Hydraulic fan at full speed

[Guest Ray Davis]

On some models, the AC condenser is cooled by a 12v elect fan so there is no need to crank up the hydraulic fan.  Well, you may want to rev the engine to spin the AC compressor faster on a hot day.   Do you know where your AC condenser is located and if it has its own elect fan?

BTW,  the Source link above has a picture of the Wax vale kit,  there is nothing electrical there.

[Flyinhy]

Ray, my system is exactly the one in the picture posted in the email I received from REV with the 2 fan setup.  The a/c condenser is mounted on the front of the charge air. None of the paperwork I have with the coach details this system. All of mine says it is supposed to have the Sauer Danfoss electric/hydraulic controller. I believe what Ivan detailed in his post is exactly what's going on with my system. I have a signal coming from the ECM telling the 12v fan controller to spin faster because something is either programmed wrong or I have a bad sensor that I'm overlooking. The wax valve is connected to this 12v controller and that might be the solution in the end. I may end up just installing a new wax valve from source  eliminating the old wax valve and the 12v coil system but will that cause higher pressure in my a/c system? I'm not going anywhere for the next 6 months or so until this job ends and that gives me plenty of time to figure out what's going on. I truly appreciate everyone's input, you guys are top shelf! 

[jacwjames]

You might try disconnecting the electric portion and see what happens.  There may not be anything wrong with the wax valve, it if is good it will open/close proportionally as to what ever the temp is.     If that works you could just leave the electric portion disconnected and/or put a switch on the dash that turns if off and on if you see a problem with Dash AC not performing the way it should. 

Here is a document I found somewhere that explains the thermovalve function, it does show the optional electronic controller, so you should be able to disconnect and the thermovalve should perform by itself. 

If you have doubts on the thermovalve there are two tests you can perform on the system to at least identify if the thermovalve is bad.  When my fan was running wide open I contacted Monaco tech support and they had me disconnect both hoses from the thermovalve 

1. I plugged both lines and the fan ran wide open

2. I then put a union in between both hoses and the fan ran at an idle.

Based on this Monaco said my thermovalve was bad so I replaced it and that fixed the problem. 

 

Thermo Valve Fan Drive.pdf

[dl_racing427]

3 hours ago, Flyinhy said:

Ray, my system is exactly the one in the picture posted in the email I received from REV with the 2 fan setup.  The a/c condenser is mounted on the front of the charge air. None of the paperwork I have with the coach details this system. All of mine says it is supposed to have the Sauer Danfoss electric/hydraulic controller. I believe what Ivan detailed in his post is exactly what's going on with my system. I have a signal coming from the ECM telling the 12v fan controller to spin faster because something is either programmed wrong or I have a bad sensor that I'm overlooking. The wax valve is connected to this 12v controller and that might be the solution in the end. I may end up just installing a new wax valve from source  eliminating the old wax valve and the 12v coil system but will that cause higher pressure in my a/c system? I'm not going anywhere for the next 6 months or so until this job ends and that gives me plenty of time to figure out what's going on. I truly appreciate everyone's input, you guys are top shelf! 

If I were you, I'd disconnect the relay, and run the engine until it gets a few degrees above normal operating temperature.
If the fan speed increases and controls the engine temp, the wax valve is operating normally.
Whatever is controlling the relay is the problem.
I'd just rewire the trigger to the relay to the A/C compressor clutch circuit, so the fans will go to high whenever the compressor is running, and operate based on the wax valve when not.

[Dave Pumphrey]

16 hours ago, dl_racing427 said:

If I were you, I'd disconnect the relay, and run the engine until it gets a few degrees above normal operating temperature.
If the fan speed increases and controls the engine temp, the wax valve is operating normally.
Whatever is controlling the relay is the problem.
I'd just rewire the trigger to the relay to the A/C compressor clutch circuit, so the fans will go to high whenever the compressor is running, and operate based on the wax valve when not.

I agree with David L!

 

[k5esx]

Hello Flyinhy and others on this topic.

About 3 years ago I worked on this subject and built a home brew electronic solution.  It's still working.

I invite you to read this pdf I wrote back then to a friend, Rick.

Post back if you have any questions for me.

MIkee

 

Fan - MIkees FDCA Replacement.pdf

[Melvin]

Hey Flyinhi,  you may have found the answer to your question by now. I have a 2001 Monaco Signature with a 500hp Cummins. In 2019 I thought I had lost a turbo all of my boost was gone. The air charge coolers tanks were a bolted-on system / not welded on and the bolts had rusted off and the boost from the turbo blowed the tanks off. I had to remove the whole cooling system cartridge to replace the air charge cooler. In doing so I replaced and rebuilt the radiator, air charge cooler and trans and hydraulic coolers before putting them back together and reinstalling them. when we got to hooking the radiator back up "Jim at source manufacturing 541-935-0308" were I purchased newly rebuilt units was a great help. There was a redundant system built into the intake manifold that would also turn the fans to high if you started building high heat in the manifolds. 

