Cold Weather Tips for Well Owners
The Pressure Switch
Problem
The temperature has dropped below 32°F for a few hours and now the pump won't turn on.
Because there is always a small amount of water in the 1/4" pipe connection to the pressure switch, it's extremely vulnerable to freezing. As the ice forms it expands, forcing open the contacts and keeping the pump from turning on.
Solution
If your switch is already frozen, you can most likely get your pump working again by using a heat source such as a hairdryer and keeping it directly on the little 1/4" pipe (nipple) connecting to the pressure switch. Depending on how solidly it's frozen this may take several minutes.
To prevent freezing, you can either wrap the 1/4" pipe with insulating material or if there is a heat source available, simply keeping the temperature of your pump house above 38°F should be enough to keep everything thawed.
The Pressure Tank
Problem
The temperature has dropped below 32°F and you notice you have little to no water pressure. The pump seems to be coming on but the pressure in the tank isn't going up.
Solution
First of all, turn the breaker for your pump off (or unplug it if it's connected to a wall socket). The reason for this is that most likely the line coming into your pressure tank has frozen. For every second the pump is running, a large amount of back pressure is being created which can be damaging to the seals. Also a great deal of heat is being created around the pump since it is running but no water is moving to cool it off. Eventually this heat can become great enough to melt plastic pipes and warp the impellers in your pump.
After the pump has been shut off, you'll need to bring in some kind of heat source. If your pipes are galvanized steel, you can use a torch to try and melt the ice. If they're PVC then you're going to have to apply an indirect heat source like a hairdryer or a floor heater. Depending on how solidly the pipes are frozen, this could take several minutes to several hours. Once you think the pipes are sufficiently thawed you can turn the power back on to the pump. Because ice expands as it freezes, you might notice a few leaks where there are any elbows or other plumbing connections. These pieces may need to be replaced as they may have cracked. If all goes well, you should see pressure building in the tank and very soon you should have water again.
To prevent freezing, it is advisable to wrap your pipes in an insulating material. If your pump house is enclosed you can also try using an ambient heat source like a ceramic heater combined with a thermosensor which can shut it off when the temperature is above freezing. The ThermoCube is a popular choice for this kind of job. It's basically a thermostatically controlled outlet extender. When the temperature drops below 35°F it activates, turning on your heating device. When the temperature again raises above 40°F it shuts off. This simple device is available at most any hardware store.
Jet Pumps
Problem
The temperature has dropped below 32°F and you've lost water. You also notice that the pump seems to be trying to come on. The motor feels very hot and it's making a humming sound. You may also notice some cracking around the pump, toward the front.
Jet pumps are extremely vulnerable to freezing, especially since they require water to be in them at all times to keep a prime. If that water isn't moving and the surrounding temperature is below freezing, the pump end will most likely freeze. As the frozen water expands, enough force is created that even the tough cast iron body of the pump cannot withstand it and cracks and breaks appear in the body.
Solution
Unfortunately at this point there's not much you can do other than replace the pump. If you've caught it early enough, turning the pump off and letting the inside of it thaw may be enough to get things working again.
The best way to prevent a situation like this is to maintain an above-freezing temperature inside your pump house. This can be accomplished by the use of a ceramic heater combined with a thermostatically controlled switch such as a ThermoCube.