Suppose you've just moved into a new house that's uncomfortably warm in spite of the air-conditioning. Or you've discovered a ridge in the vinyl kitchen floor. Should you call the builder back?

It all depends. Before you complain about the air-conditioning, test the temperature objectively. Under normal weather conditions, the cooling system ought to maintain a reading of 78 degrees in the center of each room at five feet above the floor. If it doesn't, it probably needs adjustment.

What about the ridge in the floor? The sensible thing to do is to measure it. If it's more than an eighth of an inch high, the builder ought to make repairs. If it's less, you may be noticing things that would be invisible to anyone else.

The guidelines here come from a pamphlet on performance standards packaged with every Home Owner's Warranty issued in Maryland. Model building codes, trade organization standards, and home buyer publications issued by the building industries are also useful. If you and your builder can establish the boundaries between contractor responsibility and homeowner maintenance, changes are you can settle any disputes quickly and inexpensively . . . before you end up in court.

Published standards are especially helpful when you and the builder might otherwise end up at an impasse. To a certain extent, it's normal for wallboard to show imperfections and for concrete to crack. It's also normal, if you're a buyer unfamiliar with these phenomena, to regard every variation as a sign that your house is about to collapse.

You're likely to be frightened by anil heads sticking out beyond the surface of the wallboard or by seams where two pieces of drywall come together. Both are fairly common occurrences, caused by shrinkage of framing boards and wallboard. Neither affects the strenght of the wall.

Should the builder fix them? The HOW standards hold him responsible only for messy trowel marks on the wall, blisters where wallboard seams have been carelessly taped, or other signs of poor workmanship. But many builders will go much farther. Some routinely repair all imperfections visible in natural daylight. Almost any wall, no matter how expertly worked, will show minor problems when highlighted by electric lights. If you're reasonable and remember that the builder also has tofor repainting every time he brings a drywall crew back, you ought to be able to strike a happy medium.

Concrete work is another bugaboo. Non-structural cracks are not unusual in foundation walls, basement floors and the like. The HOW booklet recommends that the builder repair foundation cracks over 1/8 inch wide - but not until the end of the first year when most of the settling is done. In the basement, cracks of 3/16ths of an inch or less are normal. In steps or stoops, only hairline cracks should occur.