OK I follow your thinking. I have to get my meter and trace those paths to see what's happening. Thanks for your time on this.
oldnslo
Super Member
Have you tried applying power directly to terminal 108 or 111 to see if relay 8 pulls in and the DC motor runs? That would be my farmer diagnostic method. Prove what needs power and then back figure why it is not getting power.
If fancy use a fused jumper to limit how many other oh sh*ts you create
or stated differently learn from my mistakes…
If fancy use a fused jumper to limit how many other oh sh*ts you create
or stated differently learn from my mistakes…Yeah, that was the first thing I did because I had nightmares imagining what a new pump would cost. Both the contactor and motor work fine when I jump them. I identified right away the problem is relay 8 isn't pulling in, I just haven't been able to figure out why. I think the help you provided reading that logic schematic will help me figure it out tomorrow when I get back on this.Have you tried applying power directly to terminal 108 or 111 to see if relay 8 pulls in and the DC motor runs? That would be my farmer diagnostic method. Prove what needs power and then back figure why it is not getting power.
If fancy use a fused jumper to limit how many other oh sh*ts you create
oldnslo
Super Member
Good luck on finding the faulty component.
And that is the problem, RL7 is energized, which is preventing RL8 from being energized. I ran out of time working backwards to see why it's being energized but I feel like I'm closing in. I have a lot of time tomorrow, crossing my fingers.
oldnslo
Super Member
One step forward
If I am looking at schematic correctly RL7 is controlled by the flow switch. RL7 also powers dump boost what ever function that is.
If I am looking at schematic correctly RL7 is controlled by the flow switch. RL7 also powers dump boost what ever function that is.
The plot thickens. The flow switch works properly, which means RL7 should be deenergized. But even with the flow switch disconnected from the circuit, connection point 115 in the diagram has 12v, which is inconsistent with the logic diagram. So the problem is starting to look more like a problem on the control circuit board that's causing 12v to be applied to connection 115 all the time. The only thing that interrupts that power is the emergency button, which is also inconsistent with the logic diagram since it implies there is a path around the flow switch to connection 115 that allows the 12v to be interrupted.
Since the system was working and then suddenly stopped, I think it's not likely a wiring problem. I don't see how it can be anything but the control board at this point. A new one costs $250, not the end of the world but a real pain to change all the wires.
I think I'll use it with just the gas engine for awhile until I decide what to do next. Most of these machines are sold with either a gas engine or a DC motor, but not both like mine. I just like the DC motor mostly as a backup in case I'm up in the air and run out of gas.
oldnslo
Super Member
Interesting on circuit board suddenly failing but anything is certainly possible and if you are like me trying to diagnose a circuit is not something I do very well.
Do those orange terminal strips clip to the circuit board or are they permanent connections?
If you leave RL7 disconnected does the gas engine circuit work properly?
Do those orange terminal strips clip to the circuit board or are they permanent connections?
If you leave RL7 disconnected does the gas engine circuit work properly?
Yeah, it's impossible to debug the board because they sprayed the bottom of the board with some kind of insulation to weatherproof it. It's also a multi layer trace so there's no way to figure out which terminals go where. I have the data sheet on the relays but it doesn't really do any good.
They're soldered then epoxied around the edges.
The gas engine works properly without disconnecting or changing anything on the machine. I thought the flow switch was to protect the pump, but looking at the hydraulic diagram I can see its purpose is to prevent both power sources from coming on at the same time. So if the gas engine is running, the DC motor can't turn on. The fact that the system acts like the flow switch is closed all the time doesn't affect the operation of the gas engine.
I stumbled on this definition of "dump boost", which is one of the things on the logic diagram we didn't understand. How is this different than the pump dump logic?
"In the context of hydraulics, dump boost refers to a system where a valve is used to quickly relieve pressure from a system, often by dumping a large amount of fluid into a tank, and a "boost" is applied to increase the pressure in the system, such as for a pressure regulator valve.
Here's a more detailed explanation:
"Dump" Valve:
A dump valve is designed to rapidly exhaust pressure from the downstream system, allowing for quick pressure release. It can be activated by solenoids, air pilots, or have override/emergency functions.
"Boost"
In this context, "boost" refers to increasing the pressure in the hydraulic system, often achieved by applying a higher pressure to a pressure regulator valve to achieve a higher line pressure.
Compound Relief Valve:
A compound relief valve, used as a pressure regulator in pump delivery, consists of two valves: a pilot valve and a dump valve. The pilot valve relieves a small amount of flow, to which the dump valve reacts by dumping a larger flow. "
"In the context of hydraulics, dump boost refers to a system where a valve is used to quickly relieve pressure from a system, often by dumping a large amount of fluid into a tank, and a "boost" is applied to increase the pressure in the system, such as for a pressure regulator valve.
Here's a more detailed explanation:
"Dump" Valve:
A dump valve is designed to rapidly exhaust pressure from the downstream system, allowing for quick pressure release. It can be activated by solenoids, air pilots, or have override/emergency functions.
"Boost"
In this context, "boost" refers to increasing the pressure in the hydraulic system, often achieved by applying a higher pressure to a pressure regulator valve to achieve a higher line pressure.
Compound Relief Valve:
A compound relief valve, used as a pressure regulator in pump delivery, consists of two valves: a pilot valve and a dump valve. The pilot valve relieves a small amount of flow, to which the dump valve reacts by dumping a larger flow. "
