Good heavens! Never mind "parallel structure" — that sentence has a dangling modifier rendering it ridiculous. The sentence says that the members and guests are heated to a comfortable temperature. I’m fairly sure that it is the swimming pool that is heated all year round, but “swimming pool” doesn’t even appear in the sentence. Possible fixes: “Members and guests can enjoy swimming all year round in our comfortably heated pool” or “Our comfortably heated pool allows members and guests to enjoy swimming all year round.” And no, I don’t see anything “parallel” about it. Could you elaborate on what you had in mind?

Thanks Nanren, Yeah, the list is noun count but first one "Heated to a comfortable temperature" is phrase(may be noun phrase) but others two are just noun. That's why little bit confused!.

https://www.evergreen.edu/sites/default/files/writingcenter/handouts/grammar/parallel.pdf says ... Parallel structure (also called parallelism) is the repetition of a chosen grammatical form within a sentence. By making each compared item or idea in your sentence follow the same grammatical pattern, you create a parallel construction. Example Not Parallel: Ellen likes hiking, the rodeo, and to take afternoon naps. Parallel: Ellen likes hiking, attending the rodeo, and taking afternoon naps. OR Ellen likes to hike, attend the rodeo, and take afternoon naps. . With the pool heated to a confortable temperature, guests, memebers and others can .. Does a list of nouns count?