New AC not so cool
Yesterday we had our 22 year old 3 ton York heat pump replaced with an Amana ASX14 1.5 ton (Our house is only 1500 sqft). The new unit us much quieter and will save us allot of $$ on electricity but it seems to cool way less than the old York it replaced.
I recall reading somewhere that the unit comes pre-charged (R410) for 15ft of tubing but the distance from my condenser to coil is easily over 30ft.
Could this be the reason why the units cooling performance is so poor?
(The installer ran the vacuum discharge for about an hour before turning the unit on, was this enough to get air out of the system?)
The installers should have adjusted and checked the refrigerant charge.
The system may be undersized. The nominal capacity of the system was cut in half. Was a load calculation done to warrant this change in capacity?
Your 3 ton may have been over sized.
How did they determine that your house only needs 1.5 tons.
Did they do a load calc, or did they just guess, based on 20 to 30 years of guessing.
Yes, a low charge does cause poor cooling.
Thanks for the quick reply!
I don't think the installer checked the charge post installation, that's my worry.
A load calculation was done during the energy audit and the old 3-ton was deemed over sized for our small house.
I will call back the installer and have him check the charge.
What area are you in. And what did the load calc say the load was.
Although not impossible for 1.5 ton to be the right size for a 1500 sq ft home.(1000 sq ft per ton)
If its a rancher, few of them get by with only 1.5 tons.
Sorry, I do not have the load calc info with me here at work. We are just outside of Toronto Canada.
After they check the charge. If its still performing poorly. I would suspect a sizing error.
I would ask to see the load calc nmbers.
Toronto, Canada summer design 87 dry bulb 72 wet bulb 48 to 49 %RH.
A high humidity level in your home will affect the cooling performance.
At this point, I would NOT condemn the sizing of the equipment.
There could be a lot of things wrong with the setup of the system!
I hope the airflow CFM is correct for the 1.5-ton system.
Have the duct system checked for hot Return Air leaks.
Should have added the correct amount of R410, - perhaps not!
IMO, in Toronto, with the proper reductions in heat gain, & correct airflow CFM, a properly functioning 1.5-ton should be enabled to work okay.
I spoke to the installer and he is coming to check out the performance this weekend.
Have him check it by Amana's sheets.
They have a good spec sheet for how your unit should be performing.
As Udarrel said, 13,500 BTUs of sensible may be enough.
Then again, it may not.
Copy only the data portions & paste in your Word-Processor, make a couple hard-copies, then get as much of this data as the tech will provide for you.
Originally Posted by TheDogFather
TROUBLE SHOOTING DATA
TXV or orifice metering device? _______
Outdoor condenser’s DB discharge-air-temperature _____
Out-Door temperature: ____
Condenser air split _____
Indoor Total-ESP _______
All Supply Air velocities in FPM: ___
I'll figure the total CFM:
Suction line pres. _____
Suction-Vapor line temperature: _______
SST – Gage - Suction Saturated Temperature. ______
Head pres. _______
SCT – Gage - Saturated Condensing Temp _______
Liquid line temperature: _______
Return Air temp DB &, WB or %RH: _______
Supply Air temp DB &, WB or %RH: _______
With the information data below and an accurate CFM airflow + sea-level height, I can ball-park its BTUH output
Return Air temp DB &, WB or %RH: __
Supply Air temp DB &, WB or %RH: __
Except for the pressures you can take most of the readings for us.
My advice: get a low cost humidity gage at a local hardware store & see what the percentage-RH is in your home, I can cross-reference that to the wet bulb depression.
Then, perhaps we can provide a ballpark BTUH & an opinion on how well the 1.5-ton system is performing. - Darrell
All good points. What indoor equipment was installed? How was the blower set up?
Originally Posted by udarrell
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...masquerading as its own cure…
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