ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals

Topic Options
Rate This Topic
#51760 - 05/09/05 12:34 PM thermocuople test
zero76 Offline
Member
Registered: 10/26/04
Posts: 26
Loc: olympia
I'm wondering how i can test a thermocouple and a uv flame sensor with a DMM. I've got both on a seed dryer that i'm trying to troubleshoot. I'm meeting the gas man down there tomorrow to look at it together. Any help?
Thanks in advance.

[This message has been edited by zero76 (edited 05-09-2005).]
Top
Work Gear for Electricians and the Trades
#51761 - 05/09/05 05:49 PM Re: thermocuople test
renosteinke Offline
Cat Servant
Member
Registered: 01/22/05
Posts: 5316
Loc: Blue Collar Country
I know nothing about the flame sensor...but, for the TC...

A TC works by generating a small voltage, in proportion to it's temperature. This voltage can only be generated if there is a sharp change from one materiel to another. Over time, this 'seam' degrades.
First check the TC fo continuity. If good, than check for a steady voltage between the leads. If the voltage fluctuates, or the meter cannot seem to settle on a value, then the TC is probably bad. Ditto if the read-out on a TC meter bounces all over the place.
Top
#51762 - 05/09/05 06:24 PM Re: thermocuople test
zero76 Offline
Member
Registered: 10/26/04
Posts: 26
Loc: olympia
thanks for the reply, So if i understand correctly: if i remove it from the ckt. it generates it's own voltage? what approximate value would it read? It's a type J tc.

BTW i can spel thermocouple but i couldn't figure out how to change the topic in edit mode. z.

[This message has been edited by zero76 (edited 05-09-2005).]
Top
#51763 - 05/09/05 07:21 PM Re: thermocuople test
frank Offline
Member
Registered: 05/29/01
Posts: 374
Loc: windsor ontario canada
I believe it's called Constantin or something like that and a typical furnace thermocouple used to generate 15mv and drop the gas valve coil out around 5mv.This was ten years ago on older furnaces,now LEDs flash a code.The tip should be cleaned of soot with steal wool when testing/suspecting or even seeing one IMHO.

[This message has been edited by frank (edited 05-09-2005).]
Top

Member Spotlight
Member Since: 02/23/13
Posts: 204
New in the Gallery:
SE cable question
Featured:

2017 NEC and Related
2017 NEC
Now Available!

Shout Box


Who's Online
0 registered (), 61 Guests and 10 Spiders online.
Key: Admin, Global Mod, Mod
 
New in the Gallery:
SE cable question
 
Top Posters (30 Days)
Admin 47
HotLine1 43
gfretwell 19
Ruben Rocha 12
Trumpy 9
 
Newest Members
KrmtFrg, Stack, Scotto, Freecrowder, clee512

ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals