Q. For the first 15 years our water closet flushed satisfactorily, but then it began acting up. We drained the tank and flushed out the jets with diluted muriatic acid and it worked for another year or two. However, a reapplication of the acid then failed to work. We enlarged a few jets, but now the unit is again acting up. We cannot duplicate the color. What do you say? Robert L. Jones Tujunga, Calif.
A. We presume you have already been in touch with the manufacturer of the water closet and discovered for sure that the color is no longer available.
''A sluggish flush may occur when one or more of the following conditions exist,'' the maker said in responding to our own letter. Here they are:
* There may be low water pressure. In this instance, you may have to enlarge the lines to the ballcock.
* Bowl may not be getting refill. The trap seat should be 2 3/4 to 3 inches. The diverter valve may need cleaning. The rim holes may be limed up and need muriatic-acid cleaning.
* The flush ball may be dropping too soon and may need to be replaced.
* The volume control could be restricted. Open and regulate for suggested refill time.
* There may be a trap leak. Fill the bowl to overflow the dam. After setting about two minutes, measure the seal depth. Remeasure in an hour. It should remain the same.
* Waterway and rim holes may be limed. You must use muriatic acid (10 percent) to remove the lime. The manufacturer suggests a 2- to 3-hour period. Avoid rubber and plastic materials as much as possible.
* The ballcock may be restricted, the plunger may be restricted and not opening, or the seat may be blocked. Remove, flush, clean, and repair.
That's the word from the manufacturer of your unit. Follow the suggestions and see if you can't get it to work.