Testing ohms/resistance

Colin K

Colin K

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Hello,
I am reasonably ok with my electrics but just wanted to check this over with any electronics experts if possible!
My Eberspacher is not staying on for more than 15 mins and have serviced it and checked the basics.(its only six months old but installed by a numpty)
Next visit I am going to check continuity of all the wiring runs but then would like to test the various componants on the unit,Pump (although will do a fuel quantity test too) overheat/flame sensor,glow plug etc. I have got the maunual and it gives me the range of resistance for each of the componants but just wanted to confirm that all you do is set your megga to the appropriate range and connect the probes to the tails of the componant? Presume you disconnect any feed wires?

Thanks for any advise, Cheers, Colin.
 
I've noticed one of the most common problems with Ebers installed by amateurs is in inadequate power supply. The Eber may start and run, but will shut down shortly after, when the battery becomes only slightly depleted.

So, measure the supply voltage at the Eber, and also at the battery, at minute or two intervals from startup. Check that it isn't falling below the specified minimum. If that's the issue, uprate the supply wiring +ve and -ve, from the heater right back to the battery.
 
Colin K said:
Hello,
I am reasonably ok with my electrics but just wanted to check this over with any electronics experts if possible!
My Eberspacher is not staying on for more than 15 mins and have serviced it and checked the basics.(its only six months old but installed by a numpty)
Next visit I am going to check continuity of all the wiring runs but then would like to test the various componants on the unit,Pump (although will do a fuel quantity test too) overheat/flame sensor,glow plug etc. I have got the maunual and it gives me the range of resistance for each of the componants but just wanted to confirm that all you do is set your megga to the appropriate range and connect the probes to the tails of the componant? Presume you disconnect any feed wires?

Thanks for any advise, Cheers, Colin.
Click to expand...

If the thing is only six months old and you suspect component failure why are you fiddling with it, take it in for a warranty claim, or get the numpy back to sort it. If you must DIY then you would be better off getting a cheap interface and downloading a free copy EDITH (or I can send you the file) , whilst the resistances given at varying temperatures are a good basic guide there is nothing to beat being able to see what is going on during real installed operating conditions, also if you wish to conduct a fuel delivery test it will allow you to set the correct Hz and time for that. For testing continuity and confirming correct pin positioning on the loom a circuit terster with small load is more useful than a multi meter. But to answer your question about component resistance just set the meter to the appropriate range on your meter. If it were a Webasto / Mikini / Wallas or M.V. I would offer a warranty inspection but can't help on that score with an Eber.
 
Colin K said:
Hello,
I am reasonably ok with my electrics but just wanted to check this over with any electronics experts if possible!
My Eberspacher is not staying on for more than 15 mins and have serviced it and checked the basics.(its only six months old but installed by a numpty)
Next visit I am going to check continuity of all the wiring runs but then would like to test the various componants on the unit,Pump (although will do a fuel quantity test too) overheat/flame sensor,glow plug etc. I have got the maunual and it gives me the range of resistance for each of the componants but just wanted to confirm that all you do is set your megga to the appropriate range and connect the probes to the tails of the componant? Presume you disconnect any feed wires?

Thanks for any advise, Cheers, Colin.
Click to expand...

Yes disconnect the component being tested from the rest of the circuit, and simply connect the probes or clips of the meter set to an appropriate range.

A bit concerned by your reference to "Megga" presumably meaning "Megger", a brand name for electrical test equipment but traditionally an instrument used for testing insulation resistance at 500volts (?) as well as continuity

Hopefully you are in fact using a common or garden multimeter with resistance measuring ranges or if you are using a modern version of the traditional "Megger" you are familiar with it .
 
Last edited:
VicS said:
Yes disconnect the component being tested from the rest of the circuit, and simply connect the probes or clips of the meter set to an appropriate range.

A bit concerned by your reference to "Megga" presumably meaning "Megger", a brand name for electrical test equipment but traditionally an instrument used for testing insulation resistance at 500volts (?) as well as continuity

Hopefully you are in fact using a common or garden multimeter with resistance measuring ranges or if you are using a modern version of the traditional "Megger" you are familiar with it .
Click to expand...