The 2 things I remember was we disconnected this feature and relied on the thermovalue on the radiator to regulate the fans speed. he sent me a peacock value that worked as a bypass that restricted the hydraulic to the fans so that they ran all the time at a slower RPM for pulling air for the A/C condenser. when the wax value opened it would speed the fans up to full.

Radiator specialty 916-381-4790 was the manufacture of the all the tanks but you had to buy them thru a rep which was Jim. It helps to know who to call. I will download a pic of my cheats we hand drew out.

[Ivan K]

50 minutes ago, Melvin said:

Hey Flyinhi,  you may have found the answer to your question by now. I have a 2001 Monaco Signature with a 500hp Cummins. In 2019 I thought I had lost a turbo all of my boost was gone. The air charge coolers tanks were a bolted-on system / not welded on and the bolts had rusted off and the boost from the turbo blowed the tanks off. I had to remove the whole cooling system cartridge to replace the air charge cooler. In doing so I replaced and rebuilt the radiator, air charge cooler and trans and hydraulic coolers before putting them back together and reinstalling them. when we got to hooking the radiator back up "Jim at source manufacturing 541-935-0308" were I purchased newly rebuilt units was a great help. There was a redundant system built into the intake manifold that would also turn the fans to high if you started building high heat in the manifolds. 

The 2 things I remember was we disconnected this feature and relied on the thermovalue on the radiator to regulate the fans speed. he sent me a peacock value that worked as a bypass that restricted the hydraulic to the fans so that they ran all the time at a slower RPM for pulling air for the A/C condenser. when the wax value opened it would speed the fans up to full.

Radiator specialty 916-381-4790 was the manufacture of the all the tanks but you had to buy them thru a rep which was Jim. It helps to know who to call. I will download a pic of my cheats we hand drew out.

Great notes, can you help me decipher a couple of words? Do you remember location of the intake manifold sensor or switch?  I remember one but thought it was used by the ECM only. I know the ISM ECM has an output for fan clutch, just not sure if it is used for anything in our configuration and the available charts don't show this detail.

[Melvin]

Hey Ivan, the bottom chicken Cratch is "that run Relay" I can't tell you what the top word is it could be shop talk for when you don't know what something is called. I did walk out this morning to look and found another cheat sheet where I removed and disconnected the electronic relay at the bottom of the radiator support that get its info from the intake manifold sensor in the bottom right it shows how I revamped the hydraulic hoses. there is a better break down of relay 87-A and how it works too. it has been 4 years since this repair it took 4 months but has worked flawlessly. it's not a one-man job either.

[Ivan K]

Thank you Melvin, this will come handy if I have this problem. Sometimes I can't read my own writing either. 

[Ivan K]

Charles, here is an official description of the solenoid valve function, just like Melvin described based on intake manifold temp:

Motorhomes equipped with an ISM engine have an electric over
hydraulic override control valve. The override valve is located at the lower
rear corner of the radiator package. This valve is a normally closed valve
which is plumbed parallel with the thermovalve. It performs the same
hydraulic signal function as the thermovalve, but is electrically controlled by
the ISM engine. The ISM engine monitors intake manifold temperature. 

The electronics of the ISM engine control an 87a relay located in the rear run box
marked Hyd. Fans. When intake manifold operating temperatures are normal,
the electronic engine energizes the coil of the relay. This energizes the coil of
the override valve and the hydraulic fluid signal flows through the override
valve to the thermovalve. If the ISM engine detects an over temperature condition of the intake manifold, the coil of the 87a relay is deactivated. Power
to the override valve is removed, hydraulic fluid flow signal is stopped and
internal spool of the switching valve moves to full open position. The high
pressure fluid is directed to fan motors cooling the radiator.

[Flyinhy]

Ivan,  

I bought a new intake sensor and installed it a while back and I still have the fans at full speed all the time. I have two options as of right now. I can call cummins and let them hook up a computer to reflash or, I can just eliminate the 12v coil valve and let the wax valve run the fans. With the information you guys have uncovered I believe it's definitely a false signal from the ecm. I've been looking for a high pressure switch for the a/c but with no luck. 

Thanks for all the help for all you guys🙏 

[BRBowers]

When the hydraulic pressure fails, the fan will automatically go to full speed, as a safety measure.

The Sauer Danfoss electronic to hydraulic valve on my coach failed back in 2013 on my '06 Camelot. At the time I found a new Sauer Danfoss Controller but the price was somewhere near $2K or more, so I called Source Engineering in Oregon https://sourcerv.com. They had a replacement kit to convert back to the original, more reliable, wax valve. The kit included everything needed to replace the Sauer Danfoss valve.  These wax valves have been used on diesel engines for years and proved to be very reliable.

At the time the cost was $600 for the kit. You'll need to get a good welder to attach the valve mount to the coolant tube, but it's pretty easy to do.  

