Desert Springs Wiring to Hydronic System

Purchasing a Desert Spring humidifier this weekend. I know where it will go but I do not know how I will wire it. Here's why. I have a Burnham oil fired furnance on a hydronic heating/cooling system. So, I have a First Company Model 30MBX-3HW (2.5 ton) vertically mounted air handler. The link is here: http://www.firstco.com/products/mbxb_hw.asp.

There are no connectors on either the furnace or the air handler for a humidifier connection. I have a hard copy of the wiring diagram but it is not on the website. I opened the unit and I can confirm there are no connections labeled EAC or HUM. There are no such connections on the furnace since it is a forced hot water unit.

Ideas for wiring a humidifier onto/into a hydronic system?

 

You have a heat coil in the air handler . So wire it in too the blower control there.

 

Ed, in my system a forced hot water pipe comes into the air handler (hydronic) from the furnace. I do have a wiring diagram that does not call out a blower control. If I could get a picture of the wiring diagram posted would that help?

To be honest, the diagram is a lot simpler than what is really in there. There is a mass of wires in the air handler.

 

There should be a wire schematic On the door of it. You can wire it to .Or you can get a A50 this will slip over a blower wire and can turn the humidifier on when the blower comes on.

 

You'll have to use a A50 or sail switch with your air handler, I had a guy about a month ago with the same air handler as you.

I am concern about the lack of humidity that this style this may not be able to do for you with the lower air temp.

 

Thanks for the replies.

Jay, what do you mean "lower air temp?" Curious about that since these humidifiers get installed into the make-up air ductwork which is cooler. What would you recommend for a DIY humidifier if you don't mind me asking?

Here is my wiring:

 

It depends on what the boiler is set at, and/or if you have an outdoor reset control that controls the water temp in the boiler when it gets at X˚ outside, the water is X˚, and will go up as the temp gets colder outside or lower as it gets warmer.

If not, what is the air temp coming off the coil most of the time?

Most retailer carries Honeywell, and that is what I have on my own, and works out well.

Your system does not have a book up, and if you go with the A50, have it wrap around the black wire down in the blower.

 

I do not believe I have an outdoor reset control but I will check.

I am not sure if I can read the air temp since it's a forced hot water furnace. I can read the boiler temp/pressure but that's it, I believe. There's nothing on the air handler that reads temp.

Thanks, Jay. Which of the several black wires (in my diagram) in my air handler?

 

You would have a digital board near the boiler with an outdoor sensor going outside.

You can, stick a temp probe like a meat probe and take a reading after the unit has been running 5-10 min.


Black wire from the blower motor in the blower section.

 

Dont sweat an outdoor control here on your unit. They are to slow to work good anyhow.Just put that A50 around a blower wire and it should come on anytime the blower runs. Now dont forget that the power to it should go through a Humidistat then the A50 then to the humidifier. As to low air temp I dont know what it is over that coil. It just dont pick up as much humidity as hot air will. I think if you look on the boiler most are set at 160o on and 180o off for the water temp in the boiler and 12 to 15 psi for one floor and about 18 psi for 2dfloor . So what temp you have at the coil is hard to say.

 

I've tried calling a bunch of local plumbing and electrical supply stores to buy an a50 and nobody sells it. I spoke with one Aprilaire retailer and he has the a51 only. He does not recommend them because he finds that they do not always work and/or you have to wrap the wire around the a50 two or more times.

He felt that the humidifier could somehow be wired with/to the existing air handler so one does not need an A50. But he also insisted that to do this you need a bit of knowledge of electricity (or his services).

Do most people purchase the A50 online?

 

Most of the people gets the A50 on line..

Could wire it some how on the air handler, but I wouldn't advise you to do it.

 

Jay, I do not believe I have an outdoor sensor. I checked the air temp (granted at a floor register) and it was 125oF so it is likely hotter than that coming out of the air handler. Boiler temp on the furnace is 195oF.

 

You should be OK. The boiler temp is pretty high to my liking.. 160˚ to 180˚ is good.

 

I may have found a solution to how the humidifier will turn on and off. It may be too simple. As mentioned I have forced hot water heat: 2 zones and hot water. When the downstairs zone requires heat the valve for that zone is actuated with 24V. I confirmed with a tester. If I simply power the humidifier off these 2 connectors on 1st zone's valve (there are 3: 2 red wires, 1 white) the humidifier works. When the heat turns off the voltage is no longer between these 2 connectors. I tested this with the humidistat and humidifier motor. Can it be this simple? I did this motor test a few times and everything works fine. I know I am not using the proper terminology in my description but with this approach the humidifier will turn on/off with the heat.

Is there something wrong with this approach?

 

You could do that of "stealing" the power from the t-stat (your case zone control) to power up the humidifier.

As long the transformer is strong enough to support you are good to go. Sounds like it is able to support it since you've already have done on another zone.

Going to do anything about the boiler water temp?

 

The humidifier is installed now and works fine so it looks like my power "theft" is fine. Installation was actually straightforward. I upgraded a few of the pieces that came with the humidifier such as buying a real 6" aluminum section of ductwork, copper tubing for the water line, etc.

What do you suggest regarding lowering boiler temp? I went through the furnace's owner's manual and found nothing on adjusting boiler temps. Am I missing something?

 

It should look something like this.

Honeywell is a pretty common one out there.

When you take the cover off, should see some dial .. report back what dial is for and settings.

 

Jay, I'll be darned. There is a shiny metal dial in there. In front of it there looks to be an arrow facing left. If so, it is set at 180oF. Does one simply turn the dial down to 170 or is there a set screw to do this?

Thanks (again).

 

Yeah, you can turn it down to 170˚. Is there a diffretal like 10˚?

 

Jay, there is a 10oF differential. So, turning the dial to 170 should be quite easy. Thanks.

 

Then you are good to turn it down.

Some time people get that turned around thinking setting it at 180˚ will turn on when its reach 170˚.

 

Jay, the minimum temp setting on the wheel is 180. That is what the present setting is so I cannot turn it down any further.

 

ok, Looks like 180˚ is it then.

Also, make sure your boiler pressure is around 12 to15psi, 18 for two story home.

Have a great day!