[RE-wrenches] Pt valves as overheat control

[Karl Schwingel]

remember that any closed system should have an adequately sized 
expansion tank.  if you're circulating potable water thru, you'll want 
one rated for potable, not the standard hydroninc one.  then, the PT 
valve is truely only a backup anyway, in the event of  a bladder failure 
or some other failure.

Karl

jay peltz wrote:
> Hi Drake,
>
> I don't know if you ever watch Myth Busters, but google them and check 
> out the water tank they exploded.
>
> Short version is they took a standard 40 gallon electric tank, put 
> into a small building, no PT valve, heated it until it exploded.
> It flew something like 200' into the air, just amazing and super scary 
> to see.  I'm with Jeff, I'd put a second in just for safety.
>
> jay
>
> peltz power
> On Nov 11, 2008, at 4:40 PM, Drake Chamberlin wrote:
>
>>
>> At 09:15 AM 11/11/2008, you wrote:
>>> My question....is there a more robust version of that P/T valve
>>> that I should be using? Something that you would use in a boiler 
>>> perhaps?
>>
>> I'm not really a hot water guy either, but I'm scheming on putting in 
>> solar hot water with a wood stove backup loop.  I was thinking of 
>> using a valve from a dishwasher or washing machine.  They are 
>> electrically controlled, and designed to take hot water straight from 
>> the tank.  Control the electric valve with an aquastat.  If there is 
>> no place to thread the aquastat into the tank, it would be more 
>> difficult, but still possible with a bit of plumbing.  For sure the 
>> T/P valve would be needed for whenever the power went down.
>>
>>
>> Drake Chamberlin
>> Athens Electric
>> OH License 44810
>> CO License 3773
>> 740-448-7328
>> 740-856-9648
>>
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-- 
Karl Schwingel
NABCEP Certified Solar Thermal Installer
NorthWind Renewable Energy LLC

PO Box 723 Stevens Point, WI 54481
Karl at Northwindre.com
Cell: 715 209 0446
Fax : 715 952 4501


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