| Author |
Message |
Buddy Tennison (Buddyten)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 28, 2006 - 8:41 am: | |
In our '80 Eagle, our coach AC has been down for about a year. Can't get the compressor to come on. Have checked all electrical connections and am getting power (12V) to them. At any rate, we have about decided to remove the coach air and add another rooftop (have 2 already).
If we disconnect the AC drives from the coach, will it cause a problem with the mitre box balance? We have a harmonic balancer in front of the mitre box, and one on the rear of the mitre box. Will these effectively "balance" or is there some other modification involved. Until we can get time to completely remove the system, can we just disconnect the two drive belts to the fan with no problem.
We are also interested in getting the additional 25 hp that some have said it takes to drive the AC system. Any thoughts and suggestions would be appreciated.
We did like the bus air when it worked. Just can't figure out why it won't work. 134 is up to snuff according to the gauges. Getting power to the compressor. Compressor turns fine with not binding. Any thoughts there, and is is beneficial to keep the system. We've read numerous posts on this and there seems to be pros and cons to both. |
Eagle 10
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 28, 2006 - 8:54 am: | |
I disconnected the drive shaft on my A/C about three years ago when I removed the whole system. The extra power is great on those long hills. I have had no problems on my 1984 Eagle 10 with the shaft gone. |
John MC9
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 28, 2006 - 1:30 pm: | |
Buddy -
Have you checked the thermostat, or the temperature sensor
for the air conditioner? On the MCI, if the sensor has been
relocated or removed, the AC won't work... it doesn't know
it should! Sometimes, remodeling removes things we didn't
think were necessary. |
Ed/Jefferson bus
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 28, 2006 - 3:19 pm: | |
You will have no problems with your coach by removing the a/c comp driveshaft. |
truthhunter@shaw.ca
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 28, 2006 - 4:45 pm: | |
Don't have any time/knowledge on a Eagle A/C , "but if the 134a is to low on system with a low pressure cut out switch , then it will not energize the compressor clutch for it's own protection". Wanting that extra horsepower on demand (only 18 hp on 40 cid/10 ton systems that are belt driven on MCI including the electricity and only when the system is cooling at maximum capacity relative to the ambient temperatures) then just hit that A/C off switch you used to turn it on with and you'll get that piddly increase in hp all the way to the top of the hill and onward until you turn it back on. The only cost in hp are when it is on and turning part of the system and of course the weight of the system. |
Buswarrior (Buswarrior)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, April 29, 2006 - 11:55 am: | |
This tangent keeps coming up...
We need some instrumented and blind testing done to properly quantify this "hidden horsepower" that the AC consumes.
I have experimented in seated coaches, and can't tell the difference, switch on or off. No difference in sensation, no burst of acceleration, no upshift in sight.
Who has the experience in setting up one of those non-profit research companies and applying for government funding? Have to hire a number of test subjects, various backgrounds, a couple of test vehicles, a few research assistants, office space and vehicle support at a qualified maintenance facility near and dear to our hearts, weave an environmental/emmission reduction angle into it, and a bunch of us will have fuel for next season!
happy coaching!
buswarrior |
truthhunter@shaw.ca
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, April 29, 2006 - 2:39 pm: | |
I based my guessulations on what I gleamed from Carrier web site for the 30 CID 5F30 http://www.xpedio.carrier.com/idc/groups/public/documents/techlit/5f,h-3pd.pdf?SMSESSION=N O with 124a factored in then uped it for the larger sized compressor I am guessing is in the this mid 80's Eagle. Of course I added a liberal dose of hp for fan belts (not knowing what drive system is on his the vague description of this Eagle) and include the electricity for the condenser and evaporator. Of course there is the caveat that the maximum is just that and not the force consumed just because the A/C is on as there is quite a variance between minimum and maximum states of pumping refrigerant (pressures & partially unloaded compressor states).
Not surp9iseing you did not end up with whiplash when turning the A/C off as even the overly generous estimate of 25 hp is not a lot of difference 25hp/300hp = 12% at full cooing mode (I still say more like 18 hp at 100% cooling)
Hope this brief detail substantiates the tangent-o-phobia and keeps this thread filled with transferable triva to related problems that others may try to resolve in similar contemplations. |
David Hartley (Drdave)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, April 29, 2006 - 7:58 pm: | |
My RTS got 3mpg with the factory air on, 6.8 with it off.
Says a lot to me.... (plus the 750 lbs of garbage pulled out! ) |
Doug G
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, April 29, 2006 - 9:15 pm: | |
We had some A/C problems. One problem was corroded electrical connections in the electrical bay. The other was a bad A/C clutch. Check the clutch first, then look for bad grounds. |
niles steckbauer (Niles500)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 30, 2006 - 3:58 am: | |
I think some people are getting confused about compressor HP and btu/hrs - let me see if I can confuse it more -
The btu's you are discussing are "cooling capacity" btu's - not the number of btu/hr or HP needed to drive the compressor
Using 1 HP = 2540 btu/hr
Then taking a "cooling capacity" of 76,200 btu/hr (6+ tons)
You first have to figure the "coefficient of performance" - this is the efficiency attained in actual 'cooling' by a particular refrigeration system - late model compressors are capable of achieving a factor of up to 3
A cooling capacity of 76,200 btu/hr with a "coefficient of performance" factor of 3 would require 25,400 btu/hr or 10 HP
Furthermore a compressor which unloads to 33% after the initial 'cool down' would only require 3.3 HP
*** DISCLAIMER (yes, this is for newer efficiency units operating at 100% efficiency - I am not commenting on the take it out/ leave it in discussion - only trying to clarify the actual loads placed on the mill - and yes I know the motors add more load via the alternator - but the COMPRESSOR ITSELF is more accurately a 5-15 HP load plus any inefficiencies in a 9 ton system) |
truthhunter@shaw.ca
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 30, 2006 - 4:36 pm: | |
Much better put NS. thanks for the elegance and simplicity |
Tom Caffrey (Pvcces)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 01, 2006 - 3:25 pm: | |
Niles, that was a very nice explanation. I would only add that the way these were used in our coach, the compressor never gets to unload; it runs at full cooling as long as it is on.
The eight tons or 96,000 BTU would require at least 32,000 BTU or 12 3/4 hp to drive it and a few more hp for the air handling.
I would figure that it would take a gallon of fuel per hour when operating.
For what it's worth.
Tom Caffrey PD4106-2576
Suncatcher
Ketchikan, Alaska |
niles steckbauer (Niles500)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 01, 2006 - 3:58 pm: | |
Tom - sorry, that was a reprint of a post on another thread - your right - I left off the part about this being for compressors that have the unloading ability - I had also posted a link to carrier's site showing such a unit - fortunately for me I have that kind of unit - thanks for the correction - Niles |