Thermal Traps

Larry (from OSHA)

I'll be re-piping/re-placing my indirect water heater soon and want to improve the current piping arrangement. I understand that traps should be 18" but is there any need to make the "U" bend at the bottom more than a couple of street 90's? Do I need any length of straight pipe between the 90's?

Also, does anyone have any preferences on which thermostatic mixing valve to use. I was thinking about the Honeywell AM101-1.

Thanks for any help.

Larry (from OSHA)

hr

I have had

limited sucess with thermal drops. I rather see a check pump and or a spring check, or zone valve. Good idea to check both sides of indirects to prevent ghost flows.

That Honeywell/ Sparco has been an excellent valve for me. Add a couple iso valves so that it is easy to service, as they do lime up ocassionally.

hot rod

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Weezbo

Larry, thermal traps indeed work,however for whatever the

reason,i have fixed and repaired some that apparently never heard that they should some cwing checks same deal, for that reason i think that drives people to go with spring checks. now let me say i have had to repair them also.so what to do? i use all of them and here are my ideas,

1. thermal traps i like on the returns,

2. swing checks i like on the flat with a definite pressure differential locking it down,

3.spring checks should be located where they dont squeal or chatter and sometimes i over size a spring check... theres some ideas , i am sure there are others. when it comes to mixers "sparky " mixing valves and taco mixers are fairly common and easily aquired. the sparco that goes cooler (60F) rather than hotter is probably the mixer i would go with, there are alot of mixers and the anti scald devise looky alot like a fixed mix so far i havent had to go to repairing any of them:)

Ron Schroeder

Sparco mixers need the optional check valves that fit in the unions. CV loss is not good for the valves without unions. Thermal traps work the best if the mixer is below the top of the indirect about 8 to 16 inches.

Larry (from OSHA)

check valves for thermo?

Thanks to all for the information.

Greg, whats the deal on the check valves? And Honeywell says these particular thermo valves do not need trapping. I don't really understand the reasoning behind trapping the valve anyway, so any illumination there would be appreciated.

My questions about traps were for the potable side and the return to the boiler. The supply from the boiler has a spring check.

Larry

BillW@honeywell

The union check valves...

are Part #AMCU1000. You also could consider the new AMX series, the check is built in. Call 401 738 4290 and choose option 7 for more tech info.

On a side note, I was expecting you to weigh in on those "keeping cool" posts. I bet you've got some good info to share!

Ron Schroeder

Larry,
Yes, the checks would be redundant with a traps. I would perfer to use the mixer without the check valves and with only traps, but convective flow can be powerful. If you set the traps correctly, the mixer will reach room temperature when hot water is not used.

Larry (from OSHA)

Thanks Bill

I hope the AMX valves are locally available.

As far as keeping cool, (I don't recall seeing those posts) there are some Minnesota Rules that apply to indoor work places. The subject of heat stress was very much front and center a few years ago when Cory Stringer of the Vikings died in a practice session on a very hot humid day. Alas, there were no regulations that were applicable in that case. But now that summer is approaching, I'm sure we'll get the usual complaints that it's too hot. Last year the one that sticks in my mind was the guy working at the pizza place in front of the oven. (As I recall, we did not cite anything there.) He probably wouldn't do very well in a foundry either!

In case anyone is interested, the MN Rule for indoor temps is at: http://www.revisor.leg.state.mn.us/arule/5205/0110.html

Cheers,

Larry (from OSHA)