Which Aquastat do I need?

[Morith]

I am interested in adding an aquastat to turn on my circulator when my boiler temperature reaches 190degrees. This will let me dump excess heat downstairs rather than down the drain when the overheat kicks in at 195degrees. I know that it must be one that closes on rise and opens on fall. The plan is to connect the aquastat to the existing relay for the existing circulator. One with an electrical sensor unit with a digital readout would be a plus. Can anyone out there supply me with a model number and company for one. My sensor well will allow enough space for as sensor that is 1/4 inch in diameter and uup to 2.5 inches long.Thank you for any help that you can provide.

 

[WoodNotOil]

I like these http://www.pexsupply.com/product_dtl.asp?pID=1738&brand=Honeywell&cID=294 as they are inexpensive and can be either a close on rise or on fall. They have two seperate screws and can do either job. This is a strap-on, but they also make ones for wells.

 

[88rxn/a]

it say circulator control. but can i hook this up to a zone valve? id like a aquastat for the DHW (strap on to the tanks line and open the zone valve when calling for heat) and i thought maybe i can use this?

 

[Hydronics]

You can use an aquastat to control zone valves also just be sure to use a 24 volt transformer

 

[Hydronics]

The Honeywell suggested is a high quality device, it sells for about $30 more through plumbing wholesalers than the website.

 

[cguida]

Question about aquastats --

The item mentioned by WoodNotOil ( http://www.pexsupply.com/product_dtl.asp?pID=1738&brand=Honeywell&cID=294 ) is described as having a temperature range (65F to 200F), and an adjustible 5 - 30 degree differential.

Does this mean that you have to use the differential feature? For example, suppose you wanted it to open-on-rise at 100 degrees. Would it then close again when the difference temperature was reached -- say 130 degrees?

Suppose you wanted it to open at 100 degrees, and stay open no matter how high the temperature went after that point. Is there a way to disable the differential feature?

Thanks

Smee

 

[chuck172]

Check out the Ranco ETC-112000-000
(broken link removed to http://www.patriot-supply.com/products/showitem.cfm/47725)
Seems like it's what you're looking for. I use it and it works well.

 

[RJP Electric]

Question about aquastats --

The item mentioned by WoodNotOil ( http://www.pexsupply.com/product_dtl.asp?pID=1738&brand=Honeywell&cID=294 ) is described as having a temperature range (65F to 200F), and an adjustible 5 - 30 degree differential.

Does this mean that you have to use the differential feature? For example, suppose you wanted it to open-on-rise at 100 degrees. Would it then close again when the difference temperature was reached -- say 130 degrees?

Suppose you wanted it to open at 100 degrees, and stay open no matter how high the temperature went after that point. Is there a way to disable the differential feature?

Thanks

Smee

If it is set to open at 100º it will open and stay open no matter how high the the temperature the pipes are, if the differential is set at 5, it will close when the pipes get 95º, that's how that works.

I have 2 of these in my setup, they can be used to open on temp increase or temp decrease, you can use them either way.

 

[cguida]

Thanks very much for that explanation!

Never underestimate the tendency of certain people (like me) to thoroughly investigate all the wrong ways to do (or think about) something...

After your explanation, it all looks so obvious -- differential action acts on the LOW side of an open-on-rise set point (duh).

 

[Eric Johnson]

I like to get SPDT-style aquastats, because they can be wired up to either make or break the connection on temp rise. The Honeywell website tells you which is which.