ACHRNEWS

The case of the heat pump freeze-up

April 26, 2000
Welcome back to “TECH TALK,” The News’ feature to encourage professional hvacr technicians to talk to each other about “live, from the field” applications, problems, and solutions.

This week’s problem comes from another homeowner, who again states, “I need help!” (You guys get to hear this a lot, don’t you.)

“We had a new heat pump installed in July 1997, and have had nothing but problems with it.

“Now [February 2000] it has begun to freeze up all of the time, even if we only leave it running for a short period of time. It’s not like it’s -20°F outside; in fact, it’s been in the 30s each time it freezes up.

“We have to turn the heat off, let it thaw, and then turn it back on. Any suggestions? I’m pulling my hair out!

“The blower is still blowing out air,” the homeowner relates, “but the unit outside is still making a humming noise….kinda like it’s running, but the fan is not blowing. It goes into that every now and then. Is it OK to leave it running when that’s happening?”

In essence, this residential split system was freezing up in the heating mode during moderate conditions — and the customer has to turn the heat off to help thaw the unit.

So tech heads, what gives here? Does this sound to you like it may have something to do with the refrigerant charge or defrost controls?

Please send your replies to Troubleshooting/Maintenance Editor Barb Checket-Hanks no later than May 8, by e-mail (checket-hanksb@bnp.com) or fax (248-244-6444). Answers will be published in an upcoming issue of The News.