HVAC

Expandable Pressure Pipe (EPP) for Radiant Piping Systems

Our Expandable Pressure Pipe (EPP) is now a dual lining system for both potable water and radiant floor! After years of research and development, Flow-Liner® is now offering EPP Radiant Piping which can be used to seal leaks in residential and commercial indoor radiant floor piping systems. The system is capable of sealing leaks in hot and cold radiant piping up to 300 feet in length with pipe tubing sizes ½” to 2” ID. It is capable of navigating around multiple long-sweep bends often found in radiant piping systems. EPP can be installed in copper tubing, PEX tubing and other types of plastic or metallic tubing used in radiant piping systems.

Lining Solution for Underground HVAC Duct Systems

Underground HVAC systems—especially those with round, spiral, or oval ductwork between 6" and 18"—are vulnerable to corrosion, groundwater intrusion, and airflow loss over time. Whether you're dealing with deteriorated joints, leaking seams, or rusting steel, excavation isn't your only option.

Flow-Liner’s HVAC lining system is engineered for exactly this kind of repair. Installed from above ground with minimal disruption, our liner is custom-fit to the host duct and provides a continuous, corrosion-resistant barrier that restores integrity and improves efficiency—without demolition and excavation of concrete slabs, flooring, walls and utilities.

This trenchless solution is ideal for repairing HVAC duct systems originally designed to be buried underground. If you're working with pre-insulated or coated metal ductwork or any type of plastic ductwork including HDPE, and facing deterioration, infiltration or leaking joint issues, our CIP-Duct liner provides a cost-effective, long-term fix without having to replace the system.

Compatible with 6" to 18" diameters and curved runs, Flow-Liner’s HVAC lining system saves time, preserves property, and keeps HVAC systems running smoothly.

The homeowner's GC praised the professionalism and courtesy of the Flow-Liner Certified Installers team, highlighting their attention to detail and collaboration with his onsite crew. He stated “It was a pleasure working with the Project Manager and his team.” 

This upscale Laguna Beach residential project took place at an oceanfront property experiencing serious infiltration issues in its underground air duct system. Located just steps from the Pacific, the ground had shifted, stressing the buried ductwork connection joints and allowing moisture and sand to intrude inside the HVAC ductwork. The homeowner's General Contractor (GC) needed a trenchless solution. Demolition of the homes concrete slab to replace the underground ductwork would have been devastating to the interior of the home, plus would have taken months to complete.

Flow-Liner’s CIP-Duct HVAC lining system was selected for the job, using ambient cure liners installed overnight to restore the ducts. The scope of work included two 18-inch ducts at approximately 90 feet each, one 16-inch duct at 60 feet, one 14-inch duct at 60 feet, and two 12-inch ducts measuring approximately 90 and 60 feet. All CIP-Duct liners had to navigate several 45-degree bends as well as 90-degree turns at the start and end of each line. No reinstatements were required.The project was completed successfully within 2 weeks time, with no demolition to the home's concrete slab, flooring and utilities. Also, no concrete dust from jack hammers and concrete saws.

The Moo Moo Car Wash, serving nine Ohio locations, boasts as “the greenest, cleanest around.”With recycled water, high efficiency equipment, and biodegradable soaps, Moo Moo insures the lowest environmental impact in the car wash industry. Moo Moo discovered one of their underground vacuum lines had a separation at a 90-degree fitting. The separation was causing a loss of vacuum power. Excavation was undesirable as the line spanned under the driveway and equipment.

A certified Flow-Liner® installer cleaned the vacuum line and installed Flow-Liner® Cured-In-Place Duct (CIP-Duct®) Liner. The liner covered and sealed the separation at the 90° fitting, resolving the issue with no excavation necessary.

In 1989, the Coshocton Fire Department moved to a new facility capable of providing housing for the firefighters and accommodating new technology and community needs. Many years later, the new facility was found to have deteriorating underground exhaust vents and in need of a trenchless technology solution. 

A certified Flow-Liner® Installer effectively lined the deteriorating underground exhaust ducts by means of Flow-Liner® HVAC Cured-in-Place-Duct (CIP-Duct®) lining. Despite a dramatic transition in the duct from 7” to 12” and a 45-degree bend, the installer completed the duct lining in only two days and with NO EXCAVATION or disruption of the fire department’s daily functions.