just thinking out loud.....overheat warning on vintage ob's?

[nwcove]

maybe its already been done, but has anyone tried using a " snap disc" thermostat to trigger an overheat warning on a vintage ob? it would require a power source on non-electric start motors, but seems like a cheap way to possibly avoid a major issue?

 

[wayne nicol]

Re: just thinking out loud.....overheat warning on vintage ob's?

what is a snap disc thermostat- tell me more!!- sounds like what i need!!!!!!!!

 

[nwcove]

Re: just thinking out loud.....overheat warning on vintage ob's?

they are normally used to protect other types of machinery from over heat. most electric hot water heaters have adjustable snap discs to turn the elements on or off. for this purpose you would need a normally open snap disc, mounted to the powerhead in a suitable location, and of the right heat range ( they come in many ranges and are cheap). for instance, if the normal operating temp was 140f, maybe a 160f snap disc would be right to trigger an alarm at that temp. you would need a power source for the buzzer, which could be a simple as a 9v battery and a 9v buzzer from radio shack.

as the title of this thread states....."just thinking out loud", which was spurred by a friend who cooked his 9.9, because of discarded sandwich bag.

 

[Rick.]

Re: just thinking out loud.....overheat warning on vintage ob's?

I had my gas dryer apart a few weeks ago and had lots of snap discs. Some to operate the gas train and some to shut things down for overheat. You see lots of them in furnaces, unit heaters etc. as well. I think you could even wire it into the kill switch wire. No alarm but it would (if normally open) shut down your spark without any power source. It's not a bad idea at all. My engineer buddy says everyone hates engineers but everybody wants to be one. I think he's kind of right but I've never told him so. LOL. Rick.

 

[F_R]

Re: just thinking out loud.....overheat warning on vintage ob's?

I guess y'all know that similar devices are standard equipment on larger motors. The idea is ok, I suppose, but you wouldn't believe how many fried motors I've rebuilt where the alarm never went off. By the time the block and head are hot enough to set it off, the pistons are already melted. It only takes a few seconds at WOT with no water as from a spun impeller hub.

 

[nwcove]

Re: just thinking out loud.....overheat warning on vintage ob's?

i thought it wasnt a bad plan! not sure about a complete shut down as opposed to a warning buzzer, but either way its an option to save a major issue on the cheap??? ?( lol, i work with two engineers, who work under a large engineering firm, and they all get poked in the ribs!!)

 

[nwcove]

Re: just thinking out loud.....overheat warning on vintage ob's?

I guess y'all know that similar devices are standard equipment on larger motors. The idea is ok, I suppose, but you wouldn't believe how many fried motors I've rebuilt where the alarm never went off. By the time the block and head are hot enough to set it off, the pistons are already melted. It only takes a few seconds at WOT with no water as from a spun impeller hub.

but how many motors were saved by "similiar standard devices which are standard equipment on larger motors"?...as compared to the ones that were saved by an alarm? my thought was about a simple cheap way to possibly save an old motor from an overheat ? and it is just a thought!!

rd

 

[wayne nicol]

Re: just thinking out loud.....overheat warning on vintage ob's?

i think anything is better than nothing. i would happily set up a system as described above, in addition to any other buzzers etc- it cant do any harm,right!!?? so why not just put it on, sounds simple and cheap.
i am sure no system is fool proof. but it would just be another safety measure.
my 110 johnson overheated the other day( kelp around the intakes!!) my buzzer didnt go off!. the mechanics had said that they had tested the buzzer ( 6 motor hours ago!!)and it was working- i have since found it is not working. but an additional, seperate system might have saved me.
wayne

 

[F_R]

Re: just thinking out loud.....overheat warning on vintage ob's?

I guess I was mis-understood. Yes, anything is better than nothing. And sometimes, they actually work! I was just pointing out the false sense of security one gets by relying on the alarm. If the overhead condition comes on fairly gradually, they work fairly well. If it is a sudden overheat like from a spun impeller or plastic bag, it probably won't respond soon enough.

BTW, there is no way to test the system other than remove and heat up the sensor. Yes, you can test the alarm circuit outside of the sensor. But even that only says it is working at the moment, no guarantee about next time.

nwcove, your idea has merit. Go for it.

 

[Rick.]

Re: just thinking out loud.....overheat warning on vintage ob's?

F_R. No misunderstanding here. I think you point was well intended and stated. Rick.

 

[wayne nicol]

Re: just thinking out loud.....overheat warning on vintage ob's?

this is what dialogue is all about- all points and ideas are well considered.
i hear you on the sudden overheat.
i had some kelp around my intakes a few weeks ago.
have to redo all the pump etc.
best regards all
wayne