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BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 22002
Experience:  Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
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My Ruud 13ajn36a01 short cycles: outside unit (compressor &

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My Ruud 13ajn36a01 short cycles: outside unit (compressor & condensor) runs for 14 minutes then shuts down for 5 minutes then repeats: on for 14 minutes off for 5 minutes leaving the inside air handler/evaporator running because the temp setting has not been reached. I tested the thermostat by bypassing and the short cycling still occurs. The system is fully charged, filters are clean, and no air restrictions exist.

How do you know if system is charged correctly? Have you checked pressures?

And if so what is the head and suction pressure while running?

For the unit to operate as you describe is directly related to a high pressure or low pressure cut out. Then once equalized the unit kicks back on.

Do you have pressures?

Customer: replied 3 years ago.

I don't know the pressure numbers but they were checked with gagues by an a/c guy 2 weeks ago - he said they were correct for the R-410a system.

Your air handler stays running proving 24v signal is continuous. This means the outdoor unit is not being turned have a water safety switch at the indoor unit that trips if the drain backs up.

Lets eliminate that you know if the indoor unit has this switch? Is unit in attic?

Customer: replied 3 years ago.

the air handler is in a first floor closet and does have a water safety switch: Rectorseal model SS2 installed to the right of the PVC drain pipe which goes to a sump pump hanging below - how can I check to see if that drain line is completely clear?

You would need to use a shop vac...and apply suction to drain/discharges.

Scenario = water fills up...switch cuts off.....water slowly drains.....switch closes.....water builds up...etc, etc.

This and the pressure switches are the only items that cause the situation as described.

It is either building/loosing freon pressure and tripping unit...recovering and starting again. Or the Y wire is losing 24v due to water switch.

If you have a meter you can test for 24v at the Y wire going outside while unit is shut down.

24 v present means that the water switch is closed and a pressure switch is tripping.
No 24 on Y wire = open switch inside.

Keep in mind that pressures (freon) can be good and yet a pressure switch be defective.


Customer: replied 3 years ago.

Thanks Billy,

I'll try your suggested troubleshoot outline,



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