Hello,
Thanks for the replies, Ooops yes you are correct I mean a multi meter thanks Vic. I bought the boat in January and brought her home to Ipswich, she was based on the IOW. I guess that I have fallen into a bit of a trap I needed the Eber to work in the Winter and so started to tinker with it re routing the rising fuel feed pipes, replacing a damaged flexi exhaust pipe that was leaking fumes like a steam train so the installer is in another oart of the country. The basrpe units are hopefully ok the unit idps dated Dec 2014 and it has a decent 801 controller which shows me the fault codes. Guess I am at a point now where I just want to get it going reliably.

Cheers, Colin.
 
As David says, if it's within warranty get it to a dealer, you "may" invalidate the warranty by playing with it yourself. If there isn't a marine supplier locally, there is most likely a vehicle heater supplier/repairer who can sort it.
 
As intimated perhaps a better first test will be to check the battery voltage at the heater and at the battery. It may be that you are losing battery voltage int he ships wiring.
An easy way to test is with the heater running put a +ve multimeter lead on the battery +ve terminal.Put the negative meter lead (you might need an extension) on the +ve input terminal of the heater. Any voltage reading here will represent loss in the wiring switching fuses etc. Any more than .2 volt might be cause for concern. If it is higher then you can while leaving the +ve lead on the battery terminal move the -ve lead back to switch fuse etc. You may find a component in the +ve supply that is dropping too much voltage. replace or wire around it.
Likewise you need to check the drop on the negative power supply. Again -ve meter lead on the battery -ve terminal positive lead on the negative input terminal of the heater.
Should be very low volt drop here. If there is any serious drop ie more than .2 volt then fit heavier wire or additional wire battery negative to heater negative.
If these tests prove OK then you should conside the battery performance. good luck olewill
 
Rather strange it runs for 15 mins and you are looking for wiring faults i.e. high resistances. The Eber has managed to start under it's highest load with the glow plug in circuit so any high resistance should/would show up then. Once up to temperature the only load should be the circulation blower and fuel pump which is a minimal current draw. Prehaps you should be looking elsewhere if no fault codes are being displayed.
 
grumpygit said:
Rather strange it runs for 15 mins and you are looking for wiring faults i.e. high resistances. The Eber has managed to start under it's highest load with the glow plug in circuit so any high resistance should/would show up then. Once up to temperature the only load should be the circulation blower and fuel pump which is a minimal current draw. Prehaps you should be looking elsewhere if no fault codes are being displayed.
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Hello,
Thanks for the replies, ive just got back from the boat SWMBO had left something on board. I had a quick unofficial 10 mins so I took my "multimeter". Fired it up and had the meter on the feed wires on the Eber all of the time, The voltage did not drop below 12.90 volts even when it fired so thats ok. Got the cabin up to 20 degrees which is what I asked it for on the 801 programmer and when it got there it cut out and putting my ear to an air vent could just hear the fan ticking over. Pressed the up arrow to 22 degrees and waited thinking it would burn again as I was calling for more heat but nope not after 5 mins. Then pressed the up arrow until it was asking for 32 degrees and off it fired. I am a bit blooming confused! At least its working and I have heat. Before I left I reset the fault codes by pressing the up and down arrows together so it was clear. Check it now and hey presto I have a new fault code 13 not had this one before I think its an over heat one historically its been failed to fire/time out codes I must follow the Espar manual and start to log them!
I can see me investing in an Edith off Ebay!

Once again thanks for all your replies, Colin.
 
Colin K said:
Hello,
Thanks for the replies, ive just got back from the boat SWMBO had left something on board. I had a quick unofficial 10 mins so I took my "multimeter". Fired it up and had the meter on the feed wires on the Eber all of the time, The voltage did not drop below 12.90 volts even when it fired so thats ok. Got the cabin up to 20 degrees which is what I asked it for on the 801 programmer and when it got there it cut out and putting my ear to an air vent could just hear the fan ticking over. Pressed the up arrow to 22 degrees and waited thinking it would burn again as I was calling for more heat but nope not after 5 mins. Then pressed the up arrow until it was asking for 32 degrees and off it fired. I am a bit blooming confused! At least its working and I have heat. Before I left I reset the fault codes by pressing the up and down arrows together so it was clear. Check it now and hey presto I have a new fault code 13 not had this one before I think its an over heat one historically its been failed to fire/time out codes I must follow the Espar manual and start to log them!
I can see me investing in an Edith off Ebay!

