DIYbanter - View Single Post - AC Circuit Problem (voltage

Fred McKenzie

In article . com,
wrote:

I have an AC circuit problem I need help with. At my mother's
boyfriend's house he has a furnace with air conditioner/heat pump
attached. When he bought the house natural gas prices were lower then
electricity and he had the heat pump disconnected but there still is a
flow shutoff valve attached to the air conditioner/heat pump that is
operated by a solenoid. The solenoid is normally energized but the
voltage suppied to it exceeds the normal recommended operating voltage
and gets very hot. The unit is an ALCO Controls, Coil Type DMG, 24
volts, 7 watts, 50 - 60 Hz. The computer in the furnace is supplying 26
to 28 volts.

Derek-

The solenoid appears to be functioning correctly, from what you've said.
Yes, it will be hot since it is burning up 7 watts of power.

The real problem is the apparently high line voltage. Unless you are
connected to a small town power source that is not connected to the
national grid, it is unlikely that your house is receiving 276 Volts AC.

What is more likely is that the neutral connection between the house and
the power company's transformer has come loose. The two 120 Volt AC
halves do not carry the same current, so voltage divides between them in
relation to the ratio of loads. If this is the case, you may measure
voltage at several places in the house, and find two values: 138 and 102,
for a total of 240 Volts.

The loose connection can be either at the power pole or at your power
meter. The power company should be able to isolate it, but the owner will
have to pay an electrician to fix a problem if it is on the house side of
the power meter.

Fred