Any HVAC techs in the house?

[General Lee]

Is this the t-stat you have https://customer.honeywell.com/resources/techlit/TechLitDocuments/68-0000s/68-0280.pdf

If so, look at installer setup # 0680 and 0690. Not sure if thats what you need, but it appears thats what tells the furnace when to start/stop based on t-stat temp. Weather you want it to control the temp aggressively (try as hard as it can to keep it right on the setpoint without going too far over/under desired temp......frequent cycling).....or a looser setting allowing a little more over/under

No, its actually this one - https://customer.honeywell.com/en-U....3.1.4.16&rank=1&v1=Sort.1.Product.Rank&asc=1

 

[General Lee]

Two things. One is the stat may be in a spot where there is airflow directly from a register. That can cause short cycling. The other is that you have a larger air handler, which is good for efficiency, but has a potential problem. Assuming it is not a variable speed unit, it should have the ability to select one of 3 fan speeds. I would change (or ask the installer to change) the fan speed to the lowest setting. Assuming that the installer used a TXV valve, it will compensate for the lower air flow rate. Normally a larger air handler has a fan with a higher flow rate. Given the size and the fact that the unit is higher efficiency, I would slow the fan to reduce the effect you are seeing.

Paul

Its possible the T-stat may be "some" register air. There is a register on a perpendicular wall but not underneath the the T-stat.

It is not a variable speed unit. I kept my old oil furnace as back up and the whole system uses that indoor fan blower. It does have a speed setting and a few years ago it was adjusted. But now the sticker is gone that showed which wires need to be where for that fan speed. And what exactly will a slower fan speed do? There is a TXV valve on the coil because that or the first new coil was not working properly, hence the new coil install the second time they came out.

 

[LD1]

Are you able to access the installer settings/options or did your installer lock you out of that?

I am guessing there should be some setting in the installer pages, but cannot find any info for that online?

 

[ultrarunner]

Brothers 1949 home or 2400 square feet had no central air or heat... just an old wall furnace and bedroom window box... several days at a time it can be over 100 and in the 90's for longer periods of time.

I went undersize due to only having 30 amps available... the entire 14 years until he sold he was the envy of his neighbors... we did spend extra installing the best ducts and making sure all was properly sealed... enen commercial metal ducts with add insulation in areas that would not be later accessible.. variable blower, 3 stage gas heat and oversize returns..

Very happy with that job and put the extra money into doing a first class install... he also planted a nice summer shade tree and we insulated and replaced all the windows...

His friend that sold us the unit said he could not put in a undersized unit... simply could not... now he will reference us on sales calls saying he has one customer that went undersized without issue.

 

[kenmac]

I sold my business a while back so I'm no expert, but With your system having old equipment mated to newer equipment could be the issue. The old blower may be moving too much air across the newer A coil. The air flow may need to be adjusted at the old furnace / air handler. It's best to have a load calculation instead of guessing the size of the unit. Your unit shouldn't be short cycling . you are using energy ,and not removing humidity from your home. Short cycling isn't good for you or your unit. JMO..

 

[General Lee]

LD1- I can access the installer options. That is how I changed it from 5 cycles an hour to 3 . Last night when the load wasn't as great it seemed to cycle 3 times an hour.



Ok - some updates . Today is in the 90's and the unit is running longer periods of time BUT its only staying off for 5-6 minutes before coming back on.

I know I have insufficient return air. A second return was added a few years back right beside the blower motor. This helped quiet the air return upstairs as it was annoyingly loud. Now some techs are saying its bad for me to be drawing in so much basement air (basement is unfinished) which is affecting the efficiency of the unit. Some techs say the more air the better. Right now the basement return is partially blocked as the latest tech feels it would benefit the unit to draw in more upstairs living space air instead of alot of cooler basement air mixing in. It would allow the TXV to open up more and produce cooler air. Only thing now is the upstairs air return is slightly louder because its drawing harder.

Now what sparked my second call back to the company was, after the new replacement coil was installed we started the system and let it run. The house temp was about 77 degrees. We had a 22* temp split at the unit and 56.5* air coming out of my closest vent. I was very pleased. Now my Temp splits are 15-16* and I'm getting 59* air out of that same vent. I thought I had a problem because the numbers were falling.

They tell me when the unit has to work harder hence the 77* air in the house my temp splits will be greater. Once the house air stabilizes or the heat load is less, it is harder to get the big temp splits. IS this true? Kinda makes sense to me.

 

[techman]

Its possible the T-stat may be "some" register air. There is a register on a perpendicular wall but not underneath the the T-stat.

It is not a variable speed unit. I kept my old oil furnace as back up and the whole system uses that indoor fan blower. It does have a speed setting and a few years ago it was adjusted. But now the sticker is gone that showed which wires need to be where for that fan speed. And what exactly will a slower fan speed do? There is a TXV valve on the coil because that or the first new coil was not working properly, hence the new coil install the second time they came out.

