Return Air problem??

[perrybucsdad]

Okay... had a service tech come out yesterday and he tested the static pressure. It was 1.2. According to the blower info, that is off the charts and that could be the whole problem.

I did tell him that the builder wants to send out the installer to fix and he pointed out a few things. He said to make sure the installer checks and cleans the coil and drain tube, but to also point out to him that it is being starved for air.

As you may remember, the night before I had removed the door infront of the blower. Well, I had run the unit all day yesterday with the door off (I placed a filter vertically over the door and duct taped it in place so as not to suck any cats or dust into the unit), and the house stayed nice and cool (72 degrees in the heat of the day .. I think we were 88 yesterday). So adding more air on the return side really helped. He felt that a whole new return duct needed to be done. He said the return lines just seemed too small. He also said that the blower was quite strong and that I should not need a larger blower as that would just be a band aid on the problem.

Anyhow, the guy really seemed to know his stuff, and was very professional. Not once did he criticize the installer, but just made constructive remarks on how the system could be improved. I wish I could get my builder to use him as opposed to the installer that we have. I would much rather go with quality over low bid any day.

[beenthere]

Keep his phone number. You may still need him after the builders guys are done.

[perrybucsdad]

Keep his phone number. You may still need him after the builders guys are done.

That's what I was thinking too. If the installer just can't do it right, I would think the builder is still liable to get it working correctly. If so I will push him to use this guy.

It was just refreshing to not hear "well whoever installed this crud didn't know what he was doing." It was more "well, here are some things that could be optimized" and "this is a bit small, but can be fixed". That and the fact that even though he knew he wasn't getting the job to repair it, he took the time to tell me what needs to be done. That I thought was really classy.

One question I didn't ask him though was this. If air is entering the blower box from the return side now, and also through the front, that basically means I need to double the air supply ( or maybe more since he said we still should have more airflow). If that is the case, how can you do that with only using the existing opening? Would the single opening be able to handle more air coming from a much larger return duct?

[beenthere]

A larger return duct will allow air to return to the air handler easier.

But, if that 1.2" is with the blower getting air from both the regular return and with the blower door off. You need supply duct corrections.

Do you know what the individual static reading are.

[perrybucsdad]

The 1.2 was with the cover on the unit. He did not do a reading with the door off.

As for the individual readings, I have those at home. But no, I don't know the individual readings right now. Will that tell me if it is more a supply or deliver side issue (or both)? He seemed to concentrate on the supply side with all of him recommendations (other than his comment about inspecting the coil and cleaning it).

[beenthere]

Yes, individual readings will tell which one has the most trouble.

[perrybucsdad]

Okay... just out of curiosity though, in an ideal system, would both numbers be the same?

[udarrell]

This thread has been very interesting.

He could & should have done a lot more pressure drop checking to pinpoint where all of the excessive pressure drops across areas are located.

The ESP when checking before blower - RA side - & before entry to the A-Coil could even be low & airflow could still be low, in that case you would check for major duct leaks on the various runs, or lint clogged blower wheel blades, etc.

A combination of major duct air-leaks & restrictions might leave you with a good looking .4" to .5" ESP, & low airflow, which calls for a tech that knows how to troubleshoot a duct system.

http://www.udarrell.com/external_sta..._readings.html
- udarrell

[beenthere]

Okay... just out of curiosity though, in an ideal system, would both numbers be the same?

In ideal land, they would be. In our world, they won't be.

[perrybucsdad]

Thanks for the great link udarrell.

In reading your link, I keep seeing things about duct leakage. I can understand this on the supply side, but do I need to worry about that on the return side?