SWISCO - The Replacement Hardware Authority

Replacement balancers, series 770. what stamps?

A quick learner from Venice, FL says:
Have tilt-out hurricane impact windows about 52"w x 31.5"h, which probably weigh about 50 lbs. Need to replace balancers in about 6 of these windows; the eye at the top of the pulley is the part that breaks. Current balancers look like your Series 770. The metal channel measures 28" but the part number marked on the existing balancers is (11/2)UNIQUE 27-E-50.

It seems that I need to purchase the 28-E option or perhaps the 28-F option. Do I need stronger balancers than my current balancers? What is the difference between the 28-E and 28-F options? What is the best option for my big, heavy windows?
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Tom from SWISCO responded:
Thanks for posting! Are you sure that your metal channel is 28" long? Based on your stamp, it should be 27". Please confirm and we can work from there! Make sure that you are only measuring the metal channel.
A quick learner from Venice, FL says:
The metal channel is 28" long from end to end. This measurement does not include any other part...just the metal channel. If your 28" channel turns out to be longer than 28", and I don't think it is, I have a hacksaw.
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Tom from SWISCO responded:
Thank you! In that case, I think it would be best if we were to get the weight of your window sash. You can determine this by removing it from the window and placing it on a scale. Any common bathroom scale should do. Let me know!
A quick learner from Venice, FL says:
Weight of window sash is 41 pounds. The glass is hurricane impact glass.
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Tom from SWISCO responded:
Thank you! That's a pretty heavy window. We do not have a standard stamp option for the S770-28 that can support that, so your balance will have to be custom made.

The stamp we'll be going with is 28H, which can carry a window sash weight range of 40 through 43 pounds. To begin, please take a look at this Custom Channel Balance Order Form that I have started for you and fill out the contact and shipping information. One of our representatives will be in contact with you shortly thereafter.
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