[vegeta535]

Recently my t-stat wouldn't respond to anything but still showed a display. I replaced it with a new honeywell T-stat and everything worked for serveral days then it compelety died. I wouldn't display anything. I checked voltage was getting 24v on red to the stat. Batteries are new and good. What could be killing the t-stats?

[PellMell]

In no particular order,

1. The thermostat may be defective.
2. The +24 line may be intermittent. Check to make sure the screw is tight and the wire if firmly in the connector.
3. The T-stat wire is solid and could be broken inside the insulation from flexing.
4. About the only thing that will permanently damage the T-stat is excessive voltage on the red wire. This problem could be caused by a fault in the AC/HP.

[KISS]

I'm also thinking static electricity especially if the floor is carpeted or you wear clothes that may generate it.

Make sure you touch the wall first before operating the thermostat.

A fix that works a lot of times when batteries are involved is to cut power at the breaker. Remove the batteries. Short the battery terminals together for 30 sec.

Re-install and turn on.

Some stats have reset buttons that must be depressed when batteries are installed.

Loose and intermittant contacts can cause both destructive and non-destructive failures. The above may fix it.

[vegeta535]

Ty for the suggestions but I tried all those things and have hardwood floors. The new one is comepletely dead . Could a broken or damaged wire to the stat from the unit be causing the burn ups?

[KISS]

Yes. It could be an loose wire.

[wmproop]

(quote) I wouldn't display anything. I checked voltage was getting 24v on red to the stat.

You said you checked the red wire and was getting 24 V ,so what wire would be broke to keep it from getting power?