Swing Check vs. dual check vs. double check valve

[Winslow]

It looks like the pressure relief valve is piped to daylight. Why not pipe the drain to daylight also. Thats the way I do it whenever possible. Otherwise according to you're drawing it might be better to put a standpipe off the tailpiece and drain it indirecly through the standpipe, maintaining an air gap between the two. I would run that by the inspector before putting in a check valve that requires pressure to open it.

 

[Smooky]

In the initial post it was said that the inspector requested the dual check. The only way sewage could get into the steam generator would be from back siphonage and not from back pressure. The inspector may have meant to put the dual check in the supply line before the steam generator. Also the water flushed from the unit would still be clean water but maybe much hotter. I would think it could be piped out to the ditch or storm sewer as mentioned above.

 

[Sponsor]

 

[hj]

quote; The steam unit is connected to the potable water supply which must be protected from backflow from the steam unit.

In that case the "backflow preventer" goes in the feed line, NOT the drain line.

 

[Tom Sawyer]

Yes, on the supply. Typically the drain will go into an indirect waste. I may have missed the opening here. Is the inspector asking for a dual check on the drain?

 

[hj]

quote; Is the inspector asking for a dual check on the drain?

The original posting said he wanted it in the "autoflush" line.

 

[Tom Sawyer]

Yep, I see that now. Sorry for the confusion. It was a long day