12 Volt Impact on Tank Sensors and LP/CO Detectors

[hanknjoycew]

  I am not an electrician..but decided to replace LP and CO detector with combined unit because both were occasionally chirping and about 5 years old. I cut the wires on the LP detector intending to leave it in place but off. Before installing the new combined LP/CO unit I noticed my waste tank lights up front are not lit. The water pump light on the same front panel does work. Should disabling one of the 12V detector wires in the read impact the tank sensors up front? I will install the combined unit today after I get some fresh crimper connections, but wonder if I somehow caused the tank lights to die. It seems a puzzlement.

Hank
SKP 67414
2005 Mandalay DP
2012 Honda CRV

[Kirk W]

3 hours ago, hanknjoycew said:

Should disabling one of the 12V detector wires in the read impact the tank sensors up front?

It just depends on how the various parts of the RV get power and where you cut the wires. The LP detectors and CO detectors that I have installed or worked on have all used wire nuts to connect them into the 12V system and it usually is a common connection point with anything else nearby that uses 12V power and/or a chassis ground return lead. That same thing is true for the combo units. If it matters, I am a 40-year electrical maintenance tech with 30+ years of RV experience.  I find this interesting as I just a few months ago did the opposite and replaced a combo unit with two separate ones. 

[oldjohnt]

Hank, not knowing just how your RV was wired and what exactly you did electrically when  you "cut the wires" its hard to say what's happening now. What makes matters worse is being an RV owner for 49 consecutive years and a past RV dealer, I SAW THINGS WIRED EVERY WHICH DIFFERENT WAY BUT LOOSE and even including loose lol. There's not so many "standard" wiring practices in the RV industry as I encountered when I practiced commercial and industrial power distribution engineering when the NEC was my bible .

If you ONLY removed one individual 12 volt feed wire to a certain detector and the rest of the 12 volt circuit (+ and -) was still intact, that shouldn't affect other loads on that same, if still intact and hot,  + and - 12 volt branch circuit. HOWEVER if there was a branch circuit and you inadvertently (when you cut wires) opened a main hot feed wire any other downstream loads would also loose power. Perhaps once you reconnect all the wires it will cure the problem in case you somehow cut open a main hot feed wire ???? I cant say not being there.  I saw BOTH wire nut and crimped connections in RV's.

FWIW I was never a fan of COMBINATION CO and LP detectors and have separate units in my current RV. It seems to me since LP is slightly heavier then air and would settle on the RV floor while CO is slightly lighter then air and drift towards the ceiling, the LP detector should be near the floor while the CO higher up, that's how mine and many RV's I encountered were installed.

NOTE I'm NOT saying they don't work and many use them, I'm ONLY saying my personal preference is to have separate LP and CO detectors. Do however you please

Get your 12 VDC test light or a volt meter and see if you have + and - 12 volts available and if you reinstall everything as it was before and all worked then you may be okay???      

Best I have to offer not being there or knowing what you "cut"

Best wishes and God Bless

John T