Limit Switch Problem?

[orf]

My heating guy replaced a limit switch on my old Janitrol 20K hanging gas heater before winter, but I'm wondering if he put in too cold of one.
The new limit switch says F130-15F and the other says L180-40F. Taking nearly 4 hours to get up 55 degrees on a 20 degree day (2 car space) Can someone tell me if a new limit switch would get this puppy cranking faster and warmer? What temp/division would you recommend?
Think it might be another problem? Never had a issue with this heater before, but it just does seem to be heating like in the past. Thoughts?

 

[rickairmedic]

Orf I would have to doublecheck with my distributor but I am pretty sure . Youre new limit switch only lets the heat exchanger get to 130*F before shutting off the flames and going back down to 115*F . Youre old one let the heat exchanger hit 180*F before shutting off the flames and cooling down to 140*F. That says youre heater isnt getting nearly as hot before the Limit kicks in . I would call the company and tell them they need to come back out and put in the right limit switch.


Rick

 

[orf]

There are actually 2 limit switches on here. The old one was not 180 (I'm not sure what it was - he took it with him). I'm thinking it has the pair of limit switches for a high (180-40 in this case) and low (and 130-15). I understand how the are measured now by your description, so can I just get a higher temp on the low end or would that risk damaging the heat exchanger or something else?
I'd call him back, but if can match the #s on the old limit switch , I almost rather fix it myself for a 5 dollar part.

 

[rickairmedic]

orf where are these Limits located that might help some if there are 2 of them on the unit most likely one of them is a high limit the ( 180-40) the other may be a fan limit switch ( the 130-15 ). They are not hard to change and if you have a Johnstone supply in the area they will most likely sell you the new ones . My Janitrol/Goodman dealer doesnt deal with commercial products so wasnt alot of help on the limits for your unit but the way I described is generally how they are figured . I will add if you have the model number off of the unit I may be able to call corporate for you and get the right limit sizes .


Rick

 

[Charles (in GA)]

If there is a wiring diagram hidden behind an access panel somewhere on the heater, it will probably have the temps next to the limit switches in the diagram, if for no other reason than to distinguish one from the other.

Charles

 

[orf]

Yeah, I looked for a wiring diagram already, but it doesn't have one. Can't seem to find anything online either.

 

[orf]

Heater is still working so-so, but I did find the old limit switch today. The heating guy didn't take it with him.

The one installed now is 130-15F and the old one is 120-30F.

Would this make a big difference in heat output and slow warm up?

 

[lametec]

It would actually make it run hotter. It would go to 130°, then cool to 115° before closing again. The old one would open at 120° and not close until 90°.