RC2000 and humidifier.

[Frunple]

I can't seem to find the post but I recall a thread describing just what I want to do so maybe this will ring a bell for someone here.
I have a powered humidifier on my furnace that runs off a "tstat" connected to the return vent. It has it's own 24v transformer and basically runs completely separate of the thermostat controlled zones.
What I want to do is connect it to my RC2000 so I don't have to go to the basement and turn it on/off/adjust it.
So the question is, what about the separate transformers? Can I just connect to the "main" transformer to use the same 24v? I would assume the RC2000 is going to send the 24v from its source so it would basically be bypassing the humidifiers transformer anyway. Or should I throw a relay in and let the rc controll the relay and leave the humidifier on it's own transformer?
Is there any other options?
thanks!

 

[Frunple]

No ideas?

 

[sic0048]

Personally, if the current system works like you want it to, then I would simply add a relay and control the humidifier off that. But I'm no HVAC expert, so perhaps I am missing something.

EDIT - I also thought that most humidifiers were set up only to run when needed and when the HVAC system was running. There is little benefit to running the humidifier if the blower isn't running to circulate that extra hummidity. In fact, I would think it could cause mold/mildew to grow in the HVAC runs because there would be super humidified air sitting in the runs without any airflow to push it out into the rooms where it would mix in with the regular air.

So personally I would not want to have the humidifier run completely separately from the HVAC system.

Oddly enough, I looked at my parents system when I was there visiting over the holidays and they have their humidifier hooked up to the fan contacts of the HVAC system so it runs only when the HVAC fan is running. I also assume (but don't know for sure), that the humidifier then only runs when it needs to (ie it isn't running every time the HVAC system is on, but it won't run if the HVAC system is off).

 

[signal15]

Ideally, you want to make sure the humidifier only turns on when the HVAC system is calling for heat, not just when the fan is on. They don't do much except waste a bunch of water unless hot air is flowing through them, at least with the panel type. If you have a drum type that fills a reservoir with a float, it won't hurt to keep it on when the fan is on.

If you live in a cold climate, you should really look into a humidistat with differential humidity control. This is where it keeps track of the outdoor temperature and lowers the humidity indoors to prevent condensation on windows, which drips down onto the wood causing rot and mold. I don't think the RC2000 does this. Several companies make standalone humidistats that have this feature, and the only thermostat I know of that does it is made by Robert Shaw. But the Robert Shaw thermostats cannot be connected to a home automation system.

If the RC2000 allows changes to humidity via an HA controller, you could put in rules which would lower the humidity based on outdoor temperature.

 

[honeymonkey]

OmniPro2 setup

I'm basically doing the same thing. My "whole house" humidifier only requires 24vac to power the water solenoid when a call for humidity request. I want to use the humidifier output on the RC 2000 HAI TSTAT to control the solenoid, but I'm not sure where to connect the "humidity" wire from the RC 2000.

I don't mind using a relay off the furnace to only have the water solenoid active when the fan is on if this is needed.

My question is, what connections on the furnace do I use to trigger the 24 vac relay and how does the humidity wire connnect to provide 24vac to the water solenoid?

I would have thought that the Omnistat2 thermostat would have been smart enough not to trigger the humidity wire when the fan and heat was not engaged. I want to do a similar thing with the dehumidifier wire, just in case the outside temperature rises suddenly, I could do something like "When the outside temperture setpoint reaches XX and if the humidity in the house is XX%, then turn on the HRV.

Any ideas for me?

Thanks,
...HM

 

[signal15]

The Robert Shaw thermostats only call for humidity when they are calling for heat at the same time. It won't turn on the humidifier when only the fan is running. I would assume the HAI thermostat does the same.

If the HAI thermostat can only control a humidifier, then your dehumidifier control is going to have to be handled with rules. You'd need to be very careful to ensure you don't program in a situation where both the humidifier and dehumidifier are running at the same time, which means that possibly all of your humidity control should be done in rules, and you can just use the thermostat to pull the current humidity level.

I'm not familiar with the options given to you in HAI for programming rules. If one was trying to do this with the ELK, it would likely result in a very complicated rule set to get things working properly. I think HAI has the "CASE" operator though, so it would make it quite a bit easier to do.

The other thing you need to figure out is the proper humidity level for a given outdoor temperature to avoid condensation. This will probably involve some trial and error, since all homes are insulated differently, and not all windows provide the same level of insulation. You may also have some windows that have lost their seal, or gotten a leak between the panes. So while the rest of the windows in the house might be fine, you could have one or two that still condense water. The best thing to do is to find someone with a thermal camera to walk around and see if any windows have problems. Failing that, you can do it with one of those temp guns, Home Depot has a Ryobi one for $30 that works fine. It's much more time consuming though.

