Living with the DuroMAX XP9000iH

[littleboss]

I shared the concerns about the fuel solenoid with my contact at DuroMax and this was his response..FWIW.

Thanks for sending that over. I’ve had my concerns on that solenoid for a while because I have seen some issues that stem from it. I know that piece was changed up (in design) but the issue is that a lot of old stock still has potential to run into the issue. The weird part is that it isn’t a high-quantity problem across the units in general, but it seems that it has something to do with the issues in the cases where problems do occur. The downside here is that I’ve tooled around with the same idea. I’m not sure who this person spoke with, but based on their wording, I can certainly tell you that it wasn’t me. Where I saw an issue with this “fix” is that the solenoid, for lack of better words, isn’t compatible with the PCB (computer). Solenoids generally operate one way… once power is received, the solenoid operates. This implies the signal needs to be momentary, and on-demand. The PCB in these inverters sends a constant signal… which now you can see why the solenoids, that do burn out, have their issues. The issue really boils down to a solenoid not holding up to the specs it was designed for. I have mentioned on several occasions to several shops that we can always try the parts (I can reimburse) and see what we get. After field testing on some other units, let’s just say my confidence in the solution is not high. The new units have been adjusted with a different setup/part just to account for the issue. It’s weird territory though. 9kWiH units, in general, do not have this problem as a common issue (which is why we are so willing to replace – generally the issue is an afterthought at that point), BUT I would also say that when they do have issues, then this problem is more common than other. Basically, it's not a mass-defect situation, but it is something we’re aware of and have changed. The issue is really that the old stock doesn’t see those changes…and this includes replacement units that dip into old stock.

found this thread while researching gensets with ATS support. A solenoid doesn't operate as you say. A solenoid has a coil of wire with a plunger inside. When voltage is applied to the coil, this creates magnetism which pulls in the plunger. For the solenoid to remain "on" the control voltage has to stay applied to the coil.. The signal is NOT momentary.
The problem is the entire time you are on propane there is current running through the coil. Obviously Duramax has a poor design or used a solenoid who's coil can't tolerate that much current over a long period..

The electronic ball values seem to take care of that problem: ALTERNATIVE TO SOLENOID VALVES- Automatically cuts off power once fully open or fully closed; This reduces likelihood of overheating, making it a great alternative to solenoid valves for projects where a valve needs to be open for an extended period of time.

This review shows that current does flow all of the time just not much so still should be fine:
Product description says: "No power expended once fully open or fully closed". Testing (DC model) shows continuous 5ma draw after actuation in either direction. (30ma during open/close, testing at 19V)


https://www.amazon.com/Motorized-El...locphy=9026799&hvtargid=pla-379266017244&th=1

 

[Symbioquine]

A solenoid doesn't operate as you say. A solenoid has a coil of wire with a plunger inside. When voltage is applied to the coil, this creates magnetism which pulls in the plunger. For the solenoid to remain "on" the control voltage has to stay applied to the coil.. The signal is NOT momentary.
The problem is the entire time you are on propane there is current running through the coil. Obviously Duramax has a poor design or used a solenoid who's coil can't tolerate that much current over a long period..

I'm not an expert, but I believe this is an incomplete/misleading summary of the operating and failure modes of solenoids. As @Hedges described earlier in this thread, you can design your control circuit to reduce the current once the solenoid has activated. Also, to a lesser degree, the current will intrinsically self-limit as a function of magnetic saturation and the operating temperature of the solenoid. (Though this effect won't protect the solenoid if the resulting equilibrium temperature exceeds the safe operating temperature of the varnish on the coil for example.)

I haven't measured the behaviour of the control circuitry and current draw of the solenoid in the DuroMAX units I've got, but presumably there's some mismatch between the typical operating conditions and the solenoids they used that causes them to burn out. Both the motorized ball valve and the solenoid will have some typical life expectancy (especially in a warm vibrating engine compartment) - the engineering problem here isn't making them last forever, just a reasonably long time.

I can't speculate on whether they've fixed the issue in newer stock of course.

 

[littleboss]

I'm not an expert, but I believe this is an incomplete/misleading summary of the operating and failure modes of solenoids. As @Hedges described earlier in this thread, you can design your control circuit to reduce the current once the solenoid has activated. Also, to a lesser degree, the current will intrinsically self-limit as a function of magnetic saturation and the operating temperature of the solenoid. (Though this effect won't protect the solenoid if the resulting equilibrium temperature exceeds the safe operating temperature of the varnish on the coil for example.)

