Rewire old warehouse heater to run fan in summer

[J3nny]

Our table tennis club is in an old warehouse without ac or fans but it does have 4 ceiling mounted heaters. Would like to run the fans without the gas burners on in the summer. Currently it is not wired to run just the fans. Here is an image of the schematic for the heater. I'm just not sure how to modify the circuit to allow control of the fan without the burners. Can anyone help?

 

[WorthFlorida]

Call a licensed electrician or a HVAC company. You doing the work there is liability issues to be concerned with especially you're dealing with gas. An HVAC tech may be able to use the thermostat wiring for a fan only operation if possible. The IMG didn't show.

 

[Sponsor]

 

[hj]

The "optional S/W (summer/winter), switch" is what does it.

 

[J3nny]

The "optional S/W (summer/winter), switch" is what does it.

Yes! Thanks for the confirmation, that's what I suspected but wasn't sure. I tried it last night and it works perfectly. The optional switch is not installed, I just temporarily jumpered a connection to see if it would work. Now I need to add a relay and add a 'fan only' connection to my thermostat. Don't know why they didn't use a 3 or 5 wire thermostat cable instead of a 2 wire cable. That would have made things so much easier.