My bedroom window air-conditioner, a seven-year-old Frigidaire, seems to have developed mold, and I’m about to replace it. It stays in the window all year. When I first turned it on about two weeks ago, I found black speck over the white carpet. The next time it was on the same thing happened. I now see black spots in the slats at the top of the air-conditioner and can see black if I look to the back of it. I have cleaned the screen, but it isn’t coming through there. Is this how people develop Legionnaire’s disease? A. Mold spores have gotten into the air-conditioner, and that is why some of the condensate is black, although the condensate should be dripping outdoors. Try this before calling a mold remediation company: Lightly spray the unit, indoors and out, with 1 part bleach and 3 parts water. For the inside of the unit, spray where the air exhausts outdoors with the same solution, and put the unit on “air” until any smell is gone. If it’s still smells, call a mold remedition specialist.

May Indoor Air Quality is a good one. All this won’t be necessary if you buy a new unit. Legionnaire’s disease is way out of my bailiwick. Q. I live in the South End in Boston and I am sorely in need of a recommendation for a skilled roofing person who can take on the stripping and replacement of our roof. Yelp is usually all over the map and leave your head spinning with the contradicting reviews. Do you have recommendations you could share? A. I used to recommend my own roofer whom I have had for 40+ years and who put on two roofs, but not any more since he inspected one section that is in bad shape and promised to replace that section. That was last autumn. You can try another clearing house such as Angie’s List, and if that doesn’t work, talk with the bigger dealers, one by one. Q. We are desperate for advice about the possible mold in our bedroom walls. We can smell the mold, but we do not know where exactly it is and what exactly is the cause. We have been thinking ice dams, gutters, the roof, but we are not sure.

Who can we contact to diagnose the situation and propose a solution that will not bankrupt us. Thank you so much for any advice you can give us. A. Here’s another example of mold resulting from moisture but no water leaks. In fact, I think the mold is resulting from condensation of moisture in the house. Since humid air rises, the mold would be more likely to occur on the second floor on walls where the water vapor condensed. how to fix a leak in ac unitYou can wash walls with a solution of 1 part bleach and 3 parts water. air conditioning unit fan not workingMost household mold is black, some is white and rarely, any color. heat and ac combo unitIf the solution works, hold down the humidity by ventilating the upstairs to release excess water vapor, or by using central air.

Globe Handyman on Call Peter Hotton also appears in Sundaty Address-Real Estate. He is available 1-6 p.m. Tuesdays to answer questions on house repair. Get Today’s Headlines from the Globe in your inbox:There are times when we have noticed water around the base of the airThe bet is that most of us do not bother about this typeWe consider it quite normal. But it is not so. conditioners should not leak water. If they do, it means that there is a block in the drain pipe or there is a permanent clog that has stoppedReasons for water leakage 1. The drain line needs cleaning: When your periodic cleaning takes place, the drain pipes may be left clogged a little. Over a period of time, this clog becomes bigger and bigger and finally results in a complete drain pipe block. Ensure that this does notThe remedy is to use the pills available for dissolving particulateThese pills are usually put in the pan under the frame. You could also use a 50/50 water bleach solution to prevent dust and

2. Air conditioner tubes may be leaking: Air conditioners have tubes that tend to leak. The water puddle you find under or around the air conditioner may be due to a simple leakage inIf you find a tube leakage, replace the leaking tube with another one. 3. The condensate pump may not be working properly: To detect any error in the pump, you need to pour water into the pump and check if it begins working. If the condensate pump does not start up, there could be a block in the electrical power or the pump is noIt is better to call over an electrician than meddle with the electrical connections. 4. Improper installation: Incorrect installation can also cause water leakage or accumulation around your air conditioner.You need to ensure that while installing, your technician places the window unit in such a way that the rear side of the unit is slightly lower than the front. This ensures proper water drainage, which in turn results in no leakage. 5. Ice formation: Water that is de-humidified can

crystallize into ice if your air conditioner ran into a problem. check for ice formation by removing the front grille, but only when the air conditioner is running. If you see ice present on the cooling coils, the water leakage could be from this ice. You will need to call the technician to clean up your machine.6. Water pool around the air conditioner in the morning: Usually, this occurs when you are nearing the end of the coolingIt is seen that when the temperature outside drops below 60°F during the night, the cooling coil within the air conditioner may iceSelecting the fan mode alternatively can help in preventing this type of leakage. Sealing the tubes can be done by reinsulation of the air conditioner. You could try to fix this problem by cutting the line near the drain pan and blowing it to remove clogged matter. For blowing, you will needA water hose will also suffice. You could also try connecting the vacuum cleaner to the outlet of the drain line.