I haven't measured the behaviour of the control circuitry and current draw of the solenoid in the DuroMAX units I've got, but presumably there's some mismatch between the typical operating conditions and the solenoids they used that causes them to burn out. Both the motorized ball valve and the solenoid will have some typical life expectancy (especially in a warm vibrating engine compartment) - the engineering problem here isn't making them last forever, just a reasonably long time.

I can't speculate on whether they've fixed the issue in newer stock of course.

Latching current CAN be less than pulling in current but I bet Duromax uses a steady current that doesn't change- therefore the solenoid coil burns up. i assume you think your statement below makes you look like you know what you are talking about? It doesn't........... LOL

Also, to a lesser degree, the current will intrinsically self-limit as a function of magnetic saturation and the operating temperature of the solenoid. (Though this effect won't protect the solenoid if the resulting

 

[Symbioquine]

I bet Duromax uses a steady current that doesn't change

I'd bet the same, but since their support person indicated otherwise it might be worth additional investigation. The solenoid is definitely driven from a board which is complex enough it could provide different initial and holding voltages. I haven't looked closely enough to see if it just uses a relay/FET to switch 12v nominal power to the solenoid or if it is more sophisticated.

i assume you think your statement below makes you look like you know what you are talking about? It doesn't........... LOL

I can only assume you're trying to troll. I literally started my post with "I am not an expert". If you want to provide a better explanation of solenoid behavior or failure modes, please do, but don't waste everyone's time implying irrelevant things about my motives in writing what I've written. Please stay on topic.

 

[Hedges]

I'd bet the same, but since their support person indicated otherwise it might be worth additional investigation. The solenoid is definitely driven from a board which is complex enough it could provide different initial and holding voltages. I haven't looked closely enough to see if it just uses a relay/FET to switch 12v nominal power to the solenoid or if it is more sophisticated.

Do you have one? Can you measure the current?

An economizer could simply be a series resistor and a transistor to bypass it.
Given previous failures I'm betting they just apply battery voltage. Maybe redesigned later.

AC works nicely because core pulling in provides economizer function. Most DC relays and solenoids just use resistance to limit current, but that limits pull-in power. Lots of parts are rated for intermittent use only, like when cranking an engine. I'd think glow-plug relay would be one (and those are/were magnetic latching.) Need one rated for continuous duty.

Costs more money (pennies?) to add an economizer for DC.
If they located relay where it got cooled by air before that's blown over the engine, or in the intake airflow, that would probably make all the difference.
Stanadyne "Pump Mounted Driver" of my K2500 is known for heat failures. There are various relocating kits. I relocated mine to the air box, which guarantees outside air drawn over it any time it is operating. And no longer cooked by heat of the block, or dependent on left pump to keep excess fuel flow for cooling.

 

[Symbioquine]

Do you have one? Can you measure the current?

Planning on it - though it might take me a bit to get to it since I'm not doing much with the generators this time of year except starting them periodically for maintenance purposes.

 

[TBoone]

Some things I've learned about the DuroMAX XP9000iH - hopefully some of this will help other folks:

Similar Generators

This generator is very similar to the following generators which can be used (with a grain of salt) as a reference when looking for helpful reviews, alternate manual descriptions, and parts/wiring diagrams.

• Predator 9500 Inverter Generator
• GENMAX GM9000iED
• TOMAHAWK TG9000i

Fuel Solenoid & Hidden Fuses

• If used regularly on propane, the fuel solenoid will burn out since it isn't rated for continuous duty (part claims 8 hours duty cycle, but realistically its days are numbered regardless in a hot vibrating engine compartment)
• When the fuel solenoid burns out, it behaves like a serious short and blows a little glass fuse (F15AL250V) behind the front panel (where all the plugs/indicators are)
• There are three such little glass fuses (of different ratings) in inline holders behind the front panel which seems like one of the less user serviceable places on the generator
• The fuse that the fuel solenoid causes to blow also means the whole front panel ends up unpowered - making the whole generator look dead
• DuroMAX's support line didn't know want or know how to walk me through even that level of troubleshooting so they sent me a whole new generator under warranty - I don't feel bad about this since I basically begged them to help me troubleshoot the one I already had and cumulatively spent more than an hour on hold
• With a dead fuel solenoid, this generator can still work on gasoline just by unplugging the fuel solenoid and replacing the blown fuse
• The fuel solenoid can be replaced with a motorized ball valve which should have a much longer service life - don't bother trying to get the barbed elbows off the original solenoid since they used some crazy locktite seal stuff and there's no place to put a wrench on the solenoid, instead just get these ones to go with the motorized ball valve linked above
• I'm still experimenting with the motorized ball valve strategy above. The main downside seems to be that it is a bit slower than the fuel solenoid which can allow a tiny amount of fuel to flow after it normally would, resulting in a backfire during normal shutdown

