Fresh air intake duct icing up - anyone have this issue before?

[nagooro]

A few days ago I noticed a fairly large piece of ice forming on the exterior of the fresh air intake duct in our furnace room. I used a blow dryer to melt the exterior ice build up, however, I can still feel a fairly large piece of ice and a bit of water on the inside of the duct.

I typically run my furnace fan 24/7, but set it to auto for now in case its making things worse by continuing to bring in cold air.

Are there any typical causes for this? ie. hole/tear in the insulated duct that's allowing the cool air to meet the warmer air inside my home and then condensate/freeze? Could my duct work be fine and its just the nature of these cold snaps?

As it gets a bit warmer I'm sure ill be left with a bunch of water inside the duct, is poking a hole to drain it manually a good idea? Or run the fan and try and evaporate it?

House was built just over 3 years ago. Going to contact my builder and see what they say, but was hoping to get some more input as well as I have little to no experience in the HVAC area...

Thanks

Few pics:
https://i.imgur.com/IqrRpwZ.jpg
https://i.imgur.com/w4FfIji.jpg

[ThePenIsMightier]

Fan running 24/7 will not make this better or worse, so go ahead and turn that back on. That's not a combustion line, that's the fresh air intake to your HRV so air is (predominantly) only flowing through that when your Heat Recovery Ventilator is on. IE: when it senses (based on your setting) that your humidity is too high.
This isn't normal, even at -40, so something is wrong but it's not a huge deal.
As a quick fix, I'd melt it and then wrap a couple old t-shirts around it, held on gently by twist ties or zip strips. Also put a bucket or tray under it.

The insulation must be messed up or missing in a patch near there. Builder should fix. The water/frost will most likely be mainly where you see it, not as much inside. (My guess).

[firebane]

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A few days ago I noticed a fairly large piece of ice forming on the exterior of the fresh air intake duct in our furnace room. I used a blow dryer to melt the exterior ice build up, however, I can still feel a fairly large piece of ice and a bit of water on the inside of the duct.

I typically run my furnace fan 24/7, but set it to auto for now in case its making things worse by continuing to bring in cold air.

Are there any typical causes for this? ie. hole/tear in the insulated duct that's allowing the cool air to meet the warmer air inside my home and then condensate/freeze? Could my duct work be fine and its just the nature of these cold snaps?

As it gets a bit warmer I'm sure ill be left with a bunch of water inside the duct, is poking a hole to drain it manually a good idea? Or run the fan and try and evaporate it?

House was built just over 3 years ago. Going to contact my builder and see what they say, but was hoping to get some more input as well as I have little to no experience in the HVAC area...

Thanks

Few pics:
https://i.imgur.com/IqrRpwZ.jpg
https://i.imgur.com/w4FfIji.jpg

There is a hole there somewhere. Could be super small but one exists.