Coleman/Evcon Model DGAX070BDTA Blower speed adjustment

irishshodan

My brother and I just installed a new Coleman furnace in my house and the fan speed on the blower is extremely fast and loud. How can I adjust the speed? I called Coleman, but they will not tell me anything because I don't work for a HVAC shop.

neilc

it should be in your manual,
you did Read The Fantastic Manual, didn't you?

EdTheHeaterMan

https://www.yorknow.com/pub/media/documentation/DGAX_Installation.pdf. Here is your I/O manual. I am looking at it now to see how to adjust the blower speed

EdTheHeaterMan

Do you use air conditioning with this furnace?
Is the coil for the air conditioner installed under the furnace?
Is the air conditioner a outdoor package unit with the indoor fan, outdoor fan, and compressor in one big box on the lawn with the ductwork connected to that box under the mobil home?
Is the outdoor part of the air conditioner the outdoor fan and compressor only?
Is the air conditioner a 2 stage unit?
(easies answer is "we don't have AC". but I'm sure it wont be that easy)

EBEBRATT-Ed

You have to get the furnace running in heating and take a temperature rise across the furnace before messing with the fan speed

EdTheHeaterMan

It appears that your furnace has 5 speed ECM motor. Which of the 5 speeds that are used are determined by the 5 different DC current control wires are connected to the HEAT SPEED tap on the blower control panel in the blower compartment. You can change the speed by swapping the Yellow wire on the PARK terminal with the Black with White stripe wire on the HEAT terminal.

There is a CAUTION that this slower speed may cause the heat exchanger to over heat and cause short cycling of the burner (gas valve going off and on repeatedly during a call for heat) or premature heat exchanger failure. In order to test the air flow temperature rise, you will need to get an accurate thermometer (a meat thermometer from the kitchen will do) and check the air temperature in the heat register outlet (deep inside the duct) closest to the furnace, and compare it to the return air temperature (at the top of furnace door) to make sure the difference is less than the maximum air temperature rise on the furnace nameplate. (should be about 45° to 70° for most furnaces)

There are details in the manual that describe and caution you with this information. If you do this without the proper tests and checks, you may cause parts to fail that may be expensive to replace. The Manufacture's Warranty only covers the Parts sometimes and will not cover labor anytime.

irishshodan

Thank you everyone. It turns out it was a very simple fix. The jumper on the fan speed came preset at Lo Cool. I put it between Lo Cool and Heat and it works as it should now. Thanks again for all the comments so quickly.