JPI 830

[Wakeup]

I noticed last week on decent the OAT was 64 and the CLD that's usually 0 was 17.   Does that mean the carb temp decreased to 17 degrees and I should watch for carb ice??  And should apply carb heat??  Be gentle in me.  I am used to flying in the dark.  Troy 

[Guitarmaster]

CLD is the rate of cylinder cooling. It is there to alert to the possibility of shock cooling.
This is mostly a turbo problem, but it never hurts to ease the power off slowly in the descent.

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[gsxrpilot]

That CLD message is actually not a warning, just notifying you of the rate of cooling. In your example that's 17 degrees per minute.  The JPI user guide suggests not allowing that to go above 50 degrees per minute. As was noted previously, this is mostly an issue for turbo Mooney's, but even so, the POH for my turbo K, recommends just keeping the CHT's above 250 in the descent.

[bradp]

I came in high last night and pulled it back to 15", full RPM, ROP and added in some side slip.  Let the Mrs know so that falling feeling didn't bother her.  Went down down down at 1500 fpm, 180 kts over the ground, and was able to slow to 120 kias (where I drop the gear) as well.  Who says you can't go down and slow down at the same time ;-)  Was fun.  CLD was reading 40.  I have an alarm set for 40 on the JPI 730.   Not pulling back the throttle as much in the descent let the MP rise a bit and cooling evened out. 

[Aerodon]

A cooling rate of 40 is not excessive, but I like setting the alarm at 40 just to remind me.  I think the rate to try stay below is 60.  You will be surprised when you see the most rapid change.  Levelling off is a big one, starting from high CHT's and you double the cooling with airspeed, halve the temperature by reducing power.  Not good.

Descending, usually not much of an issue.  Circuit generally OK unless you have to pull a lot of power off an final, and then of course after landing.

All stuff you didn't know before a JPI engine monitor,

Don

 

 

 

[Wakeup]

Thanks for all the responses.  I am still trying to figure out all the details of the 830. I hate to admit this but I thought it was my carb temp.  I know I paid extra for the carb temp probe but I do not see it on my display??  

[carusoam]

Carb temp is good to have.  Way back in the past, So few carbed planes got one on a JPI...

Nice thing about it is it's simplicity of use.  °F in a range near freezing.  Make sure the range is depicted in case you forget...

vaporizing fuel is a great coolant.

Best regards,

-a-

[Marauder]

20 minutes ago, Wakeup said:

Thanks for all the responses.  I am still trying to figure out all the details of the 830. I hate to admit this but I thought it was my carb temp.  I know I paid extra for the carb temp probe but I do not see it on my display??  

Troy -- if you ever get your butt up to one of the Mooney Fly-ins, we'll walk you through the 830. The missing parameter is called the IAT. This is what should be displayed to show the carb temp.

[bradp]

In the JPI installation manual (which is of course written by engineers and hard to follow(, there are instructions on how to configure the display.  You should be able to get the IAT to display using the programming menus.  There're a lot of options available by scrolling through with only two buttons. 

[cnoe]

Chris, I believe on non-turbo installations the display reads CRB34 (or similar) if the option is installed. He should be able to see it on the bottom of the display by scrolling through with the step button (or auto scroll). Alternatively he can add it to the static display fields on the right with an easy programming change. It appears there's already an open spot there where he has "fuel required" X'd out (which won't work unless he connects it to a GPS). If you need more help with this wakeup, just ask.


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[Oscar Avalle]

Indeed the CRB option give you the temperature of the carb and thus probability of icing. The nice thing is that you can actually configure an alarm for it. 

[Aerodon]

On 2016-11-07 at 7:37 PM, Marauder said:

Troy -- if you ever get your butt up to one of the Mooney Fly-ins, we'll walk you through the 830. The missing parameter is called the IAT. This is what should be displayed to show the carb temp.

If you look at the install 700/830 manual, the wiring diagrams appear to show IAT and CRB on pins 3 & 4.  But if you look more closely the CRB is under the 7/8/9 cylinder column.  If you look in the Q&A of tech support, here's what it says (their bold letters):

EDM-700/800 PIN ASSIGNMENTS:
yel 1, red 2, OIL
yel 3, red 4, IND
yel 5, red 6, CARB (or CDT)
yel 14, red 15, OAT
yel 16, red 17, TIT
yel 18, red 19, TIT-2 (2nd TIT)
gry 12, Remote alarm (Sinks to ground)
red 13, + Power
wht 24 , RS-232 data port
blk 25, Engine ground.   ** ( Pin # 11 not used.)

I've made this mistake more than once, and have reported this to JPI several times, being optimistic that they would in fact like to update their manual.

Don