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[stardotstar]

Well I cant stand it anymore, sinuses are too dry!

3600 sq foot home with the up and down being equal squares. They both have the same identical 4 ton Rheem A/C's and Rheem 2 stage heaters. Did this before original units where changed out so I dont think its a heater issue rather a home design or other unknown. Seeking some fresh thoughts on my problem.

Here it is:

The home is 9 years old. The ac-furnaces are located in the attic. Each floor is 1800 square feet. Upstairs is a non issue, problem is down. Nine foot ceilings and the return air is in the ceiling.

When it is cold outside, lets say 45 and below, the heater unit cycles on and then off. It is off only a short while maybe 3-4 minutes and it comes on again. We keep the stat at 70-71. With this much cycling I wake with extremely dry sinuses.

So I am looking for what is causing such a rapid cycle? The t stats are Honeywell 2 stages.

I know, like a doctor, you cannot diagnose over the phone, but I am really frustrated and looking for some new thought on this.

I also know that you will need more information, so please ask.

Thanks

[psychometric]

Are thermostats old mercury bulb type? if so, sounds like heat anticipators set too low.

[stardotstar]

T8624D Honeywells

[psychometric]

Those stats have internal setup features. One is the number of heating cycles per hour. I believe it can be programmed from 1 to 9. The higher that number is, the shorter your cycles will be. If you have the install instructions for said stat, you can step through to that category just to see if you can lower the cph.

[rimek]

What part of the US are you in?
Where do you sleep, upstairs or down?
Is it a problem with the thermostat location?
is heat anticipation/cycle rate set properly?
do you have a central humidifier on either or both units?
if so, is that installed properly and working?
are these gas fired units?
do you know what the humidity level inside the house is right now?
is the short-cycling furnace truly cycling on the thermostat, or possibly a limit/safety control?(has it been checked for proper operation?)
does the furnace staging operate properly?

[stardotstar]

It is set at the default of 6. Remeber although this is not the original Honeywell stst, it did this with the old stat also.

[Gunnery Sergeant Hartman]

Probably oversized. Perform a load calc.

[stardotstar]

What part of the US are you in?

Houston Texas


Where do you sleep, upstairs or down?

Down

Is it a problem with the thermostat location?

Could be how do I tell?


is heat anticipation/cycle rate set properly?

Dont see this as aan option on this stat


do you have a central humidifier on either or both units?

No, none


if so, is that installed properly and working?
are these gas fired units?

Yes gas


do you know what the humidity level inside the house is right now?

upstairs store bought indicates 54

is the short-cycling furnace truly cycling on the thermostat, or possibly a limit/safety control?(has it been checked for proper operation?)

Yes has been check


does the furnace staging operate properly?

Yes




Se fill in answers

[stardotstar]

Probably oversized. Perform a load calc.

Did this with the lesser original builder installed units.

[Gunnery Sergeant Hartman]

Have you had the systems serviced/cleaned recently?

Are the filters clean?

Are the evaporator coils clean and not plugged with dirt?

Call a new service company.

[stardotstar]

yes

yes

yes

As I said earlier it is more of a combination of things: how the home is built and the system. Since it is acting the smae with a totally new system and the only thing that has not changed is the house configuration, I was just seeking some new ideas.

Thanks

[chief_wiggum]

What about crappy insulation ? if the house is drafty, or loses heat rapidly, the heater will have to cycle constantly no matter what it is, or is set for.

Perhaps the problem is the HOUSE, not the UNITS ??

[dash]

With identical furnaces,two stage gas,I don't think the downstairs unit is running in low stage ,with it cycling on/off that often.I know you stated the staging was working properly ,but are you sure it is?

[Mr Bill]

Is there a hole in the back of the thermostats that might need to be sealed? it could be drawing air through it causing the stats to not work properly, what part of Houston are you in I am in Houston and I sell RUUD but it's the same as Rheem.

[Mr Bill]

Upstairs is a non issue, problem is down. Nine foot ceilings and the return air is in the ceiling.

The return downstairs is also in the ceiling? that's unusual normally they build a chase to the down for a return close to the floor.

[stonefly]

i question the premise that if your system cycled less your sinuses would feel better. i got an old cast iron teapot to humidify the house abit in cold weather . seems to help.

[stardotstar]

What about crappy insulation ? if the house is drafty, or loses heat rapidly, the heater will have to cycle constantly no matter what it is, or is set for.

Perhaps the problem is the HOUSE, not the UNITS ??

And I too think this may be an issue.

[stardotstar]

With identical furnaces,two stage gas,I don't think the downstairs unit is running in low stage ,with it cycling on/off that often.I know you stated the staging was working properly ,but are you sure it is?

Yes it is running correct because I can bump up the temp and hear it ramp up and if I am in the attic and have someone else do it i hear and see the difference in operation.

[stardotstar]

The return downstairs is also in the ceiling? that's unusual normally they build a chase to the down for a return close to the floor.


My sentiments exactly, but of course at the time of this build athe builder and local ac contractor said it was ok.

You know it really never gets warm and the air does not really seem to change over.

Wished I could figure a way to get the return down low.

[mayguy]

If your humidity level is at 54%, that's pretty good.


Sounds like the CPH is set too high, and should be lowered down to about 3. Did you see MrBilPro post of him being in Houston area?

[stardotstar]

Is there a hole in the back of the thermostats that might need to be sealed? it could be drawing air through it causing the stats to not work properly, what part of Houston are you in I am in Houston and I sell RUUD but it's the same as Rheem.



