I've had a problem with A/C at my parent's house, currently
unoccupied. We've had some temperatures over 95F and some power
outages from storms. The thermostat has a few-minute delay.

The thermostat was set on 78F. When I went over there late Friday
afternoon, the compressor was not running and it was 89F inside. I
cut off the curciut breakers and turned them back on to see if it
would reset it. After a few minutes, nothing had happened.

I checked the pan under the air handler and it was dry.

Then I saw that the batteries in the thermostat were low. I cut off
the unit at the thermostat and replaced the batteries. I turned it
back on, and in a few minutes it came on and started cooling.

This made me suspect the thermostat, but read on...

I went back Saturday afternoon and again the compressor was not
running and it was 90F inside. I cut the circuit breakers off and
back on and switched the thermostat to off and then back to cool. In
a few minutes it came on.

I went back Sunday and again today (Monday) and it is still working.

Any ideas of what the problem is/was? (At first I suspected the
thermostat, but now I don't know.)

Jan Philips wrote:
I've had a problem with A/C at my parent's house, currently
unoccupied. We've had some temperatures over 95F and some power
outages from storms. The thermostat has a few-minute delay.

The thermostat was set on 78F. When I went over there late Friday
afternoon, the compressor was not running and it was 89F inside. I
cut off the curciut breakers and turned them back on to see if it
would reset it. After a few minutes, nothing had happened.

I checked the pan under the air handler and it was dry.

Then I saw that the batteries in the thermostat were low. I cut off
the unit at the thermostat and replaced the batteries. I turned it
back on, and in a few minutes it came on and started cooling.

This made me suspect the thermostat, but read on...

I went back Saturday afternoon and again the compressor was not
running and it was 90F inside. I cut the circuit breakers off and
back on and switched the thermostat to off and then back to cool. In
a few minutes it came on.

I went back Sunday and again today (Monday) and it is still working.

Any ideas of what the problem is/was? (At first I suspected the
thermostat, but now I don't know.)

Hi,
Is it programmable 'stat? Can you tell the model?
If program is still as programmed, did you check?
If not sure, you can reprogram it or set to default program setting.
If battery low was displayed from that time battery is good
another couple weeks B4 it really goes dead.

On Mon, 25 Aug 2014 22:05:56 -0600, Tony Hwang
wrote:

Is it programmable 'stat? Can you tell the model?

It is not programmable. I can't remember the brand or model, but I
think it is Honeywell or White. I can find out in a day or two.

If program is still as programmed, did you check?

N/A


If battery low was displayed from that time battery is good
another couple weeks B4 it really goes dead.

Well, one of the batteries was leaking, so I thought it was best to
replace them.

Jan Philips wrote:
On Mon, 25 Aug 2014 22:05:56 -0600, Tony Hwang
wrote:

Is it programmable 'stat? Can you tell the model?

It is not programmable. I can't remember the brand or model, but I
think it is Honeywell or White. I can find out in a day or two.

If program is still as programmed, did you check?

N/A


If battery low was displayed from that time battery is good
another couple weeks B4 it really goes dead.

Well, one of the batteries was leaking, so I thought it was best to
replace them.

Hi,
Of course. I use Lithium ones and mine is wired so that battery is on
stand-by mode. Some 'stats can draw power from 24V AC transformer. One
extra wire run to 'stat. If it is digital model, it could be going bad
working intermittent. Or can be even loose connections at either end
('stat and control board in the air handler) When it is hung up. just
try to tap 'stat gently and see if it starts working again.

On Mon, 25 Aug 2014 22:39:46 -0600, Tony Hwang
wrote:

Of course. I use Lithium ones and mine is wired so that battery is on
stand-by mode. Some 'stats can draw power from 24V AC transformer. One
extra wire run to 'stat. If it is digital model, it could be going bad
working intermittent. Or can be even loose connections at either end
('stat and control board in the air handler)

I just had the control board and motor in the air handler replaced
about 2 months ago.

On Tue, 26 Aug 2014 00:58:55 -0400, wrote:

Have you found the operating manual for the thermostat and looked at
what all the indicators mean.

