Spring Balance #2790

Handy Person from NJ

Jun 20, 2020 2:46 pm

I see several balance springs for 27' glass (28" channel), but the one i have has a stamp saying 2790. I only see 2770 as the highest weight capacity. I am not able to weigh the sash and wondering if it may be heavier than 39 lbs.

Do you know if the spring sizes have changed?

Thanks

1 user uploaded image

4 Replies

Tom from SWISCO

Jun 24, 2020 10:23 am

The spring sizes have changed, yes. Stamps ending in "90" like yours use an old rating system that is no longer in use. One of our stamps may very well work for you, but you'll need to weigh your sash on a scale to confirm. That's the only way to be sure.

Handy Person from NJ

Jun 25, 2020 5:52 pm

Thanks for the info on the springs.

We need a little more help to identify the right product.

It looks like we have either an S351 or S390 balance. I am adding more photos. I only have photos and no way to measure the bottom shoe like your instructions say.

One photo shows the bottom shoe. Does this look like the wider S390 to you?

Thanks

4 user uploaded images

Tom from SWISCO

Jun 26, 2020 8:37 am

That's really tough to say. Since it's only a 1/8" difference, it's not always easy to eyeball. I can say that the bottom fitting in your photo does look on the large side, but that's no guarantee. The only way to be sure is to measure it, unfortunately.