I supposedly had a two ton originally. Back when it was installed in the sixties or seventies central A/C was sort of new. They really didn't know how to size them then. I probably could have gotten away with a 1.5 ton. The experience with the previous unit was great. Never noticed short cycling, not even when I only had 4 inches of insulation in the attic. I lived under those conditions for 19 years. If I was too hot or cold all the time or if I heard the thing start up so frequently, I would have fixed that sooner. The house is only 720 sq ft. Two bedrooms, one bath. I had three estimates, none of them did a calculation. Yes, I have the fancy, variable speed ECM type. Thanks for letting me know your opinion about that motor going out so soon. BTW, it was the blower motor, inside that gave out. Three cycles an hour seems reasonable to me. I'm having about 4, which isn't terrible, but, it's the swings and the humidity. I had times yesterday when the system was only on for three minutes. This morning it was 70 degrees with 58% humidity inside. May as well have been 80 degrees. I had to run the A/C until it was 68 just to get a reasonable humidity level. If my 1 y/o thermostat does not have the options I need for adjusting the cycles, I'll replace it. Also, I think I can have the blower speed adjusted. I'm not dealing with this. May as well go Bluetooth while I'm at it. I'm pretty sure the shorter cycles are from an oversized unit. Thanks to all of you for your valuable advice.

On 09/19/2017 02:23 AM, wrote:
I supposedly had a two ton originally. Back when it was installed in the sixties or seventies central A/C was sort of new. They really didn't know how to size them then. I probably could have gotten away with a 1.5 ton. The experience with the previous unit was great. Never noticed short cycling, not even when I only had 4 inches of insulation in the attic. I lived under those conditions for 19 years. If I was too hot or cold all the time or if I heard the thing start up so frequently, I would have fixed that sooner. The house is only 720 sq ft. Two bedrooms, one bath. I had three estimates, none of them did a calculation. Yes, I have the fancy, variable speed ECM type. Thanks for letting me know your opinion about that motor going out so soon. BTW, it was the blower motor, inside that gave out. Three cycles an hour seems reasonable to me. I'm having about 4, which isn't terrible, but, it's the swings and the humidity. I had times yesterday when the system was only on for three minutes. This morning it was 70 degrees with 58% humidity inside. May as well have been 80 degrees. I had to run the A/C until it was 68 just to get a reasonable humidity level. If my 1 y/o thermostat does not have the options I need for adjusting the cycles, I'll replace it. Also, I think I can have the blower speed adjusted. I'm not dealing with this. May as well go Bluetooth while I'm at it. I'm pretty sure the shorter cycles are from an oversized unit. Thanks to all of you for your valuable advice.


Until you put an hour meter on the compressor to see how much it actually runs from noon to 6pm on a typical hot sunny day in your climate, you're just guessing at capacity required.

https://www.amazon.com/Generator-OZ-.../dp/B01KAYZ0GE

Until you put an hour meter on the compressor to see how much it actually runs from noon to 6pm on a typical hot sunny day in your climate, you're just guessing at capacity required.



plus I would have to say that a change from 2 tons to 2.5 tons is not a drastic change.

I would find it hard to believe that everything could be fine with 2 tons and not fine with 2.5 tons.

Maybe the numbers are wrong or maybe something else has changed.

So lets help the lady. Short of changing the AC unit, what could she do to reduce the humidity.

Maybe she should get a stand alone de-humidifier, then the AC would not have to run as much to de-humidify and it won't be so cold.

Any other ideas?


mark

On 9/19/2017 9:14 AM, wrote:



Until you put an hour meter on the compressor to see how much it actually runs from noon to 6pm on a typical hot sunny day in your climate, you're just guessing at capacity required.



plus I would have to say that a change from 2 tons to 2.5 tons is not a drastic change.

I would find it hard to believe that everything could be fine with 2 tons and not fine with 2.5 tons.

Maybe the numbers are wrong or maybe something else has changed.

So lets help the lady. Short of changing the AC unit, what could she do to reduce the humidity.

Maybe she should get a stand alone de-humidifier, then the AC would not have to run as much to de-humidify and it won't be so cold.

