Tracing manifold lines - pure luck?

[Russell Harris]

Hello, I'm trying to figure out if there is a technique for figuring out where the 1/2" lines go from the cold and hot manifolds in our 1970s ranch. I had under slab access for awhile but could not see any routing clues for the lines in question. You can see from the picture I have a 50% chance of guessing the hot side and a 25% chance of getting the cold side correct for any given line. I'm trying to ID the lines to the Main bath so I can cut and disconnect as I work on a remodel. I wondered if I could use electronic tracing with my ethernet tool but given they're all interconnected seems like that wouldn't work. I realize this may boil down to a dice roll and I have to repair a line if I cut it and get it wrong.
Thanks!
RH in Austin

 

[RetiredInGueydan]

Have someone tap on the pipes in the MB with a wrench, this should allow you to fell that in the same pipe at the manifold.

 

[Sponsor]

 

[Fitter30]

Hot is easy just takes time. One faucet at a time feel line gets hot. Wait a hour till line gets cool try another one. Don't open any hot valves when draining down. Cold shut water off to the houseand drain it down. 5 gallon bucket of ice water, drill motor and drill pump. Pump ice water from faucet line will get cold.
www.harborfreight.com/750-gph-drill-pump-56847.html?hftm_sc=3193&hftm_source=google&utm_source=google&utm_medium=cpc&utm_campaign=21901739231&campaignid=21901739231&utm_content=171677809822&adsetid=171677809822&product=56847&gad_source=1&gad_campaignid=21901739231&gbraid=0AAAAADAHb4d3tPYcpjx3cQa9C1wEHzqv1&gclid=EAIaIQobChMIktWY9tTokAMVDkX_AR1stTjiEAQYASABEgKCO_D_BwE

 

[RetiredInGueydan]

=

Hot is easy just takes time. One faucet at a time feel line gets hot. Wait a hour till line gets cool try another one. Don't open any hot valves when draining down. Cold shut water off to the houseand drain it down. 5 gallon bucket of ice water, drill motor and drill pump. Pump ice water from faucet line will get cold.
www.harborfreight.com/750-gph-drill-pump-56847.html?hftm_sc=3193&hftm_source=google&utm_source=google&utm_medium=cpc&utm_campaign=21901739231&campaignid=21901739231&utm_content=171677809822&adsetid=171677809822&product=56847&gad_source=1&gad_campaignid=21901739231&gbraid=0AAAAADAHb4d3tPYcpjx3cQa9C1wEHzqv1&gclid=EAIaIQobChMIktWY9tTokAMVDkX_AR1stTjiEAQYASABEgKCO_D_BwE

Or tap on the pipes and be done in 30 seconds.