Bob

[dl_racing427]

On 3/16/2023 at 8:36 AM, Flyinhy said:

Ivan,  

I bought a new intake sensor and installed it a while back and I still have the fans at full speed all the time. I have two options as of right now. I can call cummins and let them hook up a computer to reflash or, I can just eliminate the 12v coil valve and let the wax valve run the fans. With the information you guys have uncovered I believe it's definitely a false signal from the ecm. I've been looking for a high pressure switch for the a/c but with no luck. 

Thanks for all the help for all you guys🙏 

Don't worry about where the A/C pressure switch is located, it may be up front.
Just tap into the wire powering the A/C compressor and use that signal to trigger the relay for high fan speed whenever the A/C compressor is running.

[Rob M cKeown]

I had a similar problem on my 03 Sig with the ISX 525. The fans would run wide open all the time. I disconnected the Sauer Danfoss controller and installed a Wax Valve. When I first connected the Hydraulic lines to the Wax Valve I had them reversed and the fans ran wide open, changed the lines and all was well. The hydraulic fans operate the way they should but kick on at a slightly higher temperature (about 2 degrees F) than before. I did talk to source engineering about adjusting the wax valve but they said more people ruin the wax valve trying to adjust it so for a couple of degrees I left it alone. Just as a matter of interest Cummins was no help on this issue as it was not provided by them on the original manufacture, it was a Monaco install.  I still have the 2 electronic controllers if anyone needs one. The Wax valve, so far, has been very reliable. 

[Bill R]

My 400ISL Hydraulic Fan was also running WAO.  I found that the Sauer Danfoss Control Board was not working.  But the Sauer Danfoss variable control valve was working.  So I just replaced the SD control board with an $18 motor controller for a proportional control of the ECM output to the variable control valve.  Has been working like a champ for 1 year so far.  Adjusts fan speed right along with Engine Coolant Temp.  Cheapest fix out there for my set up with no mechanical changes.  Requires some knowledge of wiring and fan adjustment, but not rocket science.

https://www.amazon.com/gp/product/B081YZBZ65/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[Tom Cherry]

53 minutes ago, Bill R said:

My 400ISL Hydraulic Fan was also running WAO.  I found that the Sauer Danfoss Control Board was not working.  But the Sauer Danfoss variable control valve was working.  So I just replaced the SD control board with an $18 motor controller for a proportional control of the ECM output to the variable control valve.  Has been working like a champ for 1 year so far.  Adjusts fan speed right along with Engine Coolant Temp.  Cheapest fix out there for my set up with no mechanical changes.  Requires some knowledge of wiring and fan adjustment, but not rocket science.

https://www.amazon.com/gp/product/B081YZBZ65/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

Bill,

Great FIX.  Will you please write this up as a "White Paper" and then send it to @Frank McElroy so he can add to our files.  Give some details about where you tapped in and  you wired it and how it works

Thanks in advance.

[Bill R]

22 minutes ago, Tom Cherry said:

Will you please write this up as a "White Paper"

I sure can.  I want to acknowledge that this fix is a modification of valuable information I gained from a member of IRV2 that led me down this path.  I believe what I have done is an improvement to that.  Give me a couple of weeks to put together.  Dealing with parental health challenges at the moment.

[Tom Cherry]

3 minutes ago, Bill R said:

I sure can.  I want to acknowledge that this fix is a modification of valuable information I gained from a member of IRV2 that led me down this path.  I believe what I have done is an improvement to that.  Give me a couple of weeks to put together.  Dealing with parental health challenges at the moment.

OF course....many of us have gone down that path and it take strength and patience....put it together when you can.

Thanks,

[Grey Goose]

Not sure if there is another thread but I searched for Casappa and did not find anything.

So based on what I can tell my 2007 HR Imperial has the Casappa controller and runs at high speed at all times. I removed the solenoid and it appears to be in spec when I checked the resistance on the coil. I appear to be getting 12V to the coil when I start the rig but I am thinking the valve may be seized as I cannot move it at all when I remove the solenoid and this is why the fan speed is not changing even when 12 volts is applied to the coil.

Can anyone tell me if I should be able to move the valve manually? Refer to attached photo with the solenoid removed.

 

Edited September 4, 2023 by Grey Goose

[Ivan K]

Usually the part that moves would be a plunger inside of this hollow stem that holds the coil. I don't have this exact setup but the principle should be the same.

[birdshill123]

Casappa is the correct spelling

[Grey Goose]

1 hour ago, birdshill123 said:

Casappa is the correct spelling

Thanks 

[Grey Goose]

I assume I could convert the Cassapa controller over to a whitehouse products wax valve like people do with other controllers.

If so would a 190 degree temp unit be the right temp range to get? Whitehouse part number - 553/1/09857/190

 

[birdshill123]

Call source engineering. I doubt it would work.