Any other ideas?


mark




Not hard to believe at all. Too much is too much. The AC contractor is
evidently not the best.

She could run a humidifier to remove moisture or she can run the heat if
it is not the same unit. Running heat is fairly common in places that
must have humidity control more than temperature control. I've seen it
done in a printing plant on cool damp days,

On Tuesday, September 19, 2017 at 9:14:55 AM UTC-4, wrote:


Until you put an hour meter on the compressor to see how much it actually runs from noon to 6pm on a typical hot sunny day in your climate, you're just guessing at capacity required.



plus I would have to say that a change from 2 tons to 2.5 tons is not a drastic change.

I would find it hard to believe that everything could be fine with 2 tons and not fine with 2.5 tons.

Maybe the numbers are wrong or maybe something else has changed.

So lets help the lady. Short of changing the AC unit, what could she do to reduce the humidity.

Maybe she should get a stand alone de-humidifier, then the AC would not have to run as much to de-humidify and it won't be so cold.

Any other ideas?


mark

I went back and read it again. I thought she has said they put in a 2.5
and it was short cycling so two weeks later they swapped it for a 2.
But re-reading it, I think you're right, she had a 2 ton, they
inexplicably upped it to 2.5 tons on a 750 sq ft house. Like Ed said,
I can see that creating a problem for two reasons. One is that at
2 tons, it was likely already too big, making it 20% bigger would
push it from marginal for controlling humidity to unacceptable.
The other is an old system was probably not running at full capacity.
When I had my system replaced, the new one, while of equal tons,
sure puts out a lot more cooling capacity. If I had it to do over
I'd have gone with a smaller unit too.

Another solution for these issues is the two stage units. I hadn't
thought about that from a humidity control standpoint when I was
replacing mine. But with a two stage you can have it sized bigger
so it can cool quickly when needed, but at the lower stage it can
run a lot longer for period when a lot of cooling isn't needed,
which would include to get the humidity down.

Uncle Monster posted for all of us...



On Sunday, September 17, 2017 at 11:24:31 AM UTC-5, wrote:
The question was about short cycling and how he could determine if his
was short cycling. Most of the posts here were about what temp is
comfortable and other useless information. I love the "wrong again" comment.
That was also helpful especially without a reason. I'm pretty sure my one
year old, 7K, 2.5 ton system is too big for my 720 square foot house. I had
the compressor and outdoor components exchanged for 2 ton components within
two weeks. The humidity is always in the upper fifties so it never feels
good. Another sign it's too big. Not surprisingly, the blower motor went out
at 12 months. I was lead to believe it was a manufacturing problem. Doesn't
take a genius to figure out a system turning off and on too often will also
cause wear and tear. Which leads us back to the original question....how
short is too short? It was hot here in Chicago yesterday, 85, and my newly
repaired A/C was on 7 minutes and off 7 minutes which I felt was too short.
Still at a loss given the info here. It was hot, am I wrong in thinking it
was too short? BTW, I realize insulation, window and door leaks must factor
in. Four years ago I had 8 inches of insulation blown the attic. My old two
ton A/C never had such short cycles, not even with 4 inches of insulation. I
understand on a hot day 10 minutes on and 10 minutes off or three cycles an
hour could be appropriate from info I got elsewhere. Anyone agree? Comments?
I can't replace worn out parts every year.


I've a question for you. The size of your AC unit seems to be too big for your small well insulated house, did the HVAC contractor do any calculations or take into account the energy saving measures you have taken? I've a few more questions I'm formulating since one of the things I did when I was still working was HVAC system installation and repair. ?(?)?

[8~{} Uncle AC Monster

BINGO BINGO BINGO +500

--
Tekkie

In article ,
says...

Uncle Monster posted for all of us...


I've a question for you. The size of your AC unit seems to be too big for your small well insulated house, did the HVAC contractor do any calculations or take into account the energy saving measures you have taken? I've a few more questions I'm formulating since one of the things I did when I was still working was HVAC system
installation and repair. ?(?)?

[8~{} Uncle AC Monster

BINGO BINGO BINGO +500


There is a program called Manual J that should be ran to calculate the
size of you AC. It usually runs about $ 100. The AC guys should do
that for you.

