Modifying an industrial heater to have an exhaust function

BeforeYouKnowIt · 04-29-18, 10:35 PM

Hi, I have a Reznor f400 industrial heater that is used to heat a large warehouse space. The unit is gas powered and heats air blown across a large burner by way of a fan that sits in the rear of the unit. The fan in my model runs on a Fasco D701 motor. Just in front of the fan and on the top of the unit is a vent shaft that leads to the roof.

The space can become quite warm in the summer months. There is considerable flow of air into the space through the use of air circulators but venting air has been a problem. I'm considering the possibility of installing an inline fan in the heater vent shaft in addition to reversing the Fasco fan native to the heater. Potentially these modifications could pull hot air from the space? Thoughts?

Thanks

u3b3rg33k · 05-01-18, 05:12 PM

That "vent" on top is the natural draft exhaust for flue gasses. generally speaking, it's not wise to tamper with those, and assuming the heater is sized appropriately to the warehouse, likely not big enough to produce noticeable cooling if you did.

Product - Unit Heaters - F | Reznor

Are there any windows you could open up top? an actual exhaust fan up high could be productive (3000cfm+ each). It may actually be cooler with no additional work if you turn off your air circulators - assuming they're large ceiling fans blowing the hot air down.

BeforeYouKnowIt · 05-02-18, 05:55 PM

That makes sense. I've also been considering installing a whole house fan in one of the windows, maybe even running duct work to it from the farther reaches of the space? Haven't seen any examples of that with a cursory search. The air circulators are standing floor fans. I'm fooling around now with fan placement and air flow. Had a funny thought of using bubbles to help observe the air currents.

anyways
thanks

Ator · 05-08-18, 10:22 AM

Wouldn't you start with reducing heat gain by painting the roof white or roof insulation? I think that would give you the highest benefits.

04-29-18, 10:35 PM	#1
BeforeYouKnowIt Lurking Renovator Join Date: Apr 2018 Location: Chicago Posts: 2 Thanks: 0 Thanked 0 Times in 0 Posts	Modifying an industrial heater to have an exhaust function Hi, I have a Reznor f400 industrial heater that is used to heat a large warehouse space. The unit is gas powered and heats air blown across a large burner by way of a fan that sits in the rear of the unit. The fan in my model runs on a Fasco D701 motor. Just in front of the fan and on the top of the unit is a vent shaft that leads to the roof. The space can become quite warm in the summer months. There is considerable flow of air into the space through the use of air circulators but venting air has been a problem. I'm considering the possibility of installing an inline fan in the heater vent shaft in addition to reversing the Fasco fan native to the heater. Potentially these modifications could pull hot air from the space? Thoughts? Thanks

05-01-18, 05:12 PM	#2
u3b3rg33k Apprentice EcoRenovator Join Date: Mar 2018 Location: Rustbelt, USA Posts: 114 Thanks: 5 Thanked 10 Times in 9 Posts	That "vent" on top is the natural draft exhaust for flue gasses. generally speaking, it's not wise to tamper with those, and assuming the heater is sized appropriately to the warehouse, likely not big enough to produce noticeable cooling if you did. Product - Unit Heaters - F \| Reznor Are there any windows you could open up top? an actual exhaust fan up high could be productive (3000cfm+ each). It may actually be cooler with no additional work if you turn off your air circulators - assuming they're large ceiling fans blowing the hot air down.

05-02-18, 05:55 PM	#3
BeforeYouKnowIt Lurking Renovator Join Date: Apr 2018 Location: Chicago Posts: 2 Thanks: 0 Thanked 0 Times in 0 Posts	That makes sense. I've also been considering installing a whole house fan in one of the windows, maybe even running duct work to it from the farther reaches of the space? Haven't seen any examples of that with a cursory search. The air circulators are standing floor fans. I'm fooling around now with fan placement and air flow. Had a funny thought of using bubbles to help observe the air currents. anyways thanks

05-08-18, 10:22 AM	#4
Ator Lurking Renovator Join Date: Jan 2015 Location: Netherlands Posts: 25 Thanks: 1 Thanked 7 Times in 7 Posts	Wouldn't you start with reducing heat gain by painting the roof white or roof insulation? I think that would give you the highest benefits.