King valve

Peteys

Any other purpose for a king valve other than blowing down mud leg under pressure? The reason I ask is that I thought I would be able to shut valves for summer operation but dry return vents start leaking a lot of water if closed. Aquastat on 160. Any higher and steam mains get hot.

Rod

King Valve

Hi- I found King Valves very handy when you want to just test one steam main or want to test the cut off /cut in settings in your pressuretrol / vaporstat.



Keep in mind that the Aquastat just measures the output temperature (160 F)  of your DW heating coil, not the temperature of the boiler water. If the DW heating coil is only partly submerged in the boiler water, then the boiler water temperature must be much higher temperature to maintain the 160 DW output. temperature. The solution is to raise your boiler's water line an inch or two, to completely submerge the coil, during the summer months and return it to the normal level in the fall when you are heating your home. When making steam having a partially submerged coil isn't a problem as the steam heats the coil.  I would leave King valves and Return valves open at any time I was running the boiler be it for steam or just domestic hot water.

- Rod

Jamie Hall

Perhaps a stupid question

but, did you also close the valve or valves on the return, so as to isolate the boiler from the system?  If you just closed the steam king valve, but left the returns open, I can see a situation where pressure could build in the boiler and force boiler water back into the returns...

Peteys

Yes

That's exactly what happened. Don't have a valve on my return yet. Thought I'd be able to get a higher temp to my amtrol without making steam in the house. I assume this shouldn't be done.

Jamie Hall

Not that it shouldn't be done

just that it won't work awfully well, as you found out.  You might actually do better leaving the king valve open, since you don't have a valve on the returns, thus equalising the pressures in the system.



But a valve for the returns would be a good idea anyway.  It should go on the wet return before it attaches to the Hartford Loop.  While you're at it, put a couple of handy drain valves there, too, one on each side of the valve.  Useful things, drain valves.