UL Listed Kitchen Equipment

[Bryanjh]

I am in a position that requires me to do appliance repair from dishwashers to food warming and cooking. The equipment breaks down, components wear out. My group debates how we make our repairs. One of the comments made concerns the UL listing of the equipment. It has been said that in order to "maintain" a UL listing on the equipment, we need to use listed parts. Now, here comes the confusion.
Example: Old hot cart food warmer timer switch is no longer available from the manufacturer.
What is to stop me from using any old UL listed part to do the same job, even though the manufacturer does not list a replacement? (I have considered using a timer switch from a different manufacturer's assembly and drilling holes in my old hot cart to install the part.)
Am I in violation of any rule out there that says I cannot use or should not use aftermarket parts?
Is it even possible to "maintain" a U.L. listing on a piece of equipment in a kitchen (public school setting)? I would like to use language and terminology that is accurate and true.
any advice or information would be appreciated.

 

[Jraef]

Two issues regarding listed equipment: Code and Insurance.

Code wise, in SOME parts of the country, you are required to have NRTL (Nationally Recognized Testing Lab) listing of anything that is wired into a building (portable plug-in equipment, not so much), UL is the most widely known NRTL. But once something is inspected and accepted by the AHJ (Authority Having Jurisdiction), it belongs to the owner and they can do what they like. If it gets MOVED and RE-INSPECTED, then an AHJ can indeed reject it for being modified, regardless of age (if he looks that closely). That has caused many people to regret having done remodeling, because they find out all of their "grandfathered" equipment cannot be reconnected. But other than that, it's between the owner and his maker...

Insurance is another matter. Many insurance companies will require that all electrically powered equipment bear a UL label, or at least that of another NRTL. If you didn't know, UL = Underwriter's Laboratories, as in INSURANCE underwriters. UL's very existence was brought about for the purpose of testing materials that protect against fires and injury, because the insurers are the ones who have to pay out the claims and they don't like doing that. So often times when a business owner goes to buy his insurance policy, the insurance company sends out an "underwriter" to inspect the place, or at the very least, look at the documentation the owner has to provide. Then they write the policy based on the risk involved and that policy will often have a clause or rider stating that the owner of the policy must use approved and listed equipment. Therefore if there is a fire or loss some day and the insurance company does an investigation, if they find the cause was associated with unlisted equipment or equipment that was originally listed but has been modified in ways that void that, they can refuse to pay for the damages of that incident.