Originally Posted By: pdacey This post was automatically imported from our archived forum.
I performed an inspection for a buyer about 2 weeks ago. One of my comments in the report was that the AC condenser was emitting a humming noise when it was idle.
The seller has just commented that they had something called a Termidostat (don't know if spelling is correct) installed on the AC which they explained is a variable speed fan than runs when the AC is off to keep the humidity level in the house down. Now if that is the case, wouldn't you hear the noise from this fan running inside the house? What I heard was outside at the condenser and coming from the area of all of the electrical connections and the capacitor.
I've never heard of a Termidostat and how could it remove moisture from the air if the AC is not running?
Originally Posted By: ecrofutt This post was automatically imported from our archived forum.
Two notes:
You're more likely to get a response if you are more specific in your subject line: Like - Termidistat - What is it?? Just like the guys asking for ride alongs would probably get more responses if they put their location in the subject line.
Originally Posted By: rwills This post was automatically imported from our archived forum.
Patrick, Could it possibly be the compressor warming electrical circuit? This will hum if the unit has been off for long periods to warm the compressor. Was the unit being recently operated when you arrived or had it been off for quite a while?
Originally Posted By: jpeck This post was automatically imported from our archived forum.
A Thermidistat is the thermostat / humidistat control for a variable speed fan Carrier a/c air handler unit.
The Thermidistat does the function of both.
The thermostat function operates the same as a regular thermostat.
The humidistat function runs the fan at lower speeds (because it is a variable speed fan) to keep the a/c running for de-humidification purposes without excessive cooling taking place.
This is accomplished by the a/c being turned on by the thermostat, the a/c satisfying the thermostat temperature setting, yet the air still having more humidity than the setting the humidistat portion is set to, so the fan speed drops to a slower fan speed and keeps running. This keeps removing moisture from the air, yet the fan speed is not high enough to provide additional cooling air to the living spaces (not to noticeably keep cooling it). After a programmed in number of minutes of continued operation, the humidistat section shuts the air handler off, having removed some additional humidity from the air.
This occurs after each time the a/c comes on, slowly satisfying the humidistat by getting the humidity down to the desired setting.
The main purpose of an a/c is to de-humidify the air, and this does just that, cooling as much as necessary, then continuing to de-humidify for a while longer.