VAV Box change from steam to electric heat 1

[Flashoflight]

We have a number of steam coils on our current VAV boxes. They have started to fail, and I want to switch them over to SCR controlled electric heat coils. Can you suggest a manufacturer of a pre-packaged electric heat retrofit that could be used? Current control system is Novar.

Thanks,
Steve Mathey

 

[RossABQ]

The first place I would look is to the manufacturer of the VAV box, since it would simplify installation. They all offer it as an option.

 

[atlas06]

How any boxes and why are you considering electric coils? trouble with steam traps maintenance may be?
Why don't you consider a small steam to HW heat exchanger instead? beats electricity in my opinion. If your piping is in good condition, you may be able to convert it to HW, I am not expert in converting steam piping to HW, may be others might pitch in into this thread about that.
Electic coils will require electrical upgrade and a flow switch in addition to controls. even new HW piping may not be as much as you think.
Is electricity cheap in your area? or you just don't want to bother.

Best.

 

[Flashoflight]

Thanks for the suggestions. Steam has been a problem with the associated control valves and leaky coils in this aging system. Electric re-heat is a great option because we pay only $0.051/KW for electric. Additionally, we are trying to shed load off of our boiler.

The manufacturer of the VAV box does not offer an electric re-heat option for this old box, but that led me to other mfgs. TPI Corp makes a packaged duct heater that has all the controls and safetys installed. Looks like a great option.

Thanks for your help.
Steve

 

[DrRTU]

I have had good results with Warren, Valley, Indeeco and Brasch duct heaters.

http://www.warrenhvac.com/common/products/cbk.html

http://www.indeeco.com

http://www.braschmfg.com/Products/Heaters/Heating.htm

You could install the duct heater on the discharge of the box. I would skip the SCR and use a staged sequence for heating output. A simple duct heater should cost you $450 to $650. For about $750 to $850 you should be able to by a complete single duct vav box with electric reheat box. You should be able to mount your existing controller / DDC actuator on the new box. This way you get a new box & flow bar and disconnect. If you wanted the SCR due to your heating valve being 0-10 volt or 4-20 ma. use a scaling module to stage the heat. I like to do 1 stage up to 3KW, 2 stages at 6KW and 3 stages past 8KW. Look at rise based upon flow.

 

[AbbyNormal]

SCR would be best if you just wanted discharge air control. Cheap if you did not need room reset for heat.

Thermolec in Quebec was economical

Take the "V" out of HVAC and you are left with a HAC(k) job.

 

[lilliput1]

Replace the entire VAV box with a VAV box with electric reheat coil and controls so you don't compromise safety and reliability.