# Carrier Furnace Setup Switch configuration



## Chris130 (Feb 3, 2014)

I'm hoping that some of you* Carrier* experts out there can help confirm if I have my Setup Switches configured properly. And I hope I'm providing enough of the necessary info here to do such a thing - please advise if I'm missing something...

*Furnace: Carrier 58UVB 060* (Performance 96)

*AC unit: Carrier 38TXA 024330* (which I believe is *2-ton*, based on model #)

Link to my furnace manual (pictures below come from here): Link

-------------------------------------

Assuming my AC unit is indeed 2-ton, I'm basing all of my CFM-related settings on 700 CFM, but I don't have a good reason for that other than my ducting is older and probably not sealed super-duper well, so...

*Question #1: * Is 350 cfm/ton generally a safe choice? What factors would drive using a 400 cfm/ton setting instead?

Alrighty, assuming I'm best off using 700 CFM, can you please help me ensure that my AC and CF setup switches are set properly?










Moving on to my next picture... 

*Question #3: * Regarding SW1-7 and SW1-8, what factors help determine an appropriate "Heating Mode Blower Off Delay"? 










*Many thanks* for your time and help!

Cheers, Chris


----------



## beenthere (Oct 11, 2008)

350 CFM per ton is fine for aiding in removing humidity. Continuous fan being 700 may make you feel like cool air is blowing on you in the winter, and warm air in the summer. i would go down to 400.

Adaptive heat mode is to allow the furnace board control staging. Since you have a 2 stage stat, Adaptive should be set to off.

2 minute delay may be okay. if the air tarts to feel cool at the end, shorten it to 90 seconds.


----------



## Chris130 (Feb 3, 2014)

beenthere said:


> 350 CFM per ton is fine for aiding in removing humidity. Continuous fan being 700 may make you feel like cool air is blowing on you in the winter, and warm air in the summer. i would go down to 400.


Sounds good... I decided to just reset both the SW-3 (CF) and SW-2 (AC) switches back to the factory default (DEF = all off). Trying to make heads or tails of Figure 39 there is making my head spin... Perhaps I'll re-attack those sometime later!



beenthere said:


> Adaptive heat mode is to allow the furnace board control staging. Since you have a 2 stage stat, Adaptive should be set to off.


Yep, this one is indeed a head-scratcher -- I agree 100% that what you say passes the common-sense check, but the Manual states in several spots that the "Adaptive Heat Mode" switch (SW1-2) should be set to ON if a 2-stage stat is used. 

The kicker is that in later sections, the Manual refers to this switch as the "low-heat only" switch, which I'm not convinced is a better name for it, but anyhoo, here are 2 other blurbs about it...

On pg 37 of manual, in the "1-stage Stat & 2-stage Heating (Adaptive Mode)" section, it says..."the *low-heat only switch SW1-2 *selects either the low heat-only operation mode when ON, or adaptive heating mode when OFF..." :huh: So that implies _furnace-controlled_ adaptive heating is _on_ when the switch position is _off_. 

Moving along to page 39, in the "2-stage Stat & 2-stage Heating" section, it says, "... the *low-heat only switch SW1-2* must be ON to select the low-heat only operation mode in response to closing the thermostat R-to-W1 circuit..."

This then seems to confirm that _furnace-controlled_ adaptive heating is _off_ when the switch position is _on_, so it at least seems to be consistent in its weirdness! Very strange stuff, but I don't know how else to read it...




beenthere said:


> 2 minute delay may be okay. if the air tarts to feel cool at the end, shorten it to 90 seconds.


Sounds like a plan - thanks.


----------



## beenthere (Oct 11, 2008)

If its responding to the thermostats staging calls. Then leave it set the way you have it.


----------



## jeepgrady (Dec 8, 2008)

Been There- On a similar question, I also have the Carrier system with the same set up switches. Since I have a two stage stat, I had SW 1-2 set to on. The problem I have is that the unit seems to run most of the time almost non stop in the colder od temps in low stage. I have seen it go to high stage and can hear the difference, but reverts to low stage, which I understand is normal in this set up.

Now, here's my problem, when in low stage, I get very little airflow at the end of the runs on my ranch. When I switch SW 1-2 to off, and let the furnace control the stages the entire home is much more comfortable with the higher heat and airflow. In addition, there is more down time on the system as opposed to be running constantly. Having the switch set to ON also seems to defeat the fuel saving part since the system is running much longer even though in low stage.

Since my wife and I are home all day the comfort is key. I assume I'm not doing any damage to the system with this set up as the furnace is designed with this set up as default. Please let me have your thoughts on this. As usual I look forward to your expert opinion.