 

[GotHAI]

I'm looking into this Relay thing as well. I read 2 good posts under General/Marketplace/HAI

Omnistat2 thermostat prewire
and Page8 HAI RC2000

There seems to be a common theme where the RC2000 connects to the Humidifier using a relay that will also turn on the fan.

 

[pete_c]

In FL I have a Humistat above the thermostat. It is used in the summer to keep the humidity at a certain level and it controls whether the AC is on or off. In IL I have the humdity control attached to the duct connected to the furnace. It has a temperature sensor outside. The scale on it is relative to the temperature outside. It is an Aprilare - flat plate type. I only use it in the winter and I usually increase it to get a 35-40% relative humidity setting in the MB humdity sensor. I keep my fan going 24/7 and it works with the fan on. In the summer it is off and I run a dehumidifier.

When I mentioned a combo thermostat/humidity controller to my HVAC guru he mentioned it was better to leave the controller where it was at. (in house in IL).

 

[dutchyn]

Here's what I did.

I don't have it wired so that heat and fan both are required: another relay would be involved. Since I'm working with a geothermal air handler, requiring heat isn't that useful: my output duct temperature is rarely above 90F, and never as high as for a gas-fired or boiler-based system.

Chris D.

 

[honeymonkey]

I'm looking into this Relay thing as well. I read 2 good posts under General/Marketplace/HAI

Omnistat2 thermostat prewire
and Page8 HAI RC2000

There seems to be a common theme where the RC2000 connects to the Humidifier using a relay that will also turn on the fan.

Do you have the HAI Omni controller to go with it? If so , I just did one using the outputs on the Omnipro2 and it worked out great.
I used two of the outputs. Once the omnipro decides that the hvac is in heating and a call for humidity is required, it closes one relay to the water solenoid. I used the second output to control the water cycle start time (bypassed the heat sensor) and also used it to "Pulse" the water supply to turn on the solenoid for 10 seconds every 30 seconds, eliminating much of the water that would normally go down the drain. Once the humidity comes up to normal levels in the house, I'll tweak it further for efficiency

I could not see how to do this till I upgraded the firmware to 3.0 which gives you all the new options you require. I was pleasantly surprised that you could also program in energy low, mid, high , critical times which will also change the lcd color display on the omnistat2 to give you a quick visual indication of how much energy is costing at that moment you walk by. This only applies if you are on Smart Meters of course.

If this is what you want to do , let me know and I can further detail the programing, wiring.

...HM

 

[tpboyce]

Do you have the HAI Omni controller to go with it? If so , I just did one using the outputs on the Omnipro2 and it worked out great.
I used two of the outputs. Once the omnipro decides that the hvac is in heating and a call for humidity is required, it closes one relay to the water solenoid. I used the second output to control the water cycle start time (bypassed the heat sensor) and also used it to "Pulse" the water supply to turn on the solenoid for 10 seconds every 30 seconds, eliminating much of the water that would normally go down the drain. Once the humidity comes up to normal levels in the house, I'll tweak it further for efficiency

Which humidifier do you have? Did you have to modify the humidifier itself to control the thermostat? Can you post the programming you used as well as a wiring diagram. This is exactly what I am trying to accomplish right now.

 

[fabriziojoe]

I can't seem to find the post but I recall a thread describing just what I want to do so maybe this will ring a bell for someone here.
I have a powered humidifier on my furnace that runs off a "tstat" connected to the return vent. It has it's own 24v transformer and basically runs completely separate of the thermostat controlled zones.
What I want to do is connect it to my RC2000 so I don't have to go to the basement and turn it on/off/adjust it.
So the question is, what about the separate transformers? Can I just connect to the "main" transformer to use the same 24v? I would assume the RC2000 is going to send the 24v from its source so it would basically be bypassing the humidifiers transformer anyway. Or should I throw a relay in and let the rc controll the relay and leave the humidifier on it's own transformer?
Is there any other options?
thanks!

I had my HVAC guy come in and get creative on how to control the humidifier with the RC2000. You only want the humidifier to come on with heat. His solution was to use a voltage sensor on the exhaust motor-this motor only comes on when there is heat. I have a propane Amana unit that is direct vent. So far this has been working great for the past 2 years. The humidifier is powered via 110 and there is a 24v solenoid on the water valve. I use Haiku to control the humidity as Snaplink does not have the ability to do so. I will post some wiring diagrams and pics of the install.