Running a Dehumidifier and AC Dehumidify Modes using an EcoBee and a Relay
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- Опубліковано 8 вер 2024
- Bryan teaches the Kalos techs the art of running a dehumidifier and AC dehumidify modes using an EcoBee thermostat and a 90-340 relay. The 90-340 is versatile and quite user-friendly, making it a great option for this task.
The 90-340 relay has two sets of dry contacts, which don't have a connection to a power source. Energized or "wet" contacts DO connect to an electrical source. The contactor coil is an electromagnet that energizes the relay and pulls in the contacts; when the contactor isn't energized, the path between 1 and 2 or 4 and 5 is normally closed. On the flip side, the path between 1 and 3 or 4 and 6 is normally open when the contactor coil isn't energized.
For the contacts to work as they're intended, they need to be wired as a switch, not a load. When you have a load, you need a power supply and a common for work to be done. Switches only exist to make or break a circuit.
When we use an EcoBee or smart thermostat (with humidity control) with a dehumidifier or an AC with dehumidification mode, we would connect ACC+ straight to DEHUM (DH). (ACC+ is an accessory terminal that we can program.) Dehumidification mode on AC systems lowers the fan speed. When we don't use humidity-controlling thermostats, we would use a jumper between DH and R at the terminal block to energize DH all the time (and NOT dehumidify).
Using a 90-340, you could connect the thermostat (ACC+) to one side of the contactor coil and back to common on the other side of the coil to make the circuit, forcing the system OUT of dehumidification mode. Under these conditions, the contactor coil would be energized and take the system out of dehumidification mode.
When we use an actual dehumidifier, we have to take a 24v signal from the dehumidifier transformer and energize the DH terminal to turn the dehumidifier on. Dehumidification mode for a dehumidifier is the opposite of dehumidification mode on an AC unit. On a dehumidifier, DH must be energized, whereas it must be NOT energized in the case of AC dehumidification mode. We need the relay because we need a set of dry contacts, and it allows us to work with a separate transformer: the dehumidifier transformer. When we wire a dehumidifier to the relay, we want to make sure we just have 24v out and back in.
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Always interesting even for a 40+ year tech
Good training. Excellent way to start a week of work. Hot coffee, techs gathered around and some important info to broaden understanding before you send the crews off to conquer the known universe. This is a great business practice....
Great profile pic
I remember when you posted this on FB asking for input on how to wire this up.
In commercial and in my opinion RIB makes the best relays. Both AC and DC volts can be used.
I don't feel like anything beats the classic din rail mounted socket and relay. Screw terminals are more user friendly and nice for use with meter leads.
I needed this exact thing. Thank you!
In South Texas we install carrier dehum systems all the time and use ecobees we do them quite often
What is the average indoor humidity level with the carrier dehum system vs without?
I love your classes! Can you do a class on changing out oil on a Copeland compressor. Thanks
Where were you guy's when I started?🤔
Thanks again for the videos!
🥃🥃🍺🍺🍺🎳⛳
Stay safe.
Retired (werk'n)keyboard super tech. Wear your safety glasses!
Good 👍
What do you use to make your diagrams and animations? It's very nice.
any online class or course for control wiring/bms?
Hi , i live in iran and my english langwich is very bad , but i see your video and my job is cooling systems . Plase i wants compllitly informishen about dehumidiflers systems . Thank you very much for your helps
We use the Pro T855sh. There is no need for an intermediate relay as the thermostat has both dehum and hum terminals that get directly connected to the unit. The dehum terminal can be set for NO or NC as not all units use constant energy for normal operation on the dehum terminal, we use to use the intermediate relay when the furnace had a PSC motor by simply using 2 fan speeds on the NO NC terminals but I am not sure why you are using a relay on a variable speed blower with a dehum terminal as the thermostat, at least the T855 has the relay built into the thermostat.
What does the stat control first Temperature or humidity?
Thanks
@@JohnnyJr396 HUMIDITY
@@anthonyspadafora1384 thanks !
What are y'all using for stand alone dehumidifiers, wall mounted controls?
I bought a YMKE60BNJMFMO-X york package heat pump and it's got a Dh terminal, so that would go directly to the * terminal in my nest learning thermostat?
Can you hook up a humidifier and a dehumidifier on a echo bee using this relay method
Will the acc+ won’t let cooling work if you install a 2stage Honeywell?
On stats with Dehumidification, what will the stat control first humidity or temperature?
what would the wiring be for single speed hvac and stand alone dehu? I have a fresh air intake on it's own relay... trying to figure out how to wire this up. basically 2 accessories. (dehumidify & fresh air)
Hi. Did you figure this out?
@@LastBlackStone not really. I ended up getting a whole new system lol
@@enkrypt3d oh ok. I guess I will need to do the same. Called bunch of local hvac technicians and none of them can do it
@@LastBlackStone there are ways to do it with a relay but I dont think the ecobee can do multiple accessories....
I am running a santa fe dehumidifier with my single stage system and I am using a PRO 1 thermostat. It is a lot simpler then using the Ecobee. I just have a control going from the dehumidifier terminal & common from the thermostat going to a relay. The dehumidifier 24 volts is running through the normally open contact of the relay. The thermostat is setup that if the A/C isn't running, then the thermostat will power the relay if humidity gets above 50%.
You normally do a really good job explaining concepts, this was not so good.