I have an older heat treat oven in my shop. It is essentially a Canadian version of a paragon.

The story goes like this..... I got it second hand, and after a few uses, I noticed that it kept taking longer and longer to reach temp. For example, if setting the controller to 1950F....it would take 3-3 1/2 hours to reach temp. I thought the element might be going bad, so I ordered a couple of replacements from Paragon.....after installing a new element, the oven now takes 4- 4 1/2 hours to reach the set point. The oven reaches 1000F fairly quickly (an hour or so) but beyond 1000F, it's a crawl. Here are the specs on the oven:

Cyberblade Furance
Model: DHT-16
Volts: 240
Phase: 1
Amps: 11.6
Element: Kanthal A1 alloy
2800W, 20.6amps, Max temp 2000F

How long should a heat treat oven take to reach a set point of 1950F? If the time frames I've mentioned are out of line with what should be expected, do you have any advice or recommendations?

Many Thanks!