A slower fan speed will result in a slower rate of change in air temp when the AC comes on. This will normally result in a longer run time. With a TXV valve the coil temp is maintained independent of load on the coil. Older orifice systems will have a range of delta temps as they deliver near full capacity when they run. TXV will automatically compensate.

paul

 

[kenmac]

you should not be taking return air from any space, other than living space. I would never pull return air from a non living space just to get more return air... this isn't helping you 1 bit ! Your basement return is killing your efficiency .... This company should have fixed your return air problem B-4 installing a unit...
Didn't you say in another thread that you trusted this company ?

 

[LD1]

I disagree about basement air.

The basement is the coolest place in my house. Hotter return air makes the unit work harder.

My basement isnt finished, but is occupied. Kits toy room, laundry, etc. ITs not uncommon for it to be 60 in the basement and 80 upstairs (prior to ac). When I really dont need any cooling.....rather I need blending of the air to make the whole house average out at 70.

I have a basement return, its open to pull all that cool air it desires and blow it upstairs.

As to the temp swings, the hotter the return air, the greater the swing....but that dont equate to efficiency.

And when you said "once the house stabilizes the heat loss will be less".....

Not sure what you mean by that. IF its 95 outside, heat loss will be less at 77 than it will at 72.

The greater the difference in temp between the house and outside....the greater the heat transfer. So the hotter the house is, the less BTU's get transferred to the outside, The farther the spread, the greater the transfer rate. So keeping the house cooler, equates to faster heat loss with the same outside temps.

 

[EarPlug]

No, its actually this one - https://customer.honeywell.com/en-U....3.1.4.16&rank=1&v1=Sort.1.Product.Rank&asc=1

Check Page 5 of your owners manual. There is a CIRC (circulate) mode for the FAN. Is it possible that it is just the fan coming on and not the whole system?

 

[kenmac]

LD you can disagree all you want, but you aren't correct..I was in the bus, for 35 yrs I have never taken return air form a basement or a crawl space or attic space..I don't think you'll find it in the code either.. I could go more into detail of why this shouldn't be done, but at this point I'm out.. Ya'll carry on and take return from where ever you wish

 

[ultrarunner]

The place in Washington has a daylight basement and at the suggestion of the new Heat Pump installer I have the fan default on very low when no call for heat or cooling and this has made the entire main floor and basement very nice and uniform temp/humidity wise... the upstairs has a electric heat only furnace and is separate.

 

[General Lee]

you should not be taking return air from any space, other than living space. I would never pull return air from a non living space just to get more return air... this isn't helping you 1 bit ! Your basement return is killing your efficiency .... This company should have fixed your return air problem B-4 installing a unit...
Didn't you say in another thread that you trusted this company ?

Yes, I did say I trust the company to do right. But through the years I've heard mixed reviews on the issue and the return was already installed prior to them coming into the picture.

 

[dadster4]

I was in HVAC for 30+ years in the Chicago area and did load calculations for project homes and large 3-6 system custom homes and need a little more info...ranch? two story? split level? how much glass facing south? any unusually large windows or high ceilings? is most of the basement finished? (an unfinished basement actually LOWERS the unit sizing) If an average 2000 sq. ft. home, 3-1/2 ton is too large and the 4 ton coil makes that worse, in the "old days" a 1/2 ton larger coil was common...not anymore, equipment should be matched. You mentioned that a register was on the same wall as the thermostat...I hope this is an interior wall and not exterior, but the stat should not be anywhere near a supply, it should be close to the return if possible. Another possibility is (since your return vents are noisy) the unit is oversized and the system's ductwork (especially the return sizing) is inadequate for proper airflow and the unit is shutting down prematurely on a low-pressure control and restarting 5 min. later after the control resets...creating your on-off cycle. Minimum size of return duct would be about 200 sq. in. or 24 x 8. Hope this helps :confused3:

 

[LD1]

LD you can disagree all you want, but you aren't correct..I was in the bus, for 35 yrs I have never taken return air form a basement or a crawl space or attic space..I don't think you'll find it in the code either.. I could go more into detail of why this shouldn't be done, but at this point I'm out.. Ya'll carry on and take return from where ever you wish

I am certainly all ears to more detail. Its a good discussion going here, why are you gonna take your 35 years of experience and leave? If we all agreed on everything, there would be nothing at all to discuss.

The fact that my sub-grade basement with poured concrete walls stays a good 15 cooler than my main floor, there are times when it gets hot upstairs, and I dont need ANY cooling from the compressor at all. Simply run the fan and let things "blend". This time of year is a perfect example. Gonna be sunny and ~78 today. Right now its 58. MY whole hose is nice and cool as we had windows open over the night. By 3 or 4 this afternoon, the main level will be getting warm enough I want to cool it down. Instead turning on my geo/compressor/loop pumps, I'll simple turn the fan on and bring some cool basement air up and return some of the warm upstairs air down to the basement.

