Help - In Florida with no AC

[TQ60]

Have you measured voltages yet?

[RKL]

Make sure the circuit breakers have been. Reset properly by pushing to off and then more off before going to on.. There should be 2seperate breakers for the ac. Did you try using generator to run the ac? Move thermostat to 72 and try again. At 65 mine locks out . Good luck. Rkl

[TwelveVolt]

You mention swapping parts, but have you checked voltages in the compressor circuits? Is the thermostat closing its relay (yellow Y wire to +12VDC) and in turn closing the AC's 115VAC relay? Does the 115VAC relay have 115VAC supplied to it and does it get switched to come out the other side of the relay to the compressor?

The fan is operated by a separate relay from the thermostat (+12VDC on the green G or gray wire, depending on fast or slow fan setting).

I was tinkering with my propane furnace the other day. It is on the same thermostat as the AC. The next morning the forward AC would not start. I had left the safety switch on the furnace in the OFF position.

When you are focused on the obvious source of the problem, always remember to step back and think outside the box.

[NeilV]

I almost forgot to post this info on where you can get the service manual for your Basement Air Unit and the Thermostat. These should help with trouble shooting your problem.

Here is the link to the service manuals from AirXcel RVP:
Airxcel | RV Products | Tech Info

Be sure to check out the electrical flow charts which lead you through sequence of operation checks and troubleshooting including how the read the LED lights on the controller board inside the unit.

[Maddog2020]

Yesterday I went out and got a DVM at Radioshack. I may not have time today but I agree the troubleshooting flow charts are next. Without the meter I didn't have many options so I swapped parts. The inside fan comes on, but the compressor and outside fan do not come on.

There is a Green LED flashing rapidly (outside PCB) when it should be solid. Manual says that indicates missing 115 at Circuit 1. I was able to confirm 115 was present. If not that it claims 1 of the 2 thermisters are bad. I tried bypassing them with no change. I'm thinking the outside board is bad but once I check all the voltages I should know for sure.

Thanks again for all the good suggestions!

Jim

[NeilV]

Originally Posted by Maddog2020

Yesterday I went out and got a DVM at Radioshack. I may not have time today but I agree the troubleshooting flow charts are next. Without the meter I didn't have many options so I swapped parts. The inside fan comes on, but the compressor and outside fan do not come on.

There is a Green LED flashing rapidly (outside PCB) when it should be solid. Manual says that indicates missing 115 at Circuit 1. I was able to confirm 115 was present. If not that it claims 1 of the 2 thermisters are bad. I tried bypassing them with no change. I'm thinking the outside board is bad but once I check all the voltages I should know for sure.

Thanks again for all the good suggestions!

Jim

I get one of the $1.99 DVMs at Harbor Freight to leave in the motorhome.

These occasionally go on a coupon on parking lot sale for around $2:
http://www.harborfreight.com/7-funct...ter-92020.html

I am considering getting one with an amp probe instead with the 2nd one possibly preferred due to the use of a 9volt battery to power it instead of a more expensive and hard to find button cell:
http://www.harborfreight.com/digital...ter-96308.html

http://www.harborfreight.com/digital...ter-95652.html

Their Pittsburgh hand tools come with a lifetime guarrantee so I got one or their 4 drawer kits when it was on sale for $39.99 for the RV too. Now they are on sale for $49.99 and still worth it:

105 Piece Tool Kit with 4-Drawer Chest

[Maddog2020]

I made some progress. Following the troubleshooting flow and the note about the flashing green LED.

AC present on outside PCB across Test Point 1 and 5.
Bypassed both thermisters (Indoor coil and Outdoor coil) no change.

This indicates the yellow Exclusion Relay is bad (or the whole PCB) - see picture below
https://drive.google.com/file/d/0B1n...it?usp=sharing

I was poking at the relay with a pointed piece of plastic and pressed a little too hard. I actually poked a hole into the relay and my outdoor fan and compressor came on. See stabbed relay below
https://drive.google.com/file/d/0B1n...it?usp=sharing

The temperature quickly started to drop and when 1 degree below setpoint AC automatically kicked off. Once it warmed up again it still worked.

So I isolated it to the Exclusion Relay and stabbed it to temporarily fix the problem (not recommended). It's less than $10 for the part, solders to the PCB with 8 leads. I will replace it before our next vacation in February.

Thanks again for all the help!

[bruceisla]

Originally Posted by Maddog2020

I made some progress. Following the troubleshooting flow and the note about the flashing green LED.

AC present on outside PCB across Test Point 1 and 5.
Bypassed both thermisters (Indoor coil and Outdoor coil) no change.

This indicates the yellow Exclusion Relay is bad (or the whole PCB) - see picture below
https://drive.google.com/file/d/0B1n...it?usp=sharing

I was poking at the relay with a pointed piece of plastic and pressed a little too hard. I actually poked a hole into the relay and my outdoor fan and compressor came on. See stabbed relay below
https://drive.google.com/file/d/0B1n...it?usp=sharing

The temperature quickly started to drop and when 1 degree below setpoint AC automatically kicked off. Once it warmed up again it still worked.

So I isolated it to the Exclusion Relay and stabbed it to temporarily fix the problem (not recommended). It's less than $10 for the part, solders to the PCB with 8 leads. I will replace it before our next vacation in February.

Thanks again for all the help!

Awesome !!

[Lt46]

sheesh, wish I had your repair skills LOL

[NeilV]

Ok the relay was stuck or fused. Could be symptomatic of low voltage heating things up. I would put in a Hughs Autoformer or some other form of voltage regulation that corrects low voltage/brown out conditions to help prevent further damage. I have not had any electrical failures in my coach aside from light bulbs burning out since I installed one.