Regular Guest
York Affinity 8T consuming more powerthan old goodman HVAC
Hello:
I got a local contractor to install a York Affinity 8T Air conditioner with a a matching air handler for 18 seer. They also installed a YORK thermostat with Humidity reading. I don't have an outdoor thermometer. However, my kWH usage was higher than my earlier 10 year old Goodman model. When I reported that my electricity bill was much higher, The installer sent a technician who said that the system was overcharged and released some freon.He also opened all the vents. I still feel that the fan is loud and running at full speed. The installer said that the thermostat was set for the two speeds of the fan. Some one said that the ampereage could be reduced. I am simply frustrated that after installing a new A/C I have to pay a higher bill. Please tell me what I should ask the technician to look for.
Regular Guest
Released or recovered?The installer sent a technician who said that the system was overcharged and released some freon
If it's the former, find a new service company and try to transfer the warranty asap.
Was charge was verified based on pressures alone without temperature readings?
Blower speed set correctly?
Is the system properly sized?
Professional Member
Airflow.Originally Posted by jigijumba
DONT close your vents - period. If your fan is loud, and it is a new air-handler, chances are it is an ECM motor, and it is starving for air. These fans will ramp up to extremely high speeds to try and compensate for restrictive ducts. In doing so, the fan will use 3 times the power for every doubling in speed.
Also, when the unit was replaced, did you by any chance increase the tonnage?
Regular Guest
I saw him checking the pressure for 100 and 325 and saw him also checking the temperature of the freon. I don't know whether he set the blower speed correctly. Could the humidity meter have anything to do with this problem. It is set at 50.
Regular Guest
No I did not increase the tonnage. The earlier one was 4 tons too. Do you think I should install another vent to increase duct usage?
Professional Member
Here in California there are a lot of folks who don't know about the five tier peek load pricing on the utility bill. People who have been living at a home for 20-40 yrs. have said "why is my bill so high? I have been pulling the same amount of power for 20 yrs." Well, there is five tiers. Example: !st tier would be $.59 after that 1st tier exceeds peek load second tier comes into play $.89 and so on... That may be the reason why.
Professional Member
Well if the 100 represents the low side pressure - then your coil is operating at around 32 degrees which is about 10 degrees too cold and is symptomatic of really low airflow, low charge, a restriction, moisture in the line or some combination.
This means your capacity i salso significantly diminished, so your unit will run much longer.
Yes you need ot measure/analyze airflow.
As for humidistat being set at 50% - this is actually a proper design condition, but given you're in Florida, you might want to bump it up to 55% - after you get the unit running properly.
God Speed, Jim. We'll miss you - 2-26-23
Sounds like your system is still incorrectly charged.
Regular Guest
What should the low end pressure be. One of the technicians said it was 80 and charged the system. Then the other guy said it was too charged and reduced it. Who is correct?
Professional Member
Depends on the load and outdoor temps, but a high-efficiency R410a system should be at least 120 to 140 psi. If R22, then 68 to 80 psi. Your initial pressures sound like a R410a system to me.
Regular Guest
Pressures vary - subcooling and superheat are what count. (If there's nothing wrong with the system)
There's no point of putting gauges on to a system if the blower speed isn't set correctly.
Professional Member
Sounds like one or both don't really know what's in there.
God Speed, Jim. We'll miss you - 2-26-23
Neither.
If looking at pressure is all they know. Then they have other customers in the same situation.
Can't just slap a set of guages on that unit and look at the pressures.
Regular Guest
What should the blower speed be. How can I check it.
Last edited by jigijumba; 10-29-2009 at 06:48 AM. Reason: spelling
God Speed, Jim. We'll miss you - 2-26-23
400 CFM per ton.
Professional Member
As Beenthere noted, 400 CFM/ton is the golden rule of thumb, but the actual speeds are selected during design time.
My recommendations are based on your local desing conditions. What state are you in?
If you are in a Gulf state - then I would recommend 350 cfm/ton. If you are in the high plains, desert states (So. Cal, Arizona, etc), locations with low relative humidity, then you really need to be up at 450 cfm/ton. Everywhere else you can use 400 cfm/ton.
One issue I see all the time is techs never look at the fan speed settings and leave it at factory defaults - which may or may not be appropriate for your system. With the new variable speed fans, you can have a very wide range of operating cfm's, so it is very easy to overshoot or undershoot desing (needed) cfm.
Another big problem I see is with air handlers made for heat pumps; often there is a missing internal panel (for where the electric strip heat goes) and air ends up recirculating within the box itself causing a major depression in airflow and evaporating temperatures. This usually goes hand-in-hand with techs not openign up the box to set the fan speed.
Regular Guest
I live in South Florida where the humidity is very high. I dont think that the tech touched the fan speed. Can I measure it at the intake. I don't have a heat pump.
Regular Member
My York furnace blower, my air handler, was set way high for the unit size, something like 1950 CFM for a 4 ton unit as I recall. Can't you just look at the jumpers for blower speed in the air handler and consult the installation manual for 400 CFM/ton (1600 CFM for 4-ton)? If you didn't get the manuals, is there any info on inside of the AH cover?
Regular Guest
Thanks. I will try that today when I go home. But for Florida is 400cfm per ton correct?
God Speed, Jim. We'll miss you - 2-26-23
Did they set up a slow ramp up profile?
If so. 400 may be fine. 350 tends to use more electric then 400. On hotter days when humidity removal is not a problem.
Last edited by beenthere; 10-29-2009 at 04:01 PM.
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