ReplyNo that you have painted yourself into a corner ... You need a smaller A/C unit OR a dehumidifier.Originally Posted by supermaxhd
http://ultra-aire.com/index.php?opti...id=65&Itemid=5
At > 90'F it ought to run about 54 minutes out of 60.
Regular Guest
I asked questions here back in 2010 prior to replacing my HVAC system. I have become increasingly unhappy with my system in that it doesn't keep my humidity below 60%. I see other humidity questions frequently asked in this forum but I don't see anything close to my situation so I appreciate any help with this. My system was replaced in late summer 2010 by a local authorized Trane dealer. Afterwards I was somewhat concerned about abilitiy to keep humidity low but did not question it until the spring of 2011 in which I had my local Trane dealer come and make adjustments, mainly lowering the fan speed.
This spring 2012 my allergies were especially bad, I know it was a bad season in most of the country. I became so concerned with the humidity that I purchased a humidity gauge and then realized how high it was. It was then that I realized that my system is likely oversized for my house and then now nearly two years later I don't feel I can ask my Trane dealer to correct this. I explained to my Trane dealer that before the system was replaced I was comfortable at 74-75 in the summer and now find I have to set the temperature at 69-71 to get the humidity lower. I wish I could roll the clock back to two weeks after it was instaleld and I would ask that it be fixed. My Trane dealer is now mostly ignoring me after an additional check this spring. He told me then it was not set for Comfort R mode. He did that but it hasn't helped. I have told him that I would not expect him to replace my system this late but I just want to make sure it is working as well as it can.
So here are a few details...hosue is a 1300 sq ft. ranch on a slab, house is very tight (i've had a blower door test), house had windows and doors replaced in 2009 with low e and argon glass. I have linved in the house since 2001 and my previous 2 ton system was very comfortable. I had a natural gas furnace. What I replaced it with with an XL15i 2.5 ton heat pump and natural gas XC80 furnace with a 3 ton coil and Trane Clean Effects. The let my Trane dealer recommend the size. I pressed my dealer to get me a more efficient system then he first recommended. I also find that when I walk into my house I find the air stale. I don't really know how to describe it. On a warm day 90+ at 5pm the system runs about 10 minutes on 10 minutes off. I don't believe this would be very efficent for dehumidifying the air. What can I do to better dehumidify the air in my house. Thanks for any replies.
Professional Member*
No that you have painted yourself into a corner ... You need a smaller A/C unit OR a dehumidifier.
http://ultra-aire.com/index.php?opti...id=65&Itemid=5
At > 90'F it ought to run about 54 minutes out of 60.
Last edited by dan sw fl; 08-21-2012 at 07:42 PM.
Designer Dan __ It's Not Rocket Science, But It is SCIENCE with Some Art. _ _ KEEP IT SIMPLE & SINCERE ___ __ www.mysimplifiedhvac.com ___ __ Define the Building Envelope & Perform a Detailed Load Calc: It's ALL About Windows & Make-up Air Requirements. Know Your Equipment Capabilities
God Speed, Jim. We'll miss you - 2-26-23
Other then getting a new correctly sized unit. A whole house dehumidifier would work.
Professional Member*
X2
Make your expertise uniquely valuable.
Make your influence uniquely far-reaching.
Professional Member*
Max
What is your location?
What thermostat was installed with new system? Does existing thermostat have adjustment for CPH? If so any idea what yours is set at?
Any idea of your blower setting as far as CFMs per ton?
If your blower setting is at 350-400 CFMs/ton and comfort R is set correct but not giving you the result you need, perhaps a thermostat that has "dehumidify on demand" feature might be an alternative to a dehumidifier.
Your blower fan is in auto setting for AC cooling?
Just brainstorming.
Post back.
IMO
Regular Guest
Lexington KY
Trane TCONT800 Series thermostat
CPH adjustment, I don't think so, I have looked at all of the settings in the installer setup.
blower setting CFM, don't know it
Correction to first post, I said I had an XC80 but I have an XV80.
Thermostat with dehumidify on demand, how would that work?
thanks!
Professional Member*
1) Set the blower speed down (way-down) less than 300 cfm per ton.
2) Make sure your thermostat has the ability to read humidity AND if it sees that the humidity level in the house is higher than your setting, it will turn the A/C on to remove the humidity. If you can find a good tech, he can do it easily. My house runs at 240 CFM per ton.
3) If those 2 steps won't get your humidity level down, then get a humidifier.
Good luck
Professional Member*
Max
Is your fan setting on your thermostat in "on" or "auto" ?
Should be in auto so that you don't reintroduce humidity that evap coil has removed.
Verify and post back.
Are you familiar at all with dip switch settings in the controls inside your furnace?
If not then forget about it. Installing dealer should come back and verify that Comfort R is set correctly and your CFMs/ton are set correctly.
This should be your starting point. If this does not help, then we can come back to dehumidify on demand which would involve a different thermostat like HW VP IAQ model. Dehumidify on demand allows the var speed blower to run on low with HP condenser when humidity level is above your setting.
Just curious. Did you have inside humidity issues with your old system?
IMO
New Guest
This is the Ask Our Pro's forum, and only Pro members that have been vetted by the AOPC may post advise, commentary or questions in other peoples threads. Please apply to the AOPC today, thank you.
You can find the rules for posting and qualifications here.
Further infractions may result in loss of posting privileges.
Last edited by beenthere; 08-21-2012 at 10:54 PM. Reason: Non Pro * Member
Regular Guest
I am using auto and experimented a little with circulate. Part of me wants to run in in 'on' because I paid a lot of extra money for the 'cleaneffects' air cleaner and don't feel I can fully benefit from it unless 'on'.
I am not familiar with the dip switch settings but I am confident that is something I could check out.
