How to determine if 2nd AC running 05 Dolphin 5342

[ralphl]

Anybody know how to determine whether the second basement air conditioner is running on a 05 Dolphin 5342. I have the switch in the rear driver's side compartment in the up position, but I don't think my second air conditioning unit ever turns on. Recently while the air conditioner was running, I shut off the breaker (in the main electrical panel) for the second air conditioner, and I could neither hear nor feel any change in the air conditioning. Temperature in the MH at that time was over 100 degrees, and the thermostat set to 77, so I think both units should have been running. Electrical power was being provided by the Onan generator. I took the cover off the thermostat, but without a wiring diagram I couldn't see how the AC units were controlled.

I hesitate to turn off and on the AC breakers, because I have heard that the unit can be damaged by doing so. Anybody know if this is true, or is it just and old wives tale.

Anybody know enough about AC controls to help me on this...
Thanks
Ralph

[Charlie 5320]

Don't know what kind of thermostat you have, but my 03 Dolphin has a stat that runs both airs. On mine #1 is the rear air and #2 is the front air. If I set the stat to off in #1 the rear air will never work, which I do when I'm plugged in at home as I don't have a 50 amp service to plug into. On my stat I can run either air in manual mode or auto mode. When I'm on the road, with the generator running I set them both in auto mode and let them cycle.

[Fred and Bonnie]

I can stand outside the air conditioning compartment and listen for a moment of fan silence the second compressor kicks in, additionally I can hear a slight click from the thermostat.

Fred

[ralphl]

Thanks guys for the quick response. I think I am going to have to measure this with an ammeter. I will try to find a friend that has one. Also, I would be interested to know what/where the second AC is controlled. It must be a fairly sophisticated control, since the stat setting must be at least 3 degrees below the current target temperature setting before AC 2 kicks in. Is this done in the thermostat on the wall, or is there a second control box someplace? I would like to find a control wire to see if the AC 2 is being told to turn on. Fred's comment that the stat clicks when AC 2 turns on would indicate it is done in stat. Maybe I can find a wiring diagram for it on line.

In addition, I found that if I turned off the breaker to AC 1, AC 1 would not turn back on for 3 or 4 minutes. I am guessing this is to provide time for the compressor to leak down, so that startup is not against highly compressed refrigerant. Probably AC 2 is the same way so only the first "on" is going to really start it. I took the advice from another forum to turn off AC 2 in the rear compartment (or at the breaker), start the AC, when it gets going good, turn on AC 2, and listen for the Onan to lug down a little. I did that and I noticed the Onan did lug down for a second, but then seemed to work no harder than with just AC 1 running. So I still am not sure if AC 2 is running. I will have to wait for an ammeter......

Thanks again.

[Civdiv99]

I know this is a couple weeks old, but also having an 05 Dolphin with basement air, here are my observations over the last 12 years.

If you run it with the 2nd compressor off while on genny, then switch it on (switch up in the compartment), it will pause and resume and the tone of the genny will be clear that you increased the load.

I have a surge protector that reads out the current draw and on 50a service can also see it on each leg.

It's not real obvious single vs dual operation from inside the coach as far as I'm concerned...

[2inclassof56]

On Our 2003 Dolphin LX I never knew if the 2nd compressor was even working, with the generator trick I found out it really works. Thanks for the good advice.
Bob Fitzgerald
2003 Dolphin Lx
2013 Honda Fit

[Charlie 5320]

I miss understood what you really meant. You only have one air conditioner, but it has 2 compressors. You should have what they call a 2 stage cooling thermostat, and the air conditioner should have 2 different breakers. Doubt very much if you could tell if both compressors were running by sound, you will have to use a meter to find out. I would use a clamp on amp meter to find out if the 2nd compressor is running.

Start by looking at the booklet that came with the stat and find out how it is supposed to work. It probably only starts one compressor for so many minutes and if it doesn't satisfy the set point it then will start the second compressor.

[lenjen]

My thermostat has a low and a high but I can't tell the difference. The only way I can tell is when I have 50 amp service, the switch is set for 50 amp and the RV cools much faster. I've never heard the difference.

[Fred and Bonnie]

Sandi, the "high/low" controls fan speed, not cooling ability.

Fred

[lenjen]

Originally Posted by Fred and Bonnie

Sandi, the "high/low" controls fan speed, not cooling ability.

Fred

I understand the high/low for the fan speed but I've never heard the difference.

[Fred and Bonnie]

Originally Posted by lenjen

I understand the high/low for the fan speed but I've never heard the difference.

Sorry, misunderstood your response. The difference is very slight.

Fred

[tmw188]

If you stand outside on the initial start up on a reasonably warm day you will hear the other compressor start up. On the inside you would probably only notice if you were on the Genny.

[ralphl]

Just to bring this to a conclusion: I borrowed an ammeter (the magnetic pickup kind that has a U shaped probe into which the wire to be measured fits). I took the cover off the ON/OFF switch for the second compressor that is on the rear wall of the last compartment on the driver's side. I pulled out one of the wires (doesn't matter which one) and measured the current (switch on). It showed about 11.4 amps, when the thermostat was set about 4 degrees lower than the ambient temperature.
So my second compressor was running!!! However, drawing only 11.4 amps means it is a very small compressor. My vacuum cleaner draws that much...
Thank you everybody for your responses.
Ralph

[tmw188]

What's the other reading? I think that is a correct reading.