Comcast offered a mea culpa for this week's service outage, along with a credit to impacted customers.

In an apology posted on the company's website Tuesday, network engineering exec Kevin McElearney said the issues began around 10:20 a.m. EST on Monday. On Demand video, as well as broadcast, local and cable TV channels were inaccessible for about 90 minutes for customers in regions across the country.

"We did not live up to expectations around 100% reliability with your TV service," McElearney said. "We're sorry for that, and we will be crediting customers."

A spokeswoman told CNNMoney that "even though the issue lasted about 90 minutes," customers will receive a credit for a day's worth of video service, which she guessed would be around $2.

She added that credits will vary depending on how customers were impacted. For example, some people complained that their home phone lines were beeping, while others said they had trouble accessing the Internet.

In order to get a credit, customers must call Comcast (CCV). The company can't apply an automated, blanket credit "because the impact was varied."

"We'll work with customers on a case by case basis," the spokeswoman said. Comcast will explore other ways that people can submit credit requests in the future.

Last year, when Comcast's Internet service went down for customers in parts of California, Washington and Arizona, the company set up an online form to get a credit.

Related: Blizzard 'Jonas' helps set record for on-demand TV viewing

Comcast said Monday's TV and video problems occurred because there was an error within one of the company's network devices and the way it routed video feeds.

"We know exactly what went wrong and have fixed the issue and put in place technical measures to make sure that this doesn't happen again," McElearney said.