King Valves: unsafe???

vaporvac

Hello all, I'm hoping someone can give me some insight and help. I've already received alot of help and am thankful for it all!



So, I read the books, saw the video and probably every post on king valves, and I was sold on the idea. I put them in the schematic for my new install of SF TR50s and Slantfin approved my plans. The piping is done and now the person I'm considering to put in the venting and burners says they're no good and unsafe because they isolate the boiler and can cause it to explode if they're shut off. I thought isolation was the main idea to keep the higher pressure steam out of the rest of the system during a blow-down and one set the pressuretrol to say 7lbs to cut-out.

There are a lot of other things that could likewise cause a pressure rise and the multiple safeties should take care of that, no? I will have vaporstats, 1-15 pressuretrols and the pressure relief valves, in addition to probe lwco. Should I install additional 0-30 pressuretrols. I'm a bit freaking out over here because it would be really difficult to take those king valves out and I was hoping for heat sometime this winter.



Any thoughts on the issue itself, and how I should respond.

Colleen

P.S. The fellow seems very competent and does seem to know steam and vapor. He knew all about how my valves work, the Trane air eliminator, and that it should be run in ounces. He had never seen twinned steam boilers or a dropped header (he thought that was incorrect until I showed him my install instructions), but I think that's just because he's old school. He also said most people are ripping out their vapor systems and making them one-pipe, not that he's suggesting I do that! I might have shown him the door in that case. I don't want to offend him in any way. I just want him to put in the venting and burners and controls. Thank you in advance.

Jamie Hall

I hope they're not unsafe...

since I have them on my system!  They do have to be properly installed (sorry, I haven't followed your pictures enough) so that they are after the header and equalizer, not on the risers to the header -- but I would assume you've done that.  And of course you need a corresponding valve on the wet return -- but I assume you've got that, too.



Granted, if you then close them all off the pressure will rise.  It's supposed to.  But that's what the safeties are for -- the second pressuretrol set at 5 to 7 is just fine (mine is at 5, and is a manual reset).  Plus a pressure gauge.  And then there's always the pressure relief valve...



Plus intelligent operation, about which I have no doubts in your case!



People are ripping out vapour systems and making them one pipe?  Egad... almost as bad as trying to convert them to hydronic!

vaporvac

Not exactly...

Actually Jamie, that is not exactly how we did it as we wanted to be able to isolate the two boilers and perhaps blow them down separately. Please take a look at the attached pic. I posted the schematic and noone said anything about this feature including Slantfin technical dept., but that doesn't mean it wasn't missed. Oh boy, I hope that's not the case. I suppose we could just take off the handles if it won't work this way otherwise we'd have to completely dismantle the piping and I don't have anyone to do that. we could maybe add one to the supply pipe to the mains at a later date. Actually, we need to add one to the mains take-off anyway.

MDNLansing

Not At All

First off, anything can be dangerous if human error aligns just right. But, as long as you have pressure relief valves on each boiler, INSIDE the isolation loop, you're fine. The PRVs will blow at 15 or 30 depending on the model. You're boiler isn't going to explode at 30 psi.

Dave in QCA

King valves are fine

As long as the boiler, in this case, each boiler is properly protected. That means that each should have a proper high pressure relief valve and a high limit pressuretrol. The pressuretrol would be in addition to whatever operating vaporstat set up you are using. it Will not explode.

ChrisJ

King of valves

For what its worth the inspector had no problem with my king valves.



So far the only reasons I've used my king valves were to set and test the pressuretrol and to test steam vents.



I would be unable to really test my pressuretrol without them as it would take over an hour to finally trip.

nicholas bonham-carter

First firing?

Have you now put the match to the gas on this project, and therefore have heat?

If so then big congratulations are in order!!!

Do the boilers have names yet? Maybe christened by a box of Arm&Hammer washing soda poured in to start skimming.--NBC

vaporvac

You jest!!!