Here is a link to an online calculator. I have not tried it as my AC
seems to work fine.

http://www.loadcalc.net/

That 2 to 2 1/2 ton unit seems to be about 2 times as large as it should
be unless you have almost no insulation and are in a very hot area.

I only have a 2 1/2 ton heat pump in a house that is almost 3 times that
in the middle of NC.

On Tuesday, September 19, 2017 at 8:14:55 AM UTC-5, wrote:


Until you put an hour meter on the compressor to see how much it actually runs from noon to 6pm on a typical hot sunny day in your climate, you're just guessing at capacity required.



plus I would have to say that a change from 2 tons to 2.5 tons is not a drastic change.

I would find it hard to believe that everything could be fine with 2 tons and not fine with 2.5 tons.

Maybe the numbers are wrong or maybe something else has changed.

So lets help the lady. Short of changing the AC unit, what could she do to reduce the humidity.

Maybe she should get a stand alone de-humidifier, then the AC would not have to run as much to de-humidify and it won't be so cold.

Any other ideas?


mark



Mark, I supposedly had a two ton originally. It was probably built in the 60's, it was ancient when I moved in, in '94. No one really checked, it could have been 1.5 tons. The new A/C, furnace was replaced 07/16 with a 2.5 ton. I found out it was not a 2 ton and complained to the contractor in August and they came and swapped out the outside components only, to 2 tons. It is drastically different than the old unit, not sure why. When it starts blowing, you may as well be on the tarmac at O'hare, same thing. Then it shuts off right away, 3-7 minutes. Too powerful, too fast a cycle, no time to dehumidify. A/C and furnaces from 1960 vs 2017 are very different. Now you have two stage motors, variable ECMs, programmable thermostats with bluetooth connectivity and so much more. They both are supposedly 2 tons, couldn't be more different.
The old unit ran efficiently for 22 years, for me and only needed one or two thermocouples. After 22 years, I know how it sounded, how it felt and the duration of the cycle.
These newer models are powerful. I think I will take the advice given to change the cycles per hour, etc, if my thermostat will let me. It might be too dumb. I can get a fancy, new thermostat. Another option I didn't mentioned is getting the tech to change the blower speed. I think they have 3 or 4 settings. It may be on factory default. I had them do that when they swapped out the 2.5 ton components but I have since had to have the new blower motor replaced, so it's probably still on factory default. I came here initially because my short cycling system seems worse since the new blower motor was installed on 09/01.

On Tuesday, September 19, 2017 at 12:17:35 PM UTC-5, trader_4 wrote:
On Tuesday, September 19, 2017 at 9:14:55 AM UTC-4, wrote:


Until you put an hour meter on the compressor to see how much it actually runs from noon to 6pm on a typical hot sunny day in your climate, you're just guessing at capacity required.



plus I would have to say that a change from 2 tons to 2.5 tons is not a drastic change.

I would find it hard to believe that everything could be fine with 2 tons and not fine with 2.5 tons.

Maybe the numbers are wrong or maybe something else has changed.

So lets help the lady. Short of changing the AC unit, what could she do to reduce the humidity.

Maybe she should get a stand alone de-humidifier, then the AC would not have to run as much to de-humidify and it won't be so cold.

Any other ideas?


mark

I went back and read it again. I thought she has said they put in a 2.5
and it was short cycling so two weeks later they swapped it for a 2.
But re-reading it, I think you're right, she had a 2 ton, they
inexplicably upped it to 2.5 tons on a 750 sq ft house. Like Ed said,
I can see that creating a problem for two reasons. One is that at
2 tons, it was likely already too big, making it 20% bigger would
push it from marginal for controlling humidity to unacceptable.
The other is an old system was probably not running at full capacity.
When I had my system replaced, the new one, while of equal tons,
sure puts out a lot more cooling capacity. If I had it to do over
I'd have gone with a smaller unit too.

Another solution for these issues is the two stage units. I hadn't
thought about that from a humidity control standpoint when I was
replacing mine. But with a two stage you can have it sized bigger
so it can cool quickly when needed, but at the lower stage it can
run a lot longer for period when a lot of cooling isn't needed,
which would include to get the humidity down.

