitchen Hoods in a Home
Design considerations for the level of exhaust ventilation must be addressed. Read it.

Handling Used HVACR Oils
Removing or changing refrigerant oils. Read it.

Fresh air make up
Installation requirements for fresh air dampers on commercial buildings are a local issue. Read it.

Evaporator Freeze Up
Causes for residential and commercial evaporator coil freeze ups and some remedies. Read it.

Carbon Credits for HVAC
There currently is no way for an HVAC contractor to trade carbon credits for profit. Read it.

Caution! Shipping Refrigeration
Caution requirements for shipping refrigeration materials. Read it.

Shutting Off Unsafe Equipment
Shutting off unsafe equipment and the legal issues that arise. Read it.

Removing or Adding Load
Sizing the correct unit when customers raise questions about costs. Read it.

Heat Pump Troubleshooting
Newly installed heat pump system in an attic shows excessive sweating of the air handler. Read it.

Leaking Vacuum Gauges
Read it.

Alternative Drain Lines
Bearing the costs of stolen materials, are there any alternatives. Read it.

Heater Troubleshooting
Troubleshooting a unit heater with no visible signs of damage. Read it.

Evaporator Problems in High Humidity
An evaporator coil freezes up every time there is high humidity. Read it.

Suspected Burned Out Compressors
What to do when a compressor won't start. Read it.

CFM Levels and Installations
Applying correct level of CFM's when installing equipment. Read it.

Matching SEER Requirements
Matching SEER requirements when replacing indoor/outdoor equipment. Read it.

One System, Multiple Zone Levels
Requirements when two zone levels are being supplied by one system. Read it.

Refrigerant Replacement
What to do when replacing an unknown refrigerant when the data tag calls for another. Read it.

Kitchen Hood Considerations
Design considerations to be taken to overcome different levels of ventilation. Read it.

Brazing a Refrigeration Line
Setting the regulator pressure for the nitrogen purge when brazing a refrigeration line. Read it.

Charging Blended Refrigerants
How to charge and transfer the new blended refrigerants without altering their composition. Read it.

Equipment Sizing
A safety factor is already included in load calculation methodology, so technicians shouldn't take any additional liberties when sizing a system. Read it.

Fireplaces and Manual J
Fireplaces have considerable impact on heating, but not mch on cooling. Read it.

True Duct Design
Even with a true duct design, technicians must concern themselves with the return side of the system. Read it.

Clean Condenser Coils
The importance of clean coils and how to clean them. Read it.

Nitrogen Sweeps When Brazing
Nitrogen sweeps prevent copper piping from oxidizing. Read it.

EPA Rules Regarding Leak Repairs and Refrigerant Venting
The EPA hasn't changed the rules, just clarified them. Read it.

Diagnosing System Restrictions
Mistaking a restricted system for an undercharged one is common but can be prevented. Read it.

Frost on the Suction Line
Although frost may be normal in some low-temperature systems, it's best to make sure it's not a malfunction. Read it.

Suction Line Accumulators
These devices protect the compressor. Read it.

Crankcase Heaters
Heating the compressor crankcase reduces refrigerant migration and dilution. Read it.

Filter Driers
How to know when a filter drier needs to be changed. Read it.

TXVs for Different Systems
Low- and medium-temperature systems have different TXV requirements from A/C and heat pump applications. Read it.

Evaporator Size
Under- or over-sizing and evaporator can have serious consequences. Read it.

Finding Small Leaks
Small leaks can be frustrating; here's method for finding them. Read it.

Lubricants
Today's refrigerants require different oils from the ones most technicians are familiar with. Read it.

Crankcase Pressure Regulators
In the HVAC business, CPR doesn't mean cardio-pulmonary resuscitation. Read it.

Evaporator Pressure Regulators
EPRs are particularly valuable in refrigeration and in multiple-evaporator systems. Read it.

An Overzealous Salesperson
People are trying to sell customers all kinds of gadgets and fluids they say will improve performance, but they may void the manufacturer's warranty. Read it.

Refrigerant Leaks
Refrigerant leaks must be fixed, but EPA rules allow some time to come up with a solution. Read it.

Using a Sight Glass to Check Charging
Sight glasses on TXV-equipment are useful, but there are other things the technician must do to ensure proper charging. Read it.

The Significance of Subcooling
What subcooling is, how to measure it, and what it tells you about a system. Read it.

Determining the Proper Charge
Use instrumentation to make sure a system is operating properly. Read it.

TXVs
Thermostatic expansion valves are superior feed devices, but costly. Read it.

Customer-Installed Systems
EPA rules allow customers to buy and install HVAC equipment themselves. Read it.

Troubleshooting Mold
A member asks for help diagnosing a mold issue on three registers of a 16-register system. Read it.

You're viewing our full library of technical Q&As. You can also view them broken down into the categories of Commercial HVACR, Residential HVACR, or General HVACR . You can also ask a question of your own.