Furnace Cycle Issues

KeupMittenFamily

Looking for some confirmation of my suspicions of an issue I'm having with our furnace. First, my specs:

Janitrol Furnace: Model: GMNT100-4B

Honeywell Zone Controller: Model: HZ322

I am having the issue where the furnace will follow this cycle sequence intermittently (2-5 times a week, maybe more!) I notice this when I am home in the evenings and during the night, but it could be happening quite a bit more during the day.

Actions Description: Induction = Induction Fan Burn = gas ignition and burning Blower = fan blower running My assumptions and this is where I need help diagnosing: Gas valve regulator failure Motherboard failure Any help and direction would be helpful. I plan on calling a professional in my area to do some, if not all, of the work necessary. I can replace a few things, but I prefer not to work with black iron/natural gas. Thank you!!

HVACNUT

No codes?

Does it sound like there's water in the inducer assembly? All drains are clear?

109A_5

Dirty flame sensor ? Loose or poor ground for the flame sensor return.

Intermittent pressure switch, loose wiring, partially blocked vent.

EdTheHeaterMan

You may be experiencing a micro-zoning issue. This is when there is a call for heat from one zone that gets satisfied within 3.5 minutes then after a short delay another zone calls for heat and gets satisfied within 3 minutes, and that can go on because that Honeywell control logic does not include necessary logic that will allow for delaying a call for heat from any given zone for a given specified time limit so that another zone may also call for heat and the total cycle can be longer.

There is a purge feature that will allow excess heat in the system to purge after the furnace gas valve shuts off, but that does not do what is needed to eliminate the short cycling that you are describing.

To document this you need to watch the LED indicators of the Honeywell HZ322 and see what zones are calling when the "short cycling" is actually happening. This will confirm that the same zone is calling the entire time or if the micro-zoning problem is the cause since the zone that is calling changes when that "short cycling" event happens. You do not actually need to watch it in person if you have a GoPro camera or some sort of camera that you can set up and forget about it while it records the "short cycling" event.

Since this is not a regular event, and may only happen once in a while, that is my suggestion. Then you can see the results in real time when thermostats from each zone are calling at the same time and when they may be calling at different times. Once you have confirmed (for example) that the same zone thermostat is calling the entire time as the "short cycling" event, then you will have eliminated the Micro-zone as the problem.