Cummins Marine Diesel Repower Specialists › Forums › Instrumentation & Electronics › Exhaust heat sensor
- This topic has 20 replies, 4 voices, and was last updated 5 years ago by Rob Schepis.
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June 18, 2018 at 3:45 am #33582
I’ve seen discussion of little heat pucks that can be used as additional overheat alarms.
My northern light generator started to shut down the second the shutdown bypass/preheat switch was released. Investigation showed a bad temp switch which I am replacing but it also showed my exhaust temp switches wires were. It and corroded.
It’s brutal access and the exhaust switch wires go into a harness that’s going to unleash more demons if I cut into it. I’m thinking tobuy one of those exhaust pucks and just wire it to an alarm and forget about replacing the northern lights switch.
Who makes themand whee can I buy them?
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June 28, 2018 at 1:37 pm #34150
Rob SchepisForum ModeratorVessel Name: Tenacious
Engines: 6BTA 5.9 330's - "Seaboard Style"
Location: Long Island, NY
Country: USA
Cut some test studs and JB Weld them to a metal test piece.
June 28, 2018 at 3:31 am #34131JB Weld?
Can I JB weld a pair of studs on? It’s rated to 500F…..
June 27, 2018 at 6:59 pm #34121
Rob SchepisForum ModeratorVessel Name: Tenacious
Engines: 6BTA 5.9 330's - "Seaboard Style"
Location: Long Island, NY
Country: USA
Studs for Temp Switch
Larry, zoom in on this one.
June 27, 2018 at 6:52 pm #34120
Rob SchepisForum ModeratorVessel Name: Tenacious
Engines: 6BTA 5.9 330's - "Seaboard Style"
Location: Long Island, NY
Country: USA
Those studs are welded on
June 27, 2018 at 6:47 pm #34119Idiot ^2
I just reread the entire thread, and blew up Tony’s picture of thr heat puck installation. If he had used a good camera I could answer my own question 🙂
Somehow the heat puck is bolted to the exhaust elbow by studs. What holds the studs on the elbow!
June 27, 2018 at 6:40 pm #34118I am a
I.D.I.O.T.!!!! It has 2 screw holes on the ears but I can Mcgyver a hose clamp solution somehow or other.
And yes I am alarmed with a very good raw water flow alarm and a very sensitive Borel heat sensor which has to be a ways back on the exhaust tube so as to not generate constant false alarms. When you pull back a QSM from cruise after a 5 hr steam and reduce the water flow to a trickle the exhaust tube will hit 210-220 on top for quite a while till things cool down.
I got the Borel far enough back on the tube and down not to generate false alarms but want to get a sensor on the elbow also under more independent alarms are better theory. That sensor will go with its own red LED. I guess I’ve got to play around with a heat gun some day after a long steam and see where on the elbow is a good spot to put the sensor.
June 27, 2018 at 6:07 pm #34117
Rob SchepisForum ModeratorVessel Name: Tenacious
Engines: 6BTA 5.9 330's - "Seaboard Style"
Location: Long Island, NY
Country: USA
Adhesive to install the temp switches? Not sure about that … might effect the performance of the switch, should be metal to metal contact, the adhesive may act as an insulator. Does the switch have ears on it? Can you secure it to the genset mixer using stainless band clamps?
On the QSM am I seeing a Borel sensor band and a raw water flow switch?
June 27, 2018 at 4:21 am #34074How to attach sensors to elbows?
Got the two sensors and the alarm yesterday. What’s the right adhesive to use to attach one to a stainless QSM elbow and the second to the cast Northern Lights Elbow.
Also, in the case of the QSM elbow, where should I glue it, top or bottom, front or back?
