Presidential candidates looking for love, understanding and votes would be well advised to skip the conventions that major federal and postal unions are holding this month.

At Monday's opener of the American Postal Worker's Union, members of the nation's biggest postal organization groaned at the mention of Ronald Regan, chuckled or hissed at the name of Jimmy Carter and said absolutely nothing about Independent John Anderson.

(Meanwhile, an official of the National Association of Government Employes said in Norfolk that that independent union would not endorse a presidential candidate this year.)

There are about 2,000 delegates at the APWU convention. On the surface, their mood seems to be "none-of-the-above" for president.

A handful of House Democratic friends of government workers flew here, at union expense, to say they are friends in need, and to put as much distance between themselves and party leader Carter as possible.

Rep. William Ford (D-Mich.) gave the traditional friend-of-labor speech to this 270,000-member AFL-CIO union. He warned that a Republican at 1600 Pennsylvania Ave. could lead to apple sellers and soup kitchens on Main Street U.S.A.

Ford is in line to head the Post Office-Civil Service Committee (that writes most federal worker legislation) if the Democrats continue to control the next Congress. His district covers a section of Detroit where the recession and unemployment are at their worst. Approximately 13 percent of all Michigan adults are drawing some sort of welfare payment, and 90,000 unemployed factory workers have now exhausted federal and state unemployment benefits there.

The speech that brought delegates to their feet was delivered by Rep. William Clay (D-Mo.). Clay said voters have little choice between Carter and Reagan. He suggested that U.S. workers and retirees, who represent a potential bloc of eight million votes, might want to sit out this presidential race. Clay said they should concentrate on rewarding friends and punishing enemies at the congressional level.

Earlier, Ford reminded delegates they had no better friend in the House than Billy Clay.And later Clay said that Bill Ford is the greatest champion that government employes have on Capitol Hill.

Clay said the time has come for the Democratic Party to stop taking organized labor for granted, and for labor, the poor, the minorities to stop assuming that "any Democrat is better than the Republican."

He said the choice labor has between Carter and Reagan is like asking a heavily Jewish neighborhood whether it prefers PLO leader Yasser Arafat or Adolf Hitler.

"The answer is obvious," Clay told the convention. "What choice is there between Ronald Reagan, who promises to wreak economic disaster, and Jimmy Carter, who has already done it?"

Clay said many policies proposed by Presidents Nixon and Ford that were blocked by congressional Democrats have now become law because Carter proposed them and "weak-kneed" members of Congress went along because Carter is a Democrat.

"many believe," Clay said, "the election of an acknowledged Republican instead of a 'closet Republican' who poses as a Democrat would be a blessing in disguise" because a Democratic controlled Congress could -- and would -- block such legislation.

Independent candidate John Anderson asked to address the APWU convention. He was turned down by President Emmet Andrews because, he said, of Anderson's anti-labor record.

Andrews said that Anderson had voted against liberalizing the Hatch "no politics" Act. Changes in the Hatch Act are a major goal of federal and postal union leaders. Andrews said that when he told this to an Anderson aide, the aide said, "What's a Hatch Act?"

The people who decorated giant Cobo Hall, where the convention is being held, correctly read the mood of angry political indifference of these delegates. Four giant pictures hang behind the union's national officers facing the audience. They are portraits of George Meany, Martin Luther King Jr., John F. Kennedy and Hubert H. Humphrey. As one union leader pointed out, all of them were friends of labor and federal workers.

And all of them are dead.