Q:

Identifying replacement bearings for installed heater fan motor

TLDR: Trying to identify the right kind of replacement ball bearing.  Usually they have a standard code # which can be supplied by different manufacturers.  But the ones I need don't seem to fit that system. 

We have a number of fan heaters, some of which are making noise (others are dead quiet).  These are a hot-water type which are installed in walls or in the "kickspace" under cabinets, and the fan blows air over the HW coil. 
Upon inspection it is the rotating fan / motor assembly that is producing the noise, and that whole assembly can be removed for service / replacement.  I've exposed the bearings which are noisy, but am having trouble identifying a replacement. 
The bearing is stamped BB1023 but this doesn't seem like a standard bearing code.  Does anyone know how to interpret this number and/or is there an equivalent standard code? 
Ideally someone may know of a canonical reference to bearing codes.  I have found references which purport to be such a thing, but don't include this numbering. 
(If not I will probably just measure the originals with a caliper & try to find the best match that way; this just seems more likely to go wrong because not only the obvious dimensions are important.) 

Notes:

The few bearings I can find online with that code are much more $$ than I would normally expect, so either these really are specialized and nonstandard or they are just hard to find with that nomenclature. 
In a few cases the BB1023 code seems to be cross-referenced with 627N1Z and other codes ... but I am somewhat mistrustful of the correctness of random product information.  And 627N1Z seems to be an oddball code also when I've tried to find it in catalogs. 
The heaters happen to be common Beacon-Morris models, and entire replacement fans are available but at a much greater cost than what I'd expect just the bearings to be. 

A:

The way to find different bearings is by the size bb1023 crosses to a double sealed 6.35 x22 x7  mm bearing 
Mr627zz is the same id/od and 1/4” thick so it is slightly thicker and may work under 5 bucks.  Looking at the bearing specs I would give it a try.  I cross bearings for motors all the time, I can tell you a timkin or sky bearing in some cases is worth the extra but in a light duty motor like a fan I would save a few $ 
Mr627-2rs
Mr627zz 
I thought I typed in the wrong size after double checking my answer but I just typed the size wrong in the answer corrected.