208v?

[BirdRacer]

I have a chance to get a couple of Dayton G73 heaters for basically no cost, but they are in an industrial building and the label on the back says they are 208V. Is this 3 phase? If so, is it possible/cost efficient to convert it to 240V for home shop use?

I would love to have them for free, but not much use if it's gonna cost me $500 to make them work.

 

[Stuart in MN]

They should be usable on either 240vac or 208vac single phase. Here's a link to the owner's manual for the Dayton G73 heater: http://www.air-n-water.com/manuals/G73.pdf

 

[-JP]

The G73 model is only available in a 1-Phase configuration and dual rated for 208/240V operation. This means the unit will develop a different BTU output for each of the KW ratings at each voltage. Connecting to your 240V residential service will provide more heat than connecting to a 208V system.

BTW, you are correct that 208V is a 3-Phase system but you can still get a 208V 1-Phase branch circuit from the service.

JP

 

[BirdRacer]

Cool, great info guys. Thanks!

 

[nehog]

Careful, there are two models one that is 240/208 and one that is 208 only. The heating element is likely to be different in the 208 only version, so you need to confirm which heater it is (make sure it is not actually a G74, for example) first before assuming it will work OK on 240 volts...

 

[BirdRacer]

That's what I was curious about. I would think the label would say 208/240V. I stated that it was a G73, but I could be wrong. It just looked to me like all the G73's I see on here. I will get more detailed info. I guess if I can't use 'em, but can get 'em for free, I could possibly sell them at least.

 

[BirdRacer]

Actually, after looking around, I think they are the 2 heaters below. I think I confused this for the look of the G73/G74. I do remember from the labels that one is 10KW, the other is 15KW. Again, I think I was confusing these for the G73/G74.

http://www.grainger.com/Grainger/DAYTON-Fan-Forced-Electric-Unit-Heater-2YU74
http://www.grainger.com/Grainger/DAYTON-Fan-Forced-Electric-Unit-Heater-2YU71

These say 208, Phase: 1 or 3, but the 15KW is 72 Amps and the 10KW is 48 Amps. So, I think use in my home shop is out of the question.

 

[nehog]

Actually, after looking around, I think they are the 2 heaters below. I think I confused this for the look of the G73/G74. I do remember from the labels that one is 10KW, the other is 15KW. Again, I think I was confusing these for the G73/G74.

http://www.grainger.com/Grainger/DAYTON-Fan-Forced-Electric-Unit-Heater-2YU74
http://www.grainger.com/Grainger/DAYTON-Fan-Forced-Electric-Unit-Heater-2YU71

These say 208, Phase: 1 or 3, but the 15KW is 72 Amps and the 10KW is 48 Amps. So, I think use in my home shop is out of the question.

'Dear dog', I'd love to have those heaters! My three phase generator set would be right at home with them as a load, keep my shop nice and warm. I keep looking for big three phase compatible (208 volt) heaters but have not found any that were affordable.

(BTW, the G73 and G74 should look identical, only the internals are different...)

 

[BirdRacer]

'Dear dog', I'd love to have those heaters! My three phase generator set would be right at home with them as a load, keep my shop nice and warm. I keep looking for big three phase compatible (208 volt) heaters but have not found any that were affordable.

(BTW, the G73 and G74 should look identical, only the internals are different...)

Actually, from what I can see, the G73/74 has the thermostat dial at the bottom front, but these don't.

If I'm able to get my hands on them, I'll see what we can work out. It's just a possibility at this point. My company is moving out of a building we have been leasing for a few years and they have been throwing away good stuff left and right. If these are going, I'm gonna try to snag 'em. I would hate to see them thrown away.

I had a shot at a couple of large LISTA rolling cabinets, but before I could get to them, they were picked up by a scrap metal guy with a huge claw. I almost vomited...

 

[nehog]

Cool on the heaters. Bummer on the rolling cabinets.

 

[BirdRacer]

Ok, after further research, the model number on these heaters are 3UF91 and 3UF88. It looks like they have been discontinued, but here are links to specs (on the 3UF91 only, the 3UF88 shows no specs) on Grainger's site:

http://www.grainger.com/Grainger/DAYTON-Electric-Unit-Heater-3UF91
http://www.grainger.com/Grainger/DAYTON-Electric-Unit-Heater-3UF88

The specs look identical to the ones I linked above.

So, they are 208V only, Phase 1 or 3. I assume they can't be used on household 240V power, correct?

 

[Falcon67]

FWIW - The G73 manual shows a different part number for the heating element in the 208V units.

 

[lametec]

I assume they can't be used on household 240V power, correct?

I wouldn't say they "can't", but it would be against code at the very least. They'll be warmer than they were designed for, so a potential fire hazard. The heating element might also overheat and break.

On the other hand, with them pulling that many amps, chances are your supply voltage will drop to somewhere around 208V anyway.

 

[nehog]

...
So, they are 208V only, Phase 1 or 3. I assume they can't be used on household 240V power, correct?

I'd recommend not doing it... (Not because I covet the heater since I have access to 208!)

Basically two or three things will happen:

1. The element will draw more current, and run much hotter. This will shorten the life of the element (perhaps substantially).

2. The fan motor is likely also spec'ed at 208 volts, and will also run hotter at 240. This can lead to a failure for the motor.

3. The unit will likely draw substantially more power, the current is not linear...

As lametec says, it is likely your supply voltage will drop substantially until the heater fails!

 

[Norcal]

IMO there are 3 options. 1) Leave the heaters alone. 2) Replace the elements. 3) Use a buck/boost transformer to buck it down to 208V. Use of 208V equipment on 240V is not a option.

 

[Falcon67]

Manual link with parts listing: http://raceabilene.com/machine/docs/G73_Heater.pdf

 

[BirdRacer]

Ok, thanks guys. Kinda what I thought.

nehog, I'll still see if I can get my hands on them for ya