2005 Beaver Monterey Laguna Dash Air

[Larry Moore]

We had a leak in the dash air condensing unit so we ordered a new one and replaced, all ok.. Then during the pump out and recharge the system seems to work fine except the hydro fan does not cycle on to start cooling the condenser.  Talked with Monoco and Beaver motor coach to try to find the switch that triggers the hydro fan to start when the dash air is turned on.  We have looked over the hydro fan and do not see any 'electric' relay that might trigger the fan.  We are in the process of testing the try switch on the evap unit and relay in the electrical compartment, but do not know where or what the circuit goes to in the back of the coach to trigger the fan to come on.  We are presuming that there is not an electric fan that should be on the condenser unit because it is mounted onto the coach radiator. (we are the second owners and the dash air has not worked since we have owned it).

[Lee Welbanks]

Larry,

I assume when you say hydro fan you are speaking of the main hydraulic driven fan for the side radiator which only runs when the engine is running and is controlled by a temp controlled wax valve in the hydraulic system mounted in the end of the radiator.

[Gerald Farris]

Larry,
There should be an electric fan mounted to the condenser that is turned on and off by a refrigerant pressure sensing switch.

Gerald

[Larry Moore]

Followup on the dash air -- Talked with Robert in Monaco tech support and he was kind enough to walk back into the service area and speak with Brian (the chassis expert).  Brian informed us that there is not a dash air condenser hydro fan trigger, IE the radiator hydro fan is only triggered by the radiator water temp.  No additional dash air condenser cooling is installed, so if your start the engine and dash air, the dash air compressor will cycle out when the R134A pressure reaches 325-350 on the Hi side, well before the engine water temps come up to start the fan. Running the dash air on engine start up will cause the condenser to get very hot, the engine has not yet come up to temp to make the fan cycle, so the compressor will get shut down due to excess pressure.  As long as the RV is moving down the road all should work as expected. Being and 'old' refrigeration man, that seems way to much pressure and too much temp for my personal comfort.  I am thinking that the installation of an electric pancake fan for the dash air condenser might make sense.  Thoughts?

[Jerald Cate]

Larry,

I've had the same problem for some time where I have high pressure on the high side and I've discovered my condenser fan is not coming on.  I've been to 3 places that either didn't want to tackle the job or couldn't get to it in the time frame I need.  Our coaches may not be the same chassis but I've found K3 relay, in the electrical bay, turns on the condenser fan.  If I apply a ground to the relay the condenser fan comes on and it appears to cool when I do this.  I've inquired about what energizes the K3 relay and have been told it's either a pressure or temperature switch but I have no clue where this sensor may be located.

If I understand correctly what you're saying is the engine must be up to temperature before the condenser fan will switch on.  I don't recall that being the case before my dash air quit working but then again it hasn't worked in over a year I could be mistaken.  I will definitely try my dash air again next time I get the engine warmed up, if that doesn't work it's headed to the shop when I get home.

[Lee Welbanks]

With my 06 PT as soon as you start the C 13 the fan is running, there is no on or off to it. When the water temp hits 200 the wax valve will  have the fan running at full speed, it never shuts off completely so there is always air moving over the condenser, trans cooler and radiator.
When you start your motor does your fan also start on low speed?

[Gerald Farris]

Larry,
I would not have a dash A/C unit on a Beaver without an electric condenser fan. One would be easy to install and you could just use a relay to power it that was triggered by the A/C clutch circuit. That way if the compressor was running the fan would be running. Just make sure that you are pushing the air in the same direction as the engine cooling fan.

Bruce,
Larry was saying that because his coach did not have an electric condenser fan, the engine needed to be hot enough for the hydraulic cooling fan to fully engage before the A/C would properly cool.

Gerald

[Jerald Cate]

Gerald,

Thanks for clearing that up for me, I can see why Larry would want to add an electric fan to the condenser.

I've been told that since my coach is on a Freightliner chassis I should take it to a Freightliner repair shop for dash air conditioning work.  The logic behind that was Beaver received a pre-assembled chassis with dash AC, etc. already installed so Freightliner would probably have the resources to find and fix my problem.  Any truth to that advice?  I have a Freightliner facility near home, when I get there, but Oregon is a 4000 mile round trip.

[Gerald Farris]

Bruce,
I do not think that your coach was built on a Freightliner chassis. Your coach should be on the Roadmaster M chassis. However, even if it is on a Freightliner chassis, Freightliner does not install the dash A/C units in their chassis. The dash A/C unit is installed by the coach builder. So to answer your question, no there is no logic to your statement. You should take the coach to a shop that does A/C repairs (not all RV shops work on dash A/C units), and most importantly that you have confidence in.

Gerald

[Jerald Cate]

Gerald

I stand corrected I do have a Roadmaster chassis.  Sometimes I get an errant fact lodged in my head and it will not go away.  I'll probably be telling folks next week I have a Freightliner chassis. 

I can see why some dealers won't work on this dash air, what a poor design, the location of the service ports is impossible to get to.  Someone recently mentioned being very pleased with Iron Horse RV in San Antonio, I'll have to give them a call when I get home and see if they can do me any good.  Thanks again for you're input Gerald.

Bruce