Hello,

Son is not in area, so couldn't look myself.

Has a Honeywell Thermostat (about 8 years old) that controls his A/C
and heat (forced hot air).

A/C didn't work so called in a HVAC man who found that the inside
of the thermostat had "lots of wires fried and shot to oblivion".

This seemed to happen right after he put in new new batteries in the
Thermostat. Does this once a year, every year.

No expert, but was wondering.

What could possibly "fry" the inside of a Thermostat ?
Can't see how putting in new batteries would.

Some voltage spike from the A/C ?

Eight years a reasonable life for one of these things ?

New Thermostat, and all seems happy now.

Any thoughts would be appreciated.

Bob

On Wednesday, September 20, 2017 at 11:18:10 AM UTC-4, Bob wrote:
Hello,

Son is not in area, so couldn't look myself.

Has a Honeywell Thermostat (about 8 years old) that controls his A/C
and heat (forced hot air).

A/C didn't work so called in a HVAC man who found that the inside
of the thermostat had "lots of wires fried and shot to oblivion".

This seemed to happen right after he put in new new batteries in the
Thermostat. Does this once a year, every year.

No expert, but was wondering.

What could possibly "fry" the inside of a Thermostat ?
Can't see how putting in new batteries would.

Some voltage spike from the A/C ?

Eight years a reasonable life for one of these things ?

New Thermostat, and all seems happy now.

Any thoughts would be appreciated.

Bob

IDK, it's strange. To start with, the thermostats I've had for
decades now don't have "many wires" in them. They are essentially
a circuit board. There might be a couple of wires to the batteries.
The wires in the thermostat area are generally the ones that run
to the thermostat from the system and it sounds like it's not those
that he was talking about. Some failure mode of some component on
the thermostat could probably burn up wires on the thermostat.
A lightning surge could certainly do it, but a surge doing that kind
of damage at the thermostat and not frying anything else seems
rather unlikely. Most vulnerable devices are those that have direct
connection to outside wiring, eg cable set top box, modem, phone, ectc.

Bob wrote:
Hello,

Son is not in area, so couldn't look myself.

Has a Honeywell Thermostat (about 8 years old) that controls his A/C
and heat (forced hot air).

A/C didn't work so called in a HVAC man who found that the inside
of the thermostat had "lots of wires fried and shot to oblivion".

This seemed to happen right after he put in new new batteries in the
Thermostat. Does this once a year, every year.

No expert, but was wondering.

What could possibly "fry" the inside of a Thermostat ?
Can't see how putting in new batteries would.

Some voltage spike from the A/C ?

Eight years a reasonable life for one of these things ?

New Thermostat, and all seems happy now.

Any thoughts would be appreciated.

Bob

Did he see the damaged wires, or is he simply repeating the comments
from the HVAC guy? It is hard to imagine such damage based upon what
you described. Unfortunately there are people in trades that pad the
problem when called in for a repair.

On Wednesday, September 20, 2017 at 12:26:48 PM UTC-4, Ken wrote:
Bob wrote:
Hello,

Son is not in area, so couldn't look myself.

Has a Honeywell Thermostat (about 8 years old) that controls his A/C
and heat (forced hot air).

A/C didn't work so called in a HVAC man who found that the inside
of the thermostat had "lots of wires fried and shot to oblivion".

This seemed to happen right after he put in new new batteries in the
Thermostat. Does this once a year, every year.

No expert, but was wondering.

What could possibly "fry" the inside of a Thermostat ?
Can't see how putting in new batteries would.

Some voltage spike from the A/C ?

Eight years a reasonable life for one of these things ?

New Thermostat, and all seems happy now.

Any thoughts would be appreciated.

Bob

Did he see the damaged wires, or is he simply repeating the comments
from the HVAC guy? It is hard to imagine such damage based upon what
you described. Unfortunately there are people in trades that pad the
problem when called in for a repair.

+1

I was thinking that too after hitting send. Even if there was some
damage, one guys "a bunch of burned up wires" could be very different
from the next. You would think the guy would show it to the customer.
For all we know, if he didn't see it, it could have been a loose wire
and nothing wrong with the thermostat.

In article , says...

Bob wrote:
Hello,

Son is not in area, so couldn't look myself.

Has a Honeywell Thermostat (about 8 years old) that controls his A/C
and heat (forced hot air).

A/C didn't work so called in a HVAC man who found that the inside
of the thermostat had "lots of wires fried and shot to oblivion".

This seemed to happen right after he put in new new batteries in the
Thermostat. Does this once a year, every year.

No expert, but was wondering.

What could possibly "fry" the inside of a Thermostat ?
Can't see how putting in new batteries would.

Some voltage spike from the A/C ?

Eight years a reasonable life for one of these things ?

New Thermostat, and all seems happy now.

Any thoughts would be appreciated.

Bob

Did he see the damaged wires, or is he simply repeating the comments
from the HVAC guy? It is hard to imagine such damage based upon what
you described. Unfortunately there are people in trades that pad the
problem when called in for a repair.

Would be nice to see a pix of the box. Hard to believe it could really
be fried from just a couple of batteries. I could see if he put the
batteries in backwards as messing it up, but not totally fried.

The wires comming from the AC are usually low voltage ( about 24) low
power and only go to a small part of the control unit.

Maybe the repairman was just making small talk while telling him he
needed a new one.

On 9/20/2017 2:17 PM, Ralph Mowery wrote:
In article , says...

Bob wrote:
Hello,

Son is not in area, so couldn't look myself.

Has a Honeywell Thermostat (about 8 years old) that controls his A/C
and heat (forced hot air).

A/C didn't work so called in a HVAC man who found that the inside
of the thermostat had "lots of wires fried and shot to oblivion".

This seemed to happen right after he put in new new batteries in the
Thermostat. Does this once a year, every year.

No expert, but was wondering.

What could possibly "fry" the inside of a Thermostat ?
Can't see how putting in new batteries would.

Some voltage spike from the A/C ?

Eight years a reasonable life for one of these things ?

New Thermostat, and all seems happy now.

Any thoughts would be appreciated.

Bob

Did he see the damaged wires, or is he simply repeating the comments
from the HVAC guy? It is hard to imagine such damage based upon what
you described. Unfortunately there are people in trades that pad the
problem when called in for a repair.

Would be nice to see a pix of the box. Hard to believe it could really
be fried from just a couple of batteries. I could see if he put the
batteries in backwards as messing it up, but not totally fried.

The wires comming from the AC are usually low voltage ( about 24) low
power and only go to a small part of the control unit.

Maybe the repairman was just making small talk while telling him he
needed a new one.

Most 24 volt transformers don't have that much energy to fry wires.
But, maybe if the battery was put in backwards it could fry parts, wires
if the design didn't include a protection diode.