Duct pipes frosting over in very cold temps.


  #1  
Old 12-26-17, 05:49 PM
J
Member
Thread Starter
Join Date: Dec 2017
Posts: 3
Upvotes: 0
Received 0 Upvotes on 0 Posts
Duct pipes frosting over in very cold temps.

Merry Christmas everyone! My first time posting here. As thread states, my intake and return pipes are freezing up in cold weather. We bought the house last year and there was only one intake coming into the house, no return whatsoever. So before winter I had an electrician friend install a return. He’s not qualified with heating but his brother who is, told him how to do it. Anyway, we pretty much have the same issue as before. Moisture on the exposed ducts. Before we bought the house the intake duct was wrapped in asbestos for insulation. That was professionally removed before we moved in. So I’ve now wrapped both duct pipes with new reflectix insulation. That was 4 hours ago. Just had a peek behind the insulation and it’s lightly frosted again. -30 C here. So I’m not sure if there’s an airflow problem or if the job my friend did failed miserably and needs re doing properly. I’m not that handy but am trying to learn. Getting frustrated as this is going on and on. My friend did come back and sprayed some foam insulation around the return and said that was the issue but I call BS. Please help! Cheers.

Mod note: member from Canada.
 
Attached Images     

Last edited by PJmax; 12-26-17 at 08:57 PM.
  #2  
Old 12-26-17, 09:02 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 62,035
Received 3,415 Upvotes on 3,063 Posts
Welcome to the forums.

Originally I thought you were referring to "fresh air in" and "exhaust out" lines to the furnace burner but it's the actual supply and return ducting that is frosting ?

Maybe there is a HRV (heated recovery vent) system in use ?
-30c is pretty cold.
 
  #3  
Old 12-26-17, 09:53 PM
J
Member
Thread Starter
Join Date: Dec 2017
Posts: 3
Upvotes: 0
Received 0 Upvotes on 0 Posts
To be honest I'm not sure what everything is called. I posted pictures in the original post if that helps. Basically the air duct comes from outside then there is a portion of exposed pipe that runs into the duct. That freezes up. I may have made it worse by insulating. The other piece that freezes is in the picture above with the pink insulation. Right after that the pipe leads up and to the wall and outside.
 
  #4  
Old 12-27-17, 04:56 AM
Marq1's Avatar
Member
Join Date: Sep 2016
Location: USA MI
Posts: 9,249
Received 1,100 Upvotes on 1,000 Posts
I believe this is a fresh air make up line going into the furnace. I had one once and cant recall the name but it allows outdoor air to be pulled into the furnace to mix with internal air.

Suppose to minimize air leakage around windows and doors when the furnace is running.

If that is directly from the outside and temp are -30 any warmer moist internal air will condense and freeze. More insulation might help but its simply cold.
 
  #5  
Old 12-27-17, 04:57 AM
R
Member
Join Date: Oct 2016
Posts: 2,134
Received 183 Upvotes on 169 Posts
What happened to the zoning dampers in the before pictures?
What’s indoor humidity?
 
  #6  
Old 12-27-17, 06:40 AM
J
Member
Thread Starter
Join Date: Dec 2017
Posts: 3
Upvotes: 0
Received 0 Upvotes on 0 Posts
RE the damper it wasn't hooked
to the furnace so wasn't in use and I was told it was basically redundant. Indoor humidity I turned down to 15% yesterday. Was at 20% prior. Maybe this is normal and I just have to live with it in very cold temperatures? I mean, if it's not doing harm to the furnace does it matter? Side note: when I was in the furnace room yesterday when the furnace was off, it was bloody freezing in there. Not sure if that's related. Thanks again!
 
  #7  
Old 12-28-17, 03:15 AM
S
Member
Join Date: Jan 2017
Location: USA
Posts: 447
Upvotes: 0
Received 14 Upvotes on 11 Posts
I installed one of these items in my house 40 years ago. It was more trouble than it was worth. After 2 years and numerous problems I removed it with no negative effects.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: