[DML] Re: Question about Air Conditioning cycling
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[DML] Re: Question about Air Conditioning cycling

Thanks for the replies to my cycling concern.

I have the Fan Fail Fix 2x2, and upgraded breakers, so I should be 
in good shape there.  I should probably wait for hotter weather 
before I complain about cycling, becuase the outside temp was only 
in the mid to high 60's when I encountered the fast cycling.  I 
suppose I should wait for an 80 degree day and see what the cycle 
time is then.


--- In dmcnews@xxxxxxxxxxxxxxx, "Harold McElraft" <hmcelraft@...> 
> I see numerous responses to your concern. The one thing you should 
> definitely be concerned with is the frequent cycling of the 
> fans. This could lead to an over heated fan circuit stopping the 
> fans and causing engine over heating.
> Unfortunately the fans are designed OEM to cycle precisely with 
> AC compressor. I say unfortunately because if the AC system does 
> become low charged or develop another issue to cause rapid cycling 
> of the compressor, the fans will rapid cycle too when you have the 
> AC on. The cycle of the fans with the AC compressor is completely 
> independent of the otterstat used for engine cooling although the 
> fan circuits for both are integrated starting at the circuit 
> The fans are what I would call "utility" quality. They are 
> to work in extreme conditions - to do this, their design is 
> but efficient. To start each fan requires 20 amps + or - a few 
> depending on the condition of the fans and the electrical system 
> connections, grounds, etc. This compares to 11 to 14 amps to run 
> each fan once started. As the saying goes - "you do the math". The 
> constant starting of the fans is extremely hard on all components 
> the circuit and soon leads to a failure of the weakest part in the 
> circuit - usually the OEM circuit breaker (a 35A standard duty 
> circuit breaker with "pressed" connections) or the OEM blue module 
> (notorious for poor quality inside) or the single relay (20/30 amp 
> rated ? that means 30 amps start 20 run). If you beef up one 
> another component will soon fail ? maybe in flames. BTW the motor 
> will be the last thing to go in my experience.
> All of this has been the topic of discussion ever since the 
> was introduced. As new in Houston (where I started 1982), a daily 
> driver soon experienced "fan fail" and eventually, virtually 
> everyone did.
> So, what to do? My suggestion is have the AC shop do a full 
> on the AC system including replacement of the orifice tube and 
> accumulator. Alternatively, as a minimum, have them do an 
> and refill with the proper amount of gas (say 2 to 2.25lb of 134 
> gas ? AZ 2 lb NJ 2.25 ? just my approach). A proper functioning AC 
> system will cause minimum cycling of the AC compressor and 
> the least amount of stress on the cooling fan circuit. I still use 
> 12 (2.25 ? 2.5 lbs of gas)
> Next, get one of the vendors' fixes for the cooling fans. Zilla is 
> by far the best vendor package offered in my opinion ? I have no 
> idea if you can still get one. Or, get Hervey's set up from 
>  the Dual 2X2. Or, install the DPNW modification (the least 
> expensive but effective). I'm not a big fan of the wire jumper 
> modification unless you replace the under-rated relay (Hervey may 
> still have the higher rated ones ? 30/40).
> Last, be sure all connections for the fan circuit are checked and 
> clean ? especially the grounds attached to the frame on the front.
> Another BTW - the rapid cycling is usually an indicator of low gas 
> or a restricted system (probably at the orifice tube). Normal 
> minimum cycling on a cool day is probably off and on every 5-10 
> seconds - on a hot day cycling could range from 30 seconds to 
> rarely. To get an AC system to function correctly takes the 
> tools and a knowledgeable technician with the correct specs.
> Harold McElraft - 3354
> --- In dmcnews@xxxxxxxxxxxxxxx, "sweetp01569" <paul.sweet@> wrote:
> >
> > While my car was in getting lowering springs and shocks done, I 
> asked 
> > the mechanic to check out the AC.  He said it seemed to work 
> it 
> > blows cold air and is not leaking anywhere.  However, the 
> > cycling of the cooling fans worries me.  The fans will stay on 
> only 
> > two seconds, and off for about 5 seconds, on and off on and 
> > Wouldn't this cause excessive wear on the fans to energize them 
> every 5 
> > seconds, and they only stay on for 2 seconds?  It doesn't seem 
> right.  
> > The cycle tiem seemed to be longer last year when I had it 
> in 
> > August.  I have the R134 conversion.
> > 
> > Thanks,
> > 
> > Paul
> >

To address comments privately to the moderating team, please address:

For more info on the list, tech articles, cars for sale see www.dmcnews.com

To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews 
Yahoo! Groups Links

<*> To visit your group on the web, go to:

<*> To unsubscribe from this group, send an email to:

<*> Your use of Yahoo! Groups is subject to:

Home Back to the Home of PROJECT VIXEN

Copyright 2006 ProjectVixen.com.  All rights reserved.

Opinions expressed in posts reflect the views of their respective authors.
DMCForum Mailing List Archive  DMCNews Mailing List Archive  DMC-UK Mailing List Archive