In the summer, when the vinyl wire insulation was warm and flexible, wire flexing would absorb the vibration. But in the winter, the vinyl insulation would get stiff and transmit the motion to the connector. The stress would concentrate at the point where the crimp met the receptacle. Repeated bending back and forth broke the connectors off. I then realized that if I needed to replace another connector, I should replace the wire with one long enough to include a loop to absorb the motion.
All heat pumps, including this one, contain a crossover valve. This switches the flow of refrigerant so that the inside coil cools in summer and heats in winter. Such valves are opened (for cooling) by an external solenoid and closed (when heating) by an internal spring. However, in the winter a heat pump alternately runs heating cycles (to heat the house) and cooling cycles (to heat the outside coil to melt off the rime ice which forms on it).
This unit had the flaw that the spring action was so weak and the piston so sluggish that in cold weather it could not restore to house heating after a cycle of ice melting. The colder it was, the more often it would stick. Usually, when I felt cold air blowing from the ducts for an excessive time, I could reset it by cycling the thermostat. But the problem became worse and the crossover valve had to be changed. Lacking an HVAC license, I had to pay for this one: $500.
All of this was hard on the compressor, so four years later (also on a cold winter day) it failed. Its motor ran fine, but the valves weren't working right. Trane had given up on this unit by then, so I bought another brand.
This entry was submitted by Larry Marks and edited by Rob Spiegel.
Tell us your experiences with Monkey-designed products. Send stories to Rob Spiegel for Made by Monkeys.
My broken wire was straight from the control wiring to the control board. It was just long enough to reach the board. With the break, the technician added a pig-tail to make the wire long enough.
Poorly crimped wires can certainly cause a whole lot of failures, mostly at the wrong times, like in winter, for heat pumps. The shuttle valves fail because they are of a quality not quite good enough for the job. In many circles that is called "value engineering."
One alternative choice would be to have manually operated valves to go from cooling to heating. Thgat would be much less convenient but it would be far more reliable. Of course, a large portion of our population would be unable to understand how to make the change over.
Contactors, as opposed to relays, most often have contacts that are double makeand hence double break. This gives twice the open contact gap for no extra cost, and in addition, the contacts are usually heavier material to better handle the higher load current with les heating. Also, contactors do not use flexing wire in the current path.
Today it is never safe to assume that an item needs replacement just because the srvice technician who makes the call does not know how to make the item work.
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