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Hi I'm Brian and I"m here to help!
Can you give me the make and model numbers of both your furnace and your zone controller please?
The purge LED flashing means either your supply air sensor had failed or if none is installed this is normal.
When you set one or more of the zones to heat and the setpoint well above room temperature, does the Heat LED light? Does it stay lit while the furnace goes through its cycling malfunction?
Thank you for all the info. It helps me get on the same page as your installation! :)
Ok, thanks. That is all normal. The important thing to note is if the heat LED stays on if/when the furnace cycles quickly as you stated as the original issue. If you have a failed supply air sensor or there was never one installed (a very common thing), your purge light will always blink unless the system is actually in the 4 minute purge cycle. The blink is to alert a problem with the supply air sensor and there's no way to turn this off except to install a new supply air sensor. It's much simpler just to ignore the blink :)
It's possible this is an intermittent problem. It could be either but the LED will tell you. There is also a way to override the zone panel and run the heat manually by jumping RH to W1/E on the HVAC Equipment terminal strip with a small jumper wire. If the furnace runs wild with that jumper and never does the short cycling issue then the furnace is fine. However, if the furnace DOES do the short cycling issue while you have those two terminals jumped out then the problem is with your furnace.
The steps you just performed and wrote to me about show an absolutely normal operation. You will have to catch the system in the act and note which of the scenarios with the Heat LED does or how the furnace behaves when you jumper as I state above. If the zone control LED stays lit while the furnace does its short cycling malfunction or if the furnace short cycles while you have those two terminals jumped out, the problem is indeed in your furnace and you can be assured its covered by your home warranty company.
For a copy of the manual for your Zone Controller. It may help shed some light for you.
You're very welcome! And, that's hard to say. It's not a very common occurrence for a furnace to short cycle that way that quickly. Your GUD model furnace is a modern style furnace with an electronic control board. If there is a problem with it, it has a diagnostic LED that you should be able to see through and inspection hole in the blower panel door. If that LED starts blinking a code during the short cycling then that would point more toward a furnace issue as well. Together with the zone control, it becomes a difficult system to diagnose remotely beyond telling you how to distinguish which device is causing the trouble with the suggestions I gave above. For your added info Click Here for a copy of the GUD furnace manual that may also shed some light for you. The GUD model was marketed under several different brand names. The manual I link to is under the Amana name but should be the same furnace.
I'm sorry for your continued furnace trouble. A gas furnace with a zone controller can be a tough nut to crack when it comes to an issue like this. Since the problem appears when your system is getting close to the desired temperature, it could be that the airflow of the furnace is being diminished by the zone dampers closing. This may in turn cause the furnaces high limit control to trip. If that were to happen, you should see a 4 flash code from the furnace's status led (not the zone controller's led's). It would flash 4 times then pause and repeat. Zone systems should have a bypass damper to ensure the the airflow through the furnace remains high enough for proper operation. This is my best educated guess on what may be happening. It's also possible you may have a weak limit switch on the furnace.
It looks to me like you're going to need the help of a tech on site to find the gremlin.