Originally Posted By: Ron Peters
This post was automatically imported from our archived forum.
The HVAC company is right.
The internal condensate pan, with the primary and secondary drain lines, is all that is required.
The IRC (M1411.3.1) requires a ?secondary drain or auxiliary drain pan?. The key word is ?or?. Since the installation depicted has the secondary drain at the internal pan, the auxiliary pan is not required.
Note that TREC has no requirement to identify as IR the lack of an auxiliary drain pan at HVACs (535.229 - q). However, it is required for water heaters (535.229 - k - 9) ?when applicable? (i.e. leakage will cause damage, IRC P2801.5).
The use of a secondary drain pan could add another layer of safety for when the internal drain pan corrodes or in some other form leaks. However, most of the time I have found the aux. pan littered with insulation and other dust, debris, etc. which would clog its drain right away. This ?extra layer of safety? potentially makes leakage more likely in those installations where a secondary drain line is not installed to the internal pan, and the condensate overflow would go to the aux. pan before trying to reach the aux. pan?s drain line.
I hope this helps.