Q–I have a hot water heating system with radiators throughout the house. There are two pipes coming out of each radiator–one that goes through the radiator shut-off valve to allow hot water from the boiler into that radiator, and one that discharges the hot water back into the system from the other end of the radiator.
In the basement, I can see only one main, larger-diameter pipe that connects to all the radiators, with tees that connect to both the inlet and outlet pipes of each radiator. This pipe connects to the top of the boiler at one end of the circuit, then apparently goes back into the boiler near the bottom of the boiler. I am thinking of adding at least one more radiator to an upstairs room as part of a remodeling project, but would first like to understand how this works. How can one pipe supply hot water to each radiator and then serve to also carry that same water back to the boiler?
A–All hot water heating systems form a continuous loop; the heated water goes from one radiator to another until it gets back to the boiler. In its simplest (and least efficient) form, this is a series loop so that you cannot turn one radiator off without shutting down all the radiators.
In your case, you apparently do have shut-off valves on each radiator, so you apparently have an improved design that is still a one-pipe system. That is, there is still only one main pipe supplying all radiators. However, a special type of “forced flow” tee shunts only part of the hot water out of the main pipe into the smaller diameter pipe leading to each radiator. The rest of the hot water continues on to the other radiators.
The water coming out of the radiator goes back into the same main pipe through a conventional tee, and eventually back to the boiler.
Q–A concrete step leading to my back yard patio has a black-looking, “charred” stain that looks as though the previous owner dropped some burning coals on the surface. Is there any way I can remove this stain or at least do some cosmetic work so that it does not look so ugly?
A–Try scrubbing the stain off with a strong detergent such as “Zud” or one containing TSP (trisodium phosphate).
If this doesn’t work, try a solution consisting of one part muriatic acid added to four parts water. (Mix in a glass or plastic container and wear rubber gloves and safety goggles). If this fails, then you can paint the step with an outdoor concrete “stain” or latex-type deck paint.
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Have a question about home repair problems? Write to Bernard Gladstone in care of Your Place, Chicago Tribune, 435 N. Michigan Ave., Chicago, Ill. 60611. Questions of general interest will be answered in future columns. Sorry, letters cannot be answered personally.
