distance you can solder from plastic

Ray Landry_2

On the plastic question I would say four pipe diamters but i'm not sure.. I say that b/c i think that is the rule of thumb distance you can solder from a pro press fitting. A tempering valve is used to blend together supply and return water so that a tempature (usually above 140) can be acheived on the return side of the heating boiler regardless of the cold return water coming back to it. Not sure about the wire mesh size i have always used the manf. supplied mesh which is probably about 3/8" large. hangers and supports codes change from state to state but here in mass 3/4 copper is ever six feet horizontal ten feet vertical or every story height

burnerman_2

questions

i am wondering 1.distance you can solder from plaetic 2.why you use 3 way tampering valve when return water is below dew point ?? 3 3.what is the min. wire mesh size to use on combustion air if you are wandering its for a test i have looked in a lot of books and have not found these answers one lsast distance for 3/4 copper pipe that you hang from ceiling 6feet /?

burnerman_2

hydronic test

in one book it says 30 min another its 100 pd for 15 min next ques. checking ohms in a thermosister do they increase when you set down themostat or derease when i look at many books / and the answers are different it is kinda of hard to know whatthey want is there a book on passing the maryland hvac license test ???

Cosmo_3

Generally in most manuals I have seen they want at least 18" away from plastic. Better yet, use a wet rag, or heat absorber also.

Cosmo

Pat Follo

18\" as well

All of the literature I've seen up here in CT. also says the minimum distance between plastic piping and a solder joint should be 18". I'll see if I can find anything in the Internation Residential Code regarding the other questions.

Pat Follo

Openings for Combustion Air

I don't know if this holds true in your state,but it's a start, I guess.....According to Section M1703.5 of the International Residential Code "Outside combustion air openings shall be covered with corrosion resistant screen of equivalent protection having not less that 0.25 inch openings and not more than 0.5 inch openings."