CO Sensor

• The CO sensor is very sensitive and is inside the case of the generator with the engine - any wind or attempt to shelter the generator from the wind/rain will almost certainly cause nuisance tripping of the sensor
• Unplugging the CO sensor does not prevent the generator from starting, but it does not operate normally - the oil warning light comes on and the engine runs in a weird surging version of the low idle
• I'm experimenting with operating the generator with the CO sensor removed by tying the green/yellow striped wire with the white wire that lead towards the area below the starter on the engine as shown on this video
  
  • (Please don't lecture me about the safety risks of doing this: The generator will always be operated in an outdoor enclosure away from people. It is too loud to comfortably stand near under load. We have CO sensors/alarms in our nearby living spaces. I intend to label the generator clearly to indicate that it does not have a CO sensor.)
  • Somewhat related: https://diysolarforum.com/threads/2021-honda-generator-carbon-monoxide-indicator.25808/
• I don't know whether the low oil shutdown is still functional in this configuration
• Instead of cutting the wires as shown in that video, a replacement plug can be made that shorts the two relevant pins and leaves the rest unconnected. I found that the connector was the same as one from an old computer power supply board;
  View attachment 134616View attachment 134615View attachment 134614

Efficiency on Propane

See https://diysolarforum.com/threads/how-efficient-is-your-generator.50418/

Handle Swap

The generator has two kinds of handles, the horizontal bar handles which are located on both ends of the generator and the folding ones that are bolted on to the horizontal bar handle on one end of the generator.

The folding handles can be moved from the back end of the generator to the end with the front panel. This is useful if you're storing the unit in a tight space, but still want access to the front panel - for example to plug in the battery maintainer.

I saw one Youtube comment that referred to moving the handles by drilling new holes in the other end's horizontal bar handles, but I can't recommend that strategy. The horizontal bar handles are interchangeable, but not identical. The back end has a shorter foam pad on the horizontal bar handle that fits between the bracket for the folding handles, but the corresponding foam pad on the front horizontal bar handle goes the full length. I'm pretty sure the bracket for the folding handles wouldn't fit over the foam pad nicely, and it would leave the rear handle with some unnecessary holes and a short foam pad. It's better to also swap the horizontal handles as part of moving the folding handles to the front.

Moving the handles from one end to the other doesn't require any actual modifications to the hardware, but is fairly involved because you have to take the wheels and all four clam-shell sides off the generator. Once that's done, it is simply a matter of removing the 4 bolts that hold the folding handles on, unbolting and sliding the two horizontal bar handles out and swapping them, then re-attaching the folding handles on the front of the generator.

When taking the clam-shell sides off the generator, make sure not to lose these little clips;

View attachment 135232

Future Possible Parts

When the fuel solenoid issue happened, I was worried that it might be one of the main boards (control or inverter) so I spent some time looking for possible replacement parts.

One part that looks very similar is the inverter board for the Predator 8750 - I haven't tried this yet, but I'm willing to bet it's probably the exact same part...

From Listing	In Generator
	View attachment 134622

Helpful Reviews

View attachment 134625
View attachment 134626View attachment 134627View attachment 134628

EXCELLENT discussion. I have an almost new XP9000IH and will probably just disconnect the existing propane solenoid and mount a ball valve assembly somewhere on the exterior of the genset to allow access, etc..
TBooneFisher, EE
Granbury, TX, 0TX1

 

[Symbioquine]

EXCELLENT discussion. I have an almost new XP9000IH and will probably just disconnect the existing propane solenoid and mount a ball valve assembly somewhere on the exterior of the genset to allow access, etc..
TBooneFisher, EE
Granbury, TX, 0TX1

Good to have you onboard. Please share anything you learn about these generators!

 

[turbov6]

Any update on this topic, I also own a XP9000IH. I sooke to a rep at Duromax on 12/07/2022 and he replied with:

We are supposed to be coming out with a transfer switch on this generator. Current ETA is projected at 3rd quarter 2023.

