72 degree vent air 75 degree return air

4701 Views 20 Replies 6 Participants Last post by ryanxo, Jun 9, 2011

ryanxo

Discussion Starter · Jun 7, 2011

I think the main issue is the lack of air flow. Air comes out of the vents very very soft while in everyone elses house it comes out fast. I don't know how to fix it.

2 Ton Trane XR11 outside and inside air handler is matched.
1344 sq ft single story house. Brand new insulated windows and insulation in the attic.
I've checked all the ducts and sealed them up.
All the ducts are insulated flex duct running off a main fiber board trunk.

I've had 2 ac Techs out here both say the system is fine. All they really did was check the freon, crawl up in the attic for 10 minutes, take my $100 deductible and leave.
My friend let me borrow his temp gun and I have been going crazy with it.
In the main trunk in the attic I took off one of the ducts and stuck the temp gun inside... it was 50 degrees. Used the temp gun at the vent(register) and it was 68 degrees with minimal air flow. All vents have low air flow.

At night air coming out of the vents is about 58. I dont think the issue is the ducts they all seem fairly new. A few of the runs are questionable with a 90 degree bend or 2 but still shouldnt effect air flow to ALL registers.

Is there a way to make this thing blow faster so the air has less time to warm up!?

1 - 20 of 21 Posts

beenthere

· #2 · Jun 7, 2011

Sounds like under sized duct. Might not have enough return either. How thick is the insulation.

ryanxo

Discussion Starter · #3 · Jun 7, 2011

Duct work is 6 inches except for the 2 bathrooms which are 4 inches which I think is right isnt it?
Insulation is about 10 inches deep in most places except for where I laid a board down to crawl out to each of the ducts to check for leaks.

How big is the return for a 2 ton unit supposed to be?

Marty S.

· #4 · Jun 7, 2011

How many supply registers do you have and what size is the duct?

ryanxo

Discussion Starter · #5 · Jun 7, 2011

There are 11 vents/supply registers in the house. 1 return.

Flex duct running to all of them. All are 5 or 6 inches (not sure exactly)except for the 2 going to the 2 bathrooms. They are 4 inches.

veesubotee

· #6 · Jun 7, 2011

Is the ductwork insulated? Colder air at night; sun is down, so attic is cooler.

ryanxo

Discussion Starter · #7 · Jun 7, 2011

ryanxo said:
All the ducts are insulated flex duct running off a main fiber board trunk.

sooo yes

ryanxo

Discussion Starter · #8 · Jun 9, 2011 (Edited)

5

OK guys I took A LOT of pics. Wanna help me out with a diagnosis?

OK This is the return... AKA where it comes out of my house and runs into the AC. Obviously I took the flex duct piece off so I could take a pic of inside. I put it back on and metal taped it when i was done. Why the Heck is their rust inside?

Resizing the pics ... be back in 1 sec

This is the side of my AC. Pretty fubar Duct work... really hoping that isn't the problem.

This is what it looks like with the return duct back on.

THis is the beginning of the main trunk. That 90 degree turn right off the bat cannot be a good thing.

And here is the whole thing

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Doc Holliday

· #9 · Jun 9, 2011

Your evaporator coil is more than 50% blocked so all heat that is supposed to be picked up from the living space is not being picked up and distributed to the outside condenser and out into the air. You are recirculating the same heat and not removing any.

You need a severe evaporator coil cleaning and I'd be willing to bet a condenser coil cleaning as well (to be able to get rid of the heat) and an air flow static pressure check to certainteed that your system is moving proper air flow and proper air flow is mandatory to system charge.

Have your coils cleaned alone and you'll drop 10 degrees supply air, gauranteed.

beenthere

· #10 · Jun 9, 2011

Doc Holliday said:
Your evaporator coil is more than 50% blocked so all heat that is supposed to be picked up from the living space is not being picked up and distributed to the outside condenser and out into the air. You are recirculating the same heat and not removing any.

You need a severe evaporator coil cleaning and I'd be willing to bet a condenser coil cleaning as well (to be able to get rid of the heat) and an air flow static pressure check to certainteed that your system is moving proper air flow and proper air flow is mandatory to system charge.

Have your coils cleaned alone and you'll drop 10 degrees supply air, gauranteed.

OH, that dirty thing is the evap coil. I couldn't see it at first through all that dirt.

ryanxo

Discussion Starter · #11 · Jun 9, 2011

Really? I thought it looked clean! hahaha

Doc Holliday

· #12 · Jun 9, 2011 (Edited)

beenthere said:
OH, that dirty thing is the evap coil. I couldn't see it at first through all that dirt.

hehe!! <snicker>

The poor guy, I'm glad he removed that duct so we saw it and could help him.

