Thursday, December 08, 2005

Heat Pumps

In my career field here in Middle Georgia we use heating systems called Heat pumps which for the uninitiated is using a central air unit to also be the source of heat..........got a call gotta go take care of it first. be home this evening to finish this.

Well it's been two days and I forgot what I was going to tell you. Oh yeah.

The way that it's done is the refrigerant temperature is made lower than the surrounding air allowing it to be heated up and the heat transported into your house or business.

One of the issues that had to be dealt with was that frost will build up on the condensor coil outside. To combat this a defrost system was added to periodically eliminate the frost. How most of them operate is every thirty to ninety minutes a logic circuit will test for temperature and when it senses 18 to 26 degrees on the coil it will engage the defrost cycle. Turning off the condensor fan changing the reversing valve to cool and turning on the auxiliary heating elements in the air handler(inside the house). This makes a great whooshing sound much like an old time steam freight train starting up. The compressor now no longer masked by the sound of the fan will grow louder as it heats up the coil until the defrost control times out or the sensor indicates that the coil is warm enough at which time the control board will send the unit back into normal operation attended of course by the loud whoosh but now; if there was a bit of frost built up, by a large ejection of steam and vapor out of the top of the outdoor unit. Which brings us to the crux of this article.

Every year we receive a number of panic calls from people who have never seen a heat pump go in or come out of defrost who are convinced that there unit just BLEW UP!

Mirth is my life.