So I ask, with your experience, why is it a bad thing to only run the fan to get the desired results? vs running the whole system?

I installed the Geothermal myself, but I hired the ductwork out. HE is a friend in the HVAC business and like you, has been in business for ~30-35 years. He knows all kinds of tricks. He said a large return in the basement that can be closed of or mostly closed off for winter heating, and opened up in the summer, is exactly what I needed to make the system operate at its most efficient. And said that his air to air system in his house, is setup the exact same way, only not as nice. AS all he did was cut in a 12x20 opening in his basement return duct, but a return vent over it, and use a stick on magnet/door sign to block it in the winter.

So......so far.....I have one guy (who installed my system) with 30+/- years HVAC experience that says my return air from the basement in the summer time is an excellent thing........and have one guy with 35 years of experience on the internet that says its a bad thing.

I am gonna stick with what I got. Colder air in = colder air out. And the cold air in my house is the basement

 

[Midniteoyl]

Back when I lived in a house with a basement, having a return cut in, and 2 supply vents put in- each able to be opened/closed - was the best thing I ever did. For both comfort and moisture control. In my current home on a crawl, I insulated the floor and walls, removed the insulation from the joists and dump some warm air in in the winter, with no return, and its much more comfortable in the winter.

 

[Sigarms]

So I ask, with your experience, why is it a bad thing to only run the fan to get the desired results? vs running the whole system?

I can't speak for Kenmac, but only say that good practice generailly turn into good habits, which turns into good results.

Generally you don't want to pull return air directly into the return ductwork system from an unconditioned space unless you are treating that return air with some kind of device.

A contractor installs an HVAC system and leaves. He can NOT control what the homeowner does. Sometimes it's hard enough to get the homeowner to change their air filter once a year, let alone monthly, depending on what they have.

 

[LD1]

I can't speak for Kenmac, but only say that good practice generailly turn into good habits, which turns into good results.

Generally you don't want to pull return air directly into the return ductwork system from an unconditioned space unless you are treating that return air with some kind of device.

A contractor installs an HVAC system and leaves. He can NOT control what the homeowner does. Sometimes it's hard enough to get the homeowner to change their air filter once a year, let alone monthly, depending on what they have.

I never said it was an unconditioned space. I said it was an unfinished space.

And by unfinished I mean that If I look up, I see floor joists and plumbing. If I look at the walls, I see poured concrete. And if I look down, I see the 3/8" thick 2x2 foam mats. But it is absolutly a conditioned space, laundry is down there, projector TV, Few couches, pool table, kids toys, etc.

The OP said his basement was unfinished as well. I didnt take that as being unconditioned. I took that to mean the same thing as my area. My basement is also not closed off to the upstairs. The stairwell going to the basement is open. So even if I didnt have any return ducts at all upstairs, and only supplies. That air would still find its way to the basement.

 

[General Lee]

I was in HVAC for 30+ years in the Chicago area and did load calculations for project homes and large 3-6 system custom homes and need a little more info...ranch? two story? split level? how much glass facing south? any unusually large windows or high ceilings? is most of the basement finished? (an unfinished basement actually LOWERS the unit sizing) If an average 2000 sq. ft. home, 3-1/2 ton is too large and the 4 ton coil makes that worse, in the "old days" a 1/2 ton larger coil was common...not anymore, equipment should be matched. You mentioned that a register was on the same wall as the thermostat...I hope this is an interior wall and not exterior, but the stat should not be anywhere near a supply, it should be close to the return if possible. Another possibility is (since your return vents are noisy) the unit is oversized and the system's ductwork (especially the return sizing) is inadequate for proper airflow and the unit is shutting down prematurely on a low-pressure control and restarting 5 min. later after the control resets...creating your on-off cycle. Minimum size of return duct would be about 200 sq. in. or 24 x 8. Hope this helps :confused3:

The house is a rancher w/ an unfinished basement. (walkout) Nearly 2,000 sq feet NOT including the basement. House is approx. 70 feet long with the front facing south, 7 windows facing south, 2 are bay windows and 2 are shaded by the covered porch. There is a cathedral ceiling in the living room. No register on the same wall as T-stat, the register is on a perpendicular wall. T-stat is on same wall as return duct. The main return duct is under sized, one reason they added a second return in the basement. The Main return opening is 20x20 and the downstairs return vent is 14x20. They tell me the coil being 1/2 ton larger then outside unit helps with efficiency??

 

[Sigarms]

I never said it was an unconditioned space. I said it was an unfinished space.

Kenmac stated "for 35 yrs I have never taken return air form a basement or a crawl space or attic space..". From my experience, every state varies per what people use and layout via HVAC systems, but on the east coast, from New York to at least North Carolina, in general, when you here the term crawl space or attic space, it's generally an unconditioned space.

Perhaps he misinterpreted what you stated, I'm not certain, but that is where my comment came from.

I believe what Kenmac is saying in 35 years he has never pulled return air from an unconditioned space (I also believe that is what he meant by "code").