Honeywell T4 PRO stat problem

FDNYRETIRED

It says in the manual and on the internet. Compressor protection feature is engaged. Wait 5 minutes for the system to restart safely, without damage to the compressor. My problem is that the heat on, it never stops flashing. I have set the ISU parameter #387 to 0 min and the default which is 5. Two T4 PROS which are hooked up to two modine hydronic 33,000btu garage heaters. Both of them are doing this which is strange.  It is zone 3 with a circulating pump. Stats are controlled through zone valves and Taco controller. Separate 24v transformer for that zone. 

Only way I can get the heaters to turn on. Is remove the stats. Wait till they stop flashing. Then put them back onto the wall. It will run maybe 3 min. Not even get to specific temp. Heat on starts flashing again, and heaters turn off. I have The R, W and a C wire hooked up. I have voltage to my Taco controller, transformer, circulating pump and zone valves. I have only had them for a week and now it's 20° out they aren't working the right way.  Navien 240E mod con boiler with 2 other zones and nest E's working with no problem.  Outdoor reset on. I sent a email to Honeywell customer service.  

Any ideas what it could be. 

EBEBRATT-Ed

Simple test to make sure there are no other issues is to jump R & W on the stat. I assume it runs fine when you do this?

Not familier with the stat I read the manual quickly. They don't tell you what you need to know. I see no setting for system type (steam, hot water, warm air or heat pump etc.)

The only thing I can see to try is the "System Mode" Maybe if you try Auto or heat or emergency heat it will work.

I can't see why you have to wait 5 min for a compressor delay when you don't have one but how will the stat know if you have a heat pump or not

HVACNUT

Are the T4's set up for heat pumps? That's the only reason compressor delay will show on a heat call.

EBEBRATT-Ed

@HVACNUT maybe he has the wrong model stat. The Honeywell manual I read was far from clear

SuperTech

Yeah I would go to the installation settings and set the cooling stages to zero. Then you will have a heat only thermostat with no compressor delay. Also I am pretty sure that the thermostat will operate with no delays if they are on battery power only with no common wire connected. I've seen these thermostats have a time delay after connecting the common wire. It shouldn't cause a non stop delay like you mentioned. Somehow I bet those Nest thermostats are the cause of the malfunction. 

Shane_2

Double check the wiring connections, than hook up the T4

Then go into advanced setup options, check heating type (200) and heating equipment type (205)

Link: https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Honeywell-TH4210U2002-Install-Instructions.pdf

EBEBRATT-Ed

@FDNYRETIRED what @Shane_2 found is correct. I think if you find those settings it will work. Probably set for heat pump now. The manual above will show you the changes needed

FDNYRETIRED

I have the installation Instructions and the User Guide. I have model TH4110U2005. on the ISU options my 205 is set to #2 High Efficiency Gas Forced air. My 200 is set to #1 Conventional Forced Air heat. Then it hit me I had the installer hook up the C wire for me before he left. I asked him to do it, so I would not have to be changing batteries. We never tried it with the C wire. So I just removed it and the Heat on stopped flashing. It took about 5min but they turned on. So maybe it can't run with a C-wire? Which doesn't make sense. I actually don't want a program set up, because I just want to keep the garage and Storage space at 45-50*F unless I go down there to work. Just basically trying to keep my pipes from freezing on those really cold days. I have a complete home water pressurized fire system, and my regular water lines. Which are wrapped but I can't take chances. Since I have 8 smart flood vents and they really don't seal that good. Even with the covers over them. I will let you know if removing the C-wire did the trick. Thanks it was 35*f in the garage part and 43*F in the storage when I just went down this morning.

FDNYRETIRED

SuperTech said:

Yeah I would go to the installation settings and set the cooling stages to zero. Then you will have a heat only thermostat with no compressor delay. Also I am pretty sure that the thermostat will operate with no delays if they are on battery power only with no common wire connected. I've seen these thermostats have a time delay after connecting the common wire. It shouldn't cause a non stop delay like you mentioned. Somehow I bet those Nest thermostats are the cause of the malfunction. 

My Nest E's have given me no problems. Since I installed them. They have no C wire and the lithium batteries are staying at 3.86v. Even after not running all summer, but only problem I had was losing Wi-Fi connection twice last winter. I have two other Nest Google stats which I got through PSEG with a automatic rebate. But they run off 2 AAA batteries. These need a C-wire, which is why I asked him to hook it up. If in the future I want to use them. Now I know why they were only $40.00. Compared to the Nest E's.

EBEBRATT-Ed

@FDNYRETIRED

Let us know how you make out with the nest"s with no C wire. From what we have seen the internal batteries stop charging in the "power stealing mode" and end up needing a C wire


Maybe on your Honeywell stat the other end of the c wire is not hooked on a common

FDNYRETIRED

I pulled the common off the transformer 24vac. But it's weird In the installation instructions pg 3 UWP Wiring terminal designations. It shows and says. 

C-24VAC common. For 2 transformer systems. Use common wire from cooling transformer. But since I don't have cooling and one transformer. I pulled power off of that one. Now I have a Taco SR502 which runs my zone 1 and 2 which were the orginal set up. There is a C connection in there for 2 common.

The one for the 2 modines which was just installed uses a Taco SR 501. Plus the 24vac transformer and 2 Honeywell zone control valves with a Grundfos pump. I took the 2 c-wires and spliced it onto the 24vac transformer that has a letter C on it.

FDNYRETIRED

So here is an update, Honeywell sent me a email to contact Resideo Product support. I called and the first tech told me to check voltage. Once I told her I had 26.9VAC across the load to Common. At transformer and also at the stats at the R and C terminals she had me change
(#ISU 220 to O). Which is Cool Stages/Compressor stages 200=Conv/200=HP. Also once that was done (#ISU 387 to 0). That's the compressor protection. So now it should show no compressor or compressor protection. Turned stats back on, and still Heat on flashed with Common hooked up. Removed Common and it worked.

Called them back and got another tech. He had what I did, and was surprised it registered heat on flashing. He suggested I change
(# ISU 200 Heating System Type from #1 Default Conventional Forced Air Heat. To #3 which is Radiant Heat.)
(# ISU 205 Heating Equipment Type from default #2 High Efficiency Gas Force Air. To #9 which is Hot Water Radiant Heat.) Which also cut out (#ISU 230 which is Fan control in Heat from Default #2 Thermostat controls fan.) So that cut all that out from changing anything in some other # ISU adjustments. I turn it back on and common attached the Heat on flashes and the heater fans do not operate yet. Disconnect it and they work.

Guy was really nice and told me to remove batteries for 30min, and then hook it back up. Reset Date and time and first try without batteries, and then with batteries. No joy When the Common was hooked up it caused the heat on to flash and heaters not work. So the Tech said call the installer and tell him I have two defective stats, and it is most likely the sensor. The other strange thing is. If I remove the common from the source at the transformer. But I leave them attached in the thermostat, without power the Heat only still flashes. I have to remove the common from the connectors at the thermostat also for the heaters to work.

So I called the plumber up who did all the work at 3PM, but have received no call back from him about what the tech told me. It really doesn't make any sense that both stats would have this problem. Now I am afraid to hook up the Google Nest stats. Because I have no idea what the problem with hooking a common up could be. I see no way it could be shorting out. especially if my voltage meter shows it is working and I have current.