Aprilaire 760, Bryant 340MAV 060 & New Aprilaire Model 58

I've got an older 760 that I don't think was ever used by the previous owners so it's relatively young. It is plugged in to a service outlet adjacent to my switch/disconnect for the furnace. It is operational and when I turn the old humidistat it starts up with out an issue. Though it never seems to turn off unless I crank it back. Perhaps I never let the humidifier do its job to get the levels up. Besides this point I wanted to install the new auto sensing Model 58 to use the outside temp to determine when/how the humidifier should run.

The Bryant has the HUM terminal and then it's standard Com W Y R G. Also there are the EAC-1 and EAC-2.

Condenser two wire off the Com and Y, Thermostat off the W Y R & G. I know nothing here to affect the humidifier just info i guess.

Existing Aprilaire manual humidstat white and red wires are wired to the 760 leads that clearly have a tag stating not to connect to line voltage. These go in to a wire harness inside the 760 and come out as yellow wires to the solenoid. So it's not tapped in to the furnace controls at all currently.

I am just looking for the new model 58 humidistat to operate while heat is called for (for now) as the water line is tapped off the cold water not the hot as I have seen suggested for a call for the humidifier when just the blower is on w/o heat.

I'm proficient enough to install if given a bit of clearer direction for my specific furnace. I just can't figure it out. Do I need a transformer? If so where does this connect to on my Bryant. I will thank you now for any assistance provided guys!

Am I looking to wire such as this : Perhaps #3?!?!??! I can't wire to many things to the Common can I? This is just similar to the white commons in regular electrical wiring right?

Aprilaire Humidistat Wiring Diagrams

 

yes, Diagram #3.... wire it exactly like that

 

Thanks for the confirmation!!!

 

Well after trying that diagram I think after looking at the installation manual for the Bryant it states this:

2. Humidifier (HUM)
A quick-connect terminal (HUM) and screw terminal (COM 24-v) are provided for 24-v humidifier connection. (See Fig.30.) HUM terminal is energized with 24v (0.5-amp maximum) when gas valve is energize.

So the HUM is energized with 10V during regular standby non operational times. Meaning I think I will need to use the EAC1 & 2 which are energized with 115V full time and add the 24V transformer correct?

I checked a few of the other terminals on the furnace control board are there are no full time 24V options that I could attach to.

 

you dont need full time 24V you were trying to make it so it only ran with heat, the only way to do what with a 760 is the way we discussed which will shut off the HUM including the humidistat while it is not heating. why did you not just wire the way that was discussed for diagram 3?

 

also a quick question, during the blower operations the Hstat works but then gives me an E3 error which means the outdoor sensor has an issue. I have to extend this connection as the sensor lead was only three feet and I have a 15 foot run or so from the stat up in to the attic and out the eave. Perhaps the extended lead is fouling up the sensor?

I did use solid copper stat like wire where it looks like the sensor lead is aluminum? Would this be an issue? I checked the impedance over the wires and it did not relate to the current outdoor temp. Manual state a bad sensor. I'm not going there yet. Sensor is not in the sun etc....on a West elevation and under the eave out of the sun so no issue here. I will try and check the impedance on the short 3' lead and check back with results.

 

Sorry, you are correct, I did wire it that way, and OK, I'm thinking the stat needs to be on constantly. So if I think a little more about this, my Tstat will call for heat thereby energizing my Hstat, once the blower comes on, letting it check outdoor air temp with the sensor and sensing the return air levels and will then energize and activate the Humidifier if necessary. This sound about right? Perhaps my mind was thinking this Hstat had to be "On" all the time. Not so or more not so in my case?

 

correct, it does not need to be on all the time. If the outdoor sensor does not correspond correctly via the resistance reading then you need to check it at the first junction to your extension cable. If it is still wrong there then the sensor is bad, if not it could be in your extension cable. BTW, sometimes if you run these cables next to high voltage wiring it will distort the signal. If this is the case you need to use shielded cable

 

Funny, I was actually using a shielded cable but was no where near voltage. Anyways it was an 18ga solid copper that I was using, maybe it was the junction or the wire as I replaced it with some stranded 22ga alum communications wire and the resistance reading matched after I rewired. Tested at the 3' lead and the extra length before tucking it in the ceiling. :-) So that part is good to go!

Now back to the Hstat and the humidifier. The humidifier is not kicking on. I can short it by touching the two leads together but when I connect from the Hsat off the H twin terminals nada. Once HVAC calls for heat I read something like 23.3V at the R & C terminals. So we have voltage there check. Then checking down at the H twin terminals I read something like 26.8V or so there's voltage there! I've also attempted to put it in to manual mode not using the sensor and just turn it up and nothing. Also when putting the Hstat in to test/reset mode, green light comes on the stat and nothing comes on for the humidifier.

Note that I can get the Humidifier to kick on when reconnecting those lead back to the old manual humidistat and turning it up to 40% or beyond. So is there something I'm not seeing here? :-)

One final note, all of the above was done and then at some point while the furnace was on the stat was in test I think some very "loud" and weird noises came about and it sounded like it was going to kick on but then I noticed a little smoke coming from the nice new Hstat. I quickly shut it all off as I had not idea what was going on and did not want to fry the Hstat board.

After that incident the voltages all check the same but nothing as far as activating the humidifier.

Who knew this could be so difficult!

 

is the mode switch set to B? Also, I actually read the instructions that came with your Hstat and they are completely different from those listed on the alpine page that you had linked before....

Follow this wiring diagram. R and C come from R and C on the control board of the furnace powering the Hstat all the time. Make sure the mode switch is on B.

 

OK, R to R C to C and I've got power to the Hstat with no furnace operation. Great! I connected the other setup as noted, the HUM to W/G and Cf to the C on the Furnace Control board. I did not have time to fire up the furnace for a call for heat test but I did turn the Hstat to test/reset and the green light flashes and nothing kicks on on the humidifier. Drats! I will test with call for heat after dinner. But we're getting closer. Weird thing is that I continue to get readings at all terminals and they are coming in within the tolerances. Grrrrr. And yes I am on Mode B :-) thx for thinking everything through I know sometimes its something staring you straight in the face and it takes someone else reminding you to check X and ta-da......thanks for all the help to date!!!!!!

UPDATE: We are a go! Went for the call for heat and bingo, all systems go. I will update if I have any major problems or how its operating once winter really hits. Albeit this is installed on the upstairs secondary furnace it was more a trial run for installing either another 58 stat on my old beast furnace that feeds the first floor with a new humidifier. Though I think I might swap the new one for this furnace as my beast has returns under the slab making it nearly impossible to install a humidifier that does not have a fan. I'll test how it works on the bryant before moving it to the old carrier. Thanks again for ALL the help!!!!

 

no problem..... that site with the diagrams kinda screwed you there for a min. They drew those diagrams for the old Hstats and did not update them for the new.