SWISCO - The Replacement Hardware Authority

#21 12 BSI-te heavy duty balance

A handy person from Cocoa Fl says:
Hi My window balance has the #21 12 BSI-te on them they are heavy duty they are double pain windows they have two springs in each one, one spring inside the other. They are manufactured by Silver Line windows Code s-019-2 Rating H-C40/60 2700 series- They have the top and foot that looks like the S351-21 series. But I can not tell how strong the ones you have are. Jake Thank you
Profile picture of Paul
Paul from SWISCO responded:
Thanks for posting. I would confirm the length of your metal channel. With that stamp, the metal channel should be 22" long, not 21".

Can you also tell me the weight of your sash? That will help us determine the proper strength. Finally, I would like to see a couple pictures of the balance itself so that we can confirm you have the Series 351 balance. Thanks!
A quick learner from cocoa says:
Here are the pic It is a double spring block and tackle.
User submitted photos of a window balance.
Profile picture of Paul
Paul from SWISCO responded:
Thank you! The Series 390 might be closer. You will need to measure your bottom shoe to confirm that it is the same size as ours. You can see our measurements on each Series 390 store page.

I cannot tell quite what your length is. It seems like it could be 22", but your tape measurerer is not aligned with the balance so it's hard to be sure. Make sure to only measure the metal channel. Do not include the nylon attachments.
A quick learner from cocoa says:
The window sash is 37lbs
Profile picture of Paul
Paul from SWISCO responded:
Ah, I see. That's an extra heavy sash, so we will have to custom make this balance with a special spring strength. Can you just confirm that you have the S390-22? I cannot determine this from your photos. You will need to carefully compare our pictures and measurements to your own part and use your best judgement. These dimensions are just too specific for us to judge through a photograph.

If you do have an S390-22, just tell me how many you need and I can send you a custom order link and price quote for these extra strong springs.
A quick learner from cocoa says:
Yes I do believe it is the S390-22
Profile picture of Tom
Tom from SWISCO responded:
Awesome! I just need to know how many you need and we can get this started. I am going to make you an S390-22 with a special 2175 option, I just need to know the quantity.
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)