# New Briggs and Stratton P4500 Generator - CO2 sensor a little sensitive?



## rbrown6061 (Apr 1, 2021)

New forum member here.. My old gen is a Honda EU2000i - six years old.. starts/runs like a champ every month when I test it. I needed more capacity (and am a big fan of inverter gens) - researched and then bought a B&S P4500 (model number 30795) inverter generator. Very happy with it.. except I think the CO2 sensor is a bit too sensitive. During my break in period/testing, it has worked flawlessly- but can shut off after 20-30 mins - as it THINKS the CO2 level is too high (because the CO2 indicator flashes red). Trust me.. I have this gen running in a well ventilated space in the middle of my long driveway.. so airflow around the unit is NOT an issue. I truly don't think it is defective, but, it IS a bit too sensitive. Any ideas on how to disable the CO2 detector? I found a wiring diagram at this URL P4500 Wiring Diagram but I can't discern what leads to disconnect. (Obviously, this wasn't an issue with the old Honda as it doesn't have a CO2 detector..). Thanks!!!


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## iowagold (Jan 22, 2020)

cool post!
yea i have been hearing the same on the co detectors.
one thing to try is a box fan by the gen set to stir the air helps.

do you have a good digital c/o detector yet??
try placing it next to the gen set and watch the readout...
it might surprise you on how the c/o sits close to the gen!

just for test only!
this next part is a "kids never try this at home " thing.
try unplugging the c/o unit and see if the gen set starts and runs.
depending on how integrated the detector is to the inverter unit.
it may run!
report back and see if that works!


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## rbrown6061 (Apr 1, 2021)

iowagold said:


> cool post!
> yea i have been hearing the same on the co detectors.
> one thing to try is a box fan by the gen set to stir the air helps.
> 
> ...


 Thanks Paul! I do actually have a digital CO2 meter - so will drag that near the gen for my next test. (Although.. I don't know what PPM level of CO2 will 'trip' the generator CO2 detector!). I also thought about a box fan - a bit of a pain, but, probably would help. I looked at the wiring diagram more closely, and, I'm going to GUESS (won't know until I try it) that the Orange wire is the one to disconnect - given it looks like the only wire that has an inline connector (yellow arrow) if I'm reading the diagram correctly. (See my attached pic). Next effort is to see how hard it is to get the panel off and disconnect that wire..


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## Old man here (Nov 5, 2020)

I don't know if the CO detector is a N/O or a N/C switch. If the Orange wire prevents a start-up when disconnected, try the Green ground wire to ground, 2nd wire below the Orange wire


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## Old man here (Nov 5, 2020)

I hope that CO sensor sheds all loads before shutting down the generator. If not, you are going to be replacing a lot of appliances. Not good for the inverter if everything is on line as it shuts down.


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## rbrown6061 (Apr 1, 2021)

Old man here said:


> I don't know if the CO detector is a N/O or a N/C switch. If the Orange wire prevents a start-up when disconnected, try the Green ground wire to ground, 2nd wire below the Orange wire


My bad.. I cut off the picture a bit on the bottom. I THINK the green wire automatically goes to ground?


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## rbrown6061 (Apr 1, 2021)

Old man here said:


> I hope that CO sensor sheds all loads before shutting down the generator. If not, you are going to be replacing a lot of appliances. Not good for the inverter if everything is on line as it shuts down.


I agree with you.. During my 'break in' tests so far, I was only running a couple of space heaters (to load the gen up to roughly 80% of its running capacity) - and the space heaters won't care as they are nothing more than electrical coils and a small fan. .. but I do understand real appliances might care! I'll update the forum here once I do some testing.


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## iowagold (Jan 22, 2020)

rbrown6061 said:


> I agree with you.. During my 'break in' tests so far, I was only running a couple of space heaters (to load the gen up to roughly 80% of its running capacity) - and the space heaters won't care as they are nothing more than electrical coils and a small fan. .. but I do understand real appliances might care! I'll update the forum here once I do some testing.


the over heating on the inverter is the issue during a rapid shut down event like low oil or run out of fuel with out a 2-5 min cool down period after a hard run up.

yes try unplugging the orange with the disconnect!
i bet that is the ing shut down ground when c/o is detected!
sure looks like it to me as well!


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## Sparky (Sep 29, 2021)

Has anyone been able to disable this feature? I use a generator for ice fishing and normally have a cover on my generator for when its -32 temps and a lot of others put them in the back of a pickup. I understand the logic behind it but for ice fishing its just another reason for a generator issue when your in the middle of no where and need power for heat.


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## drmerdp (Apr 10, 2018)

Sparky said:


> Has anyone been able to disable this feature? I use a generator for ice fishing and normally have a cover on my generator for when its -32 temps and a lot of others put them in the back of a pickup. I understand the logic behind it but for ice fishing its just another reason for a generator issue when your in the middle of no where and need power for heat.


I haven’t had my hands on one, but I believe it’s a module that can be simply unplugged.


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