Verify Non Tilt Window Balance Mo#

Quick Learner from Northbridge

Sep 22, 2017 8:57 am

Hi, just want to verify that the S350-37 is the correct part number to order. The plastic ends don't seem to match up though with the old one.

Thank you!
Mark

5 Replies

Paul from SWISCO

Sep 26, 2017 11:33 am

Your top balance fitting looks like our 19-002 and the bottom fitting looks like our 1-1/8" depth shoe 15-001, that makes a Series 390. The total length of your metal balance channel measures 37", so you would order S390-37 and the stamped spring weight number will be 3640. Let us know how you make out!

Quick Learner from Northbridge Massachusettes

Sep 26, 2017 12:53 pm

Thank you Paul, I've ordered 1 set. If all fits as expected, 6 more sets will be ordered!!

Thank you!
Mark

Quick Learner from Northbridge Ma

Oct 8, 2017 3:27 pm

Hi Paul, it fit perfectly. We looked at a couple of other broken ones and they are stamped 3650. Is there an upside to ordering the 3650's instead of the 3640's? We need to order 3 more sets, for all the same sized windows.

Thank you!
Mark

Paul from SWISCO

Oct 13, 2017 3:21 pm

Awesome, glad to hear they worked out! Concerning your stamps, it really depends on the weight of the sash. You may want to weigh yours on a scale just to be sure. If the windows are all the same size, I'm not sure why the installers would use some that are 3650 and some that are 3640. It could be they ran out of one, and had to substitute with the others.

Now, will it be okay? Well, if you safely installed the 3640 on your other windows, and they work fine and everything's great, then you could get away with it. I would still recommend weighing your sashes just to be sure. It is possible to have a spring that is too strong. Think of it like Goldilocks' porridge: it can't be too weak, and it can't be too strong. You want it to be just right.