storage temp gauges and sensors?

[pybyr]

Hello all--

As I plan the details of the fittings for my 6x6x5 foot storage tank, in addition to the ports for drain, overflow, and inlet and outlet, I'm realizing that I also should incorporate means to track the temperature at one or more points in the tank (seems like at a minimum,one near top and one near bottom), both to get a sense of what the temp in the tank is, and also to control the various other parts of the system (circulators, and, mostly, when the system realizes it has nothing to offer from storage and defaults back to the oil furnace)

I admire Nofossil's computer-based system, but don't believe that I could really pull that off

analog dial temp gauges would be OK with me if the price is right and accuracy is OK; industrial PLC/PID type controls might have advantages, too, although I could use some helpful pointers in zeroing in on the right ones, the right thermocouples, how/ where to best get them "in the tank" and so on.

many thanks for any suggestions

 

[WoodNotOil]

I plan to make my own wells for the sensors out of 1/2" or 3/4" down through the lid and capped. I have a digital thermometer with two sensors that came with my radiant floor package for setup purposes. I will have one sensor down toward the bottom and the other near the top. Some other people are using digital meat thermometers that have wired sensors that can be dropped down a well. I am sure there are commercial products available, but they will be out of the $25 range of meat thermometers. Here is a link to one http://www.amazon.com/gp/product/B000AY6UH8. A power adpater could probably be wired in so that batteries don't have to used all the time.

 

[WoodNotOil]

The one I have from my radiant package is the Alez DS-60. Here is the only link I could find online to one: http://www.accentshopping.com/product.asp/P_ID/149655

 

[in hot water]

The one I have from my radiant package is the Alez DS-60. Here is the only link I could find online to one: http://www.accentshopping.com/product.asp/P_ID/149655

I like that Azel too. It does some data logging, captures high and low temperatures, and can be battery or 24V powered. It also reads the delta t with the touch of a button.

i should have bought a case of them when they were 39 bucks a year or so ago :

hr(

 

[pybyr]

Thanks WoodNotOil and Hot Rod- that Azel looks like a really great little unit, and I suppose if I want to get fancy, I could install various pairs of sensors in multiple places in addition to the storage--with some switching between the sensors and the Azel gauge-- so as to be able to look at other temps like boiler intake and outlet, and the inputs and outputs of the other parts of the system

 

[WoodNotOil]

Hot Rod (or anyone else) - Do you know if this transformer would work for the Alez 24 volt hookup: (broken link removed) I want to simply take a 110 line and step it down for the 24 volts. Also, can I extend the the wire length for the probe/sensor with any wire or does it have to be high temp wire? I know in some cases 18 guage speaker wire can be used, but can it withstand the 175* temp? Looking for an inexpensive wire option as I only have to extend it a few feet.

 

[pybyr]

WoodNotOil- that ought to work, as far as supplying proper voltage, but it'd be a lot easier to mount and wire in compliance with codes and good practice if you got a plate-mount one so that the 24 VAC side is inside a box, and the 24VAC is accessible by screws (that way you don't have dangling wire nuts, etc)

like this one:
http://www.pexsupply.com/product_dtl.asp?pID=1740&cID=282&brand=Honeywell

your existing system very likely has something like that to supply the existing thermostats, and I'd be surprised if the Azel drew enough current to bother the existing 24VAC transformer

 

[in hot water]

Heck, a small doorbell transformer 8 or 10 Va would be plenty if you need a 24v source. The battery included will actually last a few years.

hr

 

[WoodNotOil]

Great suggestions. I poked around a bit at the relays I have and there are two possibilities.

1. I have a NIX Technologies Speedpump SP-82 that has a 24VAC Transformer Hot and a 24VAC Transformer Common terminals that could be hooked into. Would I put the hot wire in hot and the neutral in the common or are they both hot and the nuetral would be tied into the 110VAC neutral line? The disadvantage to using this one is that it needs a longer wire run to the Azel Digit-Stat. Here is a link to the manual (broken link removed to http://www.azeltec.com/images/sp8183.pdf) (pg. 2)

2. I have a Honeywell R845A right next to where the Azel Digit-Stat would need to go. However, though it claims to have a transformer in it I can not tell where I would tie into it. I don't want it to go on and off with the relay, I just want a constant feed. Here is a link to the manual http://customer.honeywell.com/Techlit/Pdf/60-0000s/60-2481.pdf (pg. 5 top right)

Any help figuring this out would be greatly appreciated. Thanks.

 

[pybyr]

WoodNotOil- I read the diagrams/ manuals at both the links you indicated, but am really hesitant to give advice without knowing/seeing how things are hooked together; erroneous suppositions can lead to bad zorch effects.

I'm to a very, very large degree going to/ hoping to be following in your footsteps regarding use of a plate HX and back-to-back circulators for an unpressurized heat tank.

I am very good with electrical things; been doing that with success from batteries to kilovolts since I was age 10 or so.

But on the hydronic side of things, I have been on a steep learning curve with the flow rates, velocities & etc., as well as whether one dares use iron circulators on the unpressurized storage tank side of the HX without having circulator problems or clogged HX problems.

if I remember, you're in the Champlain islands or Franklin Cty; I'd be more than willing to come by (I'm near Montpeculiar) to do an electrical consult & assist, in exchange for being able to talk & see about the pump/ pipe/ flow/ HX layout and sizing you are planning.

please send me a note or PM on whether we may be able to exchange skills here- it'd assist me a lot, and I would be glad to make it reciprocal in offering whatever I can on the wiring side

 

[in hot water]

There is usually a way to grab 24V off of those relay boxes. On the NIX it should be Rt and C. Check it with a meter. Not sure about the Honeywell, you may need to get at the back of the circuit board?

Here is a shot of the back of the Azel. The 24V is not polarity sensitive, don't worry about hot & common. Be sure to keep all the wiring at least 6 inches away from line voltage wiring.

The battery actually last more than 3 years according to the instructions.

hr

 

[DaveM195352]

I'm looking at the Alez-D60 as a great way to "monitor" the temp in my DHW tank.
A wee bit pricey for what I want, but looks great - I like the idea of it recording the high and low also.

My question ( as raised in above posting) what kind of wire can be used to extend the distance between the sensor and the readout? I'd like to mount it about 25 feet from the tank.

Also, another stupid question, but..... The indirect tank I have has an immersion well, where the existing temp probe is. Can I use the P-01 probe that comes with the Alez-D60 and just insert that into the well?

Thanks in advance for your help
Dave from Maine

 

[pybyr]

I don't have an Azel yet, although I probably will eventually- when I get to the control and monitoring parts

I think wire gauge and type is non-critical for the length you're talking about- although it is important to keep it away from any AC cabling that could induce currents that'd confuse things

I can't see any reason not to put the Azel's probe in the monitoring well