Honeywell Tru Steam humidifer

Steve Ebels_3

I'm trying to install one for a customer with an old oil furnace. Knowing that the furnace has no fan control except the fan/limit, I specifically asked the distributor if the humidifier had relays to make the blower function correctly. They said if I bought the humidifier that came as a kit with the equipment interface module I would have everything I need to make it work.................Right............



So, I've been through all the tech guys at the distributor plus two different people in Honeywell "tech" service and they haven't been able to give an answer as to how to wire this thing up. It appears that i will have to field engineer it myself but I can't even get a straight answer from Honeywell regarding what terminals are powered and what ones are dry contacts. Different answers to that question from two different Honeywell personnel. Getting a little frustrated and so is my customer.



Anyone worked with one of these and integrated it into a system lacking normal  R,W,Y.G,C contacts ?



Anyone know of a particular person I could ask for at Honeywell that actually knows what they are talking about?

Bob L_3

Honeywell rep

I can't image it being too hard to field modify, I don't have any wiring diagrams on me for it. Our Honeywell rep is Gary Crosby, he's a smart guy who used to be a serviceman himself. I'm sure he would be more than happy to help. I believe he is located in Indiana.

Good luck with it, I haven't really thought about your application coming up before so I' curious myself.

Paul Fredricks_3

My take

I don't think the truesteam has a relay for the fan, I think you'd need to add a fan center. It does have terminals to energize the fan center.



In this application I think you'd want to use the TrueIAQ humidistat from Honeywell. That way you can schedule when the humidifier/fan will run so that the occupants don't feel the cold drafts. If they are out during the day schedule it then, or else at night while they sleep.



The TrueIAQ stat uses the 2- 24v and the HUM terminals, R and C go to 24v on the fan center, and Gf operates the fan center, telling the fan to run.



Pretty sure that's it. Variable speed blowers are nice as they can run at 50% speed to humidify. A mutli speed DD motor can kind of do the same thing. I am assuming you have a belt drive blower, so you are stuck on one speed.

JStar

Wiring.

I can't find an installation manual to give you an exact, detailed answer but I have done this before.



 To only have humidity on a call for heat: You can set up a relay that closes on a call from the thermostat and wire the normally open contacts in series with the humidistat to turn on the humidifier.



You can also set it up to come on with any use of the fan, but you might have to cut into the blower wire leads; and set up a relay the same as before with the blower wire energizing the relay coil.

Constantin

IIRC, that's an RS485-based system...

Carrier and others have competing products that don't play nice with it. The RS485-based approach is nice in the sense that you can pass lots of information back and forth on just two data wires and the other two are for power. The honeywell stuff unfortunately is not part of the climatetalk alliance (IIRC), so by default you'd probably have to use a honeywell thermostat to talk to the humidifier.



I'm unfortunately in a rush right now out of the house for a work day, otherwise I'd try to hunt down the details for you (I have some business cards from honeywell from the AHRI show).

TonyS

Aprilair uses a induction

type relay that clamps on to the fan speed wire.  They are easy to use and work fine.

Big Ed_4

Humidifier

Tru Steam unit ?? Does it take long for it to make steam ? Would you like it to run just on the heat cycle ? Then the mentioned clamp on Amp switch connected to the blower lead could work .... the amp switch would be tied in after the unit control .. on the humidistat circuit "Hum " If you want it to work independent of the heat cycle , you would need to add a fan switch so the humidifier can control the fan ...

TonyS

Here is a schematic of this relay

http://electronicaircleaners.com/aprilaire-51.aspx

Constantin

How about page 16...

The manual does have a diagram on page 16 which illustrates how to wire the thing independently of a furnace. I wonder if the illustration there would work for you, i.e. power the fan independently of the furnace. To make it safe, wire the 24VAC power supply for the external fan relay into the mains power supply for the furnace (or perhaps the furnace can supply the 24VAC power already, who knows). That way, if the power to the furnace is cut, the power to the fan is cut also, regardless of who/what is calling for power.



The truesteam unit does seem to have lots of interface options, modern and legacy. I'd definitely wire the air flow sensor also, to ensure that if someone turns off the furnace that the TrueSteam does not condense up the ductwork.

Steve Ebels_3

Got it going

I had to add a fan center and use G from the humidifier itself to bring on the fan during humidifier only operation. R&W run from the equipment interface module to the TT on the burner relay. It took about 3 hours of phone time and in the end, it was the tech guy at Johnstone that waded through everything with me.

HW tech support on this product was a bit of a joke. The lady I talked to first could not understand how the furnace fan on the old ThermoPride ran off the fan/limit control. I even gave her the Honeywell part number of the fan limit and she said she had never heard of such a thing. The guy I spoke to after her went through a whole lingo about how the TruSteam is made to interface with an electronic type fan control and wound up saying "that's your problem". I wonder what they get paid?  

geno54

Opinion

Steve - Would like to hear your opinion on operating the humidifier while running the fan. I recently installed one this way (which is the preferred way) and got complaints from the customer about the drafty feeling. So I rewired it and set it to run only when the furnace is on. Furnace is constant speed not variable. Not the best but it does work. 

Constantin

Could see that happening...

... especially if the ductwork is running through unconditioned space. Good point!



Most humidifiers are meant to only operate in conjunction with a hot-air appliance, presumably to increase the ability of the air to uptake the humidity (from evaporative, etc. units), to decrease puddling/condensation, and to minimize comfort issues.



Most of the time, the need for humidification and heating should coincide, so this approach is likely to work fairly well. I.e. the colder it is outside, the less water vapor the outside air can carry, ergo the lower the indoor RH as outside air infiltrates. At the same time, the heating system is running more often to keep up with the heat loss.



The only potential disconnect here is a vastly oversized hot-air system that can satisfy heat demand so quickly that the humidifier can't keep up. Additionally, if the house has had the opportunity to dry out for a while, the humidifier may be running for over a week straight to get vapor everywhere - see the instruction manual.