I'll have to look up the model, but it is a simple one. When my
parents upgraded their A/C system, they first had a very sophisticated
programmable thermostat. But you had to go through a menu to do
everything - even on/off and up/down! They never could learn how to
use it, so we replaced it with a simple one.


If not, I would start by carefully cleaning the battery contacts. If
the batteries were leaking, it could have corroded a contact or two.

We cleaned one of the contacts, but didn't have what we needed to do
it properly.

Usually there are status indicators in the thermostat that say whether
it is calling for cool or not,

Yes, it was calling for cool (it is a heat pump).

On 8/25/14, 10:49 PM, Jan Philips wrote:
I've had a problem with A/C at my parent's house, currently
unoccupied. We've had some temperatures over 95F and some power
outages from storms. The thermostat has a few-minute delay.

The thermostat was set on 78F. When I went over there late Friday
afternoon, the compressor was not running and it was 89F inside. I
cut off the curciut breakers and turned them back on to see if it
would reset it. After a few minutes, nothing had happened.

I checked the pan under the air handler and it was dry.

Then I saw that the batteries in the thermostat were low. I cut off
the unit at the thermostat and replaced the batteries. I turned it
back on, and in a few minutes it came on and started cooling.

This made me suspect the thermostat, but read on...

I went back Saturday afternoon and again the compressor was not
running and it was 90F inside. I cut the circuit breakers off and
back on and switched the thermostat to off and then back to cool. In
a few minutes it came on.

I went back Sunday and again today (Monday) and it is still working.

Any ideas of what the problem is/was? (At first I suspected the
thermostat, but now I don't know.)

Was the blower running? If neither the blower nor the compressor was
on, I'd get a volt meter and see if there was 24 VAC on the cooling
terminal of the board that controls the heat pump. I believe that's
usually the yellow wire.

I once had voltage at the thermostat end but not the control board end.
The wire had broken about 4 feet from the control board. I located
the break by moving the cable at various points, starting at the control
board.

On 8/26/2014 12:16 AM, Jan Philips wrote:
If battery low was displayed from that time battery is good
another couple weeks B4 it really goes dead.

Well, one of the batteries was leaking, so I thought it was best to
replace them.

To isolate the problem, going to take some trial
and error, and some testing. The corroded contacts
inside the stat are good place to start. Do you want
a few ideas? I'm much less skilled with heat pumps,
but happy to share what I know.

Was the readout on the stat saying it was calling
for cooling?

--
..
Christopher A. Young
Learn about Jesus
www.lds.org
..

On 8/26/2014 2:49 AM, J Burns wrote:
Was the blower running? If neither the blower nor the compressor was
on, I'd get a volt meter and see if there was 24 VAC on the cooling
terminal of the board that controls the heat pump. I believe that's
usually the yellow wire.

I once had voltage at the thermostat end but not the control board end.
The wire had broken about 4 feet from the control board. I located
the break by moving the cable at various points, starting at the control
board.

I think you are on to something, here. Of course
may HVAC techs are not able to take VOM readings,
so it's good to be careful encouraging a Usenet
list reader to take readings.

Jan, are you skilled with a volt meter?

--
..
Christopher A. Young
Learn about Jesus
www.lds.org
..

"Jan Philips" wrote in message
...
On Mon, 25 Aug 2014 22:05:56 -0600, Tony Hwang
wrote:

Is it programmable 'stat? Can you tell the model?

It is not programmable. I can't remember the brand or model, but I
think it is Honeywell or White. I can find out in a day or two.

If program is still as programmed, did you check?

N/A


If battery low was displayed from that time battery is good
another couple weeks B4 it really goes dead.

Well, one of the batteries was leaking, so I thought it was best to
replace them.

Check to see if the leaking fluid has not dinged the hidden circuit.

On Tuesday, August 26, 2014 9:27:10 AM UTC-4, NotMe wrote:
"Jan Philips" wrote in message

...

On Mon, 25 Aug 2014 22:05:56 -0600, Tony Hwang

wrote:



Is it programmable 'stat? Can you tell the model?



It is not programmable. I can't remember the brand or model, but I

think it is Honeywell or White. I can find out in a day or two.



