Remote slow to respond. Sometimes does not respond. Yes, I replaced the batteries.

Sorry, that should say the *box may need to be replaced.

... problems with the remote control response time with the DVR box. ...

With older legacy cable boxes, when the box received a signal from a remote it acted on that signal directly. I believe digital adapters also work that way. But X1 boxes are different.  When using a remote to control an X1 cable box:

1. The remote sends a signal to the box
2. The box uses an internal modem to send that signal to a server at Comcast and ask for instructions
3. The server at Comcast decides how the box should respond and sends back commands and data
4. The box receives the commands and data and does as instructed

This design means that X1 is very flexible, but more delicate. If any of the links in this more complicated chain are weak or broken, the response to signals from the remote is sluggish, or fails completely. When that happens you can try changing the batteries in the remote, rebooting the cable box, and checking the coax (or fiber) line and connections.

If the remote still doesn't work properly, you'll probably need to ask Comcast to send out a premise tech to troubleshoot the problem. If the tech finds bad coax, splitters, amplifiers, or connections in your home (even if Comcast originally supplied them) you'll probably have to pay for the visit ($70-$100) unless you have their Service Protection Plan (https://www.xfinity.com/support/articles/service-protection-plan, closed to customers that don't already have it). If the trouble is due to a faulty Comcast rental device or anything outside your home you shouldn't be charged.

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