small supply ductowrk

sig

I was recently called to look at a system with airflow problems. I found a 10ish yr. old gas fired furnace with add-on a/c with a 1940s or 50s octopus type duct system with pretty heavy gauge 3"ish flexible metal supply ducts feeding a Coleman vertical combination supply and return diffuser box. The box starts out larger at the bottom and it gradually tappers thinner toward the top. There is a lower return louvre and an upper supply louver. A few standard 6" dusts were added at some to feed the basement. The blower motor was recently replaced by another contractor but it vibrates and is noisy. There is velocity noise at the Coleman supply/return boxes.

Any ideas on what the original furnace would have been? My guess is high temp. with low velocity.

bob_46

That is a Coleman Blend-Air system, 31/2" ductwork and special diffusers in the walls early 50's. High pressure, high velocity.
Not a good or successful system. Noisy.

sig

Thanks bob. It's a bad system alright, to make matters worse everything is on the interior walls and the 100+ year old house and the original 6' high windows. With the velocity noise bad at a 1/2" I can't imagine what it'll sound like any higher.

GW

Yes that's a classic, "happens every day" mistake. I'd presume 90% of techs don't know how to check static pressure. I'd presume 50% of installers don't check temp rise. Some people don't get it, hence the general post stating, "my new system isn't working normally", or, "my 3 year old system just lunched a blower motor".

Gee I wonder is super heat / sub cool was looked at and adjusted

Gary

j a_2

GW said:

Yes that's a classic, "happens every day" mistake. I'd presume 90% of techs don't know how to check static pressure. I'd presume 50% of installers don't check temp rise. Some people don't get it, hence the general post stating, "my new system isn't working normally", or, "my 3 year old system just lunched a blower motor".



Gee I wonder is super heat / sub cool was looked at and adjusted



Gary

Those techs that don’t are not techs….There fakes…The other 10 percent should be real busy….And for that matter a business owner that sends out fakes should be held accountable, for stealing from customers….