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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: robert on June 07, 2006, 02:43:22 PM

Title: roof air
Post by: robert on June 07, 2006, 02:43:22 PM
Help, Help.
It is 93F in Omaha and one of my 3 roof airs went out. The old one when turned to "cool " would trip the breaker. After some investigation it was concluded that the compressor was froze up. So $600.00 later I installed a new in the box 13,500 btu "Duo Therm" by Dometic. It does not blow even cool air. So I re-installed the old one and now it to blows hot air but it no longer trips the breaker. My question is, is there a thermostat in the cool/air or warm/coo swithces?????????? I tested the power to the unit and it is getting 108 v and Dometic says you need at least 104 v. Any help would be great.

I ran everthing on the bus , I wonder if that is why I am only getting 108v
Title: Re: roof air
Post by: Len Silva on June 07, 2006, 02:53:24 PM
Robert

Two things to consider:

1.  Even though 108 volts is within their limits, it's still pretty low. Try to get to a source that's at least 115v.

2.  Did you wait long enough?  I'm sure there is a time delay before the compressor kicks in, maybe even a couple of minutes.

Len
Title: Re: roof air
Post by: DrivingMissLazy on June 07, 2006, 02:58:12 PM
I have never heard of a roof mount A/C without a thermostat that you turn up or down depending on how cold you want the coach. Did you hear the compressor kick in after you turned it on? Did you find the warm/cool control?
Richard

Quote from: Len Silva on June 07, 2006, 02:53:24 PM
Robert

Two things to consider:

1.  Even though 108 volts is within their limits, it's still pretty low. Try to get to a source that's at least 115v.

2.  Did you wait long enough?  I'm sure there is a time delay before the compressor kicks in, maybe even a couple of minutes.

Len
Title: Re: roof air
Post by: robert on June 07, 2006, 03:04:23 PM
Thanks for the help. I turned the warm/cool switch several times on both units, well with both units installed. the inside with the switches is originall and the new one did not have the inside mounting and switches. thanks
Title: Re: roof air
Post by: TomCat on June 07, 2006, 03:35:47 PM
Quote from: robert on June 07, 2006, 03:04:23 PM
I turned the warm/cool switch several times on both units, well with both units installed. the inside with the switches is originall and the new one did not have the inside mounting and switches.

You may need the interior parts that are made for use with the new unit for it to work properly.

Jay
87 SaftLiner
Title: Re: roof air
Post by: Ross on June 07, 2006, 04:32:21 PM
When I bought my Duotherms 2 years ago one was bad.  I got it replaced and the replacement was bad.  Got that replaced and got a good one.  After all that, someone mentioned something about a relay or something being wired wrong.  I don;t remember if it was someone here, someone from Dometic or one of my RV dealer friends.  I don't remember what it was but I remember it was something simple...Like a missing jumper wire or something like that.  The unit would come on, but the compressor would not run.
Title: Re: roof air
Post by: Nick Badame Refrig/ACC on June 07, 2006, 05:53:39 PM
Robert,

I will be the first to admit, Last year we purchaced  41 roof top dometic/ duotherm units, 9 park model units, 18 of theese units were bad in the box,

and 5 were bad in the box the second time!!! This is not a good ratio for Dometic. However, I had a worse ratio when I was a Coleman dealer.

With that said, A good friend is a Carrier RV suplier, No better on his end either!!

The truth is, they have such a competive market to compete that each company has to be at the same price level as the other or they sacrafice their volume .

Volume is the secret to being a major league company!! weather your product is durable or not!

Nick Badame
Title: Re: roof air
Post by: NJT5047 on June 07, 2006, 07:12:35 PM
Hi Robert,
Regarding your problem with Dometic rooftop AC units...this may not have anything to do with what you're experiencing, but my Duotherms have about a one minute plus delay, built into the compressor controlling electronics, when first turned on.  The fan comes on if on "auto" and the compressor comes on a minute or two later.  Once that cycle is complete the compressor and fan will come on together.   Seems like it may be heating up the compressor or something.  Both units work exactly the same. 
Another issue with Dometic ACs is if you use a wall thermostat, the thermo connecting wiring is computer cabling (cat 5 I believe?), not phone wire.  Ax me how I know about this.  I can also advise that mixing up the phone vs computer cables will not damage the thermostats or AC units.
Nick can advise, and this may apply to heat pumps only, but seems that there were some dip switches that had to be set if you wanted specific interation between the units...or zoned control.   
I've got two Dometic rooftop heatpumps and they work great.  Both on heat and cool.  The low fan setting is not especially noisy, and I like the noise anyway.  We go to music festivals and the fan white noise drowns out ambient noises.  I leave the fan on "on" and enjoy...the compressor cycles as heat or cooling is called for.   
Good luck on your ACs!  Nice to have them working this time of year.
Regards, JR
Title: Re: roof air
Post by: Nick Badame Refrig/ACC on June 07, 2006, 07:38:55 PM
Yes Robert,

The cat5 and dip switches come into play with either Hp's and zoneing more than 1 unit. :o

I mean, when you actually have to change the dips. You koow, Read The Manuals ;D

Nick-