Solar water heater temp sensors? Buy where?

Anyone know where I can buy water temperature sensors for a solar
water heater system?
I want the kind which would screw into the water pipe with say a 1/2
inch fitting. Also called "on-line". And I could use a "T" fitting at
the water heater and at the pipe on the roof, then screw these sensors
into the "T" fitting (is the idea).
I'm designing/programming my own controller, so just need the sensors.
Reply to
Bill
Loading thread data ...
If you are designing the circuit there's nothing cheaper than diodes:
formatting link

Tape them to the pipe under the insulation. The TO-220 package makes better thermal contact.
Transistor base-emitter junctions work fine too.
jsw
Reply to
Jim Wilkins
Try the auto parts store. They have thermistor based sensors in a good brass screw in package. I use the one with a 1/8" thread (Jeep) in a 1/2" bushing so you have enough meat for threads to mount a spade connector for the common lead. They can be very accurate if you use a whetstone bridge feeding an op amp (LM324) with a pot on the matching leg and a couple 10k resistors for the other legs
Reply to
gfretwell
You can make use of the car coolant temperature sensor and connect it to your controller.... no need to redesign the wheel ....
Reply to
Sunpower
Can you suggest an appropriate one? Asking the counter clerk to help engineer a project isn't always very productive. =BFAlguien habla Ingl=E9s?
jsw
Reply to
Jim Wilkins
I use this one on my spa controller The plot I got for the Omix-ADA # 476801 (replaces 3177594) the numbers on the box
750 ohm @ 62f 468 @ 83f 403 @ 90f 342 @ 98f 324 @ 100f
There may be some variation between units but this should get you in the ball park.
I suspect most automotive units are roughly the same. This one said it was for a Jeep and I was using one for a Ford before but the threads were 1/2" requiring a trick to hook up the ground. (I used a ground rod clamp but it was ugly)
Reply to
gfretwell
Thanks
formatting link
If I drove up in my 20 year old pickup and asked for a Buick Park Avenue part they might mistake me for a mechanic and give me a discount.
jsw
Reply to
Jim Wilkins

Site Timeline

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.