336 ELH CAT Excavator. Serial #CAT0336ECRZA00244 the warning light came on and when you cut the machine off you hear fluid running back to the tank any ideas how to proceed?
Good day Suggest you check out the non-return valve that retains the pressure. Kind re
Your machine is an XE machine that has a different hydraulic system than other F series machines. There are 2 large high pressure accumulators and 1 small low pressure accumulator for the swing circuit. The warning you see can be for any of them so you need to go into the diagnostics and look for the specific code there to know which one it is that has the problem, look for E1435, 1436, 1437, 1438 or 1565 codes Usually the problem is for the high pressure accumulators and I don't recommend anyone that doesnt have the correct schematics and T&A procedure to work on them because they store alot of energy and if the valves don't work properly that energy won't be released when the machine is shut down. But with that said, the sound you hear when the machine is turned off is most likely the high pressure circuit dumping to tank which is normal and can take up to 2 minutes to drop all the way to zero.
Where is this located? The only non return valve I see is not for this system
The codes 1438 and 1565. What should the charge pressure be on the accumulator? Thanks.
Thanks, just read through the post and the testing procedure will help tremendously. Do the codes that I just posted indicate anything? Thanks again for the help guys.
I think I may have misled you. Is that machine a hybrid. If so, there are two more LARGE accumulators for swing regeneration. In other words, ignore everything above except Per Eriksson's post. 1438...Low swing accumulator #2 gas pressure. 1565...isn't in my book. And, as stated above the swing accumulators are under VERY high pressure and must be serviced following all the steps, to a tee (and they are not the steps above).
E1565(1) Event - Swing Accumulator Gas Pressure Mismatch Event occurs when the pressure difference between Accumulator Gas Pressure Sensor 1 and 2 is greater than 3200 kPa (464.128 psi). No impact on machine efficiency. Operator will continue to see pop-up message "Accumulator Pressure Warning" on the monitor until serviced. Determine the accuracy of the accumulator gas pressure sensors, refer to Troubleshooting, "Pressure Sensor (Swing) - Functional Test". If sensors are good, obtain an accurate temperature / gas precharge measurement, then adjust per specifications. Refer to Troubleshooting, "Accumulator (Swing) - Functional Test". Also Testing and Adjusting, "Accumulator (Swing) - Test and Charge"and, "Accumulator (Swing) - Test and Charge - Nitrogen Booster Group". Follow the correct testing and charging procedure.
E1438(2) Event - Low Swing Accumulator #2 Gas Pressure Event will only be detected after 6 hours have passed from the previous key off. Event is active when the gas pressure is below 13000 kPa (1885.5 psi) @ 20° C (68° F). - Accumulator System is Disabled - Event deactivates when pressure is in normal range, 16200 kPa (2349.6 psi) @ 20° C (68° F) to 22000 kPa (3190.8 psi) @ 20° C (68° F). This reset requires a 6-hour interval from the previous key off. Check indicated swing accumulator for damage. Check the precharge pressure with a gage and then charge back to specification. Refer to Testing and Adjusting, "Accumulator (Swing) - Test and Charge"and, "Accumulator (Swing) - Test and Charge - Nitrogen Booster Group".
Hi Mr.Nige, Could I ask Caterpillar 336E is a "HYBRID" excavator???
Not an excavator expert by any means. Per Eriksson is probably the best guy to answer your question. I think it depends on the Serial Number prefix whether or not it is hybrid - and there are about 20 different prefixes of 336E.
Thanks for your information. I think it's a "HYBRID" excavator because a normal hydraulic excavator doesn't have "SWING ACCUMULATOR" , is it right??
I suspect that you are correct regarding this particular machine. I understood your question to be "are all 336E excavators of the hybrid type.?", to which the answer is I don't know.
I just have found out specalog of CAT 336E L H. It's definitely a hybrid excavator. http://www.teknoxgroup.com/attachment/3004/336E Hybrid.pdf
There's both an 336E XE which is the hybrid version with it's own hydraulic system but also as a regular 336E with the same hydraulic system as all other E series machines so you have to look at the serialnumber prefixes to know for sure. These are XE or hybrid RZA HDW JEA SSL GNY While these are normal machines YCE YEP BMH DPX BZY The big accumulators have a precharge of 2785psi @ 68F with a gas volume of 8.45 gallons so a normal nitrogen gas bottle won't be of much use when filling these so you can use either a booster pump or as we can do around here, order special nitrogen bottles with a higher pressure and special regulators fitted on them, expensive but not as crazy expensive as the booster pump setup.
Thanks for your informations, especially about accumulator specifications and how to recharge it. In the other way, we can rent a portable gas (nitrogen) booster, it is cheap also. I think we can tell the difference by looking at the model name, where H means hybrid, is it right? 336 E L H meaning: E = series E; L = long crawler; H = hybrid.
By the way, let me introduce a nitrogen booster that we make ourselves.
I had to use a booster when I was in the US Navy for charging helicopter landing struts. I don't remember for sure but it would push up the gas to some crazy pressure. All this sounds like some more money is going to be required to maintain or repair all this high tech.
Sorry for the delayed response, but weather and other priorities have delayed this project. We are going to pull the accumulator, rebuild it in house and have CAT recharge it. Thanks for the input.