CSLB C-46 Solar ContractorSolar Thermal System InstallationEasy
A solar thermal installer is positioning a flat-plate collector array on a commercial building's flat roof. The array consists of three collectors in series. To ensure proper drainage and air venting, what minimum pitch should be maintained for the collector headers and piping?
- A1/4 inch per foot
- B1/8 inch per foot
- C1/2 inch per foot
- D1 inch per foot
Show answer & explanationAnswer & explanation
Correct answer: B. 1/8 inch per foot
Maintaining a minimum pitch is crucial for proper fluid movement, drainage, and air elimination in solar thermal systems. A common standard for this pitch is 1/8 inch per foot.
Why the other options are wrong
- A. While a 1/4 inch per foot pitch would work, it's not the minimum required and may lead to unnecessary elevation changes.
- C. This pitch is excessive for typical solar thermal piping and could create installation challenges without significant benefit.
- D. A 1-inch per foot pitch is far too steep and impractical for most solar thermal installations.
Collector Pitch
The minimum slope required for solar thermal collector headers and piping to facilitate fluid drainage and air removal.
- Prevents air pockets
- Ensures complete drainage (e.g., for freeze protection)
- Standard minimum is 1/8 inch per foot
Memory trick: Pitch the pipe, lest air it grip.