Trader_4, the two stage unit is a great idea for someone looking for a new system. I just spent 7K, so I can't do that. I wish I had. I think it would be great way to dehumidify. Also, it would be good for people that dislike the fluctuations. It's a drag when you get cold and wonder when the heat will kick on next. Less hot/cold spots. A smaller unit would be good too. Also,not an option for me now. I cannot stress enough to people who know my story. Don't let them sell you an AC that is too big and get a Manual J calculation.

On Wednesday, September 20, 2017 at 12:14:23 AM UTC-5, Patricia N. wrote:
On Tuesday, September 19, 2017 at 8:14:55 AM UTC-5, wrote:

Until you put an hour meter on the compressor to see how much it actually runs from noon to 6pm on a typical hot sunny day in your climate, you're just guessing at capacity required.

plus I would have to say that a change from 2 tons to 2.5 tons is not a drastic change.

I would find it hard to believe that everything could be fine with 2 tons and not fine with 2.5 tons.

Maybe the numbers are wrong or maybe something else has changed.

So lets help the lady. Short of changing the AC unit, what could she do to reduce the humidity.

Maybe she should get a stand alone de-humidifier, then the AC would not have to run as much to de-humidify and it won't be so cold.

Any other ideas?

mark

Mark, I supposedly had a two ton originally. It was probably built in the 60's, it was ancient when I moved in, in '94. No one really checked, it could have been 1.5 tons. The new A/C, furnace was replaced 07/16 with a 2.5 ton. I found out it was not a 2 ton and complained to the contractor in August and they came and swapped out the outside components only, to 2 tons. It is drastically different than the old unit, not sure why. When it starts blowing, you may as well be on the tarmac at O'hare, same thing. Then it shuts off right away, 3-7 minutes. Too powerful, too fast a cycle, no time to dehumidify. A/C and furnaces from 1960 vs 2017 are very different. Now you have two stage motors, variable ECMs, programmable thermostats with bluetooth connectivity and so much more. They both are supposedly 2 tons, couldn't be more different.
The old unit ran efficiently for 22 years, for me and only needed one or two thermocouples. After 22 years, I know how it sounded, how it felt and the duration of the cycle.
These newer models are powerful. I think I will take the advice given to change the cycles per hour, etc, if my thermostat will let me. It might be too dumb. I can get a fancy, new thermostat. Another option I didn't mentioned is getting the tech to change the blower speed. I think they have 3 or 4 settings. It may be on factory default. I had them do that when they swapped out the 2.5 ton components but I have since had to have the new blower motor replaced, so it's probably still on factory default. I came here initially because my short cycling system seems worse since the new blower motor was installed on 09/01.


The last system I installed 5-6 years ago had a variable speed ECM blower motor that ran at an almost imperceptible speed at all times to keep the air circulating in the house. When the compressor kicked in, the fan speed slowly increased to full then continued to run at full speed for a few minutes after compressor shutdown before slowing down to air circulation speed. If the cfm, blower speed, is too high, the evaporator coil(cold part) on the furnace/air handler, doesn't efficiently remove moisture from the air. The air handler and evaporator coil have cfm ratings and need to be matched. I hope you can find an HVAC contractor who knows what he/she/it is doing. ヽ(ヅ)ノ

[8~{} Uncle AC Monster

.. It is drastically different than the old unit, not sure why. When it starts blowing, you may as well be on the tarmac at O'hare, same thing.

snip

. If the cfm, blower speed, is too high, the evaporator coil(cold part) on the furnace/air handler, doesn't efficiently remove moisture from the air. The air handler and evaporator coil have cfm ratings and need to be matched. I hope you can find an HVAC contractor who knows what he/she/it is doing.. ヽ(ヅ)

snip

It sounds like you might be able to improve things by getting the blower to run at a slower speed. That is usually a minor modification. I'm not sure how you would do that on your particular unit but an HVAC guy should know.


mark

On Wednesday, September 20, 2017 at 2:00:02 AM UTC-4, Uncle Monster wrote:
On Wednesday, September 20, 2017 at 12:14:23 AM UTC-5, Patricia N. wrote:
On Tuesday, September 19, 2017 at 8:14:55 AM UTC-5, wrote:

Until you put an hour meter on the compressor to see how much it actually runs from noon to 6pm on a typical hot sunny day in your climate, you're just guessing at capacity required.

plus I would have to say that a change from 2 tons to 2.5 tons is not a drastic change.