Funny, if only it were true! I have to see if he'll accept the job. It's for the venting, burners (gas line is done) and wiring for controls ( needs grounding) . He said he could do it, but he couldn't guarantee it would run like I thought it would!  Maybe he'll research twinned boilers and dropped headers, etc. He just didn't think my King valves would pass muster. I'm sure it's a bit intimidating to walk in on someone else's work, especially if it's something really different to the norm.

 I go t the impression he thought my vapour system needed something I'm not aware of to work. I personally don't see why the manner of heat should matter so long as the boiler makes steam and the pressures are low. He also said  a multi-staged burner doesn't work for steam so he didn't see the point to twinning. Like I said,  just old school, but he definitely knows steam and how to do what I want him to do. I'm hoping for a warm holiday.

I have a feeling the bubbly I'll be popping in front of the boiler won't be baking soda! At least not on the first fire. Whew, at least it's warm here today. Opening the windows to warm up the house!.

nicholas bonham-carter

Will Santa bring the boiler in time?

We are all on tenterhooks waiting for news of the first firing, are as are you I am sure.

I will be very interested in hearing how it works, and what adjustments will be made to get it into low earth orbit.

Jstar had a good piece of advice: to set the cutoff of the lag boiler to that pressure which is required to get the air out and fill the pipes.--NBC

Hap_Hazzard

If they are then so are main and radiator vents.

Eventually any steam system becomes a closed system under pressure. Even if you close the king valves, the boiler will do what it usually does--cycle on pressure until the thermostat is satisfied. That might not be until spring, but we usually don't run with the king valves shut.

ChrisJ

Yep

Another good reason for king valves.

You can test the safety devices while monitoring the system to make sure they do their job.

The Steam Whisperer (Formerly Boilerpro)

Nonsense...hogwash

1. King valves are required by code (international mechanical code Section 1005.1) on all  boilers except on systems having a single low pressure steam boiler.

vaporvac

Post reference?

Thank you NBC. Do you remember the post that was in. I'll need to figure out how to do that.

No heat yet. My "bid" (after a week) came back crazy: no breakdown, no help with starting it up or anything. The other owner says a bid like that is when someone doesn't really want the job, but will take it for a certain sum. I think he didn't like the whole set-up of the boilers, twinned wet-base for steam, king valves, vaporstats on header, drop header, etc. He was kind of shaking his head the whole time and couldn't believe it was approved by the manufacturer. I mean, I know it's not perfect, but SF did say it should work, although we MAY need a condensate tank. He did say the piping looked good in terms of the actual connections. However, I can see his point of view so onward and upward. My long-time original heating guy, who's i more or less retired, did tell me today that he could put in the venting and controls and help me get it up and running if I find someone for the burners. That's if I'm totally stuck.



Frustrating because it's so close and doesn't need much...just stuff I can't do.

vaporvac

That could explain it!

He had never seen twinned steam boilers much less know the codes for them! That 's good to know. I actually figured it COULDN"T be correct, because my original piping has them to isolate the coal and gas boiler. ( So now I don't have to put one in the supply riser.) He also said he didn't think the a drop-header was allowed.



I've been following threads since the time The Steam Whisperer WAS Boilerpro and have never seen it mentioned. Thanks for settling that, SW.



Thank you all for responding. It is good to know they have other uses besides the blow-down.

nicholas bonham-carter

The light at the end of the.........

Pipe! Here is the thread with Jstar's advice:



http://www.heatinghelp.com/forum-thread/148469/Timing-is-everything



How much piping is left to do?

Get as far as you can, and then do time and materials with the burner man to finish. You should be able simply to follow the default settings instructions for the burner to get it running, and then Mr. Burner man can come over and make the final adjustments, and be amazed that he is learning something new about steam.

Some of the manufacturers show a drop header in their installation instructions, so maybe that will put him at ease. They also show twin boilers with a double drop-header, and king valves.--NBC