Cold air coming from heat pump is puzzling

Q. I have a heat pump about which I am puzzled. The heat pump runs nicely with the thermostat set at 70 F. It goes on and off about six to seven times per hour, which I was told is normal. After the heat is on about hour or so, cool air starts coming out. Why is this happening? Is this normal, and for how long does the cool air continue?A. There can be several reasons. I assume the fan is running while you feel the cold air coming out of the unit. It may be normal. The anticipator switch, set by the HVAC contractor who installed the unit, may need to be adjusted. The air-handler may be cycling down. Your best bet is to call the contractor who installed it or any other HVAC contractor familiar with heat pumps. Have them check the unit and make any necessary adjustments.Q. Thank you for your prompt reply regarding the problem I have been having with the premature failure of the IKO shingles on my roof, and the unsatisfactorily low offer I received from them when I made a warranty claim. When the manufacturer honors a roof-shingle warranty, do they normally use the original cost or replacement cost? For what it is worth, the Behr paint company paid for the replacement material costs and half the labor to restain our house since it was very evident their product did not stand up to their claim.A. I am glad to hear that there are manufacturers who stand behind their products and offer a fair settlement when they fail. Roof-shingles manufacturers offer a prorated amount based on the purchase cost of the material and the ratio of years the shingles have been on the roof compared to the warrantied life.Q. My son-in-law in Colorado spread Revive on his lawn before last spring's snowstorm in Colorado. He didn't have a chance to sweep the particles off the concrete driveway and sidewalk. The result was heavy brown iron stains on all concrete. Someone suggested muriatic acid, but the runoff would be harmful to lawn, pets, etc. Any suggestions?A. Rust stains that have not penetrated deeply into concrete can usually be removed with a solution made of 1 pound oxalic acid crystals per 1 gallon water. (Adjust the proportions as needed.) Mix the crystals until they are completely dissolved. Sprinkle the solution on the stains and mop it thoroughly. Wait a couple of hours before rinsing with clear water while scrubbing with a stiff broom. You should be able to buy oxalic crystals or powder from a janitorial supply house. Be very careful handling it, as it is a very potent chemical. Use rubber gloves, eye protection and old clothing. Do not use any metal tools or containers; use glass or plastic, such as a 5-gallon drywall compound plastic pail. You may need to repeat the treatment. Deeper stains are much harder to remove and should be dealt with by an experienced concrete contractor.Q. We have ice-dam buildup on our roof in the winter, and we know we need to repair or replace the roof entirely. It is too difficult for us financially to replace this roof until next spring. Are there any temporary things we can do to the roof over the winter to help us avoid this problem? We thought that even if we could use something like a tarp on the roof, that might help. We're concerned about ending up with a mold problem also. Also, in one of your columns, you said there was a particular type of shingle that you would not recommend. Can you tell me again what that brand was and if you have any type of shingles that you especially recommend?A. Replacing the roof will not eliminate the ice damming. Ice dams are caused by heat loss from the heated building that melts the underside of the snow pack. When the meltwater reaches a cold surface - like the eaves or a roof over an unheated area, like a porch - it freezes and forms an ice dam. Further snowmelt becomes trapped behind the dam and finds a way into the building. You need to find out where the heat loss comes from and correct it. You may also need additional insulation in the attic, and, perhaps, some improvement to its ventilation - although that is not always necessary, needed or desirable. For protection against ice dams, when you reroof, you should install an ice and water protective membrane on all eaves and 2 feet up the roof above the heated area, as well as on all valleys, around skylights, chimneys, plumbing stacks and all other roof perforations. Meanwhile, a tarp may be a temporary solution. If your roof pitch is steep, the snow may shed off the tarp and solve your problem. The tarp will have to be fastened in a way that the wind and the snow load will not tear it off.I have had personal experience with two roofs that had IKO shingles, which failed prematurely. I have spoken with several contractors and roofers who have had similar experiences. A number of readers have e-mailed or written me about their own problems with these shingles and with CertainTeed shingles. I have not heard anything negative about BP shingles, and that is the brand I recently installed on our roof.Q. When I went into the kitchen this morning, I looked under the kitchen sink and discovered that an unopened bottle of white vinegar had sprung a leak and flooded the cabinet. When cleaning up the mess, I found that when I stepped in front of the cabinet, our vinyl floor was squishy. Apparently, when the vinegar leaked, it flowed out of the hole for the pipes and seeped under the cabinet and under the vinyl. The vinyl has a plywood subfloor. Will the vinegar evaporate eventually? Can mold grow under vinegary conditions? Do I need to have the floor ripped up and replaced?A. The vinegar is likely to evaporate within a few days. The plywood subfloor would absorb much of it, and it is more likely that most of the vinegar ran down the same plumbing holes to a lower floor. If the situation does not correct itself shortly, you may want to call a resilient flooring contractor to investigate and recommend a solution. I doubt that mold can develop under these conditions, since vinegar is an acid. bull; Henri de Marne was a remodeling contractor in Washington, D.C., for many years, and is now a consultant. Write to him in care of the Daily Herald, P.O. Box 280, Arlington Heights, IL 60006, or via e-mail at henridemarne@gmavt.net.#169; 2010, United Feature Syndicate Inc.