I would find it hard to believe that everything could be fine with 2 tons and not fine with 2.5 tons.

Maybe the numbers are wrong or maybe something else has changed.

So lets help the lady. Short of changing the AC unit, what could she do to reduce the humidity.

Maybe she should get a stand alone de-humidifier, then the AC would not have to run as much to de-humidify and it won't be so cold.

Any other ideas?

mark

Mark, I supposedly had a two ton originally. It was probably built in the 60's, it was ancient when I moved in, in '94. No one really checked, it could have been 1.5 tons. The new A/C, furnace was replaced 07/16 with a 2.5 ton. I found out it was not a 2 ton and complained to the contractor in August and they came and swapped out the outside components only, to 2 tons. It is drastically different than the old unit, not sure why. When it starts blowing, you may as well be on the tarmac at O'hare, same thing. Then it shuts off right away, 3-7 minutes. Too powerful, too fast a cycle, no time to dehumidify. A/C and furnaces from 1960 vs 2017 are very different. Now you have two stage motors, variable ECMs, programmable thermostats with bluetooth connectivity and so much more. They both are supposedly 2 tons, couldn't be more different.
The old unit ran efficiently for 22 years, for me and only needed one or two thermocouples. After 22 years, I know how it sounded, how it felt and the duration of the cycle.
These newer models are powerful. I think I will take the advice given to change the cycles per hour, etc, if my thermostat will let me. It might be too dumb. I can get a fancy, new thermostat. Another option I didn't mentioned is getting the tech to change the blower speed. I think they have 3 or 4 settings. It may be on factory default. I had them do that when they swapped out the 2.5 ton components but I have since had to have the new blower motor replaced, so it's probably still on factory default. I came here initially because my short cycling system seems worse since the new blower motor was installed on 09/01.


The last system I installed 5-6 years ago had a variable speed ECM blower motor that ran at an almost imperceptible speed at all times to keep the air circulating in the house. When the compressor kicked in, the fan speed slowly increased to full then continued to run at full speed for a few minutes after compressor shutdown before slowing down to air circulation speed. If the cfm, blower speed, is too high, the evaporator coil(cold part) on the furnace/air handler, doesn't efficiently remove moisture from the air. The air handler and evaporator coil have cfm ratings and need to be matched. I hope you can find an HVAC contractor who knows what he/she/it is doing. ヽ(ヅ)ノ

[8~{} Uncle AC Monster

Agree with that. I have a variable speeed ECM and it starts up
very slowly. Also, the speed is programmable via dip switches
on the furnace control board. Suggest she look online for an
*install manual* for her unit. It will define how the unit works,
the options, switch settings, etc. At a lower blower speed you
would expect it to remove more humidity and to run longer.

Also, I guess what I thought initially was right, that they put in
a 2.5 ton then swapped it out to 2 ton because of the complaints.
AGain, given it's only 750 sq ft and that there was trouble, you'd
think they would have gone to 1.5.

On 09/20/2017 12:40 AM, wrote:

[snip]

Trader_4, the two stage unit is a great idea for someone looking for a new system. I just spent 7K, so I can't do that. I wish I had. I think it would be great way to dehumidify. Also, it would be good for people that dislike the fluctuations. It's a drag when you get cold and wonder when the heat will kick on next. Less hot/cold spots. A smaller unit would be good too. Also,not an option for me now. I cannot stress enough to people who know my story. Don't let them sell you an AC that is too big and get a Manual J calculation.


I'm in east Texas, which has had a big humidity problem. I got a 2-stage
A/C (3 ton for about what you paid) a few years ago, and it has really
helped.

--
96 days until the winter celebration (Monday December 25, 2017 12:00:00
AM for 1 day).

Mark Lloyd
http://notstupid.us/

"FAILURE IS NOT AN OPTION. It comes bundled with the software."