Top window falls automatically

Hi - i have a problem with my double hung windows. When ever i "unlock" the window, the top window slides down automatically. Ideally i guess one pulls down on the top window for it to slide down. But this one just comes sliding down automatically as soon as i unlock it.
Could you please tell me what is causing this to happen. I also like to fix things myself - is this something i can do by myself or do i need to call window-repair for it?
Thanks for any advise...
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Counterbalance is not working. Could be weights and pulleys, could be the spring things on the sides. Determine what type you have first, then either repair the cords or replace the parts. Could be some newer version too, but you didn't give much to go on.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks. It's a double-hung window - installed 5 years ago. I cannot seem to find the maker - but it looks like the anderson double-hung 200 series. I do not see any "pulley/weight" system. The top window falls on its own as soon as it is unlocked - it is supposed to slide down only upon pulling it down. I do not actually see any mechanical system after it slides down (or after pulling down on the top window). Not sure how much more details to provide...
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@gmail.com writes:

There seems to be a recall on the latch for that series:
http://www.cpsc.gov/cpscpub/prerel/prhtml01/01231.html
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I have some Andersen double hungs and they are controlled by a very thin sash cord, hard to see even if you know it is there. On mine, there is a double channel guiding the window, and the cord is well hidden in the channel closest to the outside; it gets there through a break in the upper frame, that almost looks like they just cut the frame a little too big for the channel divider. If the cord was broken, I think it would retract and you would not see anything. Do you have another window without the problem? If so, look at it and see if there is a sash cord.
snipped-for-privacy@gmail.com wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The 200 is a "tilt out for cleaning" window. You are not going to find a cord.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Learn something new everyday. I thought the 400 was the tilt and the 200 the narrowline???
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

They call the window:
Andersen 200 Series Tilt-Wash Double-Hung Window
There are even pictures. No cord.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.