June 19, 2018 at 6:58 pm #33657
Tony AthensModeratorVessel Name: Local Banks
Engines: QSB 6.7 550 HP
Location: Oxnard, CA
Country: USA
From what I have seen, NL makes very nice cast SS mixers that are very inexpensive, in fact they are dirt cheap compared to what I could make… To not replace it seems silly to me.. Call these guys–they stock all of them.. In fact anything NL, this is where you want to go…
AAA Marine, Ventura, Ca………… http://www.aaamarineventura.com/ ………………………… Ask for Erith..
Tony
June 19, 2018 at 6:34 pm #33656
Bill DesmaraisModeratorVessel Name: Extremist
Engines: Cummins 6BTA 370
Location: Portsmouth, NH
Country: United States
Larry,
I had the same NL 753 generator in my former 1996 Blackfin.
I replaced the exhaust mixer and recall it was metal.
The old one had rusted up pretty good.June 19, 2018 at 12:56 pm #33643
Rob SchepisForum ModeratorVessel Name: Tenacious
Engines: 6BTA 5.9 330's - "Seaboard Style"
Location: Long Island, NY
Country: USA
The elbow is metal for sure —- either cast iron or 316 SS
That section of wire appears to have been chafed through, and then the conductors corroded, shorted, or both…
June 19, 2018 at 4:58 am #33623ain’t pretty but maybe this is metal?
1st shows the puck, 2nd misses it but shows the elbow better, 3rd is the piece of wire that I cut out thatsas frayed and corroded through.
June 19, 2018 at 4:51 am #33622Northern Lights M753K
And yes, I sure wish I had studied the parts diagrams as well as the wiring diagrams before I started chasing this problem.
June 19, 2018 at 4:46 am #33621
Rob SchepisForum ModeratorVessel Name: Tenacious
Engines: 6BTA 5.9 330's - "Seaboard Style"
Location: Long Island, NY
Country: USA
Wow, that bad, I guess (or I hope) the “service side” has the better access than the non-service side. Not that there’s anything mechanical or electrical in a boat that is “service-free”!
Try to take some pics when you get in there (wishful thinking, I know..)
What model NL unit is it? Especially in limited access situation it’s best to study pictures & diagrams BEFORE you get into it so you know exactly what you are looking at……
June 19, 2018 at 4:40 am #33620Yes on elbow
Everything in the genset is coated in white paint, it very well may have been a metal exhaust,imgoing to have to crawl back in there to find out, ugh…
June 19, 2018 at 4:21 am #33619
Rob SchepisForum ModeratorVessel Name: Tenacious
Engines: 6BTA 5.9 330's - "Seaboard Style"
Location: Long Island, NY
Country: USA
There was a glue on puck there already so maybe there is a metal flange it attached to.
Where, on the genset exhaust elbow?
June 19, 2018 at 2:53 am #33618I’m still ordering 2
One is going on my QSM exhaust elbow as yetanother independent insurance policy and I’ll figure out something on the Northern Lights. There was a glue on puck there already so maybe there is a metal flange it attached to. As I said, access is horrible and I didn’t really examine the exhaust tube where it was attached. Definitely fiberglass tube once it’s out from behind the genset where I was hoping to attach it.
June 18, 2018 at 6:51 pm #33607
Tony AthensModeratorVessel Name: Local Banks
Engines: QSB 6.7 550 HP
Location: Oxnard, CA
Country: USA
Our heat sensors are NOT designed nor do I believe they will work well on a FRP tube.. The switch is N.O. and closes at 165F.. FRP is not a good / quick transfer medium of heat changes.
Tony
June 18, 2018 at 4:44 pm #33604Thanks Rob
Exactly what I was referring too. I just ordered a pair. Any advice on how to best stick it to a fiberglass exhaust tube?
June 18, 2018 at 5:27 am #33583
Rob SchepisForum ModeratorVessel Name: Tenacious
Engines: 6BTA 5.9 330's - "Seaboard Style"
Location: Long Island, NY
Country: USA
Like what is sold here:
https://www.sbmar.com/product/smx-exhaust-heat-sensing-thermal-alarm-switch-180f/
Or Google “snap disc”
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