I need an aquastat !

[ejhills]

I've been trying for days it seems and I can't seem to find the right part.

Im looking for an aquastat that will make on rise , say 140, run up to 240 and stay closed, then open when it returns to 140 and below.

Any suggestions for the truly frustrated would be appreciated.

Thank you
Truly Frustrated

 

[brenndatomu]

No help on the aquastat from me...but could you use a programmable temp controller like this one? Different application here, but I would think you could still use one with a thermocouple in a well filled with oil (same as an aquastat) https://www.hearth.com/talk/threads/everything-drolet-tundra-heatmax.140788/post-1926802
There are tons of different controller configurations available...

 

[maple1]

Maybe a Johnson A419? Not in front of my computer so dont have the specs for mine.

That's a really big diff though and really high cut out - what are you doing with it?

 

[ejhills]

A wood master miniboiler with Renovator 30

The pellet boiler runs out to set point and stops.
However the PLC does not have anything but the digital temp probe for the burner.
So I'd like an aquastat to stop the circulator between the boiler and the storage.

I'll burn fewer pellets and run the pump less.
When the pump runs 24/7 I am short cycling against the cold bottom of the water storage and my stack temp is consistently lower.

 

[Fred61]

What you need is a locking relay with a manual release. I think they exist??

I built something like what you're looking for several years ago using a standard relay and a time delay relay but I don't have a drawing for it and with Parkinson's now affecting me I am now unable to think through schematics.

If you have a friend or aquaintence with electronics experience he or she should be able to build something.

 

[maple1]

Looks like the Johnson won't work. Or at least the one I have. Has a max 30c differential, and max temp of 100c. So it could start at 140f/60c, and stop at 194f/90c.

Altho still don't have my head around exactly what you're doing, and not sure I can get it there anyway.

240 is really hot - are you really heating water that hot?