Cased Coil Misalignment

By April 26, 2019

Cased Coil Misalignment

On occasion, you will either find a furnace or be tasked with installing a furnace where the coil overlaps the edge of the furnace because the coil is wider. In the case of a Carrier CNPVP coil, you need to ensure that you align the coil according to the manufacturer's specs, or you risk cutting off about 1/3 of the airflow.

The best-case scenario is to use a coil that is a sizer match for the coil, or you can buy or make a tapered metal transition between the furnace and the coil. In the case of the CNPVP, the manufacturer allows the coil to be offset to the left.

In this video, we illustrate replacing a leaking coil and reconfiguring it in the proper orientation.

—Bryan

Check out our most recent video

How to Evacuate an AC system, Full Vacuum Procedure

Our latest Podcast

HVAC School – For Techs, By Techs

Real training for HVAC ( Heating, Ventilation, Air Conditioning and Refrigeration) Technicians. Including recorded tech training, interviews, diagnostics and general conversations about the trade.

In this short podcast episode, Bryan talks about motor speed and other basic electrical topics as they relate to motors in HVAC equipment.

In a typical single-phase PSC-type (induction-driven) motor, the speed is primarily determined by the electrical cycle rate, also known as the hertz. The hertz represents the speed at which the electrical current changes direction (positive to negative) per second; in the USA, that number is typically 60 hertz. Unless we’re dealing with ECMs and VFD-driven motors, the motor speed will be partially influenced by the hertz or frequency as determined by the utility company or a generator.

Motor speed is also determined by the number of magnetic poles in the motor. A motor doesn’t make a complete revolution per cycle; a cycle only refers to the distance between two poles. The more poles we have, the shorter the distance needs to turn per cycle. A two-pole motor rotates all the way every cycle, resulting in 3600 RPM under no-slip conditions (synchronous speed). A four-pole motor has half the RPM, and an eight-pole motor has 1/4 of the RPM of a two-pole motor.

Speed taps add winding resistance between run and common to create slip and slow the motor. A six-pole motor has 1200 RPM synchronous, but 1075 is the effective speed with slip factored in. Each speed has a different level of winding resistance, which slows the motor as you move from high to low; the lower-speed tap has higher resistance than high-speed taps.

ECMs and VFD-driven systems convert the frequency and don’t depend on the electrical frequency from the utility or generator.

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Search Episodes

Motor Speed – Short #164

05/30/2023

Bryan Orr

Growing in Productivity and Confidence as a Tech w/ Refrigeration Mentor

05/25/2023

Bryan Orr

The Art of Unteaching w/ MeanHVAC

05/18/2023

Bryan Orr

Floating vs. Fixed Suction and Head – Short #163

05/16/2023

Bryan Orr

Humidity Utopia w/ Nikki & Bryan

05/11/2023

Bryan Orr

What the Flux? – Short #162

05/09/2023

Bryan Orr

The Impacts of Duct Leakage w/ Steve Rogers

05/04/2023

Bryan Orr

Launch of the Sensi Touch 2 Thermostat

05/02/2023

Bryan Orr

Why and How to Create an Internal Training Program W/ Eugene S.

04/27/2023

Bryan Orr

When Subcooling is Meaningless – Short #161

04/25/2023

Bryan Orr

Search Results placeholder

Related Tech Tips

Don't Forget the Suction Filter Drier

Courtesy of Emerson It is important to have refrigerant free from debris and contaminants, and we control these issues on many different fronts. 1. Proper tubing handling prevents copper shavings, dirt, and water from entering while installing. 2. Flowing nitrogen while brazing prevents carbon build-up. 3. Deep vacuum of 500 microns or less removes air, […]

VRV Basics

This tech tip was written by experienced tech and VRV specialist Ryan Findley. Thanks, Ryan. This is a quick overview, not a substitute for taking proper manufacturer training. This tech tip is geared towards the mechanic who is fairly new to VRV systems. As with anything, before we harness the ability to install or […]

Powered Attic Ventilation

When I first started in the trade, I used to advise customers with hot attics to install powered attic ventilators (PAVs) to “suck” that hot air out of the attic. It just made sense to me at the time; if the attic is hot, get the hot out! When I started learning more about design, […]

More tech tips