If program is still as programmed, did you check?



N/A





If battery low was displayed from that time battery is good

another couple weeks B4 it really goes dead.



Well, one of the batteries was leaking, so I thought it was best to

replace them.



Check to see if the leaking fluid has not dinged the hidden circuit.

If it was me, I'd figure out the two wires that need to be connected at
the thermostat to make the system cool. Probably red and yellow. Connect
with a jumper and see if the system works OK during observation. If it
does, then it's likely a bad thermostat, corrosion damage, etc. During
testing, the system should be off for about 10 mins before restarting.
Thermostats do that, by directly connecting wires, you would need to
make sure if you stop it, you allow that period before restarting.

trader_4 wrote:
On Tuesday, August 26, 2014 9:27:10 AM UTC-4, NotMe wrote:
"Jan Philips" wrote in message

...

On Mon, 25 Aug 2014 22:05:56 -0600, Tony Hwang

wrote:



Is it programmable 'stat? Can you tell the model?



It is not programmable. I can't remember the brand or model, but I

think it is Honeywell or White. I can find out in a day or two.



If program is still as programmed, did you check?



N/A





If battery low was displayed from that time battery is good

another couple weeks B4 it really goes dead.



Well, one of the batteries was leaking, so I thought it was best to

replace them.



Check to see if the leaking fluid has not dinged the hidden circuit.

If it was me, I'd figure out the two wires that need to be connected at
the thermostat to make the system cool. Probably red and yellow. Connect
with a jumper and see if the system works OK during observation. If it
does, then it's likely a bad thermostat, corrosion damage, etc. During
testing, the system should be off for about 10 mins before restarting.
Thermostats do that, by directly connecting wires, you would need to
make sure if you stop it, you allow that period before restarting.

Hi,
Yes. 'stat has built-in pause period to protect compressor for too many
cycles without resting(like safety lock out) Think this is unique
feature for heat pump controlling thermostat. Dumb 'stat won't have
this important feature, only tjhing it has will be an anticipator.

On 8/26/14, 12:51 PM, Tony Hwang wrote:


Hi,
Yes. 'stat has built-in pause period to protect compressor for too many
cycles without resting(like safety lock out) Think this is unique
feature for heat pump controlling thermostat. Dumb 'stat won't have
this important feature, only tjhing it has will be an anticipator.

My thermostat is for conventional heating with air conditioning. I
bought it to replace a mechanical thermostat. I was glad to read about
the delay in the specifications.

When the display says "cool," that's supposed to mean the cooling relay
is closed and there's 24 VAC on the terminal for the yellow wire. When
I went to run the AC for the first time this year, I turned the
thermostat from "off" to "cool." "Cool" flashed and the AC didn't come
on. Seven minutes later I realized it was the delay. Now I know what it
means when "cool" flashes.

I want to sue the manufacturer for my 7 minutes of anxiety! I hope he
has deep pockets!

On my Hunter thermostat, if I go directly from off to cool, there is a delay in starting the indoor air circulating fan and the outside compressor and cooling fan, I don't remember now how long. If I go from off to heat for a couple of seconds and then quickly go thru off to cool, the compressor and fan and indoor air circulating fan all start up immediately. I have been doing this for years, that's why I don't know how long the delay is when going directly to cool mode, but it hasn't seemed to have harmed anything.

It was working again until today. The thermostat is a basic Aprilaire
model.

I left it set on 74 and it was 77 when I got there - same as before,
but not so hot, so it must have been working until a few hours ago.

I went through the procedure that worked the other two times. This
time it did not work. The 'stat has an indicator that indicates that
it is calling for cooling. It was flashing "cooling" when I turned it
back on. Then after the minute or two delay, I heard the click that
is made when the compressor starts. But the compressor did not start.

We are renting out this house starting sometime in September, so I
need to make sure it is fixed, so I called my usual repairman.

Thanks for all of the helpful replies and ideas.

On 8/27/14, 2:19 PM, Jan Philips wrote:
It was working again until today. The thermostat is a basic Aprilaire
model.

