Coil balance System

A home owner from Illinois says:
Hi I am looking to replace the window balance systems in 10 windows in my house. My house was built in 1996. I currently have double coil window balances, one coil is #5, I can't see a stamp on the other coil. The windows are single hung vinyl windows, can't tell the manufacturer. The pivot block is 1-1/4" x 1-1/2" x 1/2". The window sash weighs 18 lbs. Do you have a replacement coil part that would work? Can I replace the window balance with a single coil system, or do I need to use a double-coil system?
Thumbnail of the uploaded file named 20221010_134236.jpg
Thumbnail of the uploaded file named 20221010_134244.jpg
Profile picture of Tom
Tom from SWISCO responded:

Your balance system has been discontinued by the manufacturer and has been replaced with the 15-140 balance shoe and Series 150 coil spring. 

We also sell the 15-144 bushing cap, 15-143 bushing, and 15-145 barrel.

How to remove window pivot shoes
How to remove window pivot shoes
VIDEO
WATCH >
Anatomy of a tilt window
Anatomy of a tilt window
VIDEO
WATCH >
Reply to Thread
Use this form to ask a follow-up question or to share your experience regarding this subject.
(your email address will be kept private and is only used to inform you when a response has been made)
Current wait time is 3-4 business days
We promise that one of our experts will personally get back to you as soon as they are able. Thank you very much for your patience and understanding. If your inquiry is time-sensitive, please feel free to reach us at (888) 991-1929 or at help@swisco.com.