----------



## Chris130 (Feb 3, 2014)

jeepgrady said:


> Been There- On a similar question, I also have the Carrier system with the same set up switches. Since I have a two stage stat, I had SW 1-2 set to on. The problem I have is that the unit seems to run most of the time almost non stop in the colder od temps in low stage. I have seen it go to high stage and can hear the difference, but reverts to low stage, which I understand is normal in this set up.
> 
> Now, here's my problem, when in low stage, I get very little airflow at the end of the runs on my ranch. ...


I'll be curious to hear others' thoughts on this too. 

Unsure if this can be considered related or not, but I'm now re-thinking my SW1-4 setting (Comfort/Efficiency Adjustment) - I have it ON now, but that sure does take a lot of oomph out of the low-stage airflow, in particular... 

With that switch ON, my Stage 1 Delta T is in the upper 1/3 of range (~61 in the 40-70 window), and with SW1-4 Off, it brings that Delta T down to ~51. I'm not sure which end of the range is better to lean toward...

Interesting stuff to play around with!

Cheers, Chris


----------



## jeepgrady (Dec 8, 2008)

Chris- I've also gone back and forth with that SW1-4 switch. As mentioned in my previous posting my problem is not enough airflow and heat in first stage. I turned the setting to off to raise the airflow. My furnace has a temp rise listing in low stage at 30-60 deg. With the switch on I get a 45 rise and with it off I get about 40. Yet I cannot feel any significant difference in the airflow. When in high stage my rise goes up to about 48 which I still consider rather low yet it's within range and my Tech. says it's ok. My system is 60,000 BTU's. Is yours larger?
I'm sure that the fact I have a 14 ft. cathedral ceiling in my main living area and master bedroom contributes to my problem, as well as being on a slab.

By the way, my system is two zones. The ground floor is on one zone and the FROG is on another.


----------



## Chris130 (Feb 3, 2014)

Crazy stuff, ain't it? I feel like the more I dig into this stuff, the more confusing it gets! I think I'm a perfect example here of a little knowledge being a dangerous thing :laughing:

My system is 60K-max BTU as well, and I have no zones (pretty small 1.5 story house). My system rarely goes into High heat - I suspect the only time that happens each day is when it warms the house from 62 to 68 each evening, but I'm rarely home yet when that actually happens. Otherwise, it maintains temp via low-heat only, which I suppose is quite normal.

When I was doing my Delta-T tests with both SW1-4 on and off, I noticed the airflow for both stage 1/low and stage 2/high was noticeably stronger with the switch OFF. No shockers there... I haven't yet run my system for an extended period of time with SW1-4 OFF - I think I'll try that soon to see what sort of day-to-day comfort level difference it makes... I guess I've just gotten used to "whatever it does, it does, and I just live with it" 

That being said, I doubt I'm honestly gonna actually notice an appreciable difference whether I have SW1-4 on or off, so for me, it would boil down to what's better for the equipment itself... Is it "harder" on the furnace components to run with higher airflows (switch OFF), but on the other hand, those higher airflows bring my Delta-T's down closer to mid-range, so perhaps that's a good thing? 

Which of those benefits is most beneficial in terms of equipment health & lifespan? 

Argggh, each question brings a new question, lol!... Perhaps I just need to leave all the switches set at default and walk away from it :whistling2:


----------



## beenthere (Oct 11, 2008)

jeepgrady said:


> Been There- On a similar question, I also have the Carrier system with the same set up switches. Since I have a two stage stat, I had SW 1-2 set to on. The problem I have is that the unit seems to run most of the time almost non stop in the colder od temps in low stage. I have seen it go to high stage and can hear the difference, but reverts to low stage, which I understand is normal in this set up.
> 
> Now, here's my problem, when in low stage, I get very little airflow at the end of the runs on my ranch. When I switch SW 1-2 to off, and let the furnace control the stages the entire home is much more comfortable with the higher heat and airflow. In addition, there is more down time on the system as opposed to be running constantly. Having the switch set to ON also seems to defeat the fuel saving part since the system is running much longer even though in low stage.
> 
> Since my wife and I are home all day the comfort is key. I assume I'm not doing any damage to the system with this set up as the furnace is designed with this set up as default. Please let me have your thoughts on this. As usual I look forward to your expert opinion.



Won't harm it at all.

May want to see about switching it back, and setting your first stage fan speed/CFM higher. Also, if your thermostat has CPH. Might want to set the first stage to 3, and second stage to 1. Tends to make it finish heating in second stage.

If first stage is 65% of second/high fire. Then it can run for 92 minutes in first stage, and still only have used as much gas as second stage would in an hour. Thats just to give you an idea of fuel consumption comparison.
Was your furnace ever set up with a manometer and combustion analyzer.


----------



## beenthere (Oct 11, 2008)

Chris130 said:


> I'll be curious to hear others' thoughts on this too.
> 
> Unsure if this can be considered related or not, but I'm now re-thinking my SW1-4 setting (Comfort/Efficiency Adjustment) - I have it ON now, but that sure does take a lot of oomph out of the low-stage airflow, in particular...
> 
> ...


