Recently had an issue with our upstairs heat pump. It’s a Goodman unit that’s almost 3 years old. The “defrost board” had to be replaced. Since then the heat will come on and run for less than a minute then shut off. The temperature stays at 70 degrees upstairs. This occurs when it’s in the 50s outside so not really cold. Seems something is too sensitive-thermostat? Don’t notice this happening when it’s 40s or colder….
HVAC Experts? Question
- Thread starter PontiacHO
- Start date
That's a tough one. I was going to suggest a setting in the thermostat, but the way you describe it my suggestion would be backwards?
Might be something on the defrost board, since the issue began when it was replaced.
Might be something on the defrost board, since the issue began when it was replaced.
It really could be the thermostat. Is it a Honeywell?
I put in a new furnace with HW thermostat recently. Because of their insistance on that stupid (IMO) Cycles per Hour, I've seen the t-stat initiate a call for heat that only lasted about a minute (ended before the fan even engaged). Like your situation it occurred on a warmer, sunny day when there didn't seem to be any reason for the furnace to cycle.
I put in a new furnace with HW thermostat recently. Because of their insistance on that stupid (IMO) Cycles per Hour, I've seen the t-stat initiate a call for heat that only lasted about a minute (ended before the fan even engaged). Like your situation it occurred on a warmer, sunny day when there didn't seem to be any reason for the furnace to cycle.
Yes. It is a Honeywell Pro T6. Has to be the thermostat causing it. You can hear click for on and in a minute click for off. Did you figure out a work around. It’s annoying not to mention hard on the compressor.
Room thermostat has nothing to do with defrost comes from the temp sensor going into the board. 40° to 50° peak defrost timing.
See how to adjust the Cycles per Hour setting on pages 8 & 9 of the Honeywell Pro T6 Installation Manual linked below. As Touring5 stated, if the number of heating cycles are set too high, the thermostat will call for heat momentarily to meet that programmed frequency per hour, even if it is not needed to maintain the indoor temperature setting. If you can call up ISU# 370 (1st stage HP) and ISU# 371 (2nd Stage HP), you can try resetting the heating cycles rate down a bit (i.e., one or two cycles lower than the current setting) to reduce unnecessary short cycling.
Honeywell Pro T6 Installation Manual
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T6s are junk. I replaced 2 brand new ones last year because they were acting stupid. Get an Ecobee 3 lite or Pro1 T855 and throw that T6 in the trash.
Nick1994
$100 site donor 2024
What happens if you turn the thermostat up like 10 degrees?
Thanks. That’s what I need.
