Found these guys on Amazon and ordered a (cheap) "open-box" humidistat to replace my "faulty" unit. Open-box part arrived quickly but was dead-on-arrival. NA HVAC paid return shipping and sent a "sealed-box" replacement at no charge, how great is that! Turns out that new part, although was working perfectly, did not fix problem. Problem turned out to be a VAC tech who (for some reason) cross-wired the furnace power wires before winter season which cause humidistat output relay to not activate. Reversing the 2 leads (wiring the green wire to the terminal marked "R" at the humidistat) fixed the problem and I put my original unit back in service. Upon attempt to return this second unit, Amazon informs me that I need to pay return postage. I actually WANT the seller to charge me a restocking fee because it should not be a burden to NA HVAC for my mistake.
In summary, this seller, contrary to other reviews, did well for me and I would again buy from them