[bnoji]

Having a lubrication issue with an '03 735SL-Y (GMK 3092):

We were getting Alarm 1021 (Lubrication Pressure Operated Cut-Off Switch Defective). We replaced the pressure switch just in case, but this seems to be an issue with the exhaust valve on the pump not venting the lines back into the res when the pump stops, keeping the pressure switch closed. The pump produces 24bar, pressure switch closes, pump turns off but the line pressure hangs around 18-20bar.

After taking the pump apart and cleaning it out, the exhaust valve is still not working 100% but we don't have a replacement right now and we're no longer getting 1021. The alarm did change to: Alarm 1009 (Defective Lubrication) which lists the following possible causes:

• Low Tank Level (Tank is full. Unplugging float switch to simulate a low tank level gives alarm 2055 like it should)
• Oil leakage in the system (No obvious leaks, system holds pressure longer than it should)
• Air in the lubrication system

I'm leaning more towards air in the system since it was just disassembled. The maintenance guide recommends running the pump manually to clear air from the lines, which we've been doing without success.

How is the control determining there is air in the system or that there is a leak? It seems like the only related sensor is the pressure switch.

[bnoji]

Well. It looks like the rubber diaphragm on the dump/exhaust valve is bad, which is preventing the oil in the lines from returning to the res.

[russormrod]

Have you contacted Eurotech? They have great phone support


Russ

[bnoji]

russormrod,

I did talk to Eurotech and they were helpful, but they only stock the entire pump assembly, which is in good condition aside from the rubber seal. We were able to contact Technosystems in Italy and are in the process of ordering a few backup parts. For reference, the dump/vent valve is part #46366.

We were able to "repair" the broken diaphragm by putting a screw through it to hold it together, so it's up and running until we get the backup parts.

[russormrod]

Sounds good. Good luck! Bad ass machines


Russ

[wizard]

Having a lubrication issue with an '03 735SL-Y (GMK 3092):

We were getting Alarm 1021 (Lubrication Pressure Operated Cut-Off Switch Defective). We replaced the pressure switch just in case, but this seems to be an issue with the exhaust valve on the pump not venting the lines back into the res when the pump stops, keeping the pressure switch closed. The pump produces 24bar, pressure switch closes, pump turns off but the line pressure hangs around 18-20bar.

After taking the pump apart and cleaning it out, the exhaust valve is still not working 100% but we don't have a replacement right now and we're no longer getting 1021. The alarm did change to: Alarm 1009 (Defective Lubrication) which lists the following possible causes:

• Low Tank Level (Tank is full. Unplugging float switch to simulate a low tank level gives alarm 2055 like it should)
• Oil leakage in the system (No obvious leaks, system holds pressure longer than it should)
• Air in the lubrication system

Are you sure you understand how this system is suppose to behave? Normally you pump / pressurize the lube system and shut the pump off. If the lube system fails to reach pressure set point you get alarms similar to what you have above. This is in a general sense as I have no experience with Eurotech.

As to holding pressure longer than it should, oil based systems make use of metering valves so there should be pressure maintained for a bit. In any event I read those error makes sages as indicating that the control did not get the expected feed back that lube system pressure was reached. So I'd look at your pressure switch agains and your pressure gage.

I'm leaning more towards air in the system since it was just disassembled. The maintenance guide recommends running the pump manually to clear air from the lines, which we've been doing without success.

If there was air in the system, a possibility you would need to purge the plumbing. However if your gage is reading the right pressures then your pressure switch should toggle, if not you have a problem.

How is the control determining there is air in the system or that there is a leak? It seems like the only related sensor is the pressure switch.

Generally when the pump runs for a few moments and the control fails to see a pressure feedback.

I use the word generally because most lube systems behave in the same general way.

[bnoji]

wizard,

It's a single line system that should vent the line pressure back into the res when the pump is turned off. These use a little quick exhaust valve on the pump outlet.



It's fixed and working now.

The pressure switch error was a result of the vent valve getting stuck (the rubber diaphragm tore) and keeping the system pressure high. This caused the control to throw an error thinking that either the pump was running non-stop or the switch was bad (stuck closed). It wasn't that pressure was never reached, but that it never dropped.

[wizard]

Good to hear that it is working!

wizard,

It's a single line system that should vent the line pressure back into the res when the pump is turned off. These use a little quick exhaust valve on the pump outlet.

A rather strange arrangement.

It's fixed and working now.

The pressure switch error was a result of the vent valve getting stuck (the rubber diaphragm tore) and keeping the system pressure high. This caused the control to throw an error thinking that either the pump was running non-stop or the switch was bad (stuck closed). It wasn't that pressure was never reached, but that it never dropped.