I left it set on 74 and it was 77 when I got there - same as before,
but not so hot, so it must have been working until a few hours ago.

I went through the procedure that worked the other two times. This
time it did not work. The 'stat has an indicator that indicates that
it is calling for cooling. It was flashing "cooling" when I turned it
back on. Then after the minute or two delay, I heard the click that
is made when the compressor starts. But the compressor did not start.

We are renting out this house starting sometime in September, so I
need to make sure it is fixed, so I called my usual repairman.

Thanks for all of the helpful replies and ideas.

What about the blower that blows air across the evaporator indoors?
Does that come on?

If the contactor clicks but the compressor doesn't start, and it works
normally other times, that sounds like a bad contactor. I've read about
the opposite situation, where the contactor sticks and wrecks the
compressor. It happened to me, but I had the great luck to catch it
even before the blower turned off.

It seems to me there were 13 wires connected to my contactor. I had to
get a clipboard and draw a diagram to replace it.

On Wednesday, August 27, 2014 3:09:34 PM UTC-4, wrote:
On Wed, 27 Aug 2014 14:19:08 -0400, Jan Philips

wrote:



It was working again until today. The thermostat is a basic Aprilaire

model.



I left it set on 74 and it was 77 when I got there - same as before,

but not so hot, so it must have been working until a few hours ago.



I went through the procedure that worked the other two times. This

time it did not work. The 'stat has an indicator that indicates that

it is calling for cooling. It was flashing "cooling" when I turned it

back on. Then after the minute or two delay, I heard the click that

is made when the compressor starts. But the compressor did not start.



We are renting out this house starting sometime in September, so I

need to make sure it is fixed, so I called my usual repairman.



Thanks for all of the helpful replies and ideas.



Be aware there may be a time delay relay in the compressor control box

that prevents it from starting within 3-5 minutes after the call for

cooling on a restart.

Which could be a factor, especially since she said the thermostat was
*flashing* cooling. I think that's a sign it was enforcing it's delay
before restarting, meaning the thermostat thought the compressor had been
switched off within the last few minutes. As you point out, if the
compressor also has it's own protective delay, it could just be that the
delay at the compressor is longer than the delay of the thermostat.

The obvious questions is what happened after about 10 mins? If it
didn't start then, she can rule the delay out. Also the fact that the
temp was 77, while set to 74 suggests something isn't right.

On Wed, 27 Aug 2014 12:45:42 -0700 (PDT), trader_4
wrote:

Be aware there may be a time delay relay in the compressor control box

that prevents it from starting within 3-5 minutes after the call for

cooling on a restart.

Which could be a factor, especially since she said the thermostat was
*flashing* cooling. I think that's a sign it was enforcing it's delay
before restarting, meaning the thermostat thought the compressor had been
switched off within the last few minutes. As you point out, if the
compressor also has it's own protective delay, it could just be that the
delay at the compressor is longer than the delay of the thermostat.

The obvious questions is what happened after about 10 mins? If it
didn't start then, she can rule the delay out. Also the fact that the
temp was 77, while set to 74 suggests something isn't right.

My compressor has a 5 minute delay. About the temp settings. My T-stat
has a feature - something to do with ~ 2° or so. IOW, if set at 78°
cooling may not start until ~ 80°. Not an HVAC tech but that is my
understanding from the tech.

2¢ worth

--
"No matter how cynical you become, it's never enough to keep up."
-- Lily Tomlin

On 8/27/14, 3:09 PM, wrote:
On Wed, 27 Aug 2014 14:19:08 -0400, Jan Philips
wrote:

It was working again until today. The thermostat is a basic Aprilaire
model.

I left it set on 74 and it was 77 when I got there - same as before,
but not so hot, so it must have been working until a few hours ago.

I went through the procedure that worked the other two times. This
time it did not work. The 'stat has an indicator that indicates that
it is calling for cooling. It was flashing "cooling" when I turned it
back on. Then after the minute or two delay, I heard the click that
is made when the compressor starts. But the compressor did not start.

We are renting out this house starting sometime in September, so I
need to make sure it is fixed, so I called my usual repairman.

Thanks for all of the helpful replies and ideas.

