Humdifier control trouble

[felixrosbergen]

Hi Gents,

I recently got a Aprilaire Hudmifier model 400 installed (profesionally, as per manufacturers directions, manual mode). I also have APrilaire 8870 communicating thermostats and an Aprilaire humidity sensor model 8062 . http://www.smarthomeusa.com/ShopByManufacturer/Aprilaire/Item/8062/manual/

So the 400 series hudmifer has it's control mounted on the return duct in the HVAC room and the sensor is thus in the return duct.

My 8062 is located in the living room next to the T-state.

The odd thing is that the 400 humdifier's sensor reads nearly 10% RH higher than the 8062. Both are supposed to be accurate. I have a cheapy RH meter as well which agrees with the 8062.

So...why would humdity in the return duct read 10% RH higher than the rest of the house? The T-stat is actually pretty close to the return intake as well.

THis has me puzzled a bit. I have the 400 set for it's highest setting (45% RH) but it reaches it..and then the 8062 (which i think is right) only reads about 35% RH.

Any suggestions? I'm considering removing the 400 series control and just putting a relay in and letting Elve activate the humdifier instead...

 

[felixrosbergen]

ouch..no takers? Come on guys. lol

Should i repost in Automation forum?

 

[tmbrown97]

Just for grins, can you put your cheapo portable unit at/in the return to see if it gets the same higher reading there?

Also - have you looked into calibrating your humidistat? I did a quick google and didn't find anything specific for aprilaire, but one post claimed there's a screw inside most of them for adjustment/calibration. Would be worth a little more research.