Check the heat pump first. Get a second opinion on adding a return. Try a new company. You need as much area as the sq inches of the filter. Sometimes a super filter is too much.

Both heat pumps have been checked. So far the only thing wrong they have found is a bad sequencer on the downstairs unit. The sequencer was only energizingone of the three heat bars.

As for filters, I used to use the pleated filters, but have switched to the cheap blue ones to reduce air flow restrictiion.

I have had two companies look at my system. The only thing they seem to agree on is that my air flow was too low. The second company is scheduled to come out Monday to replace the sequencer and wants to increase the size of the flex line from 12 to 16 inches on the upstairs return and mount the another return on the air handler downstairs. I just want to make sure that I am not throwing good money after bad here.

Will these changes make a big differance? Will the "increased" airflow help the heat pump produce more heat so it does not depend so heavily on the aux heat?

Check your fans and coils to make sure they are not dirty. I had bought a house where the previous owner had pets and NEVER installed filters. Big Difference after cleaning layers of pet hair off the coils and fan. (So bad I had to remove the blower to clean it)

reduced air flow by too small of duct affects operations. Air flow is very important.

I did have that checked, in fact it was the first thing I had both companies look at. A little dirty so they cleaned them out. Did not make much of a differance. The air flow is so low that both of the heat pumps freeze up near the compressor when the air conditioner runs. My main question is changing from a 12" line to 16" line going to make that much of a differance for the air return. They are using the same air return grate 14"x24" and just increasing the air return line diameter by 4". To me that does not seem like it is going to help much. Would a whole new separate air return be much better?

Any other ideas guys? I have the guy coming in tommorrow. I just want to make sure that I am not wasting money.

Thanks

If the unit is not keeping up I'm not sure increasing return size is going to help how many sqft is your upstairs is your ductwork in the attic and is it properly sealed

About 800 sqft. The attic has about +12 inches of blown insulation in it. The duct work is insulated flex line

jbelle

I suggest taking some supply temperature readings at various locations within your home from both systems running. Assuming each system is operating correctly and are charged within specs, one has to look at other possibilities such as poor ductwork design, insulation issues, and finally undersized systems(which is all too common). Ask your dealer to also check the temperature differential between supply and return temp. Normally the differential should be 16-20 degrees.

IMO

Update:

The repair guy just left and here is what he found.

The upstairs unit's air flow was low and he fixed that by chaning the 12 inch line with a 16 inch line. Still not sure if that was better choice than putting another air return, but he says it has about 800 cfms now which is suitable for a 2 ton unit.

It turns out that my downstairs unitl had too high of an air flow with about 1500 cfms for a 2.5 ton system. He "repaired" that by putting a piece of sheet metal in the basement return to reduce it's air intake. The heat seems to be hotter coming out of the vents now, but some of the vents have very low air flow. Damned if I do, damned if I don't situation.

After he got the air flow "corrected" he finished checking the system and found that both heat pumps are still freezing up at the compressors and they are building up way too much pressure. He thinks that both of the coolant lines have blockages or are restricted. If these blockages are not fixed he says the cooling/heating compacity of both systems will remain greatly diminished and that the one compressor will probably fail within a year due to the constant overpressure.

Anyone else have any experiance with this? How about home warrenties, do they typically cover situations like this?

Thanks

The proper air flow for a 2 1/2 ton system is 1000 cfm. The speed is set electrically at the air handler not by installing a piece of sheet metal. The rest is duct work Poor design/installation results in poor air flow. Jacking up the blower speed will not do much for circulation. The blower max pressure is .5"wc. I don't care how big the blower is thats the limit and your air flow will be limited by the pressure.

Your systems are icing up due to low air flow or improper refrigerant charge. You really need someone who understands air flow, how to size and set up a system. All we can do is guess.

Good luck,

My 2 1/2 ton is at 1200 cfm and my 2 ton is at 800 cfm so
neither system has low air flow anymore. The sheet metal was put in place to reduce the air intake on one of the returns.

The sheet metal was put in place to reduce the air intake on one of the returns.

that is like saying my water hose was putting out too much water so i crimped the hose to reduce it instead of simply turning the spigot down some. the "tech" should have changed the jumper in the airhandler to lower the fan speed, NOT blocked the airflow. if anything he just made the blower work harder and possibly you will start to hear whistling inthe duct fromthe restriced air flow. heck, mine whistle if i forget to change the filter on time.

I would contact the National Comfort Institute. They may have a contractor in your area that specilaizes in air flow. I don't know much about the NCI, but its worth a shot, considering the hacks that are out there.

www.NationalComfortInstitute.com

Good luck.