I’ll follow up to see if they have any updates on it.

 

[Symbioquine]

Not sure why I didn't get a notification about your post @turbov6

It's not full off-the-shelf auto ATS functionality, but on page 2 of this thread I described the pins on the ATS plug which cause my XP9000iH units to start/stop. Using that (assuming your unit is the same), it should be possible to DIY an auto start/stop solution of some kind. Not sure if that helps, but I think that's the best option at the moment. DuroMAX' website just lists manual transfer options and panel interlock kits - as far as I can tell nothing that integrates with the XP9000iH ATS plug.

 

[Encrypted]

I bought this generator (the Duromax xp9000ih) in May 2023. I test ran it on propane for about 20 min then, ran fine. Just had our first 30 min power outage and it again worked great. I slowly unloaded the circuits down to zero, disconnected the cable, then shut it down using the rocker switch. After it fully stopped running (engine was still), I heard a VERY loud bang - much louder than the sound the generator makes while running. Now, the start light will no longer come on, and pressing the button does nothing.

My question to those of you that have had blown solenoids - is that what I heard? I haven't had time to open it up yet and look for what it may have been, but will after work. Just wondering how loud a solenoid is when it goes, or maybe if I have a different issue.

[Edited year 2024->2023, lol thanks @Symbioquine ]

 

[Symbioquine]

I bought this generator (theDuromax xp9000ih) in May 2024.

Welcome time traveler!

After it fully stopped running (engine was still), I heard a VERY loud bang - much louder than the sound the generator makes while running. Now, the start light will no longer come on, and pressing the button does nothing.

My question to those of you that have had blown solenoids - is that what I heard? I haven't had time to open it up yet and look for what it may have been, but will after work. Just wondering how loud a solenoid is when it goes, or maybe if I have a different issue.

I'd be surprised if the solenoid makes a loud bang noise when it fails.

However it is pretty easy to get these generators to backfire when running on propane if you shut off the generator via the start/stop button (or fob). I believe this happens because the start/stop logic controls the choke, starter, and spark separately from the fuel solenoid (which appears to get activated when in propane mode and the engine is spinning). Thus, some unburned fuel can still flow past cylinders and into exhaust system after the stop logic has shut off the spark. If the muffler is still hot enough, it ignites the bit of propane and causes a loud bang noise which might have been what you heard.

Tip: That backfire is pretty easy to avoid if you manually turn off the propane and let the generator run out of fuel and turn off that way.

That said, I've never had any apparent damage from my generator backfiring and I can't explain why - if it was a backfire you heard - the generator would stop functioning after that.

I'd still check the fuse for the fuel solenoid though since that's a pretty easy thing to diagnose and would produce the behavior you're seeing now. (dead panel, not starting, etc).

 

[Encrypted]

Welcome time traveler!



I'd be surprised if the solenoid makes a loud bang noise when it fails.

However it is pretty easy to get these generators to backfire when running on propane if you shut off the generator via the start/stop button (or fob). I believe this happens because the start/stop logic controls the choke, starter, and spark separately from the fuel solenoid (which appears to get activated when in propane mode and the engine is spinning). Thus, some unburned fuel can still flow past cylinders and into exhaust system after the stop logic has shut off the spark. If the muffler is still hot enough, it ignites the bit of propane and causes a loud bang noise which might have been what you heard.

Tip: That backfire is pretty easy to avoid if you manually turn off the propane and let the generator run out of fuel and turn off that way.

That said, I've never had any apparent damage from my generator backfiring and I can't explain why - if it was a backfire you heard - the generator would stop functioning after that.

I'd still check the fuse for the fuel solenoid though since that's a pretty easy thing to diagnose and would produce the behavior you're seeing now. (dead panel, not starting, etc).

Thanks!
I just went out and tried it on my lunch break, and it actually started up again. So it had to be as you described, a backfire. I hadn't shut the gas off first, so this tracks with gas hitting the hot muffler. I couldn't fathom how a spark could have ignited gas in an unmoving engine. The CO2 light was not lit, so it wasn't that.

All that said, this thread now has me quite worried that I shouldn't run this unit on propane as it is a ticking time bomb. I'm going to reread everything again and perhaps post some follow up questions.

Thanks for your help.

 

[Encrypted]

Since my solenoid is clearly still ok, I suppose the lingering questions I have are:
1) How well is the motorized ball valve working out for folks that primarily use propane fuel? Any problems other than backfiring on shutdown?
2) Is it possible to identify if any particular unit has been 'updated' to not have this solenoid issue, or do we just wait for failure?
3) I am guessing that getting Duromax to proactively fix a unit that hasn't failed yet is probably a lost cause. Anyone try?

