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Topic: Operating temperature range of Onan 12.5 (Read 767 times) previous topic - next topic
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Operating temperature range of Onan 12.5

Yahoo Message Number: 62068
I have a 2002 Affinity with Onan 12.5. I had coolant and all hoses changed a month ago and for some reason that took out the thermostat. Replaced that. Yesterday we were driving in N California and running generator and two roof airs. Temp was getting up into the 222 degrees area. I remember the gen seemed like it used to kick off when it got to 218. I then ran with one roof air and it stayed at around 212. The load meter was way down in the 10% range.
So my question - how hot is this supposed to run? What is normal operating temp range. I tried looking up in the manuals last night and could not find it.

Re: Operating temperature range of Onan 12.5

Reply #1 –
Yahoo Message Number: 62070
What temp thermostat did you up in? The temp is marked on the thermostat. They usually use a 180 degree thermostat. If you wound up with a 195 degree it will run hotter... Another issue with generators is getting all the air out of the system. An air pocket will cause it to run warm and bleeding the cooling system can take patience and a good sense of humor.

Mikee

Re: Operating temperature range of Onan 12.5

Reply #2 –
Yahoo Message Number: 62072
Mikee can't believe you made such a basic mistake. The thermostat only controls the minimum temperature at which it lets fluid to the radiator. If the unit was operating at 222 degrees the thermostat would be no part of the equation . It would have opened at 180 , 195 ( whichever was selected ) and allowed the radiator to do it's job. I agree on the possibility of air in the system, but the 180 or 195 thermostat would have played no part in the unit running at 222 degrees.

Ron Baran 09 Magna 7025

Re: Operating temperature range of Onan 12.5

Reply #3 –
Yahoo Message Number: 62073
Mikee can't believe you made such a basic mistake. The thermostat only controls the minimum temperature at which it lets fluid to the radiator. If the unit was operating at 222 degrees the thermostat would be no part of the equation . It would have opened at 180 , 195 ( whichever was selected ) and allowed the radiator to do it's job. I agree on the possibility of air in the system, but the 180 or 195 thermostat would have played no part in the unit running at 222 degrees.

Ron Baran 09 Magna 7025

Re: Operating temperature range of Onan 12.5

Reply #4 –
Yahoo Message Number: 62080
Depending on the thermostat and cooling system.. the thermostat can cause overheating, especially if it should be a bypass thermostat and is not, there are also full flow, controlled flow type of thermostats. The wrong type of thermostat can cause overheating. The absence of a thermostat can also cause overheating due to coolant circulating too fast to dissipate the heat.
I did not make a basic mistake, I was attempting to offer some suggestions with limited condition information.

Mikee