15 replies to this topic

[bullittman]

I have an Intertherm A/C unit that is driving me crazy! The inside (blower section) is working as advertised, temp rises above set temp and the unit comes on, Problem is the outside (condenser unit) works intermittently. It has gotten progressively worse. I read for power and have the 240 where it belongs and the 24 where it belongs. My first thought was that the thermostat was not sending the appropriate signal (it was an older digital thermostat). I replaced the Thermostat turned on the unit and it worked fine. I was happy problem solved. NOT SO MUCH! The next time the unit cycled off and back on the outside unit did not start up. The only thing I had done was take the thermostat off the wall and hook up the new one. So I took the thermostat off, let it set for a couple of minutes and then put it back on again. Unit worked. Now I am lost! Is there something in the circuit card on the outside unit that could be sticking that resets when I remove the thermostat because it creates an open? Is there a chance that the relay is just weak and it is a coincidence that it works after the thermostat has been pulled for a few minutes and hooked back up? On occasion it works like it should (yesterday it worked all day long then last night did not) It's driving me crazy!

I wish I could provide more info on the model of the unit but the information tag on the outside of the unit has almost completely faded. Anyone have any ideas?

[RegUS_PatOff]

... Is there a chance that the relay is just weak and it is a coincidence that it works after the thermostat has been pulled for a few minutes

could be ...
Does the outside Relay energize when calling for cooling ?
Does the Compressor try to start or make any noises ?
Does the Outside Fan run at that time ?

[bullittman]

the compressor does not make ANY noise and the fan does not try to run when it does not work. when it does work like it should, the compressor starts right up and sounds normal in every way (in other words it doesn't wine then slowly kick on). If the outside unit comes on the fan blows if the unit does not come on it is just silent.

[RegUS_PatOff]

may be a weak Relay / Contactor
is there 24vDC at the Relay Coil Terminals when there should be ?

[bullittman]

oops sorry in the picture above I should get 24v at the red and black wire when the stat calls for the unit to turn on correct?

[jumptrout]

The 2 small wires on each side is the low voltage points.
If this is a heat pump with a defrost control board in the condensing unit you can locate the red incoming thermostat wire connection on the board.
Remove then replace the wire. If the unit comes on you need to replace the defrost control board.

[bullittman]

in this picture I have 24v at the when I read from the yellow to the black wire (the wires that come from the thermastat) nothing at the red wire (all when unit is calling for the compressor)




If I read this schematic right the circuit card above is a time delay and when the thermastat calls for the unit to come on I should have 24v at the red wire correct?

or am I just all messed up?

I currently cannot get the unit to work to see if it is getting 24v when it works correctly.

if I am supposed to have 24v at the red wire coming off that time delay and I do not then that should be what is wrong correct?

[bullittman]

may be a weak Relay / Contactor
is there 24vDC at the Relay Coil Terminals when there should be ?

sorry it took so long I had to get home to double check before answering, the answer is no! At least not right now! If I can get it to come on again I will learn a lot more ( I THINK )

[jumptrout]

This is not a heat pump.
The time delay relay can be eliminated due to the digital thermostat.
The thermostat has a time delay built in to it.
Take the red and black wire off the board and wire them directly to the 2 incoming thermostat wires.
When the stat it set to cool and is not in a time delay mode you should have 24 volts at the condenser on what appears in your photo as red and white.
If you do not have 24v there you have a stat problem or a wire problem.

[RegUS_PatOff]

hard to read, but yes, I think so...
You could try removing (and bypassing) the Time Delay from the circuit ..
You shouldn't run it that way much, because if the Compressor tried to start right after it stopped (no time delay)
it could hurt the Compressor.

edit> OR what ^he^ said

[bullittman]

ok so I am 98% sure that it's the time delay! now how do I figure out what to buy since I can no longer tell what model condensor unit this is (all faded off)

By the way jumptrout it is not a heat pump unit.

[RegUS_PatOff]

Any part numbers on the Time Delay ?
The wall Thermostat may have a built-in time delay...
model number ?

[bullittman]

hard to read, but yes, I think so...
You could try removing (and bypassing) the Time Delay from the circuit ..
You shouldn't run it that way much, because if the Compressor tried to start right after it stopped (no time delay)
it could hurt the Compressor.

edit> OR what ^he^ said

ok so once it finally broke for good it helped with the troubleshooting! I took the delay out of the system and it works, The question I have is should I replace the time delay on the condensor unit or will the one that is in the digital thermastat protect the unit?

If I do need to replace the one on the unit can anyone tell me what I should buy? Are they generic?

Oh yeah and THANK YOU for the help! I really hope I can re-pay it somehow in the future!

[RegUS_PatOff]

Any part numbers on the Time Delay ?
The wall Thermostat may have a built-in time delay...
model number ?

[bullittman]

no part numbers on the time delay card outside that I can read. The digital thermastat does have a built in time delay (originally while I was trying to troubleshoot it drove me crazy) part number of the thermastat is rth2310b

[RegUS_PatOff]

yes, that Thermostat has a delay,
you should be OK without the Time Delay Board