York furnace slow fan speed

emerald

Hello group. New to using fourm. Have a york 95% furnace that runs 600 cfm when in cooling mode. Heat mode ramps up normal. 2 units in house doing same thing. I thought control board at first but what are the chances of both going. Any thoughts would be greatly appreciated.

ratio

What's the cooling speed set to?

It usually takes me a half-hour to figure out the DIP switch settings each time, I don't play with them often enough.

emerald

No Dip switch on this board. I am unfamiliar with york equipment and this board.

mattmia2

did it ever work?

emerald

Good question. Last year it froze up and flooded the bedroom below. I was called in the fall for no heat. After checking the motor I Determined the board was bad. Replaced board and heat was operating. This was in November so I didn't run the ac. This call I don't believe the ac worked at before I arrived. I never worked on 2nd unit in basement. While there today I went to basement and found the unit operating same manner. Cfm light is blinking 6 times calling for 600 cfm. Units are both 12 yo and in good condition otherwise.

mattmia2

is y from the t-stat connected to the control board(or is it a communicating t-stat)? is it an ecm motor or is the speed set with tap connections on the control board?

essentially rtfm

emerald

Yes the condenser comes on with call. Ecm tested and runs. Fan runs properly in heat mode.

EdTheHeaterMan

Need the model number of the 95% York furnace so I can look up the necessary settings to make the fan operate at the proper speed needed for the matching condensing unit.  If you have a 1.5 ton condenser, then 600 is the correct fan speed. if you have a 3 ton condenser then you want to use 1200 cfm. or thereabouts.    

If the fan operates at a higher speed for heat, then there has to be a way to adjust the cooling fan speed based on the size of the outdoor unit.

The York 95% furnace can be a single stage gas valve or a two stage gas valve or a variable input gas valve. Each of those furnaces has a different model number and therefore a different instruction manual and perhaps a different fan speed controller. There are also PSC motors and ECM motors that will be adjusted differently. I assume that you have the variable speed ECM fan motor by the previous statements you made, but the model number will tell all that is needed.

mattmia2

https://forum.heatinghelp.com/discussion/comment/1858726#Comment_1858726

that isn't what i asked. i asked if y from the t-stat was connected to the control board(or is otherwise made to do a high fan call on y or g, newer air handlers will just do low fan with g)

emerald

Mdl Tm9v100c16 yes ecm motor. 4 ton unit. So I know I should be getting 1600 cfm .

emerald

Yes y is connected to the control board on from thermostat.

EdTheHeaterMan

https://forum.heatinghelp.com/discussion/comment/1858748#Comment_1858748

So you are not using the communicating thermostat ABCD. but you are using the Legacy thermostat with R W1 W2 G Y1 Y2 C terminals

Are you using a 2 stage thermostat?

Are you using a 2 stage condensing unit?

You might want to set the fan based on these instructions: From page 33 of the manual.

There are more details in this manual: TM9V C Series I believe the York and the Johnson are identical units

emerald

Thank you for the information ed. No booklet left from the installer. This is very helpful and I am going back tomorrow. I will let you know how I make out. Thanks again

emerald

Finally fixed. Upon arrival this morning unit was running correctly. I watched for a couple cycles and then slow fan again and no condenser. I checked voltage and only had 19 on y. Ran new thermostat wire and and problem solved. Thank you for all the information provided. Enjoy your summer

EdTheHeaterMan

Another happy customer!

ratio

Two units, both with defective stat wires? That both failed in the same manner?

I don't doubt you, but that's really strange. The failure mode is really strange, too. Doubly strange. Quadruply strange??

Defective stat wire? Overly excited helper stapling up the wire?

emerald

Homeowner tells me the units have never worked correctly or consistently since installed. Several freeze ups over the years.