Author Topic: Honeywell TH8320R  (Read 1699 times)

Offline David DeBord

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Honeywell TH8320R
« on: February 21, 2018, 02:42:32 PM »

I recently Installed a Honeywell TH8320R T-stat, with an Outdoor Sensor, for a Goodman H.P., and Miller Condensing gas furnace.

My Customer had a "Brown Out" where the Utility Power Dropped, & then came back to Normal several times, over a period of about 3- 5 minutes. This has happened before in my Customers area, although that was several years ago.

After that "Brown Out", she told me that infrequently, when the temperature changed over a five day period that "Wait" would show on the T-stat, but instead of the "Wait" period lasting 5 minutes as programed, that it lasted for time periods lasting from 30 minutes to 45 minutes.

My Customer then Called me.

Physically, I have not as yet found anything wrong with this T-stat. I did not find the T-stat going in to a "Wait" period, other than the programed 5 minute "Wait" period, & I do Trust my Customer, for I've been doing work for her for more than 20 years.

As in the operation of a Computer, .... Could this "Brown Out", have altered the programing, &  would Ya'll recommend my shuting down the power, pulling the batteries, waiting a few minutes, re-installing the batteries, & reprogramming the T-stat?

Offline Admin

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Re: Honeywell TH8320R
« Reply #1 on: February 21, 2018, 03:42:26 PM »
This sounds like the 5 min compressor protection.  I assume the client is using the heat pump in heating mode.  Could there be a lose wire that is causing it to lose it's 24V and interrupt the 5 min compressor delay then cause the delay to restart?  Is there a condensate pump with a safety wired in series with the heating wire?  I have seen a problematic condensate pump safety cause the problem you're describing.  Maybe there's another control somewhere interrupting the 24V supply.

Otherwise I would disable the 5 min compressor protection mode and see if the client has the same problem repeat itself (Option #324 in the installer menu).  You could try to reset the thermostat to factory settings in case something was affected by the brown out.  There's a factory reset option in the installer menu.  Is the heat pump and/or furnace transformer supplying 24V?

You could remove the thermostat batteries and turn off the furnace power and heat pump power and let the thermostat sit for 5 - 10 min. 

You could also use the Data Log option and load the data onto an SD Card and use a PC to narrow down the problem.  There's an Alert Log as well.

It might just be quicker to buy a new thermostat and sensor and replace both.  If the problem never returns just return the old parts under warranty as being defective.

Good luck, I feel your pain.  I do not think it's a coincidence the problem started after the brown out.  I like to know what's going on too but replacing the thermostat and sensor may save you a lot of time and aggravation.