I recently had a Goodman system installed and have some questions about the installation. My only request to the installer was that I wanted a heat pump with gas backup (no resistive heat). I also wanted high efficiency units. I went through an internet based HVAC sizing questionaire and it said a 2-ton system was sufficient. I'm a technical person but don't know much about HVAC and mostly want to understand what I can expect from the system and if the components were matched correctly. Here is what he installed:
1) heat pump - CPLT24-1B
2) gas furnace - GMS90453BXA
3) coil - CACF030B2A
4) return duct consists of 4 side-by-side 6" flexible ducts (the sticker on them says 4000fpm)
It is installed in an updraft configuration (I think that is what it is called - vertical with air entering the bottom side and exiting the top) with two PVC vents. I was poking around in it and figured out that the blower is set for high speed for cooling and medium-low speed for heating. I found the spec sheet on Goodman's website and it says that high speed it ~1128 CFM and med-low speed is ~884 CFM if ESP is 0.5.
Can anyone help me understand how this thing will perform and if there are any problems with the matching of components?
I read the site rules and I assure you this is not a DIY job - like I said, I'm just a technical person looking for answers.
If it was sized according to Manual J, the upflow system would require a nominal range of about 800 cfm.
The coil product # indicates it is 2.5 tons, which is fine when matched with a 2 ton outdoor unit.
The return duct appears to be undersized.
4, 6" flex ducts?? Is that all of the return air this system uses?
When using flex, the friction rate for that material indicates that 4, 6" flex runouts gives less than 1 ton of airflow which is grossly undersized and we haven't even considered ASP or supply side sizing.
More information is needed.
If you'd like, E-Mail me the specs and dimensions and I'll get you some answers.
[Edited by chillbilly on 04-29-2005 at 10:43 PM]
4 - 6" flex return ducts is it?????????
Furnace.....please give me air, I need....AIR!
BTW, pictures are becomming the norm.
(we would love to see pictures of this)
[Edited by jultzya on 04-29-2005 at 10:44 PM]
I don't know how to describe the supply side, and I don't know what ASP is. Sorry for not being much help getting all of the info up here.
But yes - 4 6" flex ducts is what he ran for the return. I just seemed undersized to me and I have considered letting someone else look at it and fix it if needed.
From the info I provided, can you say how big the return should be?
Thanks for the comments!
One 6" flexible duct at a .10 static pressure can only produce around 80 cfm's. All you have is approx. 320. Well short of 800 cfm,s (2 tons)You need larger reurn ducts depending on locations and chase openings provided by the installer.
For a two ton system you should have a minimum of (1) 14" or (4) 9" returns. A 6" pipe maximum CFM is 100 CFM so you have (4) you have 400 CFM recommended capacity. You desparately need to talk to a minimum of two quailfied contractors to get your installation installed properly. With that return air system you need to install zippers on the compressor to make them easy to change when you destroy them.
If you just paid someone to install this system, then why would you call another company to fix the problems and not the original installer. If this was really not a DIY install and the company you hired to install this system ran 4 6 inch flex ducts for the return I can promise you that there are more problems than the return to deal with and I would have another company check it or post pictures on this site.
OK. I guess we've established that I'm going to create a boom in the compressor industry if I don't get it fixed. I'll definitely have it looked at and replaced.
Any comments on the matching of components other than the return?
No this was not a DIY job. It was done by a friend (he is an HVAC installer) as a favor to my mother-in-law since we are building on to our house so she can come and live with us after her husband died last year.
[Edited by subwoofer on 04-29-2005 at 11:12 PM]
If your installer is a technician he should be responsible for the equipment he sold you. You should be asking him or his distributor these questions.
If the installer is not qualified, which has already been ascertained, you should call the distributer that he bought the equipment from to get their technical support involved before you destroy otherwise good equipment.
Government is a disease...
...masquerading as its own cure
Ecclesiastes 10:2 NIV
Before I started posting here, we went over our "uneducated" concerns with the installer and he felt like there was nothing wrong with the installation. We have already been in touch with another contractor but have not started any rework yet.
I am not planning on running the system until this is resolved.
Not only are you going to boom the compressor company, you will be booming other manufacturing plants as well.
Ex. heat exchangers, blower motors, inducers, ignitors, high limits, the list will never end!
The reason for calling two new contractors instead of the installing contractor is quite simple, he has no idea what he is doing. The suggestion of calling the distributor is even funnier. You are in real trouble if you depend on a distributor to know what to do. First they are generally less quailfied than the contractor and they are going to agree with their dealer almost always, he pays their bills. First get two contractors, second get a good lawyer and sue the original contractors fanny, he deserves it if he is as unqualified as you are making him appear.