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Fan RPM

Anyone know what the hydraulic fan speed on the two cooling fans should be at high speed?  2000' U320 with Cummins ISM450.  Currently they are spinning opposite directions and maxing out at 250 RPM (I know they are both supposed to be spinning the same way and drawing air in from outside - that is part of the problem)


I am trying to get this info for Cummins as they and Foretravel have been playing phone tag the last 3 weeks ... figured I'd ask here and get an answer for them quicker here ;-)

If there is a document that would have any other specs on the fans/controller I'd be grateful as I will pass this along to them as well.

Thanks, Tim

P.S. Tomorrow I am trying, once again to coordinate a call between both parties in the hopes they can get our rig back to us.

Re: Fan RPM

Reply #1 –
Are you saying one of your fans is sucking  and the other one is blowing. The fans are
2 speed and I don't know which kind of controller you have. The high speed comes on
by temperature.

Re: Fan RPM

Reply #2 –
Quote from: Kidspot –
Currently they are spinning opposite directions and maxing out at 250 RPM
Sounds like a hydraulic hose is connected incorrectly at one of the motors, causing it to run "backwards".

A incorrectly connected hydraulic hose might also cause the fan speeds to be reduced.

Don't recall seeing any documents mentioned around here that would give specific fan speeds for your 2000 model U320.  AFAIK, most Forum references to fan speed just say "high speed" or "low speed".

Keep trying to get with FOT - they would be the best source for specific fan RPM info and correct hydraulic hose plumbing diagram.

Re: Fan RPM

Reply #3 –
Quote from: Kidspot –
Anyone know what the hydraulic fan speed on the two cooling fans should be at high speed?  2000' U320 with Cummins ISM450.  Currently they are spinning opposite directions and maxing out at 250 RPM (I know they are both supposed to be spinning the same way and drawing air in from outside - that is part of the problem)


I am trying to get this info for Cummins as they and Foretravel have been playing phone tag the last 3 weeks ... figured I'd ask here and get an answer for them quicker here ;-)

If there is a document that would have any other specs on the fans/controller I'd be grateful as I will pass this along to them as well.

Thanks, Tim

P.S. Tomorrow I am trying, once again to coordinate a call between both parties in the hopes they can get our rig back to us.

A picture of the hydraulic lines on the fans would tell me if they are the same as mine. The master motor passes the fluid to the slave motor so the flow would be in the same direction and so would the fans.

Re: Fan RPM

Reply #4 –
The two fan motors could have been installed so they counter rotate for better airflow (both pulling air through the radiator). Naturally, the blades would not be oriented at the same angle on both fans. Many twin engined aircraft have counter rotating engines/props for airflow but not for the same reason. Compare the blades on each fan.

Pierce

Re: Fan RPM

Reply #5 –
Boats with twin engines, the propellers turn in opposite directions. Cat bulldozers
the fans could be turned to suck or blow. It was so in the winter the operator could
keep warm having the fans suck.

Re: Fan RPM

Reply #6 –
250 RPM seems way too low even at idle. Here is a document FOT sent me for the U300. Almost all configurations should be close to 2000 RPM at WOT. (wide open throttle)

The reversed fan flow seems weird to me but FOT will have to answer that question.

see ya
ken

Re: Fan RPM

Reply #7 –
Trace the hose connection at the fans.  One must be reversed.

Re: Fan RPM

Reply #8 –
Looks like I will play intermediary for a bit - FOT is sending me the specs that Cummins is wanting and I will get them to Cummins ... The phone tag is frustrating all 3 parties

Thank you for the help and specs provided here - appreciate your quick help.

- Tim

P.S. FOT did confirm both fans are to draw air in, and the fans should be spinning a lot faster than 250RPM (they are sending me actual specs shortly)

Re: Fan RPM

Reply #9 –
Yes, if one fan is sucking air from the outside (as they both should) and one is blowing air to the outside, check hose connections to the two fan motors.

Correct before addressing RPM.

Can you post pictures of the hose connections on the two fans? 

Re: Fan RPM

Reply #10 –
It would enhance the Forum data base if you could post copies of whatever you get from FOT.  There seems to be a "gap" in our group knowledge pertaining to this subject.  8)

Re: Fan RPM

Reply #11 –
Tim I believe your year has the wax fan control valve. The fans speed is variable from low to high. The low background speed is adjustable. Definitely sounds like someone reversed the lines causing reverse rotation. The oil flow threw the wax valve adjusts the speed. More restriction causes higher fan speed. Less reduces speed. Fan speed will be low if temperature is low. Some hydraulic motor rotation can be reversed internally by reversing a flow plate. I haven't had a pump on our coach apart yet but has anyone had yours apart?
Scott

Re: Fan RPM

Reply #12 –
Quote from: dsd –
Fan speed will be low if temperature is low.
Scott

Yup, based on coolant temperature. It will not/should not go to high fan speed until several degrees above "thermostat fully open".

Re: Fan RPM

Reply #13 –
The 2001 and later with the electronic control could be commanded to hi buy removing control harness closing control solenoid.

Re: Fan RPM

Reply #14 –
Quote from: Chuck & Jeannie –
It would enhance the Forum data base if you could post copies of whatever you get from FOT.  There seems to be a "gap" in our group knowledge pertaining to this subject.  8)


Here ya' go :-)  Direct from Foretravel Tech dept:

Year        Engine          Unit #    Full Throttle RPM   
1993    3116        4501    2769      
1994    3116        4532    2849      
1994          6V92        4566    2829      
1995    M11        4848    3160      
1995    8.3            4771    3161      
1996    M11        4964    3009      
1996    3126        4963    3009      
1996    8.3            5023    2981      
1996    3176        4965    3107      
1998    M11/450    5425    3089      
1998    ISC 8.3        5461    3036      
1999    M11/450    5534    2934      
1999    ISC 8.3        5655    2760      
1999    M11/500    5548    2733      
2000    ISC 8.3        5731    2655      
2000    M11/450    5789    2769      
2001    ISL8.8        5953    2657      
2001    ISM/450        5954    2698      
2002    ISM/450        6024    2870   24"fan blades
2002    ISL8.8        6118    2710      
2003    ISL8.8        6194    2750      
2003    M11        6229    2668      


Re: Fan RPM

Reply #15 –
Quote from: dsd –
Tim I believe your year has the wax fan control valve. The fans speed is variable from low to high. The low background speed is adjustable. Definitely sounds like someone reversed the lines causing reverse rotation. The oil flow threw the wax valve adjusts the speed. More restriction causes higher fan speed. Less reduces speed. Fan speed will be low if temperature is low. Some hydraulic motor rotation can be reversed internally by reversing a flow plate. I haven't had a pump on our coach apart yet but has anyone had yours apart?
Scott

I thought it had the danfoss control unit - which foretravel replaced last fall when we had it there for the bulkhead repair.  And yes, both our fan pumps have been rebuilt in the last year - looks like we have to take it back to the last guys either way as it's still leaking and when Cummins sent it back to the factory they were told it was not the pump leaking ... this one was rebuilt in February, so still under warranty (one of the few things still under warranty lol)

Re: Fan RPM

Reply #16 –
Quote from: wolfe10 –
Yup, based on coolant temperature. It will not/should not go to high fan speed until several degrees above "thermostat fully open".

it should have as it was up to 226° - they also unplugged the control unit, which should have put it into "hi" speed - both times it just ran at 250 rpm max ... 

Today Chad from FOT was able to get the Cummins tech on the phone (he's been persistent trying to get him) and got him the specs I posted above - We (and lots of others) are praying they can get things running correctly as we are scheduled to leave for the west coast in a little over a week for work obligations...

Thanks again everyone for the advice posted - gives me some things to pass on to the Cummins crew as they finish up

Re: Fan RPM

Reply #17 –
Formatted Kidspot's posting is attached

Re: Fan RPM

Reply #18 –
Thank you, Barry & Cindy.

Re: Fan RPM

Reply #19 –
Removing one line on the danfoss control unit and capping and plugging it would also command fans to hi speed.
Scott