# New Thermostat & Hydro Air Fan Control Relay wiring Help



## SIERRADMAX (Nov 22, 2013)

My house has older thermostats and two hydro-air fan coil units for both heat (Oil fired H.W.) and A/C (condensers outside). FCU has 4 wires coming out and being used. 

I'm assuming Red is common, White is heat, Green is fan, Brown is A/C. Here's the current wiring schematic.





I've decided to join the 21st century with touch screen, programmable thermostats. Specifically, the Honeywell WIFI 9000. Now, when the wife asks me what's it like outside today, I can tell her to look at the thermostat. Here's what I bought.
http://www.homedepot.com/p/t/203926327#.Uo9m4uIgM7c

I've also purchased new Hydro-Air Fan Control's. I always had to play with the aquastat on the FCU's and could never get them tuned properly. I would always have false calls for heat and often had the fan coils blowing cold air at the end of each cycle. I purchased these guys to help solve the problem.
http://s3.pexsupply.com/product_files/Taco - HAFC201-4 - Install Instructions.pdf

I think I have the wiring figured out. Any thoughts?


----------



## fbelec (Nov 23, 2013)

hi sierradmax
i think you could save some money and return the taco controller. hook it up the same way it was. this is the first time i ever seen a 24 yolt condensate pump. usually i see 120 volt plug in. i don't think you'll gain anything using the taco controller. the existing way it was hook up should be fine if it's blowing cold air at the end of it's cycle try turning the aquastat up to 130 degrees or 140 but you'll have to be careful turning it up to much it might start cycling on and off. and or if the air handler has a multi speed fan turn it down. the air will go across the coil slower and won't feel as cold because going by the coiler slower it will pickup more temp.

the condensor is usually connected yellow and common or y and c
also i think i would take out the jumper across rh and rc. depending on the switching relay. if the switching relay has it's own 24 volt source it could have a fight with the 24 volt source at the air handler and one or both transformers will smoke and die. i've seen it happen a few years down the road of working fine then one day no heat.

frank


----------

