Simple remedy for condensation
The first thing to do, says the plumbing of Littleton experts, is to turn the toilet supply valve off, flush and dry the toilet tank with a towel and hair dryer. When a cold surface contacts warmer moist air, moisture will condense on the colder surface. Such condensation causes sweating toilet tanks, and over time this moisture can rot the floor. Insulation kits are available to prevent this. They require that the tank be flushed and dry.
Installing the anti-sweat valve
An anti-sweat valve mixes a small amount of hot water with the old water flowing into the tank, raising the tank temperature just enough to keep moisture from condensing on the outside of the toilet tank. Some valves have a manual control to vary the mixture for different humidity levels.
Shut off the water to the house. Using the manufacturer’s instructions as a guide, cut the water lines to the bathroom. Cut pipe to fit your installation. Dry-fit the pipe before soldering the joints, making sure everything fits perfectly. Keeping all the parts at the correct angles, pre-solder any joints that will lie too close to the joists when installed and might pose a fire hazard if soldered in place.