Jaredg
Hello, folks. This is my first post here. I'm having trouble getting my geothermal system started on generator power. Below are some of the particulars on the equipment:

Generator
Model #:04390-2
Serial #:
Total run hours: est. 50
Fuel source:  LP:
Length of fuel run: 150 ft
Diameter of fuel pipe: 3/8"
Last maintenance date: 7-2019
Last valve adjustment date: 2017
Last battery replacement date: 2016
Error Code: N/A
_____________________________________________
Climatemaster Geothermal Unit
Model: TTV064AGC01ALKS
RLA: 25.6
LRA: 118
Install Date: 2006
Blower Mtr: FLA 7.0
_____________________________________________
Hyper Engineering Soft Start for Geo System
Model: SS1B16-32SN
Install Date: 2016


I bought the generator used and installed it in early 2016 for selected circuits using a 0E7970 transfer switch. I was concerned that the geo system would be hard to start, so I installed the Hyper Engineering Sure Start soft start right from the beginning.

This system seemed to perform well enough. The generator could start the geo system and run it. You could hear the generator pull down some for a few seconds during the start, but that seemed reasonable to me.
The last couple of months I noticed that the generator won't start the geo system. I went through and looked at all the connections without any improvement. I'm getting a low voltage error from the Surestart unit, which, according to the manufacturer, occurs at 195VAC. It works just fine on utility power.

I attempted some measurements today. With only some lighting loads of 2-3Amps, the generator output was 247V and 61.5Hz. Each leg to neutral was pretty much even. I then powered the geo unit. Before starting the compressor, it ramps up the fan. The compressor failed to start and tripped on low voltage. I recorded it with a Fluke 189 meter and saw a minimum voltage of about 140. I don't know duration, but it was a fraction of a second.
The fan continues to run while the starter waits 3 minutes to make the next start attempt. During this time the fan continues.
After the failed start attempt, I noticed that the voltage had climbed to 276V. I didn't check each leg individually as I was concerned about damage. I turned off the geo breaker and my voltage returned to the 245-247 range. 

I know that's a lot of info and there are surely some things that I missed. Does this point to anything in particular that I should be looking for? I appreciate any guidance.
Thanks.


Jared

Quote
murphy
Have you tested the capacitor in the compressor cabinet?  They go bad quite regularly which severely increases the start current.  The one in my regular air conditioner had dropped from 45 mfd to 0.7 mfd the last time I changed it.
Quote
78buckshot
I agree with murphy, check the factory compressor run cap in the Climate Master, I would also consider replacing the voltage regulator in the generator.
Quote
Peddler
The dash 2 4390's date to about 2003-2004 I think and so there may be some degradation of the unit over the past 15 years or so.  First the no load Hz should be about 65Hz and the no load voltage should be 245 VAC.  Second I would check the fuel pressure under load and it should be 12" water column under load.  I would check the valves and would like to know how the unit starts cold and if it is popping or backfiring any.  Those had weak coils and if they start to deteriorate the timing can be off.  Lastly I agree that I would replace the voltage regulator if it hasn't been changed and while doing that measure the ohms to ground of the #4 wire to the VR if it is over 25 ohms clean the slip rings.  Lastly that is a 5 ton geothermal heat pump which in my opinion your generator is a little too small or at best marginal.
Quote
78buckshot
I was thinking the same thing about running 5 tons on the 13/15kw, pretty good load for the old girl.
Quote
Jaredg
It will be several days before I can look at it again, but I'll answer what I can for now. 

I checked the valves a year or two ago because I hear a faint popping occasionally. They were within tolerance and it didn't seem to make a difference.
It starts right up, but it does tend to die right at about 15 seconds after the initial start if it hasn't been started for days. It re-fires and then runs fine after that. 
I'm sure the voltage regulator is original. I can look into that.

You're probably right about the generator being marginally sized. They claim that the in-rush should be about 40A with the soft start and my compressor. It was working, so I'm hoping I can get it back. If I remember correctly, the geothermal unit as a whole drew about 23-25A at maximum.

Thanks for the suggestions. I will update when I get time to investigate more.
Quote
78buckshot
Sounds like it could also be fuel related, I would go through the LP system with a fine tooth comb looking for correct pipe size, pressure, regulator vent, length and size of pipe between the reg. and generator(fuel reservoir) etc.
Quote
Jaredg
I ruled out the capacitor this morning.  It tested out perfectly. I forgot that it was changed a couple years ago as a preventative measure. 
Quote
grsthegreat
you posted 150 foot fuel run at 3/8"....is that right. thats way too small of gas pipe
Quote
Peddler
The gas line is probably 3/8 ID and high pressure with a regulator at the unit which would be plenty.
Quote
78buckshot
3/8 soft copper is normal for LP from the primary regulator to the secondary regulator, primary is set at 10psi, secondary at 11 - 13 in.w.c. At 10psi it's dang near still liquid in that line and has a great btu content.
Quote
78buckshot
Jaredg, do you have the means to measure gas pressure, also do you remember how much and what size the piping is from the secondary regulator to the genset?
Quote
grsthegreat
78buckshot wrote:
3/8 soft copper is normal for LP from the primary regulator to the secondary regulator, primary is set at 10psi, secondary at 11 - 13 in.w.c. At 10psi it's dang near still liquid in that line and has a great btu content.
Really, not here in Idaho. 3/4" absolute minimum used. ive never seen 3/8" used.
Quote
78buckshot
Bigger is better!
Quote
Jaredg
I looked up the paperwork and the line is actually 1/2". There is a secondary regulator at the generator with a larger pipe that connects to the generator. I'll have to measure the larger pipe and report back.
I don't have anything to measure the pressure with myself. I do recall the LP supplier setting it to the 11-13 " w.c. when it was installed.
Quote
78buckshot
I have had good success with LP after building a fuel reservoir between the secondary regulator and the genset. In two locations I used a 3 inch by 24 inch black pipe with 3 x 3/4 reducing couplers on each end, this is piped in downstream of the secondary regulator and gives the generator a ready supply of fuel as the regulator is reacting to demand. I'm suggesting it per your description of the engine dying 15 seconds after the first start. I also recommend a new voltage regulator and cleaning the slip rings and replacing the ignition mags as Peddler suggests, or a new larger generator.
Quote
Jaredg
Here's an update. I cleaned the slip rings and installed a new voltage regulator. The resistance from wire 4 to ground started at 36.9 ohms before cleaning and 20.5 ohms after.
The result was that it behaved exactly as it did before. The geothermal compressor faulted on undervoltage after a fraction of a second and the generator voltage shot up 20+ volts and remained high until I turned off the geothermal breaker.
Does the increased voltage after the failed attempt at starting the compressor make any sense to anyone? The only load on the generator after the start attempt is the HVAC fan, which is only a few amps.
Quote
Peddler
The increase in voltage, does it stay or bleed off?  The load hit causes the governor to pull open then the load dumps and the unit revs up but should settle.  What are the no load voltage and Hz?  What kind of meter are you using?  If not a True RMS it could be giving you poor readings
Quote
Jaredg
The voltage increase held steady 60-90 seconds after the initial start attempt. I shut the breaker off soon after that. The last time I tested it the voltage stayed high until I turned off the HVAC breaker.
No load was 61.7 Hz and 248-249V.
I'm using a Klein MM2000 meter that says it reads true rms.
I couldn't really hear the generator react to the compressor load. It's such a short duration before the starter goes to lockout mode.
Quote
78buckshot
Remove the Sure Start from the compressor circuit, re-wire per original schematic found on the geo panel, try the system by itself with generator power.
Quote