The lower temp rise is better. Tends to lessen the cold draft feeling after the furnace shuts off.


----------



## jeepgrady (Dec 8, 2008)

It's at the highest setting which is 400 cfm. Stat does not have cph settings. Based on install manual, it is geared to run in the lowest stage required. So it will maintain the first stage as long as it is not falling behind. As far as set up it is in a new home two years old. Installer has checked and claims gas 
pressures and everything else is good. Burns clean.


----------



## beenthere (Oct 11, 2008)

Honeywell thermostats do very good on 2 stage systems. Since they use CPH.

Your zone system doesn't have a bypass damper does it.


----------



## jeepgrady (Dec 8, 2008)

No bypass. The stat is part of the Carrier "Zone Control II" platform.


----------



## beenthere (Oct 11, 2008)

jeepgrady said:


> No bypass. The stat is part of the Carrier "Zone Control II" platform.


Does it also control blower speed/CFM.


----------



## jeepgrady (Dec 8, 2008)

The furnace is the Carrier Infinity 59TN6a. Not sure if the zone control or the furnace does.


----------



## beenthere (Oct 11, 2008)

Zone control controls blower. Unless the furnace board detects a problem. Se the zone control for efficiency, if its not already set to it.


----------



## jeepgrady (Dec 8, 2008)

The setting for comfort/efficiency is on my furnace board, which you discussed with the original poster. In one of my previous postings I stated that when I set the comfort/efficiency to "Efficiency" I don't feel any increase in airflow.
Right now it is set to comfort.


----------



## jeepgrady (Dec 8, 2008)

Been There- I also have a bypass humidifier on the return side. On my furnace control board there is a setting labeled: "Low Heat Rise Adjustment". It states: "Turn on to increase low airflow by 18%. This compensates for increased return air temp. caused by bypass humidifier. Also, increases low inducer speed by 15%".

I have it set to off since I only have about a 40 deg. temp rise in low speed, when my temp rise is rated for 30-60. Even though my temp rise is this low, should this setting be on to push more air?


----------



## beenthere (Oct 11, 2008)

Your temp rise is fine. And allows for the filter to gt dirty. Set it to increase the air flow. And see what your temp rise is then. As long as your above the min, no harm will come to the furnace.


----------



## jeepgrady (Dec 8, 2008)

I just tried the efficiency setting with the Stat controlling the staging. My lat was only 103 deg with my room temp.at 73, which is right at the minimum of the rise. The wife commented how chilly it was. 
I then tried the comfort setting. Lat was 111 which still seems a bit low.


----------



## beenthere (Oct 11, 2008)

jeepgrady said:


> I just tried the efficiency setting with the Stat controlling the staging. My lat was only 103 deg with my room temp.at 73, which is right at the minimum of the rise. The wife commented how chilly it was.
> 
> Good thing you don't have a heat pump then.
> 
> I then tried the comfort setting. Lat was 111 which still seems a bit low.


I run my oil furnace at about 118. Not hot, just warm enough for me.

Your first stage input can be raise to give you a higher temp.


----------



## jeepgrady (Dec 8, 2008)

Actually, my system is dual fuel. While we do expect less than toasty temps when the HP is on, we don't expect those low temps. while burning the propane. I get to about 118 while in second stage which is comfortable. 

How can the input be raised to get the higher temps? When the tech was here doing the yearly maint., he said it is right on specs.


----------



## beenthere (Oct 11, 2008)

The first stage manifold pressure can be raised. While spec may list 6"(some are higher some are lower speced), it can be raised to 6.5" to get a better temp rise.


----------



## jeepgrady (Dec 8, 2008)

Been There- I know I'm opening an old thread, but I want your expert opinion. Had a tech here today. Changed the dip switches to increase air flow. Measured first stage manifold pressure. Spec. lists it at 5.8. With that I was getting 27 deg. rise. He upped the pressure to 9.0. Said it won't cause a problem. Now my rise is 37 which is within the specs. So I now have my increased airflow, with decent temps. i will see if the wife is comfy. What do you think about what he did, especially the gas pressure increase?


----------



## jeepgrady (Dec 8, 2008)

Are you out there, Been There? Can anyone else offer their opinions on my most recent post?


----------



## beenthere (Oct 11, 2008)

With this cold weather. I get a bit busy.

Unfortunately. Your furnace is now burning less efficiently. Since he increased the low fire gas pressure higher then recommended for first stage. The inducer is not pulling in enough combustion air to burn the gas properly. If he had used a combustion analyzer, he would have seen that your exhaust CO is higher then allowed by GAMMA code.

Furnace should be reset to proper manifold pressures, and combustion checked, and air flow set for proper temp rise at those pressures.

Then if air flow is not enough for you/your wife. the furnace can be set to go to second stage right a way.


----------

