I was hoping to control this unit with a crestron control system (system integration) and the Crestron communicating thermostats. I am told by crestron that this unit has a variable speed fan and that their thermostat would not work.
Will Aprilaire communicating thermostats control variable speed blowers on Bryant and Carrier FV4 series units?
Is there some work around for variable speed units to be controlled by external integrated control systems? Anyone had some experience (1) integrated whole house control systems and (2) use of variable speed fan unit, specifically the Bryant FV4?
Yes, either of these thermostats will work. I believe the FV4 is a simple two stage control scheme and doesn't use the infinity control system. (If I'm wrong someone correct me, please). If it does use the Infinity controls Carrier has something cooking too. The only sticking point will be whether they release the protocol.
The Crestron and Aprilaire 8870 are single/two stage t'stats. I hate the 8870. The temperature varies too much from the SP and the deadband and cycles per hour can't be set. Also, the 8870 is usually powered off it's own transformer, although it doesn't have to be. If that transformer fails you loose all of your t'stats.
The Crestron CHV-TSTAT is pretty good with the latest firmware and if the communications fails the thermostat keeps going.
If the current t'stat is a thermidistat, you will loose the dehumidification feature.
Any good HVAC company should be able to help with the connection of the thermostat to the unit.
See my past post on Communicating Thermostats.
Every seems to be hung up on the "Variable Speed" Fan!
Because of the Variable speed fan, Crestron says it won't work. The HVAC guy is not much more encouraging. I have used it on the FX series Carrier unit but not the FV. (apparently Bryant and Carrier are the same unit) I am told that the Air Handler takes it's command for the variable fan from the thermostat, and has something to do with Humidity controll by turning the fan on "low" to dry up the humidity....or something like that.
Is the variable speed fan that important? If crestron, or aprilaire won't control the variable speed fan and send the unit the command it's looking for, how will the air handler react? Will it just turn on the fan on high?, not at all? and will it affect the overall operation of the unit? How big of a deal is the dehumidification feature? How is humidity usually dealt with if the humidification feature is disabled, or doesn't exist at all?
As you might can tell, I'm kinda in a pickle and looking for a way to confidently say the Crestron thermostat(firmware V2) will work fine. Hopefully based on information from someone who has proven it! thanks Rob! You've given me more encouragement than I've had all day.
The HVAC guy is going back to Bryant to get some more info. I am curious to see what they come back with.
I replied in the other thread to the original questions.
To the point of dehum, the Carrier control is looking for a lack of 24V on the DEHUM terminal to slow the blower. Simply put a dehumidistat between R and DEHUM to control this feature if your Crestron can't do it.
You could just put a jumper between R and DEHUM and have full fan whenever system operation is requested by the Crestron control.
It's not a big deal. Plenty of FV air handlers running without a dehumidification control.
Just to keep from posting in two threads, I'll reply to your other questions here:
Go to this site: http://www.commercial.carrier.com/co..._SIT12,00.html
Download the installation manual for the FV. Look on page 7, 8 or 9.
Then, go here: http://www.commercial.carrier.com/co..._SIT12,00.html
Download the FX installation manual. Again, look on pages 7, 8 or 9.
You will see that there are a couple more terminals on the FV...DEHUM and Y1.
I'm going to presume that you generate 24V outputs with your Crestron system to control the FX. Same thing needs to be done for the FV. As I state earlier, the FV is looking for a lack of 24V on the DEHUM terminal to trigger the slower fan. Notice the jumper in the wiring diagram that needs to be removed IF you are going to dehumidify.
Read the FV manual starting on page 14 to understand the dehumidification function.
If the Crestron can't do the dehumidification function, then follow the earlier post. Dehumidistat between R and DEHUM or keep the jumper installed.
So there is your answer. The Crestron Thermostat is just a regular 1 or 2 stage thermostat. It has the same wiring as any other thermostat plus the cresnet and the external sensors. Crestron assumes that the A/H uses proprietary controls for the V/S function. It does not. The A/H you are talking about is a variable speed but, it runs at a set speed for 1st stage and a set speed for 2nd stage. The thermostat only controls whether 1st or 2nd stage is activated. You shouldn't have any trouble. The CHV-THStat will also control a humidifier via 24v switched lead.
Fire up the simpl and get to work!!!
Also, see the literature jr Linked to. You'll understand the A/H a little better then.
For the curious, here is the Crestron thermostat literature.
"FE" units and Crestron Thermostats?
Now that I've just about mastered the FX and FV units, what about the "FE". It's kinda of ironic, the last 3 contracts we've signed over the last 3 weeks have all wanted to integrate HVAC, but all 3 have been a different model. Can I assume the FE will work since the FX and FV family can use the Crestron Thermostat? I saw mentioned here that the the FE uses a "Communicating Thermostat". Does that mean it is a proprietary thermostat and thus will not work? The installation manual for the FE looks a little different.
Thanks for the help.
[Edited by avdesign4u on 06-02-2005 at 10:42 AM]
FE won't work with your Crestron product unless something has been released by Crestron.
FE uses a 4-wire communicating thermostat...User Interface...and a communicating variable speed motor...GE ECM 2.5. It ain't the same ol' stuff.
If Crestron has released a module to make it work, you'll need to see their website.