www.jaysmodelkits.com / ZC 1.5.7d / PHP 7.4.33

I have received an email from a customer who states that whilst browsing the store the shopping basket kept emptying, it happened twice.
Whilst browsing and selecting items to put in to the basket he spent time away from the computer to check something and came back to find the basket was empty. Total time period spent was 1 to 2 hours from the time he started browsing.
Sounds to me like ZenCart has a time out feature which seems to empty the basket of items when a certain length of inactivity has been reached.
Is this correct? and, if so, what is the time limit set to and can it be changed? Fortunately the customer was persistent and refilled his basket for a third time. But, I can see this could annoy some people leading to lost custom.
Thanks in advance.