# Heat Pump/AC not cooling, new home



## harleyrider (Feb 20, 2007)

Pay for a second opinion............


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## MechanicalDVR (Jul 4, 2007)

Maybe call the rep in the area for the type of heat pump you have and see if they can recommend a local service contractor to troubleshoot your system.


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## Malcolm (Jun 7, 2007)

eshipler said:


> Hi Everyone,
> We moved into our newly constructed home last summer and have constantly had problems with our cooling unit. We have a heat pump and an a/c unit. When the temperature outside gets above 95ish, the a/c won't cool our home lower than 79 degrees. It will stay at 79-82 degrees the entire day, depending on how hot it is outside. Even if we have it set at 74 in the morning, the temperature in the house will steadily rise as it gets hotter outside.
> We have had the contractors out at least 5 times and they insist that everything is working properly (vent flow/temp in pipes). Our neighbors have the same type of system and have no problem cooling their homes to 75 or lower during the summer.
> If someone might know what the problem could be, or has any suggestions, I'd love to hear them. Thank you so much!



Are you sure your neighbor has the same type of system? Is it the same size? I would look at duct problems. It could be duct leaks or incorrectly sized ducts. It could also be an undersized unit. Also, I hope you aren't just looking at the number on the thermostat to come to your conclusion that it isn't working. Thermostats can be out of calibration. The important thing is to feel comfortable. Have the next technician take the temp difference between the return and supply air. It should be between 18 and 22 degrees. If the room temp is 79 degrees and you are reading 86 degrees at the return plenum, you know you have a return duct leak. There are too many variables. Call a company and tell the receptionist that you have had 5 other companies come out and look at you system to no avail. Tell her/him you want their best tech to come out for diagnosis. This will usually get a decent tech out to your house.


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## eshipler (Jul 23, 2007)

Thank you for your replies so far!
I know that thermostats can at times be out of whack, which is why we also have a digital thermometer to gauge the temperature in the house. The thermostat and digital actually read within 1 degree of each other at all times, so I feel pretty confident that it is accurate. Also, it has not been comfortable in the house with indoor temps above 80. It's better than outside, but unless we're sitting still it's hot!

I have it in the back of my head that if it is 106 outside, I should be able to cool my home to 78 degrees. Hopefully that isn't unreasonable--I haven't ever heard of anyone having difficulty doing this, especially with a new house and a new a/c unit. The model home's a/c for our development kept up with no problem--they kept it at 71 during 100+ temps last summer when our home wouldn't get below 81. They may have a different model of a/c, though.

If that is the case, would it be unreasonable to ask the contractor or developer for a different model that keeps up effectively (like the other units in our development do)? We're young, 1st time homebuyers, and sometimes I feel like we get brushed over because of our age and inexperience. The excuse so far has been that they heating/cooling contractor was just required to put in certain size units, no requirements on brand, seer rating, etc. Our home is 1400 sq. feet and the a/c unit is a Goodman CPLE36-1C, 10 seer unit. 
BTUH cooling capacity: 35,000 
BTUH heating capacity: 33,200 


The same company is coming out again to take readings tomorrow, and I'm a bit annoyed because they've waited from April until now (end of July) to do this. Of couse the temperature has dropped this week by over 13 degrees and our air conditioner has no problem keeping up with the 90 degree outdoor temperature.  

One more question: on the return and supply air, is it possible for it to work within the 18-22 degree parameters when it is around 91 degrees outside and for it NOT to when it is 106? 
Thanks again.

oh--forgot to mention that when they came out in March, it wasn't blowing cold air, and he had to put a can of "Boost" on the compressor outside. It worked okay for 3 days, then the same problem. He said something about adjusting levels for it to work right--maybe freon levels? Would this be a sign to anyone that it might continue to have problems? He told us that it would work fine after the one can of "Boost" stuff.


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## Malcolm (Jun 7, 2007)

eshipler said:


> Thank you for your replies so far!
> I know that thermostats can at times be out of whack, which is why we also have a digital thermometer to gauge the temperature in the house. The thermostat and digital actually read within 1 degree of each other at all times, so I feel pretty confident that it is accurate. Also, it has not been comfortable in the house with indoor temps above 80. It's better than outside, but unless we're sitting still it's hot!
> 
> I have it in the back of my head that if it is 106 outside, I should be able to cool my home to 78 degrees. Hopefully that isn't unreasonable--I haven't ever heard of anyone having difficulty doing this, especially with a new house and a new a/c unit. The model home's a/c for our development kept up with no problem--they kept it at 71 during 100+ temps last summer when our home wouldn't get below 81. They may have a different model of a/c, though.
> ...



You have a 3 ton unit. That should be more than enough to cool your house on 90 degree days. On really hot days when it gets to 106 degrees your unit will probably run all day just to maintain around a 78 through 82 degree level. I am not sure where you live, but they should have sized your unit accordingly. If you have 100 plus degree days frequently, then your unit should have been sized to handle it. A heat load calculation should have been performed to include all of these parameters. Goodman is junk in my opinion. It is a lower end unit. They installed a 10 seer unit. Usually seeing a Goodman unit installed on a new construction house means the builder is cheap or the HO wasn't willing to pay for a premium unit. I know of a 100 plus condo unit that installed all Goodman units with a poor duct design. They all struggle to maintain 76 - 78 degrees. You are asking a lot of your unit to drop from 106 to 76 degrees. That is a 30 degree temp drop. When was your house built? You can't even buy a 10 seer unit anymore. The seer rating has to do with efficiency not effectiveness in cooling your house. You should write down what the techs tell you. Usually companies that do mainly new construction have really bad technicians. Their companies just specialize in install and not service. To diagnose your system you need readings like subcool, superheat (if you don't have a TXV for a metering device), delta T, etc... I don't know what you are referring to by boost. It almost sounds like you are talking about putting in a can of refrigerant into a car. Are you sure he didn't add a superboost? This is a hard start kit to get the compressor running.


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## eshipler (Jul 23, 2007)

> Are you sure he didn't add a superboost? This is a hard start kit to get the compressor running.


Yes, you are right, it was a superboost.

They came today and the supply temp at the unit was 54, and the return temp at the grill was 79. The contractor is going to send in the information to Goodman, and they'll decide if it's running up to their specs. I did get a copy of the sheet he filled out, so we have some documentation now.

Thank you again for all the advice and help.


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## Malcolm (Jun 7, 2007)

eshipler said:


> Yes, you are right, it was a superboost.
> 
> They came today and the supply temp at the unit was 54, and the return temp at the grill was 79. The contractor is going to send in the information to Goodman, and they'll decide if it's running up to their specs. I did get a copy of the sheet he filled out, so we have some documentation now.
> 
> Thank you again for all the advice and help.



There is your problem right there. I usually see Goodmans that have only an 18 degree split. You have a 25 degree split. The guy must not know what he is doing if he needs to talk to Goodman. He should have taken a superheat reading (if non txv) so he could see what is going on. Here is what you/they need to check. You more than likely have an air flow problem.

-check your air filter. You may have more than one. I have seen install guys stick a filter in a return grill even though it wasn't a filter back grill. Check your return grills for filters and your unit. 

-Your duct work may be undersized. You really can't do anything on your own here. You need a competent tech to look at the duct sizing. The majority of service technicians no very little about duct work. You will probably need a different company to state that it is too small. Unless it is a minor fix. It will cost too much money for them to redo the ducts. Since your unit is borderline functional. They will try to BS you.

-Your coil may be dirty. I know I know. Your unit is new. How can it be dirty. Well, they usually run the units during the construction process. If no filter was installed it, will get plugged very quickly.

-Check your fan speed


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