Heat Trace on Sloped Boiler Drain LInes

[dave2109]

I have a question about heat tracing for an application where there are outdoor, continuously sloped boiler drain lines (1.5" to 2", sch. 80 and 160, CS and P22) running to a blowdown tank. I can undertand the need to heat trace upstream of the last block valve in the line but what about heat tracing downstream of the valve? Could there be an issue with having to drain a cold boiler where these lines could freeze while draining? The lines are insulated. The boiler is in Illinois. Anybody have experience with this situation?

 

[pmover]

thinking about this . . . if there is any possibility of the drain piping freezing in a critical operation, then heat tracing seems the logical solution.

i have seen the results of frozen hydrates in gathering systems, once broken loose by alcohol injection. The gathering piping system was shutdown, yes - in below-freezing climate, and repairs made.

i hope this helps your analysis.

good luck!
-pmover