Exhaust water temp alarm

[Ripster]

I know this subject has been covered before but I wanted to know what typical temp readings and alarms peops are using as a comparison. Engine is a VP D1-30F - 11.3m AWB, fixed 2 blade prop on a sail-drive.

I have fitted one of these Nasa probes with a temp gauge and alarm. What is your regular running temp say at about 2200rpm and what do you set your warning alarms at?

 

[Storyline]

Have to stop reading this forum as every few days I read about something I would like to have. This time though I am going to get one of these asap as I have a dodgy temperature gauge on the engine. So thanks for posting

As to the answer, I am no marine diesel engineer but may I suggest you run the engine until the thermostat opens and then set that as the normal temperature as a start and then adjust as you go along. I would guess that all engines vary slightly due to the setup and amount of raw water going through and whether heat exchanger is fitted etc. All these may alter the temp of the cooled exhaust gas slightly.
I would have thought the function of the device is to warn of a failure on the raw water side rather than give an absolute reading. Maybe I am completely wrong and you want to know if your engine is running hotter/cooler than that recommended.

I would also be interested in knowing how many degrees hotter the alarm should be set at. Should imagine the temp will soar rapidly should the impeller fail or water inlet get blocked so maybe the alarm temp could be quite coarse.

 

[nigelmercier]

Have to stop reading this forum as every few days I read about something I would like to have...

Then wait no longer: http://amzn.to/1ltWKc6

 

[Spirit of Glenans]

Note the temperature after you have been running for a while at high revs in warm weather, then set it for a few degrees higher.

 

[superheat6k]

I fitted two of the ones Nigel shows two years ago. Still working just fine, wired into the otherwise unused glow plug warning lamp on the VP dash panel. My engines are a little bigger, but run at around 40oC flat out in the Summer, so I set them at 45oC, this way I will know if the water rises after just a few degrees.

I mounted the probes in some short copper tubes grafted on to the the injection bend using a large jubilee clip and epoxy putty. We used this method for large fridge systems requiring a reliable and fast temperature change measurement.

The module is simple to adjust the setpoint where you want it, and has a NO contact pair you can wire an external alarm to.

 

[Avocet]

About 25 degrees, just downstream of the elbow at 2000-ish RPM (or about 2/3 power). It's only a 12HP raw water cooled engine though.

 

[Storyline]

Then wait no longer: http://amzn.to/1ltWKc6

Now that is a good deal !

 

[West Coast]

Then wait no longer: http://amzn.to/1ltWKc6

Bought a couple of these (on your suggestion ) a few weeks ago, now arrived. Question which the instructions don't answer - is it ok to extend the probe wires, any limitations if so?

 

[Norman_E]

Then wait no longer: http://amzn.to/1ltWKc6

I am looking at that and thinking of it as a fridge controller to replace the control gear that was contained within my failed CLD Inverter. If it has two relays inside I might be able to modify it so that both close when cooling is demanded so that one of them starts the mains compressor and the other one starts the 12 volt water pump. There are ones available that work on mains voltage which will simplify matters. Thank you for the link.

 

[Avocet]

Bought a couple of these (on your suggestion ) a few weeks ago, now arrived. Question which the instructions don't answer - is it ok to extend the probe wires, any limitations if so?

I was lucky. I've got a couple of them (one for exhaust one for engine temperature) but they're very close to the engine so I didn't need to extend the wires. I think you probably CAN extend them, because the sensors are NTC probes and I think they have a pretty high resistance anyway (10k or so) - in which case, a bit more wire shouldn't be a problem. Besides, in the settings you can change the zero offset and calibration factors a bit on that box if you need to tweak it slightly to be accurate. However, you can also get NTC probes with longer wires quite cheaply anyway:

http://www.ebay.co.uk/itm/3m-NTC-Te..._Measurement_Equipment_ET&hash=item51a539e6a1

 

[nigelmercier]

... However, you can also get NTC probes with longer wires quite cheaply anyway...

Not all probes are compatible, the Amazon one is "NTC 25 Celsius degree=10K B3435", but it is easy enough to extend the wires.

 

[West Coast]

Not all probes are compatible, the Amazon one is "NTC 25 Celsius degree=10K B3435", but it is easy enough to extend the wires.

Cheers.

 

[Storyline]

Then wait no longer: http://amzn.to/1ltWKc6

A bit confused here, do these do any more than measure & display the temperature - ie do they have an alarm function so I could connect a buzzer/siren to them ?

 

[prv]

do they have an alarm function so I could connect a buzzer/siren to them ?

Yes, they do.

(At least, the very similar-looking ones I bought from eBay a while ago do. Really ought to get round to fitting them... )

Pete

 

[Storyline]

Yes, they do.

(At least, the very similar-looking ones I bought from eBay a while ago do. Really ought to get round to fitting them... )

Pete

Thanks, that must also explain why the one in the link kindly provided by Nigel says it is rated at 10 amps. Maybe

 

[Avocet]

Yes, they can be programmed to "do something" when the temperature exceeds a set threshold (r drops below it) and they can switch a load of 10A (at 12V). I bought an 85dB buzzer and just connected it up. Worked fine, but might go for something slightly louder if I was doing it again.