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[on:]

Hello , i want to build a system for controling circulators and valves for a heating project in a house... I want to measure the temperature of water.

What do you recommend ? thanks !

[Reply #1 on:]

This would be the obvious choice:

http://www.ebay.com.au/itm/280989134906?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

Note that the probe is 50mm, which is a lot longer than most. I guess there wouldn't be much pressure in a heating system and you could safely use some sort of compression ring system, thereby having the probes wet. This would probably entail using brass fittings.

[Reply #2 on:]

Size of Stainless steel sheath:6*50mm

I think that size might have been a typo. It is probably 6.50mm or .255" which could be made to work with a 1/4" compression fitting.

[Reply #3 on:]

6x50mm, i.e. 6mm diameter

[Reply #4 on:]

Oops! Thank you Nick.

Tony

[Reply #5 on:]

Hello , i want to build a system for controling circulators and valves for a heating project in a house... I want to measure the temperature of water.

What do you recommend ? thanks !

You could splice a very short section of copper pipe into the plastic pipe run, the measure the temperature of the outside of the copper pipe.

[Reply #6 on:]

Check the mains wiring regulations before adding a copper water pipe section or
adding anything that's not electrically insulated.  Earth faults can rarely cause mains
shorts to return to earth via building water pipes and thus the pipes usually have to be
earthed at every separate metal section I believe.

[Reply #7 on:]

You might even be able to pick up a coolant temp sensor designed for a car and use it depending on the range it supports. Certainly it would cover room temp up to past boiling. But I suspect probably go below freezing as well.

http://www.ebay.com/itm/NEW-DELPHI-COOLANT-TEMPERATURE-SENSOR-TS10208-MERCURY-NISSAN-1993-2007-/160618336472?pt=Motors_Car_Truck_Parts_Accessories&hash=item25659950d8&vxp=mtr

I think this one goes from -55C to 110C.

You'd have to calibrate your program to know the relationship between ohms and temp. But that shouldn't be too hard.

I would think these might be more rugged and are designed to normally work under pressure of 1 to 2 bar.