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GC/Master Plumber/Mech
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Discussion Starter #1 (Edited)
A couple of days age I replaced a condenser and a coil in a mobil home.

It was a 3.5 tn, 13 SEER, R-410a. My distributor said that they had a mobil home coil because a 13 SEER A-coil would not fit due to height restrictions.

The old coil was an A-coil and the new coil was a N-coil.

Couple days later I get the call that it will not cool below 75 deg. I went and hooked up gauges High 325 and I had a 13 sub cooling. Low was 108 and I had a 20 super heat. Amps were 13.5
Out Amdient was 85
Inside wet bulb was 70

So I thought low air flow. My rep said to just add more vents because of low air flow across the coil. In which I told my rep that it worked fine until the old compressor shelled so why add more vents. I have a 12x14 trunk and eleven 6" branchs to register that are 4x10

I talked to another tech who said that N-coils do not work in mobil homes and to replace it with an A-coil.

I can get a 13 SEER A-coil from a mobile home supply that will fit but,

My question is will a N-coil work or not work in a mobil home down flow.

The furnace is a 80% downflow
 

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Mobil homes are some weird beasts compared to residential.

I have my own suspicions on why the N coil did not work but I want to hear from somebody with more knowledge on the subject, but I think there is an issue of getting enough air thru it. I have had some narrow plenums that wouldn't accommodate an A coil for the tonnage I was using. Put in an N coil and had to pull it and use the A coil with anew plenum. Air flow problem there too.

I have always used OEM mobil home coils to avoid the problems.
 

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GC/Master Plumber/Mech
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Discussion Starter #3
Me too. After doing some sizing I think I have enough main duct and branch ducts. But my rep keeps saying add another 7" and a 4x12 reg.

I just don't get that with the old system being a 3 1/2tn and an a-coil and worked fine until compressor melt down that just adding more branchs will help.

I am ordering an a-coil in the am and replace on thursday.

I have only had to call my rep 3-4 times in the last couple years and every time it's add more duct. He and I will have a chat in the am.

HO called another company and they also said that needs an a-coil. She said that she called another company because she didn't want any more registers and I had to agree.

Thanks clover.

I had to kick my own arse because I had forgot that I had an account with a coleman distributor..should have put a coleman in.
 

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GC/Master Plumber/Mech
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Discussion Starter #4
Mobil homes are some weird beasts compared to residential.

I have my own suspicions on why the N coil did not work but I want to hear from somebody with more knowledge on the subject, but I think there is an issue of getting enough air thru it.

I have always used OEM mobil home coils to avoid the problems.

Do you think it is because of the return on most MH are not ducted and have the filter rack and intake right on the furnace??????
 

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Do you think it is because of the return on most MH are not ducted and have the filter rack and intake right on the furnace??????
No I think that the N coil takes up too much lateral space and it probably cause a lot of turbulence in the plenum.

I have never heard of adding more ducts to a mobile home. They are either AC compatible or not.

The non compatibles are all old models and would need pkg units.

I think your rep needs to brush up on mobil homes.
 

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Those N coils need a good opening into the duct to move air. Almost need a space between them and the duct.

You can get Mortex coils for MH applications. They're short enough.
 

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HVAC / Plumbing
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let me quess . It is a rheem coil right ?? the coil is uncased correct ??? If your talking about the rheem N coil .. I installed 1 in a M.H. on top of the air handler using the same 10 seer condenser last month..I called the cust several times & they say all is well The M.H.is about 2000 sq... I hate those :censored:coils & hope I never see 1 again
 

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GC/Master Plumber/Mech
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Discussion Starter #9
Ken,

N-coil is an ICP product and I installed ot on a coleman downflow


Been, tell us more
 

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In a slab installation, where you have a plenum under the coil. You still get good air flow from them.

But, when the trunk is fastened to the coil. You lose air flow from the coil. The right side, seems to interfer with the air comong from the A part.

Why, not sure. Just the way the work.
 

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Hvac Pro
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Probably turbulence. I am sure the air coming out of a direct drive fan may have some turbulence due to the fact that the motor blocks 1/3 of one opening. Lennox won't allow RA ducts to be mounted to the back of furnaces anymore. Side connection only.
 

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Discussion Starter #12
Those N coils need a good opening into the duct to move air. Almost need a space between them and the duct.

You can get Mortex coils for MH applications. They're short enough.

Thiw would explain why my rep called and said to put a piece of 3/4 conduit under the coil on each side. What total BS
 

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Probably turbulence. I am sure the air coming out of a direct drive fan may have some turbulence due to the fact that the motor blocks 1/3 of one opening. Lennox won't allow RA ducts to be mounted to the back of furnaces anymore. Side connection only.

Are you saying this as new news? Just trying to get clarification cause all my peers have avoided rear RA taps since I can remember.
 

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The hackers will hack em in that way. Run into a few old belt drives that came in the back, especially the over 200,000 BTU big old boys. Cannot put cooling coils in the RA duct of newer units either.
 

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HVAC / Plumbing
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Ken,

N-coil is an ICP product and I installed ot on a coleman downflow


Been, tell us more


The 1 I used was a rheem coil.. I installed it on a coleman 3.5 Ton down flow.. I didn't like it( the N coil ) but It worked well. It is uncased & sits on top of the A. H... Problem I had was trying to figure out where to mount the TXV blub. I haven't heard from them . So, I assume every thing is working fine. I Hope I never have to use an N coil for a M H again. I will go miles out of the way to get an A coil.. Your install may be somewhat different, than mine.. The 1 I installed sits on top of the A.H. uncased.. The A.H. sits behind a luvered door. All the return air comes through this luvered door across the coil... There is no duct work at all attached to the coil
 

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GC/Master Plumber/Mech
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Discussion Starter #16
Mine was mounted below the AH and was behind a louvered door.

This mornig my rep called to let me know that on a 3 tn or larger to install an A-coil and 2.5 and below it would be OK to use a N-coil.

I'll be replacing the coil on thursday and let ya all know what happens.
 

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Good luck .. The A will probably cure the problem. I've only worked on 2 M.H ac's & both coils were on top of the A.H. I didn't know they came both ways....
 

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Yuri, Been, Clover or anyone.... I guess this applies to a wannabe also:eek:
Maybe one of the others will know what your trying to say.

Its over my head.
 

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GC/Master Plumber/Mech
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Discussion Starter #20
Over his as well:thumbup:
 
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