"Engineers are notorious for mistakes and the attempt to blame the contractor when things do not work."

That's not a particularly useful, informative, or reliable statement.

I'm an engineer now making a pretty good living correcting systems ill-designed and / or poorly executed by contractors without a clue as to the underlying science and principles of load, heat transfer, psychrometrics, duct design, etc. In the land of the blind, a one-eyed man may be king.

Dick - is the itty bitty strip you bought compatible with HVAC air handlers? Our typical strips are extended coils that count on very high air velocities available right at the blower exit throat while also offerring fairly low resistance to that same airflow.

Curt, the strip is a Tempco 1100 watt CSF00013. I got it here:

http://www.grainger.com/Grainger/TEMPCO-SS-Heater-2XDX2?Pid=search

It will be mounted right above the 5 KW element that CM puts in the cabinet right above the blower (vertical configuration cabinet), so it will get the full flow of air past it. In the above URL, under "Application," the description reads: "Ideal for Forced Air Systems, Heat Pumps, Tempering Air in A/C Systems, Convection Heating, Incubators, Drying Ovens and Food Warming." Any thoughts you have on this would be appreciated.

Consider yanking the 5 kw to reduce restriction on air flow, since you don't intend to use it. Reduced restriction allows blower to slow a bit (fewer blower Watts) to maintain same airflow. Strips are placed at the very highest velocity area of the air system, so removing one has benefit.

Ensure that the 1 kW has low restriction to airflow.

Another thought is that such a low aux heat requirement could be met by a single $40 plug in oil filled space heater

My experience with MEs at arch. firms is many have little real world experience and over rely on calculations. Mny also seem to have little knowledge of the local codes or forget to incorporate it in design.

While I don't necessarily agree that they "blame" installers for problems I have certainly been treated like an un polished rube by someone who offered a very poor design for a system that still can't keep up with demand.....

I was told to get 175 CFM through a 6" branches with resi furnaces and after commenting that 130 was more likely I was told "that's residential, this is commercial"........how does the air know?

j

They need a ductulator and a trip into the field with a flow hood.

Perhaps the additional noise, FPM and static pressure is acceptable in commercial - they deal with inches (plural) blowers rather than the fractional inches we have to play with.

No excuse for them to treat trades as rubes.

I once asked a brand new ME graduate to describe what goes on in a window airconditioner...he hadn't the foggiest notion.

Dick...... I would really like to see your spreedsheet. Is there a way you could post it here? I find it very interesting to see how you were able to reduce the tonnage that much. I just want to learn all I can about this!