I think my best course of action is to have the motorized ball valve and fuses on hand, and wait for the failure. Would be ideal not to have to do emergency repairs in a blizzard though.

 

[Symbioquine]

1) How well is the motorized ball valve working out for folks that primarily use propane fuel? Any problems other than backfiring on shutdown?

I don't know if anybody else here has done the same, but the motorized ball valve is working fine for me. (I only use propane.)

The main downside I've noticed is that it is a bit slower than the solenoid so it more frequently takes the generator a little longer to start. i.e. it cranks for a few seconds then waits and cranks again - at which point it starts. Occasionally it takes in the first cranking attempt, but rarely. Similarly, it takes a few more pulls to start if you use the pull cord.

I don't think I've ever had a backfire when I shut down the generator by turning off the propane so the backfiring issue may or may not be a problem depending how you use the generator.

2) Is it possible to identify if any particular unit has been 'updated' to not have this solenoid issue, or do we just wait for failure?

Wish I knew. I have two units one that already has a failed solenoid and one that does not yet. Will update here if the second one also fails the same way. (Though so far this season I've put most of the hours on the first one - the one with the motorized ball valve. 102 hours on the first unit as of yesterday vs 21 hours last season on the second unit - basically just broken in and started occasionally to test since.)

3) I am guessing that getting Duromax to proactively fix a unit that hasn't failed yet is probably a lost cause. Anyone try?

I'd guess probably a lost cause. Though if your solenoid fails they might just send you a whole new generator like they did for me. (Might be an ethical issue to go down this path once you already know it is easily fixable by reading this thread. Your call. FWIW I didn't know then and DuroMAX didn't walk me through troubleshooting the fuses even though I indicated I has happy to do that sort of thing.)

As I mentioned earlier in this thread, the unit they sent me under warranty was actually manufactured 10 month earlier than my first unit that had the failed solenoid. However since that unit's solenoid hasn't failed yet, it is possible they modified that generator while it was in their inventory to fix the issue. Maybe there's some revision number on one of the boards that I haven't noticed yet that might lend a clue. I'll try to look next time I have them torn apart - though I can't say when that might be.

 

[Encrypted]

Thanks again @Symbioquine
I have the parts ordered to be ready for the failure if it happens. I plan to replace it myself if it dies for the faster turnaround time. I am skeptical if they would even honor the warranty since I cannot register with a Canadian address.

Folks are saying there are 3 fuses that might need to be changed - you mentioned the specs on the first one (F15AL250V), which I already have lying around. Do you know what the other two fuse specs are? I'd rather not remove the panel just yet until I have to.

I assume when you replaced the solenoid, there was enough slack in the gas lines for you to simply cut near the solenoid, and install the new barb/NPT fittings. I took a look last night, my solenoid matches your picture identically, so I think I'll have enough slack to do this as well (if I need to).

 

[Symbioquine]

Folks are saying there are 3 fuses that might need to be changed - you mentioned the specs on the first one (F15AL250V), which I already have lying around. Do you know what the other two fuse specs are? I'd rather not remove the panel just yet until I have to.

One of the other fuses is for the 12v (cigarette style) socket on the front panel so you can put any reasonable size fuse on that e.g. 5A/7.5A/10A. I think it might be a 10A, but I'm not sure. In a pinch you can also "borrow" that fuse as part of the solenoid replacement fix (make sure to actually replace/disconnect the solenoid first) as long as you don't intend on using the front panel 12v output socket.

I can't remember what the third one is for or what its size is though.

Maybe worth noting, I swapped my solenoid fuse/holder out for a standard automotive ATS fuse/holder which I already keep on hand for other reasons. I used something like this: https://www.amazon.com/dp/B081DHT8Y7/ Just double-check the actual operating voltage on that third fuse (the first two are 12v nominal) if you end up going that route, the ATS fuses are only rated for 32v I think.

I assume when you replaced the solenoid, there was enough slack in the gas lines for you to simply cut near the solenoid, and install the new barb/NPT fittings. I took a look last night, my solenoid matches your picture identically, so I think I'll have enough slack to do this as well (if I need to).

I didn't cut it IIRC. I just slid it off the old barbs and onto the new ones. Not sure if there is enough slack to cut the hoses.