Clearance requirement for DDC controller

[John Paul]

Fellas,

My mechanical co-worker asked if there's a NEC clearance requirement for a HVAC controller that is powered by 120V. I said no but that I'd verify with a credible source.

Apparently there's yet another govt building being built with a too small mechanical room. The contractor wants to install the controller on the wall behind a pump pedestall or some such thing, so access will be difficult. But what do codes have to say?

Thanks

 

[John Paul]

A little more info. This are the main HVAC controller cabinets for the building. Good constrction practice would seem to say don't install behind anything but can you apply NEC 110.26 like someone told him he should?