Author Topic: Dash air conditioner condenser fan runs continuously.  (Read 2045 times)

Steve Humphrey

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Dash air conditioner condenser fan runs continuously.
« on: January 25, 2019, 08:29:21 PM »
On our 2005 Monterey the condenser fan runs continuously to a point it destroyed the fan hub and the blades disconnected.  I have replaced the relay, checked the high pressure switch both are good. Is there a temperature switch in the system and if so does it also control the hydraulic fan on the radiator?

Mike Shumack

  • Guest
Re: Dash air conditioner condenser fan runs continuously.
« Reply #1 on: January 26, 2019, 12:13:53 AM »
From what I have read, your Condenser is mounted to the radiator/CAC and there is a single hydraulic fan. The fan is used for both the Radiator/CAC and the AC Condenser.

The Monterrey manual mentions an "electronic override" on the fan's hydraulic switching valve (the valve that controls fan speed) so I "assume" that when the AC is turned on, the electronic override engages the hyd fan to run at a faster speed (regardless of engine temperature). I have not been able to find any specific info on this setup but I will keep looking (until someone else comes along with more knowledge on this).

You said the fan was destroyed.
How do you know the Air Conditioning system was the reason? Could the Wax valve or Switching valve just be stuck open (causing fan to run all the time) with no relation to the AC system?

Also, I am attaching a snip from my '05 manual on how the hydraulic fan system works (thermo-wax valve, switching valve, etc.) if you have not already read this in your manual, it may help you understand how the fan works.
« Last Edit: January 26, 2019, 12:21:37 AM by Mike Shumack »

Steve Humphrey

  • Guest
Re: Dash air conditioner condenser fan runs continuously.
« Reply #2 on: January 26, 2019, 06:02:49 PM »
That clarifies what is happening.  It makes me think it is a bad thermal switch since the hydraulic fan and the condenser fan runs continuously.  The wax controller does not control the electric fan. Thanks for your help. Steve Humphrey and Cathie Parks

Mike Shumack

  • Guest
Re: Dash air conditioner condenser fan runs continuously.
« Reply #3 on: January 26, 2019, 11:24:39 PM »
Steve,
You said the Hydraulic Fan and the Condenser Fan are running continuously. But they are the same fan.

To clarify some terms, the electric fan in the front dash area is for the AC "Evaporator" fan. That's the fan that blows the air of the dash ducts. The hydraulic fan in the rear is for the engine Radiator/CAC and the air conditioner "Condenser".

So it sounds like both the front (Evaporator) fan and rear (Condenser) fan are both staying running.

I have this AC electric/vacuum diagram for a Monaco Dynasty. I think it is similar to your coach - and may be useful in understanding how the (dash) AC system works.



Steve Humphrey

  • Guest
Re: Dash air conditioner condenser fan runs continuously.
« Reply #4 on: January 27, 2019, 02:26:35 PM »
On our coach there is a secondary electric fan on the condenser that is attached to the radiator.  It is supposed to operate when the radiator temperature is above a set temperature or the Freon pressure is above a set point.  I have checked the high pressure switch and it is good, so I'm thinking it is the temperature sender.  Thanks for your help. Steve Humphrey and Cathie Parks

Mike Shumack

  • Guest
Re: Dash air conditioner condenser fan runs continuously.
« Reply #5 on: January 27, 2019, 02:38:30 PM »
Now I understand. Thanks.