One Rooftop AC Not cooling

[superk]

I have dual rooftop ACs and an intellitec management system. Unfortunately, on this older model there is no amperage draw system. It has 30 amp service labels. I have an onan marquis 5500 generator. 1999 Fleetwood bounder ford f53


I have opened the interior panel already and checked the intake filter, while it was dirty, inside the access was spotless, like new. Zero dust. The fins are clean, but warm, not even remotely cold.

The wires do not appear to be damaged, they are practically new.


http://home.comcast.net/~robmorg/discovery/ecc.pdf <---this is my system (or so it seems)

Just for fun, I checked the +12 going to the ac (wire labelled Y on ac) for activation of the compressor. I got no current. So I located the control module above the fridge and slid the test switch to front. The generator went nuts. I think that the AC was drawing wayyyyyyyyy too much power. In the end, it stabilized and the rooftop unit started up. After a few minutes of waiting I checked that same +12v line, and it had current! Still no cold air though.

What would you do next? I am fairly handy and consider myself a do it yourself-er in most cases.

• 
  
• Is the unit intentionally not powering the compressor? (Perhaps it senses some sort of overload)
  
• Or, Does the unit have an issue and is just not powering up the compressor due to defect.
  
• Both?
  

[Dachristianman]

Given the price, it's probably safe to just replace it. Even if you repair it, what's to say it won't give you more issues in 3 months when it gets really hot out. They're not really designed to be serviced, and if you can replace it yourself, you'll be better served by just buying a brand new unit.

That's my two cents and worth about 1/2 that.

[10forty2]

Your diagnostics would seem to indicate exactly the conclusion you have come to. As such, depending on the age of the unit, it probably had the old-style freon in it. That stuff is hard to come by and is very expensive...at least here in the US. Plus, if a tech will have to cut the line to put a vacuum on the system and then put the freon back in and then hopefully get the line re-crimped good enough that it won't all leak out, and hopefully the original leak's not in the expansion/radiation coils where you can't fix it....well, I can see where that's going to get pretty expensive pretty quickly. I think I might be looking towards replacement instead of repair. Just my thought pattern on it.....

[stillthinking99]

I used to have a 2002 mh with the intellitec climate control and replaced the front roof air after a lot of frustration with only blowing cold air when it wanted to. You haven't mentioned if the control panel shows its shedding power. Is it? Mine would run the blower but seldom kick on the compressor. New ac did the same thing.
turns out it was the brain in the ecc. I replaced it too with no better result. The fix was an upgrade to a pure sine wave inverter charger with the ability to regulate the battery charging rate. I'm pretty sure the ecc brain is very fussy about the 12v it gets to run. The last time the ac wouldn't bliw cold, i also mean stop shedding power, i found a house battery cable loose and dirty. I cleaned and tightened it and then tried the ac and it worked.

[superk]

Today I went up on the roof. I brought a variety of tools, including a clamp on ammeter. I had my friend Al helping me downstairs with passing of items and flicking switches. At first, the compressor tripped the circuit and was powered down. I then went to look at the caps. I unplugged, discharged, and tested all 3. All 3 tested and visually inspected ok. Plugged them back in, had Al turn it on, and the compressor fired right up. Unfortunately, however, it did NOT produce cold air.

At this point, I think its reasonably safe to say that the coolant has leaked, and there is also potential for complete compressor failure.

Is it worth it to have an HVAC guy hop up on the roof and try to refill this thing? I checked and it is sealed. Ends would need to be cut open, pump applied, and then crimped closed again. I assume there is a tool that does all this without leaking the gas. If the fluid is indeed gone.... there is a leak somewhere right? That could be anywhere in the system.

[Tinstar]

I would guess the capacitors. They go out and a lot of time a new one will fix the problem. They are cheap and easily replaced. Just be sure to discharge them before touching. They hold a lot of electricity.

[JimM68]

First, do all your testing one a/c at a time, that will hopefully take the power management out of the system.

As I'm sure you know, the electronics and the blower motors are 12 volt.
The compressors need 110ac...
And your power management will only give 110 vac to one unit at a time.

The clamp on VOM will be a big help..

I've had one like this (2000 pace arrow) the power management is "kinda smart" but not full on brains. I would check and trouble shoot each a/c separately.

[stillthinking99]

Look on youtube for a "how to" video - Check both capacitors, the start and the run capacitors. They are accessed by removing roof ac shroud and then finding them in a metal compartment of some kind.
You need a meter to test their ability to store power, like a battery. Be careful of stored power. A visual inspection may show them burnt and leaking meaning a replacement is due.
i found a meter at Lowe's that had a, "Cap" setting for testing. Be careful aound electricity, make sure all power is off.

[superk]

Well, ill be climbing up onto the roof hopefully wednesday, if not, then almost certainly this weekend coming.

I will have a clamp on ammeter with me and a few other diagnostic tools and will be hopefully getting to the bottom of this.

[Mandalay_Parr]

I would call a mobile AC tech.