Be aware there may be a time delay relay in the compressor control box
that prevents it from starting within 3-5 minutes after the call for
cooling on a restart.

Switching the thermostat off could account for the two-minute delay
while the display flashed. The subsequent click shows that the
compressor was getting the "start" signal.

My guess that it was a bad contactor was ignorant. It's usually the
capacitor. They can lose capacitance over the years. If the compressor
starts sometimes but not others, the capacitance is probably marginal.

Replacing a capacitor seems like a DIY job. Buy the right size and
switch off the breaker.

On Wednesday, August 27, 2014 5:52:23 PM UTC-4, J Burns wrote:
On 8/27/14, 3:09 PM, wrote:

On Wed, 27 Aug 2014 14:19:08 -0400, Jan Philips

wrote:



It was working again until today. The thermostat is a basic Aprilaire

model.



I left it set on 74 and it was 77 when I got there - same as before,

but not so hot, so it must have been working until a few hours ago.



I went through the procedure that worked the other two times. This

time it did not work. The 'stat has an indicator that indicates that

it is calling for cooling. It was flashing "cooling" when I turned it

back on. Then after the minute or two delay, I heard the click that

is made when the compressor starts. But the compressor did not start.



We are renting out this house starting sometime in September, so I

need to make sure it is fixed, so I called my usual repairman.



Thanks for all of the helpful replies and ideas.



Be aware there may be a time delay relay in the compressor control box

that prevents it from starting within 3-5 minutes after the call for

cooling on a restart.



Switching the thermostat off could account for the two-minute delay

while the display flashed. The subsequent click shows that the

compressor was getting the "start" signal.


My interpretation of that was the click was the *thermostat* relay
closing. She didn't say she was outside to hear the contactor.





My guess that it was a bad contactor was ignorant. It's usually the

capacitor. They can lose capacitance over the years. If the compressor

starts sometimes but not others, the capacitance is probably marginal.


I agree, that's a possibility.






Replacing a capacitor seems like a DIY job. Buy the right size and

switch off the breaker.

wrote in message ...
On my Hunter thermostat, if I go directly from off to cool, there is a delay in starting the indoor air circulating fan and the outside compressor and cooling fan, I don't remember now how long. If I go from off to heat for a couple of seconds and then quickly go thru off to cool, the compressor and fan and indoor air circulating fan all start up immediately. I have been doing this for years, that's why I don't know how long the delay is when going directly to cool mode, but it hasn't seemed to have harmed anything.

Try this -- about 2pm tomorrow, turn on the heat, then walk over and stand in front of the fan. Let us know how it works out.

On 08/26/2014 09:13 PM, wrote:
On my Hunter thermostat, if I go directly from off to cool, there is a delay in starting the indoor air circulating fan and the outside compressor and cooling fan, I don't remember now how long. If I go from off to heat for a couple of seconds and then quickly go thru off to cool, the compressor and fan and indoor air circulating fan all start up immediately. I have been doing this for years, that's why I don't know how long the delay is when going directly to cool mode, but it hasn't seemed to have harmed anything.

That delay is to protect your compressor from trying to start too soon
after it has been running (to allow the pressure to relieve so it isn't
trying to start against too large a load). Bypassing it can burn out a
compressor. Want to know how I know? I was told by the guy who
replaced my compressor.

On Fri, 12 Sep 2014 16:23:22 -0500, cjt wrote:

On 08/26/2014 09:13 PM, wrote:
On my Hunter thermostat, if I go directly from off to cool, there is a delay in starting the indoor air circulating fan and the outside compressor and cooling fan, I don't remember now how long. If I go from off to heat for a couple of seconds and then quickly go thru off to cool, the compressor and fan and indoor air circulating fan all start up immediately. I have been doing this for years, that's why I don't know how long the delay is when going directly to cool mode, but it hasn't seemed to have harmed anything.

