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Brian HVAC Guy
Brian HVAC Guy, HVAC Technician
Category: HVAC
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Experience:  I have been an HVAC/R mechanic/technician for 30+ years.
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I have a Honeywell HZ311 on my central a\c unit, the only thing

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I have a Honeywell HZ311 on my central a\c unit, the only thing that works is when the thermostat is in the fan only position the fan runs. In cool mode nothing happens.
Thanks ken

Brian HVAC Guy :

Hi, I'm Brian. I'm here to answer your HVAC question to your complete satisfaction! I have worked on a great deal of Honeywell zoning systems but never the hz311 but I have looked up the documentation and thought I might be able to help.

Brian HVAC Guy :

What is the brand and model heating/cooling thermostat connected to the HZ311 controller?

Customer:

Hi BrianI am not sure but I will find out, this unit just stopped working last week. When the thermostat is set to cool the damper for that zone opens but the air handler or compressor wont start. hope that helps.

Brian HVAC Guy :

Yes but you say that if you put that same thermostat on "fan on" the fan comes on so that is a bit strange. If I understand the 311 correctly if any zone calls for cool that zone damper should open and the system should call for fan and cooling. Because the fan comes on that tells me the air handler is fine and the control circuit should be fine for the cooling. If you have a voltmeter that can read 24-28 volts ac and a couple of jumper wires we can probably narrow down the problem to the suspect component.

Customer:

Yes I have a voltmeter what should I jump?

Brian HVAC Guy :

Ok great. Is your heating/cooling system an air handler with heat, a furnace with a coil or a heat pump?

Brian HVAC Guy :

Well regardless of system type, with all your thermostats turned off you should check that you have 24-28 volts ac between terminals Rh/Rc and Y, W and G respectively on the terminal strip marked 'equipment'. That will tell us that the control circuit for your heating/cooling system is all intact. You can then jumper Rc/Rh to G and your air handler fan should come on. Jumping Rc/Rh to Y should bring on your compressor outside. If that all works then your equipment is fine and the problem either lay in the thermostat(s) connected to the zone terminal strips or the Zone controller itself. Let me know what you find with these tests and we can go from there.

Brian HVAC Guy :

It almost seems you may be having trouble reading my posts or having trouble with the chat format here. I think it would be best if I switch to the Q/A format where we exchange messages back and forth with a lot more reliability. It is a little slower that is all.

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Ok we will continue our conversation here, exchanging messages one at a time. Thanks, -Brian
Customer: replied 3 years ago.
Hi Brian I'm getting the text but I am on the road right now .this unit is only a/c no heat I will jump the wires when I get home I will sent you the results probably in a couple of hours Thanks for now Ken
Ok Ken that's great. We will figure it out after a while. I'm sure we can get to the root of things. Thanks, -Brian
Customer: replied 3 years ago.
Hi Brian I'm back When I jumper the compressor nothing happened when I jumped the air handler the fan turned on
Customer: replied 3 years ago.
At the compressor I opened the cover inside it looks like the the fan speed control has a burnt spot on it. Can that be by passed? To seeks the compressor is working?
It's hard to visualise what you are talking about but it sounds like there is an issue with your condensing unit for sure. If there is a burnt spot you may not have power there and the control system may be still calling for it to run. What is the make and model of your condensing unit and I will try to get on the same page as you.
Ken, I have to step out for a bit but will check back later. Please let me know what the make and model of your condensing unit it and also it might be helpful later in the process if I knew what the make and model of your zone thermostats are in case there is also an issue on that side of the system. Thanks, -Brian
Customer: replied 3 years ago.
The compressor is a soft sound 1400T model# XXXXX
Customer: replied 3 years ago.
The thermostat is a LUX heat & cool there is no model #. Inside there is TX9000LC
Hi Ken sorry it took so long. I am not seeing anything for the make and model of the outdoor unit. Since you see a burnt spot it is certainly likely that there is a problem out there but it's hard for me to help with that beyond basic steps such as making sure you fix any burnt wires, make sure you have 24-28 volts ac on the two low voltage wires that come into the outdoor unit, making sure the compressor contactor engages with that 24 volt signal, making sure you have 240 volts to the unit available. On the thermostat side the lux you stated is a simple enough thermostat and the 311 is just looking for contact closure from R to G and R to Y so you could jump those same terminals on the thermostat connection on the 311 terminal strip for that zone (probably zone 1) just like you did on the other side on the equipment terminal strip. It seems to me that the control system is working and there is just an issue with the outdoor unit.
Customer: replied 3 years ago.

Ok unable to work on it tonight I will touch base with you tomorrow about the outside unit

Very good I will be here until about 3:30 EST and checking messages after that.
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