How to fix air conditioner condensate drain pipe?

Dashi Powder

Hi,

We’ve noticed a small hole/gap where the internal AC unit connects to the exterior piping. This gap appears to be allowing moisture or humid air inside, as we are now seeing mold forming on a small patch on the wall inside the house directly above the unit.

Could you please advise on the best way to fix this?

• What is the best sealant or material to close the external gap?
• Do we need to treat the internal wall to ensure the mold doesn't return? Currently we have cleaned it with some vinegar + water mixture. Thanks!

• 

JacobZ

Hi @Dashi Powder,

Welcome to the Bunnings Workshop community, it is fantastic to have you with us.

While moist air in the eaves could be a contributory factor, as there is currently mould and the potential for further moisture issues, I wouldn't simply assume this is the cause. I'd suggest you contact an air conditioning technician and have them come out to inspect things, to confirm that there is not an issue such as poorly insulated refrigerant pipes as they can often be the cause of condensation forming and transferring into the wall.

That said, it is still a good idea to seal the gap in the eaves to prevent moisture, drafts, or pests from entering. An exterior grade silicone is generally the way to go, but if the hole is larger than it appears with the cowl in place, expanding foam can be used.

Cleaning the affected wall area with a vinegar and water solution is a good first step which should neutralise the mould. Once the area is fully dry and the moisture source is addressed, the mould should not return. If you would like extra protection, a mould resistant paint can be used after the surface has completely dried, but this shouldn't be necessary if the mould has been killed and the moisture issue has been managed.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob