Community Forums

jonemw · 10-31-2017, 05:22 PM

Doing some intensive study around the interwebs turned some info about the Sauer -danfoos fan speed controller. That is , the Allure and maybe others have this unit up until model year 2006 or so, then after that the controller is deleted and fan speed governed by the Engine ECM directly? This means that 2007 or 2008 owners do not need to spend $$ for wax valve conversion ?

Since there are many owners of ISL prime movers here, any further comments appreciated...

smlranger · 10-31-2017, 05:34 PM

Not sure what you are asking but it does seem with the 2007 and later ISL's with DPF (clean diesels), our fans are controlled by the ECM and a little solenoid mounted on the hydraulic fan motor.

Along the line of fan control, it seems CC started using Eaton hydraulic fan motors in later model years. Mine has the Eaton. Unfortunately, there seems to be no replacement for the motor they used so if your's fails, the only option is to have it rebuilt. However, according to a local hydraulic motor shop in my area, they are not sure they can get parts to rebuild it.

Roadking · 10-31-2017, 06:06 PM

The FCU in My 2006 Cat C9 is controlled by the ecu. The ecu monitors engine and air temps and also receives the high head pressure siGnal from the AC compressor. The ECU provides a pulse width modulation signal to the FCU. The FCU makes this a higher current pulse modulation which opens the hydraulic valve an appropriate amount. My FCU failed, the fan ran at high speed only. I did the wax valve replacement. I also added a pair of electric fans that are controlled by the AC high head pressure signal. These fans kick in when running AC and engine temp is not high enough to call for hyd fan cooling. I added a light to the circuit and I know these fans are needed and they work.

Earlier engines had water and air temp sensor inputs and AC head pressure inputs that fed directly to the FCU. No ecu involved.

So yes. In later engines The ecu controls the FCU but the FCU still controls the hyd valve. And the FCU still fails and can be replaced w the wax valve providing you also keep the AC unit cool as required.

BrianGlenn · 11-01-2017, 08:47 AM

I did not know the wax control valve upgrade was applicable in units with ECM controlled fans. Time to do a little more research...

I have the ECM controlled fan drive control module (with one 3 wire plug). In addition I have a Sauer Danfoss hydraulic fan drive motor.

I must have the hybrid model with mixed up parts from both generations. I also have a 400ISL with no emissions (no EGR or DPF, engine build date Dec 16, 2006). Coach build date April 2007 (#31563), Allure 470 Sunset Bay.

Good info. Thanks.

Brian

Roadking · 11-01-2017, 05:20 PM

I had an ECM controlled FCU and installed wax valve. Also have the sauer danfoss fan motor. The Wax valve directly controls the hyd fan motor speed by controlling the hyd press/flow to the hyd motor control circuit. The wax valve totally replaces the ecm controled FCU.

2 Stroker · 11-01-2017, 05:34 PM

Had mine installed last year. Remember to change the hyd filters, I have changed mine 3 times so far. Also keep the AC in the off position until things get warmed up.
2 stroker

BrianGlenn · 11-01-2017, 06:15 PM

Thanks guys for the additional posts. I see I can replace the ECM controlled FCU with the wax valve. I do like the infinite variable speed for the fan, vs the slow, medium, fast of the ECM controlled fans.

I understand the AC condenser restrictor orifice on start up; I do like the slow/no fan at start up so has anyone modified the orifice on Source Eng endorsement to allow slow/no fan at start up (low coolant temp?).

I do "hate" the fast fan speed on engine braking (roar) from the ECM controlled FCU. I could ask Cummins to program that out....

Thanks,
Brian

jonemw · 11-02-2017, 07:08 PM

Ok, all very good info. I guess I was hoping I did not need to budget for future fan controller problems. i am trying to get a handle on potential major expenses, and was hoping to forget wax valve(they a re near 1k $ now), but no such luck. My current fan setup seems to work just fine but danger always lurks I guess

dons2346 · 11-02-2017, 08:29 PM

Quote:

Originally Posted by jonemw

Ok, all very good info. I guess I was hoping I did not need to budget for future fan controller problems. i am trying to get a handle on potential major expenses, and was hoping to forget wax valve(they a re near 1k $ now), but no such luck. My current fan setup seems to work just fine but danger always lurks I guess

Well there is the old saying "if it ain't broke, don't fix it'

If your Sauer Danfoos controller is working, don't worry about it. It could break tomorrow or six months or a year down the road. You can find one on the internet for 3-500 bux.

bneukam · 11-03-2017, 01:35 PM

Quote:

Originally Posted by BrianGlenn

Thanks guys for the additional posts. I see I can replace the ECM controlled FCU with the wax valve. I do like the infinite variable speed for the fan, vs the slow, medium, fast of the ECM controlled fans.

I understand the AC condenser restrictor orifice on start up; I do like the slow/no fan at start up so has anyone modified the orifice on Source Eng endorsement to allow slow/no fan at start up (low coolant temp?).

I do "hate" the fast fan speed on engine braking (roar) from the ECM controlled FCU. I could ask Cummins to program that out....

Thanks,
Brian

I removed the in line orifice from Source. Had no fan speed at startup. Drove it easy, and used no dash air until engine temp was up to 180. Jim at Source said this was fine as long as you don't get any red light warnings from your CAC.
This was on a 02 36' Intrigue with the 400isl, so it didn't take much pedal to get it going.
Brett

dons2346 · 11-03-2017, 09:55 PM

Brett, make sure that you don't have the controls set to "vent" either. Having the vent selected will cause the AC compressor to run just as if you have the AC turned on.

bneukam · 11-03-2017, 11:13 PM

Quote:

Originally Posted by dons2346

Brett, make sure that you don't have the controls set to "vent" either. Having the vent selected will cause the AC compressor to run just as if you have the AC turned on.

Was not aware of that, but the coach already had a secondary toggle switch for the compressor. It was installed at the factory so you could recirc the air without having the max a/c on which is the only setting that allows it.

BrianGlenn · 11-04-2017, 07:37 AM

On my 2007 the AC compressor clutch engages on AC and defrost. I am pretty sure it does not engage on vent setting. I have watched it for 10 minutes

. I already set it to vent when I start up and leave the campsite as I want the fan on low - and I typically idle out in drive. That helps keep the noise and dust down on my ECM controlled unit.

Roadking · 11-13-2017, 09:00 AM

I got my wax valve on eBay for under $200. It's rated at 2850 psi whereas the one from source is rated at 3000 psi. I also added two 14 in. electric pusher fans switched on via relays controlled by the ac high pressure switch. Works great.