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BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 22508
Experience:  Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
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I have a fujitsu air conditioner model no AST24RGB-W purchased

Customer Question

I have a fujitsu air conditioner model no AST24RGB-W purchased in 2007.Retailer no longer in business.
Unit wont heat.
Fan Speed pulses on very low. Unable to adjust fan speed in Heating.
Solenoid valve on reversing valve is getting power when switching from cool to heat.
Could Pipe temp thermister be faulty? how to check?
Thanks Billy
Submitted: 2 years ago.
Category: HVAC
Expert:  BillyHvac replied 2 years ago.
so in heat mode the reverse valve drops out...does it do same in cool mode?
use reply
Customer: replied 2 years ago.
Hi Billy
The solenoid valve is switching when going from heat to cool.
It gets power when in Heat mode and sounds like the "slug" gets pulled as it clicks.
When switching to Cool, the solenoid clicks again as power drops off.
I can't check if the unit is cooling at the moment as our outside temp is only 15 DegC and
the minimum setpoint for cool is 18 DegC.
Could I try to get it to cool if I warm (hold on to) the inside unit inlet air thermostat?
Expert:  BillyHvac replied 2 years ago.
yes...even warm it with hair dryer.
Customer: replied 2 years ago.
So if it doesn't cool could it need a re-gas.....?
If it does cool, what would be the next step?
I noticed on my other split system that there's a time delay between
switching the unit on and the fan speed getting up to the "high" that
I selected using the remote.
What condition does the unit wait for in this case?
Could it be the "pipe temp" thermistor that I mentioned in the original question?
Can I swap the inputs from the ambient and pipe thermistors around to check it?