Heat Pump Efficiency VS AHU CFM

[54regcab]

Some systems are actually smart enough to adjust the blower speed based on air discharge temperatures. The blower can slow down to increase discharge temperatures.

[pendetim]

Wow, automaticly slow down to maintain (or at least reduce the droop ) of the discharge air.
This is a Goodman AVPTC3137 AHU mated with a ASZC18 HP and a CTK03 Stat so it is pretty smart.

Does it have this capability?

[54regcab]

Not sure. Have to know the specific system or pull the install manual to know.

[pendetim]

Hi 54regcab,

Here is what I have installed, does it have the smarts to slow down the blower based on delta T or some other parameter to allow the discharge temp to rise as OAT get cooler?

Amana 3 Ton 18 SEER 2 Stage Heat Pump Condensing Unit ASZC180361
Goodman 3 Ton Low Leak Variable Speed Air Handler AVPTC313714
10 KW 60 AMP Heat Strip for Air Handler HKR-10C
Goodman Comfort Net RedLink Communicating Stat CTK03AA
RedLink outdoor thermometer

Many thanks for any information!

Tim

[54regcab]

I'm not a Goodman dealer, so I'm not familiar with their higher end stuff. Goodman is good about putting their manuals online, many of them are on their website. You can pull the PDF's and read through them.

[pendetim]

Thanks, I looked through the setup manual but did not see that feature. Just hoping that I may have missed it.

No big deal I will just turn it down in Jan/Feb if cold breezes become noticeable.

Tim

[tedkidd]

Nice thread Penditim. Very interesting to learn about the Goodman system and hear install feedback.

Comfort issues? Do you find yourself frequently occupying a space wher there is direct airflow?

[54regcab]

Most 2 stage systems I've seen is compatible with varying the speed from low to high when the condenser changes speed. Some of the newer systems with communicating thermostats can vary airflow by delta T, but most are simple hi/lo based on condenser speed.

[pendetim]

Hi tedkid,
No real comfort issues currently as the system has been running mostly on low speed due to the warmer than usual weather the mid-Atlantic has been experiencing (knock on wood!) recently. I know however that sooner or later mother nature will dish out a load of cr*p and the outside will get colder. I am just seeing what the options may be if needed later in the winter.

Not sure what you mean by "occupying and area with direct airflow" but if you mean do I set next to a register, the response is: no. Sometimes however when the system is on high fan during a "recovery" from 65* overnight->68* wakeup, there is a slight noticeable coolness. The register temps are in the 90-92* range which is the same as on low fan so I am attributing this feeling to the increased air velocity and possibly moving some cooler air out of the corners of the room.

This 36KBTUH 2 stage heat pump system is replacing a grossly over-sized propane hot air furnace (90% eff 80KBTUH input) that my wife used to liken to a jet engine when it came on. We NEVER was comfortable with that. It went from too cold, cycle on, hot blast, too hot, comfortable for a few minutes, too cold, rinse , repeat. LOL