AC Compressor Stopped

[Photolomy]

When we turn on the forward salon AC, everything works normal (pump, fan) but the compressor is not turning on. After troubleshooting, I don't even think it is getting power (no humm, nothing). After researching the site, this would indicate a bad TRIAC, but where exactly is it?

It is AC unit #2 in the following picture...



Also, for future reference, where is the starting cap?

 

[Pascal]

I don’t have any on my chiller system but I thought triacs were used to activate the sea water pump.

It sounds like the control isn’t send the signal to the compressor. Either an issue with the Tstat in the room or a problem with the control board in the box on the left of your unit which should also include the start cap

What kind of controls do you have? Most modern controls have a “compressor on” indicator. Does it come on ?

 

[Photolomy]

I still have the original 3 knob rotary controls. Are you saying that the fault might be there?

 

[Boatsb]

It's time to get a real schematic and or someone who knows the systems.

There's more than 1 triac. More than one circuit to be tested. More than 1 capacitor.

It's not a simple cut and dry determination.

You need to test the circuit and components until you find the problems.

 

[Pascal]

I still have the original 3 knob rotary controls. Are you saying that the fault might be there?

Yes. If the control doesn’t send the run command the compressor will not start.

 

[SeaEric]

IIRC the compressor won't run if it's low on freon.

 

[Photolomy]

IIRC the compressor won't run if it's low on freon.

It won't even try? It seemed to cool fine before.

 

[Pascal]

No the low pressure switch will stop It from even starting.

 

[Captain Ralph]

I still have the original 3 knob rotary controls. Are you saying that the fault might be there?

I have found behind the old 3 knob control, a few times, a burnt wire crimp.
If you back the panel off of the bulkhead just a couple of inches, with breaker off, you can see the slip on crimps.
Also, these wires may go to a terminal strip within 3 feet of wire with a plastic cover, found a bad crimp under there also.

 

[Captain Ralph]

No the low pressure switch will stop It from even starting.

Rite on. Must have pressure to turn on.

A volt meter either at the compressor or on the capacitor will prove ACv at the condensing station.
Pretty sure there is no Triac on your 3 knob control system.

 

[JuiceClark]

<I share this only for chuckles - there's no lessen here!>

Whatever that controlling solenoid is, which turns on the water pump when any of the units is switched on, was bad on my a/c system. So, the previous owner actually ran a new wire directly from the water pump to the breaker panel. (one of those solid yellow wires you use in the house) So, you had to go into the ER and throw the raw water pump breaker before turning on an a/c system.

I had to completely replace the 8kw system in the master because the compressor was somehow completely shorted out.

No biggy - it was only $7,000 to replace the blown system, undo the silly business and get all four units running properly. I've spent about that same amount renovating the entire rest of the boat so far.

Actually, there probably is a lesson in there...or I'm just pandering for sympathy.

 

[Jammin']

No biggy - it was only $7,000 to replace the blown system, undo the silly business and get all four units running properly. I've spent about that same amount renovating the entire rest of the boat so far.

Actually, there probably is a lesson in there...or I'm just pandering for sympathy.

You've spent nowhere near enough money to garner any sympathy from me!

 

[Captain Ralph]

You've spent nowhere near enough money to garner any sympathy from me!

Sad part, I understand this comment well..

 

[JuiceClark]

You've spent nowhere near enough money to garner any sympathy from me!

Sad part, I understand this comment well..

I'm just getting started. We'll be able to commiserate soon enough! A full paint job is really gonna hurt.

 

[oscarvan]

Rite on. Must have pressure to turn on.

A volt meter either at the compressor or on the capacitor will prove ACv at the condensing station.

Wait, you mean actual trouble shooting? That's crazy talk.

 

[SKYCHENEY]

To answer the original question:

The triac will be in the control box on the side of that compressor.

 

[Photolomy]

To answer the original question:

The triac will be in the control box on the side of that compressor.

Thanks

 

[Photolomy]

So, after some troubleshooting, I have ruled out the switches and the high pressure switch (my AC units do not have low pressure switches). I will probably replace the caps (cheap) but I don't think that has anything to do with it, because the compressor would hum at least. At this point I believe it to be the relay, which is behind the control box (between the compressor and control box). Has anyone replaced the relay? In the Cuiseair service manual it is called the Start Relay.

 

[Photolomy]

Here is a picture of the control box. Obviously, the cap needs replacing, but as I said in the prior post, the symptoms are not that of a blown cap. Also note that the relay is not in the box, it is behind it.

 

[Photolomy]

Here is a picture of the relay (this is on the unit above the unit not working)...