Coleman Furnace

[Joal]

I have a Colman Evcon furnace and have installed to coils. One coil is for my air conditioning and recently installed a coil for an outside boiler. The volume of air that blows out the duct work has been reduced tremendously. My furnace model# is 4084-701/B.

The blower motor is 7995-591 it is 1/4 hp.

I would like to go to a larger H/P motor, do you think that would increase my air flow.

There is a tag on the furnace housing that has different blower motor ratings. The 7900-651 is a 1/2 hp motor will that work for my funace and blower housing.

[Joal]

Help

[Robert]

Hi Joal,

Are you referring to the outside a/c condensing unit as a boiler ?

I'm guessing the two coils you speak of are the condensing unit outside and the A-Coil inside ?


Any time you add a/c, you must upgrade the motor IF it is not an a/c rated motor.


Will check Monday and find out what options you have as I'm fairly certain your motor is not rated for a/c.

You will most likely have to purchase an entire blower assembly as most a/c rated motors need larger blower wheels and do not fit in the smaller heating only blower housings.


Will let ya know Monday. I stay very busy, in and out of office, so if you don't hear from me by Monday evening, holler back at me here to remind me. (age does that sometimes, LOL)


Take care and best wishes,
Robert

[Joal]

I,m sorry for the misunderstanding. I have a down draft furnace with an a coil in the plenum. I also have an outside boiler unit I purchased and it also has a coil that goes inside my duct work. Now I have less air flow through the system, which i would expect adding coils. I would like to increase the cfm going through my duct work. I have 15" of height where my existing blower is. Any help in this case would be much appreciated.


Thanks
Joal

[Mark]

I believe there's too many variables for us to say what to do. Most likely a larger blower assembly would do the trick, but then you need to be sure you have enough air coming in to support it.

Mark

[Joal]

Thanks

What blower do you recommend using to get more CFM. Also do you have the dimensions of the larger blower. This would help me in knowing if it will fit.

[Robert]

Hi Joal,

Your furnace and a/c combimed will dictate the amount of cfm required. By adding the boiler coil, you may have went past the limit for MH ducts.


What is the furnace model number, with that we can see what size blower it can handle.

You must be very careful as MH ducts cannort support the cfm of airflow generated in normal duct systems.

Your best option would be an onsite analysis by an HVAC Tech knowledgeable with MH units and duct systems.


Thanks,
Robert

[Joal]

The furnace model number is 4084-701/B. What does MH stand for on the duct work.

[Robert]

Hi,

Our database does not list a specific motor for use with added a/c to your furnace.

With that and the added boiler and coils in the duct, your best course is to get an HVAC Tech out to look it over and decide best motor that falls within the duct specs for motors allowed.

MH = Mobile Home .


MH ducts are smaller than normal home ducts and cannot support the same motors and with the furnace, a/c, boiler and coils in the duct, you most likely will not be able to get a motor big enough that can be used in a MH duct.


Take care and best wishes,
Robert