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mcp6453[_2_] mcp6453[_2_] is offline
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Default Heat Pump Thermostat Problem

Back in November, my HVAC guy replaced my thermostat on my heat pump with a
Honeywell TH8320. He did it at the same time that he corrected a wiring problem
near the air handler underneath the house. A terminal overheated and melted a
wire. The thermostat wiring was not affected. The heat has been working fine.

Today it got warm enough that we turned on the air conditioning. After a few
minutes, we noticed that it had gotten noticeably warmer in the house. The vents
were blowing very warm air. The heat strips may have been on.

My natural assumption is that the new thermostat is wiring wrong. Here is the
way it is wired:

RC - Red (cooling power)
R - no connection (heating power)
O/B - Orange (changeover valve)
Y - Yellow (compressor)
G - Green (fan)
C - Blue (common)
E - White (emergency heat relay)
AUX - White (aux heat relay)

E and AUX are jumpered together.

The manual says that R and RC should be jumpered together UNLESS the system is a
two-transformer system. My system has only one transformer.

Here are my questions, with what little I know:

1. Should there be a jumper between R and RC?
2. If there should be a jumper, how is heat working with a wire going to RC?

While I was troubleshooting, my HVAC guy called me back. He's in bed with the
flu. Just my luck.

I'll post a picture to the present wiring in a few moments. You guys have helped
me tremendously before. Thanks!