10 K sensors....

Dave_4

It can happen, apparently. I was involved with an installation with hundreds of thermistor temperature sensors and I can't remember one failing, although humidity sensors were almost a consumable. The thermistor sensors fitted to boilers and cars seem to fail much more frequently, for some reason.

None of the usual causes? Sunshine, heat losses through the wall, extractor fans, air from inside flowing up the cable conduit, etc..

J.C.A._3

10 K sensors...

Today, for the first time ever, I had an outdoor sensor telling the Tekmar control that it ws 85° outside. My trusty thermometer was telling me it was around 65°,( a most lovely day indeed!)in the same spot.

I thought ...maybe it's the wire???? After pulling the cover and ohming the sensor, sure as poop it was giving the reading for 85°.

How often has anyone seen these fail? In the 5 years I've been dealing with them this is my first. Chris

Glen

Not often - but.....

they are mechanical devices - designed by humans - etc etc. I like to have at least one ODS and one 10K on hand. And at least one of the dhw and boiler sensors for the Viessmann equipment as well. A variance of a few degrees is not unusual - more than 5 deg C - and it's time for replacement.

J.C.A._3

Aidan,

Purposely placed where it resided because of its proximity to the elements and path of the sun. The only thing that has changed since it was installed was a few plantings around it. Maybe the combination of mulch and some watering of the area had an effect? It is a pretty well sealed unit but probably not completely waterproof.

I'm pretty sure these folks don't use any chemical fertilizers or de-foliants as most lawn companies would.

I hope this is an isolated incident. I also keep a couple of thermisters on hand for the most part, but this is the first outdoor one I've had to replace. Thanks. Chris

Paul Pollets

Testers

Tekmar makes a tester for the devices. It costs around $125.00. I've replaced my share of OD sensors and #2 sensors over the years. Rare, but it happens. I wonder if they fail less than thermocouples?? Paul

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Alan(CaliforniaRadiant)Forbes

Just had

my first one fail on in a Danfoss zone control panel. It had a Heat Timer DRC outdoor reset controller with two sensors; one, outdoor and the other one was a supply sensor. The supply sensor went bad.

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J.C.A._3

Has to be ...

Shoot, I replace more thermocouples in 6 months that don't register than 10K's in a lifetime I'm sure.

My tester is a trusty ohm meter and the table from the manual. When the control (Tekmar) is stating the obvious... I just have to test.

Guessing is NOT an option. Heating season is upon us. Imagine the time it would take for someone trying to troubleshoot something so.... obvious, to the educated, but not known to the newbie in the fold?

I think it's time for another electrical meter reading "shop meeting" in the VERY near future.

BTW, My tester cost about 80.00$ at Radio Shack, and has survived more falls from a water heater than most of the big money meters that I've owned, have taken. The only meter I WON'T part with is my old Simson. It seems to pick up things that any digital meter doesn't have the ability to catch, and it's been paid for about 30 years now. Like the Snap-On guy says.... Quality is priceless. Chris

Andrew Hagen (ALH)

063's

Had a terrible time with the last batch of 063 RTU's. 3 out of 11 read at least 4 degrees off. One always read the same temp. In my mind 4 degrees is significant in a room temperature. 507's have had their share of trouble too it seems. Mostly problems with the displays. Discovered the bad rtu's on an internet controlled job where there were redundant sensors for the internet control. Who knows how many were off when we had no redundant thermometer checking them.

Not to pick on Tekmar. Their stuff is high quality, well designed, and well made. We've just had a few warrantied t-stats and rtu's this year.

-Andrew

Unknown

Chris

In over 20 years of being around tekmar controls, I have not had a single Outdoor Sensor go bad. That is unless an Outdoor Sensor case being completely knocked off of a building by a VERY diligent fellow with a power washer counts as going bad! We found that one about 50 feet from the building in the brush.

I have had Supply Sensors go haywire though from time to time. I also advise that the contractor leave a spare #071 inside the control case for future service calls. As far as Paul's statement regarding a $125.00 tester goes, I'm not sure why anyone would invest that much when a simple Multitester or Ohmeter works just fine.Hope this helps.



Glenn Stanton

Manager of Training

Burnham Hydronics

U.S. Boiler Co., Inc.

hr

The tester, Paul, or

the simulator? Most radiant manufactures use the simulators to set up pre built panels. Does this act as a tester for the sensors also?

I'd check with a second meter before replacing the sensor.

The most often tekmar sensor to fail is the slab sensor I have had several outdoor, and a hand ful of the o70 go bad. Good idea to keep some spares of each on the truck, considering the cost vs a return trip.

hot rod

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Unknown

Hot Rod

I think that paul is probably referring to the #002 Simulator too. I have one of these that I take to system startups occasionally to simulate outdoor and system temperatures instead of having to wait for cold weather to do so. A very good tool indeed!

Glenn Stanton

Manager of Training

Burnham Hydronics

U.S. Boiler Co., Inc.

hydronicsmike

10 K Sensors

In the 8 years I have been married with tekmar Controls (for the last 5-1/2 years worked there), I can truly and honestly say that I have only seen a handful of the 10K Sensors come back due to failures.

I agree with the fine gents above that it is not impossible and that failures can occur, but those are rare. Keep a couple on hand to avoid time delays and other related issues if it is a concern to you. If it is a big bother in any case, call the factory at 250-545-7749 and one of the Customer Service Staff will be glad to find a way to make you happy.

Anyways, couldn't have this post noticed and not reply.

Enjoy your day!!

Mike

Mr.Bill

OHM meter

I second the ohm meter as a great tool for lots of stuff including sensors,

Just be carefull, not all sensors are the same. They can have different ohm values, increase or decrease resistance on temperature change.

For instance the Tekmar sensor, Heat Timer sensor and Danfoss ECL sensor are all different and cannot be interchanged.

[Deleted User]

3...

I've had three sensors fail in 10 years of working with tekmar. Exempelerary rate if you ask me...

Finest control company in the WORLD.

ME

Unknown

Agreed!

I'll second that!

Glenn Stanton

Manager of Training

Burnham Hydronics

U.S. Boiler Co., Inc.