Hot water heater lines - which line is cold (in) line?

[kpauls]

I'm trying to winterize my 2015 Jayco Jayflight SLX travel trailer for use in winter (we're in Arkansas). I have winterized with RV antifreeze as normal while I'm applying heat tape and getting things all set up. Because I've emptied the water heater, set up the bypass valve and run antifreeze through the lines I can't easily figure out what line going into the hot water heater is cold (in) and which is hot (out). I'm setting up heat tape but need to put the thermostat on the cold line. The lines are not marked red/blue as some have said they should have been. One is in the bottom of the unit and one is on the top. My thinking is that, due to convection, it would make sense for it to be cold into the bottom and hot out the top. I don't have the manual for the hot water heater. Any clues?

 

[Route 66 Traveler]

Most water heaters I've seen have cold at the bottom; hot on top.

 

[Grumpy]

Most water heaters I've seen have cold at the bottom; hot on top.

Always......

 

[Petes6.7]

Most water heaters I've seen have cold at the bottom; hot on top.

Same is true on the Girard tankless.

 

[Jagiven]

Most water heaters I've seen have cold at the bottom; hot on top.

X+

My pipes are not marked either. I put a sharpie marked arrow on the pipes to indicate water flow. Primarily incase the DW or kids, need to know.

 

[us71na]

I wouldn't recommend using any heat tape that is thermostat dependent on plastic water piping. Thermostats can be unreliable on temperature control. I would use Frostex self regulating heat tape. They have no thermostat and never get hot enough to melt plastic.

Don't forget your outside shower will also need freeze protection.

 

[Tunce the traveler]

X+

I put a sharpie marked arrow on the pipes to indicate water flow. Primarily incase the DW or kids, need to know.

X2 and never gave it a thought that others should know.