That delay is to protect your compressor from trying to start too soon
after it has been running (to allow the pressure to relieve so it isn't
trying to start against too large a load). Bypassing it can burn out a
compressor. Want to know how I know? I was told by the guy who
replaced my compressor.
A/C compressors generally don't have an unloader valve like an air
compressor - and a short power interruption can even give some
compressors a problem. That's why bigger ones use magnetic starters

I only pull the immediate heat to cool trick when starting up the AC for the first time, I'm fully aware of the need to delay to allow the system pressure to equalize.

On Friday, September 12, 2014 6:08:15 PM UTC-4, wrote:
I only pull the immediate heat to cool trick when starting up the AC for the first time, I'm fully aware of the need to delay to allow the system pressure to equalize.

I guess the confusing part is that every thermostat I've owned, the only
time there was a delay in turning on the compressor is if the compressor
had shut off within the last 5 or 10 mins. Then it delays to give the
system pressure time to equalize. Otherwise, whether you go from off, or
heat or just lower the thermostat, the compressor starts up right away.

On 09/12/2014 06:43 PM, trader_4 wrote:

[snip]

I guess the confusing part is that every thermostat I've owned, the only
time there was a delay in turning on the compressor is if the compressor
had shut off within the last 5 or 10 mins. Then it delays to give the
system pressure time to equalize. Otherwise, whether you go from off, or
heat or just lower the thermostat, the compressor starts up right away.


I now have an electronic thermostat (which enforces the delay), powered
by the indoor unit. When I open the cover to clean the filter, the 24VAC
is cut off. No matter how long it takes to clean the filter, there will
be a A/C start up delay.

BTW, It's actually cooler outside right now (66F). I have the A/C off
and back door open. That's unusual for summer in east Texas (where
September IS a summer month).


--
103 days until the winter celebration (Thursday December 25, 2014
12:00:00 AM for 1 day).

Mark Lloyd
http://notstupid.us

"Most people are bothered by those passages of Scripture they do not
understand, but the passages that bother me are those I do understand."
-- Mark Twain

On 09/13/2014 10:15 AM, Mark Lloyd wrote:
On 09/12/2014 06:43 PM, trader_4 wrote:

[snip]

I guess the confusing part is that every thermostat I've owned, the only
time there was a delay in turning on the compressor is if the compressor
had shut off within the last 5 or 10 mins. Then it delays to give the
system pressure time to equalize. Otherwise, whether you go from off, or
heat or just lower the thermostat, the compressor starts up right away.


I now have an electronic thermostat (which enforces the delay), powered
by the indoor unit. When I open the cover to clean the filter, the 24VAC
is cut off. No matter how long it takes to clean the filter, there will
be a A/C start up delay.

BTW, It's actually cooler outside right now (66F). I have the A/C off
and back door open. That's unusual for summer in east Texas (where
September IS a summer month).


Great, isn't it? I'm in Austin, and I'm blowing outside air through the
house for the first time in months.

On 9/13/2014 12:53 PM, cjt wrote:
BTW, It's actually cooler outside right now (66F). I have the A/C off
and back door open. That's unusual for summer in east Texas (where
September IS a summer month).


Great, isn't it? I'm in Austin, and I'm blowing outside air through the
house for the first time in months.

Where is Al Gore when we need some
global warming?


..
Christopher A. Young
Learn about Jesus
www.lds.org
..

On 09/13/2014 01:28 PM, Stormin Mormon wrote:
On 9/13/2014 12:53 PM, cjt wrote:
BTW, It's actually cooler outside right now (66F). I have the A/C off
and back door open. That's unusual for summer in east Texas (where
September IS a summer month).


Great, isn't it? I'm in Austin, and I'm blowing outside air through the
house for the first time in months.

Where is Al Gore when we need some
global warming?


.
Christopher A. Young
Learn about Jesus
www.lds.org
.

There's plenty of global warming going on -- way too much, in fact.

On 09/13/2014 11:53 AM, cjt wrote:

Great, isn't it? I'm in Austin, and I'm blowing outside air through the
house for the first time in months.

Here, todays high temperature was 72.

--
103 days until the winter celebration (Thursday December 25, 2014
12:00:00 AM for 1 day).

Mark Lloyd
http://notstupid.us

"Most people are bothered by those passages of Scripture they do not
understand, but the passages that bother me are those I do understand."
-- Mark Twain