This project shows how to install a Panasonic WhisperFit EZ bathroom fan model #FV-08-11VFL5 in an old work/retrofit application by removing the old fan, mounting and wiring the new fan and wall switches.
Panasonic WhisperFit EZ Overview
The WhisperFit EZ features the “Flex-Z Fast” mounting bracket and is ideal for old work/retrofit applications where a old fan is being replaced, especially between floors where attic access is not possible. The fan has a low profile 5-5/8 inch high housing to fit between 2×6 floor joists. I bought the FV-08-11VFL5 model from Amazon.com which has a light and night light in addition to a 80 or 110 CFM motor speed selector switch.
The fan fits 3 and 4 inch diameter ducts and includes a reducer for 3 inch duct:
How to Install a Panasonic WhisperFit EZ Bathroom Fan
This is the 3rd Panasonic Whisper series fan that I’ve installed in my home and each installation had it’s unique challenges:
- A Panasonic FV-11VQ5 installed in the 1st floor master bathroom which required replacing a long run of 3 inch sheet metal duct with 4 inch insulated flex duct.
- A Panasonic FV-05VQ5 installed in the kids upstairs bathroom where I replaced 3 inch uninsulated flex duct in the attic with 4 inch insulated duct and installed a new soffit vent.
Separate the Duct Adapter from the Fan Body
Begin by removing the ground screw to slide the duct adapter off the fan body:
Then unplug the two wiring plugs from the junction box. One plug is for the fan motor and the other for the fan light and night light. Notice the large oval hole in the fan body flange showing the duct adapter mounting hole for a screw. The large oval hole provides generous clearance when inserting the fan into the ceiling open to mate with the duct adapter. The details will be explained later in the project:
With the ground screw and wires unplugged, the duct adapter easily slides off the fan body:
The duct adapter and junction box will be wired and installed in the ceiling first, then the fan body is inserted into the ceiling opening to mate with the duct adapter. This is why the duct adapter and must be separated. (Wish the Panasonic instructions explained this step back when I installed the FV-11VQ5 in the master bathroom, however the instructions at the time only covered new work installations.)
Project Series Index
The fan installation is covered in a four part series:
- How to Install a Panasonic WhisperFit EZ Bathroom Fan. (You are here.)
- Panasonic Bathroom Vent Fan Electric Cable Fishing.
- Panasonic WhisperFit EZ Fan Old Work Ceiling Mount and Junction Box Wiring.
- Panasonic WhisperFit EZ Fan Installation – Wall Switch Wiring.
Panasonic WhisperFit EZ Fan – Project Planning and Wiring Diagram
Electrical safety: Shutoff the electricity at the circuit breaker panel before proceeding to avoid injury, shock, fire and/or death! If you are uncomfortable working with electricity please hire a licensed electrician.
The old bathroom fan in the water closet includes a main light. There are two wall switches for the fan motor and light:
The new Panasonic WhisperFit EZ FV-08-11VFL5 needs three (3) switches: fan, main light and night light. Because the old switches are in a double gang wall box there only room for two devices. I need a combination switch using the Leviton No. 5634 for the light and night light and a Leviton No. 5691 single switch for the fan motor. I also bought a Leviton unbreakable nylon wall plate to fit the new switches:
The old fan only required two electrical cables:
- NM-B 14/2 for power from the circuit breaker.
- NM-B 14/3 for the fan motor and light.
I made a WhisperFit EZ wiring diagram which shows I can reuse the NM-B 14/3 cable for the light & night light but I’ll need to pull a new NM-B 14/2 cable (right side of diagram) for the fan motor and fan switch:
Remove the Old Bath Fan
Remember – the electricity has been shutoff at the circuit breaker! I removed the screw holding the grille and light unit to the fan body then unplugged the light:
Next unplug the fan motor which unsnaps from the fan body. Use the tip of a flat head screw driver to wedge it free:
Although the electricity was shutoff at the circuit breaker, always check the wires for voltage first! I ran a battery check on my Fluke 2AC VoltAlert voltage tester by pressing the test button. The tip glows red when voltage is present:
And held the tip of the voltage tester against each wire to verify the electricity is Off:
Unscrew the wire nuts then untwist the wires. Pull off the green ground clip with a needle nose pliers:
The cheap contractor grade bath fan installed by the home builder was “permanently” fastened to the floor joist with metal staples… as if it would never need to be replaced with no thought for future maintenance. Using a large flat head screw driver, I pried and bent the sheet metal fan body and staple off the joist:
The fan body is now released from the joist:
Move the fan over to expose the duct connection. I never cease to be amazed at the lack of workmanship done by contractors. As I said in other projects, “Everything is built by the lowest bidder”. The contractor used duct tape instead of metal foil HVAC tape. Duct tape is not for ducts! The duct tape was barely sticking on and loose leaking air:
Remove the fan from the ceiling, straighten the wires and pull out the NM-B 14/3 cable:
Pry the plastic grommet off the fan body with a screw driver to release the NM-B 14/3 cable:
Bathroom Fan Ceiling Duct and Wire
I looked inside the bathroom ceiling between the 1st and 2nd floors to inspect the duct and see how the electric cable was routed. My home was built in 2000 and I don’t know if IRC 502.8.1 (.pdf) or equivalent was enforce back then for notching and boring holes in joists. The problem is the home builder bored a 4-1/4 inch in a 2×10 floor joist which exceeds 1/3rd the joist depth. I blame the architect and home builder for failing to consider how ductwork would be routed to the outdoors:
Looking towards the bathroom door the NM-B 14/3 cable is routed through the 2×10 floor joists towards the wall switches:
This project is continued in Panasonic Bathroom Vent Fan Electric Cable Fishing.