Q. We own a small four-unit apartment house which is heated with hot-water radiators. I do not know if the water in the system is stagnant; or if fresh water is somehow introduced into the system. Won't the water get rusty and eventually cause leaks? Is there a publication that would explain the care and upkeep of a system such as ours? Edward B. Miller Northfield, Ohio
A. Here's a response to your question from one of the largest mechanical engineering construction firms in the US. William Lieber, executive vice-president of University Mechanical Engineers-Constructors, 400 Hester Avenue, San Leandro, Calif. 94577, writes:
"Your hot-water heating system has a fresh cold-water makeup valve in conjunction with the expansion (or leveling) tank and makes up evaporated or lost water in the system automatically. There is a great benefit in keeping the same water in a hot-water system during the first year of use. Also, it is good to assure that the water which constantly circulates through the system stays clean.
"Large commercial hot-water systems do have a small pot-type chemical feeder to keep the water clean; however, many residential and small commercial hot-water heating systems work successfully for years without any water treatment. (For example, most of our hot-water systems have been in service for 30 years or more.)
"The item that needs regular attention is the hot-water boiler (burner and safety controls)."
For a pamphlet explaining the care and maintenance of your system, write to the manufacturer which made the equipment; or ask for available information on the subject from the Consumer Information Center, Pueblo, Colo. 81009.