I-10 and Fry road area.

[stardotstar]

If your humidity level is at 54%, that's pretty good.


Sounds like the CPH is set too high, and should be lowered down to about 3. Did you see MrBilPro post of him being in Houston area?


Yes I just did, thanks!


Regarding the CPH it is set at 6. What bothers me the most is with as low as we keep the setting, it just seems to cycle too often and too many times. Then when it does come on, your really dont feel the warm turn over of air, if that makes any sense.

[vtinknocker]

4 tons for 1800sf seems a bit much but i dont know the load
look arround by the stat and see if there are any supply registers affecting it

close any register with in ten feet and see if that makes a differance.

see if your contractor can slow the blower down a tad and set the stat for a longer cycle

most of the time with short cycleing it is a supply affecting the stat:)

[stardotstar]

Well right next to this is the master bedroom. If I close the door, it still does it.

At one time I had found a guy that did infra red camera stuff, but I lost contact. I should have the house checked for leaks.

Here is a picture of the return air and area.

http://images18.fotki.com/v375/photos/7/734253/3414627/PICT0003-vi.jpg

[mayguy]

Yes I just did, thanks!


Regarding the CPH it is set at 6. What bothers me the most is with as low as we keep the setting, it just seems to cycle too often and too many times. Then when it does come on, your really dont feel the warm turn over of air, if that makes any sense.

6 CPH is pretty high, and will cycle often as you mention about. Also, 45 degree temps is not that cold, and your furnace is maybe oversized. How many BTU is the furnace?

[stardotstar]

I think the furnaces are: RGPL10EBRMR.

[smokin68]

Probably not what you want to hear, but solving problems costs money. We can sit and guess all day, or you can have it solved. You need a company that specialises in Indoor Air Quality. Your systems are probably way too big, and you might need a humidifier.

You need a place to start....

1) Load calculation....determines heat loss/gain for your home

2) Manual D-lays out the duct system (see if yours is O.K.)

Otherwise just keep guessing.

[stardotstar]

Probably not what you want to hear, but solving problems costs money. We can sit and guess all day, or you can have it solved. You need a company that specialises in Indoor Air Quality. Your systems are probably way too big, and you might need a humidifier.

You need a place to start....

1) Load calculation....determines heat loss/gain for your home

2) Manual D-lays out the duct system (see if yours is O.K.)

Otherwise just keep guessing.


Not looking for a freebie, but also not looking to get taken, again! Builder and his AC contractor already did that.

The manual J that was supplied with the house called for 2 3 ton systems, after being in the house it was quickly realized that they would not cut it. Ran all the time and never comfortable, high electric bill.

Builder agreed to up the units and reinstalled the 2 4 ton systems. It was believed that the 2 stage would help the down stairs situation. Definately no A/C issues in summer up or down, but the down in the winter is always cold. I have to crank up the heat to 74-76 if I want it comfortable.

I dont think its the HVAc, I think its the house.

[stardotstar]

6 CPH is pretty high, and will cycle often as you mention about. Also, 45 degree temps is not that cold, and your furnace is maybe oversized. How many BTU is the furnace?

So am I understanding this number: If it is set to 6, then the unit will cycle a mandatory/minimum 6 times per hour per the thermostat programming but, it can actually cycle more due to demand?
So basically demand plus 6?

[gonekuku]

Per what I understand, if you are set to 6 cycles/hour, then this would cause this thermostat to pre-calculate (learn) how to "enforce" 10 minute on/off cycles. Try 2 and see how that works.

If that doesn't help...

How far is the thermostat from a register blowing hot air on it? Is there a heat source behind the wall? Any other heat sources?

See link below - Have your HVAC tech try the installer system test (page 8), and check the wiring.

http://customer.honeywell.com/Techlit/Pdf/69-0000s/69-1412.pdf

See if Stage 1 is really stage 1, and stage 2 stage 2.

[stardotstar]

You cant do 2, your only options are 3. 6. 9. You can set each stage individually.

[Mr Bill]

The manual J that was supplied with the house called for 2 3 ton systems, after being in the house it was quickly realized that they would not cut it. Ran all the time and never comfortable, high electric bill.

Builder agreed to up the units and reinstalled the 2 4 ton systems. It was believed that the 2 stage would help the down stairs situation. Definitely no A/C issues in summer up or down, but the down in the winter is always cold. I have to crank up the heat to 74-76 if I want it comfortable.

I dont think its the HVAc, I think its the house.


What you just said here I have preached on this forum for a couple years now most of these contractors don't understand Houston and the climates and a lot of them think I am crazy and some do understand but here manual J alone will get you butt into trouble trust me been there done that, you will need manual J, common sense and experience in Houston. :D

[stardotstar]

can I email you? MrBillpro

[vtinknocker]

even tho you need to realize we are only taking guesses
from that picture you showed and the location of the stat in the hall near a stair well i tend to think the draft of the stair well may be causeing fauls readings on the stat. Heat riases and cold air falls and a stair well is the best place for this effect to happen.

might be worth a try to move the stat to the mater bed room away from the stairs:)

[stardotstar]

That may be easily doable because of the comon wall, also be advised that right in the master bedroom there above the door is another ceiling return air.

[Mr Bill]

can I email you? MrBillpro

Yes, my email is in my profile, I don't know how much help I will be, I am no air specialist by a long shot, we are more into the service side of the business, Residential and Commercial Service but I have over 30 years of experience and common sense. :D