Once again thanks for all your replies, Colin.
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Did you have the battery charger on when you run this test? 12.9 volts is high for a rested battery, let alone one with a reasonably high current bring drawn from it. Something sounds wrong.
 
neale said:
Did you have the battery charger on when you run this test? 12.9 volts is high for a rested battery, let alone one with a reasonably high current bring drawn from it. Something sounds wrong.
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Hello,
Yes sorry should have said battery charger was on and on shore power its always on, its a Ctrek automatic battery charger fitted by Fairline from new. I think its quite a beast. The batteries are brand new.

Cheers, Colin.
 
Hello,
Well I had my night on board and went straight to the Eber multimeter at hand. Just to warm it a bit I fired it up after I opened up the bilge its in. Blow me down as she was firing I picked up the feed wires and there was a crackle. Eber cut out and I quickly squeezed the wires to start it again to cool it quick. Took the bull by the horns after and unwrapped the mess of amalamating tape. The main feed wires were joined by cheap yellow bullet connectors. I therefore ripped them out and replaced them with something more substantial. Whilst at it I replaced the seven joins to the wires to the controller which were equally rubbish.
Fingers crossed I fired it up and hey presto perfect, it worked all evening and responded to any call for heat be it just an extra degree. Then the blooming disaster!
Left it on overnight asking it to maintain 18 degrees, At 3 am I woke up cold, the cabin was at 16 deg and the Eber not responding it did not fire back up until I turned it off and back on. Aaaaah.
Whilst rewiring I cleared the fault codes and now I have two. F1 is 13. And F2 is 12.

Also when I rewired her I did the resistance tests these were :-

Flame sensor should be 1056 to 1100. Mine is. 1075
Overheat sensor should be 59.3 to 65.8. Mine is 65.40
Pump should be 9.0 to 10.0. Mine is 9.8
Glow plug should be 0.42 to 0.7. Mine is 0.9.

I wonder if the high reading on the glow plug could mess it up? Anyone come across this?

Appreciate any ideas, Cheers, Colin.
 
Colin K said:
Hello,

Also when I rewired her I did the resistance tests these were :-

Flame sensor should be 1056 to 1100. Mine is. 1075
Overheat sensor should be 59.3 to 65.8. Mine is 65.40
Pump should be 9.0 to 10.0. Mine is 9.8
Glow plug should be 0.42 to 0.7. Mine is 0.9.

I wonder if the high reading on the glow plug could mess it up? Anyone come across this?

Appreciate any ideas, Cheers, Colin.
Click to expand...

It is difficult to measure these low resistances accurately. Did you check the reading when the meter probes were simply shorted together. A "zero error" could easily account for up to 0.5 ohm.
 
VicS said:
It is difficult to measure these low resistances accurately. Did you check the reading when the meter probes were simply shorted together. A "zero error" could easily account for up to 0.5 ohm.
Click to expand...

Hello,
Ha ha actually I did but I had no idea why I checked the readings shorted out on each setting!!

The readout shorted was for the glow plug 0.9 !! And it didnt occur to me thats the reading across the terminals! Does that mean its got a fault (although it does fire up from start)

Cheers, Colin.
 
Colin K said:
Hello,
Whilst rewiring I cleared the fault codes and now I have two. F1 is 13. And F2 is 12.

Also when I rewired her I did the resistance tests these were :-

Flame sensor should be 1056 to 1100. Mine is. 1075
Overheat sensor should be 59.3 to 65.8. Mine is 65.40
Pump should be 9.0 to 10.0. Mine is 9.8
Glow plug should be 0.42 to 0.7. Mine is 0.9.

I wonder if the high reading on the glow plug could mess it up? Anyone come across this?

Appreciate any ideas, Cheers, Colin.
Click to expand...

Despite the overheat / temp sensor being within tolerance on your meter (abait well at the upper end), with those codes my next step would be to replace it with a known good one and monitor the result, easy for me as I don't have to buy one to do that but if you can get hold of one I would look to try it. Another thing I would be looking at is the duct dia / length and total numbers for all bends, elbows, tees, outlets etc against the total allowance.
 
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