OP, air flow is critical and you have none. That is filthy. You need to have the return air duct/chase checked all around the system to ensure you are not pulling any dirty air from anywhere other than your filter grill and keep your air filters new and clean, after you have those coils cleaned.

beenthere, you made me smile. Thanks bub.

ryanxo

Discussion Starter · #13 · Jun 9, 2011

The sad part is I've had one guy clean it and 2 other AC techs come out and tell me there was nothing wrong. Yet with one little picture u guys pointed it out. Now how the hell should I clean this thing? Go at it with a can of evap coil cleaner? I don't wanna take it out of the system.

Thanks btw!

Doc Holliday

· #14 · Jun 9, 2011 (Edited)

ryanxo said:
The sad part is I've had one guy clean it and 2 other AC techs come out and tell me there was nothing wrong. Yet with one little picture u guys pointed it out. Now how the hell should I clean this thing? Go at it with a can of evap coil cleaner? I don't wanna take it out of the system.

Thanks btw!

You can use a hair brush from the 99 cent store and stroke from top to bottom WITH the "grain" of the fins so as to not bend them. You remove all of the cover dirt with a brush, be it a hair brush as aforementioned, or a wire brush and yes, you then can use a can of evaporator coil cleaner and spray it into the coil. You can pick up an environmentally friendly no rinse foaming action can of evaporator coil cleaner from The Home Depot for $4.99. Get two cans. It is a no rinse formula because the condensate from the coil (humidity pulled from the air) will rinse it off once the system is back up and running. Clean the coil with the system off.

And you're welcome.

ryanxo

Discussion Starter · #15 · Jun 9, 2011

Here is a close up. Forgot I took this one too.

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Doc Holliday

· #16 · Jun 9, 2011 (Edited)

It doesn't look so blocked in the close up. I'd clean the condensing coil as well and yes, that entails removing the lid of the condenser as well as the outter gaurds (pretty much taking the condensing unit completely apart) and spraying a CONDENSER coil cleaner into the coils from both the inside and the oustide. That you can not find at The Home Depot but I notice you have the evap coil cleaner from an hvac supply house in a pic (green can) so if you can get your hands on the CONDENSER coil can of cleaner, do that as well and that WILL NEED RINSING as in with a hose.

Reactions: 1

Doc Holliday

· #17 · Jun 9, 2011

2

ps, you're ducts ARE NOT SEALED with that cheap and weak foil tape that is already peeling off. Use mastic aka hardcast and be done with it. Yes, around where the ducts attach to the plenums and everywhere you have air flow.

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beenthere

· #18 · Jun 9, 2011

A spray can of evap cleaner sprayed on both sides. Often, dirt can remain on the fins of the coil that you can't see. You can see where he sprayed the most cleaner, and where it barely had any cleaner on it, or it was really dirty in the other areas, and didn't clean the fins off very well. Also, you might want to clean your condenser coil. After cleaning the condenser coil. You may find that it freezes up. This would indicate that it was low on charge.

biggles

· #19 · Jun 9, 2011

check the bottom seal of that supply duct at the air handler TEE-Ys would given a better catch on that supply air might be dried out with that tape if it was used...are the squirrel rounds clean and you should be HI speed in cooling mode.with the unit running how's the drag on that return grill holds up a sheet of paper:wink:

ryanxo

Discussion Starter · #20 · Jun 9, 2011 (Edited)

Outside coils were cleaned by the same guy that cleaned the inside ones. He took most of the panels off and sprayed cleaner all over it. Then went to town with the water hose.

I don't know how to put it in high speed mode. I tried to look at it and figure it out but there are just random wires that go everywhere. Not nearly as simple as everyone made it sound.

Yes it passed the intense sheet of paper test!

I really don't think it's leaking ducts that are the issue. I've been up there every day this week with the AC blasting and cannot find any leaks that are big enough to feel any air at all. The only way I can tell is with a temp gun right on the duct it is cooler than the air around it.

Yesterday, my AC was running literally ALL day. There was condensation constant dripping out the pipe out back. The copper line was sweating so much that the slab the AC is on was wet and thats with the copper line having brand new rubber insulation on it. Bought that from Lowes.

It's cooling its just not pushing out hardly any air. I am beyond frustrated with this damn thing.

Should I just rip all the freaking duct work out and redo it? I'm completely at a loss here on what to do.

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