The old system was a 1994 10 seer American Standard. I had previously spent money to fix it and didn't want to spend more on it to get it fixed. The tax breaks made my new system made it very attractive and I felt I got a very good dea at the time. Yes, the old system was very comfortable at 74-75 while keeping humdity down.
God Speed, Jim. We'll miss you - 2-26-23
jcool, this is the Ask Our Pro's forum, and only Pro members that have been vetted by the AOPC may post advise, commentary or questions in other peoples threads. Please apply to the AOPC today, thank you.
You can find the rules for posting and qualifications here.
Your post has been deleted.
Further infractions may result in loss of posting privileges.
Regular Guest
I believe my installer had good intentions and felt the larger unit would help me on my heating side and it likely has. I don't believe any calculations were made when the system was sold to me. The owner of the business who sold it to me had been doing this work for 30+ years so I trused he would get it right. Since I didn't press the issue right after it was installed I feel this is mostly my problem at this point.
Regular Guest
My thermostate does not read humdity. I think you mean I should get a dehumidifier. I have found that I have to set the thermostat at 67-68 sometimes to get the humdity down to 55%.
Sponsor & Professional Member*
You have got a lot of advice, some very good. This must be confusing to a homeowner and the local tech.
I see the priority this way.
1. You need a 45-50^F a/c cooling coil to get to <50%RH at 75^F . This is more than a 25^F temperture drop of the air flowing through the coil to remove the right amount of moisture quickly.
2. The a/c needs a cooling cycle long enough to load the cooling coil with moisture and drip to the drain. 10 mins. is too short. It takes +20 mins. to load a coil and start draining. Slowing the fan will get you the cold coil. Increasing the dead band of the t-stat to increase the time of the cooling cycle. During the hottest days, your a/c will maintain <50%RH. During days of low/no cooling loads, it is impossible for any a/c to maintain <50%RH when the outdoor dew points are +55^F. You need supplemental dehumidification to maintain <50%RH which is a must to avoid mold and dust mites. On cool wet days, you must dehumidify 3-4 gallons of moisture everyday to maintain <50%RH. This is the moisture from the occupants and the infiltrating/ventilating fresh air.
You have additional indoor air quality problems in addition to high indoor %RH. You need an fresh air change in 4-5 hours to purge indoor polutants and renew oxygen. This would be 50-70 cfm of fresh air when the home is occupied at a minimum.
I suggest you get you a/c setup properly and then get a small whole house ventilating dehumidifier like the Ultra-Aire 70H. This type unit will provide the right amount of friltered fresh air on a occupancy schedule and maintain <50%RH when the a/c does not have enough cooling load.
Fresh air ventilation and <50%RH will make your home healthy and and comfortable. It will take a month or two of fresh air and <50%RH to stop the dust mites and mold from affecting your allergies.
Regards TB
Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
Use +Merv 10 air filter. -Don't forget the "Golden Rule"
Regular Guest
I think I like the idea of a whole home dehumidifier. I just watched a couple of youtube videos Without being specific what would something like an Ultra-Air 70 H cost? I have no idea, a few hundred, a thousand or a couple of thousand? I googled and can't find a price on amazon, ebay or the manufacturers web site.
God Speed, Jim. We'll miss you - 2-26-23
Neither prices nor pricing questions are allowed.
Call local contractors and have them give you estimates.
Professional Member*
If it was comfortable before at 2 tons AND you made improments to reduce energy use, you probably needed a 1.5 Tons or another 2 ton unit. +1 on dropping hte blwoer speed. The XC allows a lot of flexibility. You will also want ot use Dehumidify on demand not COmfort R.
TO make matters worse, I wonder if they matched a 3 ton coil with you unit. A common thing to do, and not a problem if the unit is correctly sized. I have a 2.5 ton coil on my 2 ton system. But I'm cooling a 1500sqft upstairs.... and your climate is comparable to where I am, with a little more mild winter, and slightly more humid, but not much. Depending on shade and overall insulaton, 1.5 ton wouyld have been plenty.
But that's water under the bridge. Contractor that do load calculation and follow all good industry practices are far and few between. The whole house dehumidifier is your best bet. Not cheap, but it will extend the overall life of your systme since it will run less, bring in fresh filterd outside air and pressurize you home slightly (great for allergies) and drop you humidity to <50%RH...even better for allergies. On the few cloudy days when our house gets up to even 55%RH, I can tell the difference. Our noses get stuffed up. 45-50%RH is best. IT will allow you ot keep it aroudn 75-76F as well and overall you should save energy.
Professional Member*
Dehumidier machine is the last resource.
Why buy the rags to clean your oil spill, where you can stop the oil spill????
I am sure there is a GOOD tech out there can help you resolve your problem with what you have.
As for your FAN MODE, leaving it ON all the time is not help you at all. Instead it does worse. BUT you need it ON for the filter system to work.--- Can you set it to CIRC (circulating mode) ? My guess is that your thermostat does not have this CIRC feature either. It does not have the DEHUMIDIFYING feature too. If the answer is NO to both than you are not taking FULL advantage of the system yet.
Get a GOOD tech.
Regular Guest
Yes, the coil is 3 ton. I remember having specific conversations about the 3 ton coil when it was recommended to me and I asked if it was too much. I was assured it wasn't and that it would help me get the 15.5 seer rating and help me the heating side. As I have previously corrected the furnace is an XV80 and not the communicating model. Does that mean it does not have 'dehumidify on demand'?
I am starting to look at whole house dehumidification units now. Is the Trane 'fresh effects' such a unit? It talks about capability to dehumidify incoming fresh air but it doesn't look like it does what the ultra-aire 70h does.
Regular Guest
I do have CIRC but no dehumidify.
Posting Permissions