Low point drain valve install

[bubbalowe]

Want to put valves on low point drains and fresh water tank drain and eliminate caps. Never used low point drains except when winterizing but now want to lose extra water weight towing and refresh water routinely. Plan is use 90’s and short pieces of tubing and put drains at outside edge and be easily accessible. What and where to get plastic valves? Don’t want to use brass to reduce weight hanging. Been to Lowes and HD, doesn’t seem to be anything available in the home market? Thanks

 

[Willhound]

I'd be surprised they didn't have anything. Won't be labelled RV drain valve. Look up "plastic ball valve" or "plastic quarter turn valve" and all kinds pop up.

 

[NMWildcat]

I'd be surprised they didn't have anything. Won't be labelled RV drain valve. Look up "plastic ball valve" or "plastic quarter turn valve" and all kinds pop up.

Exactly. Look in the PVC fitting section. Should be boxes and boxes of them. Take a cap with you to ensure the right size.

 

[* Boondocking *]

Here you go my friend.

PVC Valves at Home Depot

 

[Mr. Dan]

I bought 1/2" quarter turn PCV valves for drains from Lowe's.

 

[NXR]

Remember to evaluate whether road debris or maybe something thrown by a tire could damage a valve hanging down and cause a loss of all water.

That's why I put the valves inside and still left the caps off underneath. I'd never used Pex tools before but it was easy to do.

Ray

 

[Aussieguy]

take a cap with you to the store to match threads
(turn off the water first)

 

[Mr. Dan]

take a cap with you to the store to match threads
(turn off the water first)

.. or as NMWildcat said

Exactly. Look in the PVC fitting section. Should be boxes and boxes of them. Take a cap with you to ensure the right size.

 

[Minthillbill]

Got these from HD. Not expensive too.
https://www.homedepot.com/p/Everbilt-3-4-in-PVC-FIP-x-FIP-Sch-40-Ball-Valve-107-134EB/319340961

 

[Minthillbill]

Link did not work…

3.74 ea. in plumbing section. Called a ball valve.

 

[* Boondocking *]

PVC Valves at Home Depot

 

[aceinspp]

Link did not work…
View attachment 305855
3.74 ea. in plumbing section. Called a ball valve.

That is what I used. Later RJD

 

[GolfingDave]

My low points were straight threads and not pipe threads which a lot of ball valves are if threaded.

I understand making it easier to drain but that is negligible weight and then bypassing your water heater each time you drain? I have to take out a kitchen drawer to get to mine though.

A pair of shoes is probably more weight then the water in the lines.

 

[bubbalowe]

My low points were straight threads and not pipe threads which a lot of ball valves are if threaded.

I understand making it easier to drain but that is negligible weight and then bypassing your water heater each time you drain? I have to take out a kitchen drawer to get to mine though.

A pair of shoes is probably more weight then the water in the lines.

Correct, the fittings are straight thread and use a gasket in the cap, that’s the issue finding a ball valve. Having a valve on the red line and opening sink valves will drain the hot water tank. 7 gallons of water weighs 58#, that’s a little more than a pair of HeyDudes lol. We normally empty most remaining fresh water into black tank before driving to dump station but also drain fresh water before leaving, it’s a hassle reaching way underneath trailer to get to drain cap.

 

[Willhound]

When you guys say "straight threads" not plumbing threads, do you mean it's threaded like a 1/2" bolt? Never see such a thing on a piece of pipe. Pipe thread is pipe thread, unless it's a compression fitting.

 

[5picker]

Correct, the fittings are straight thread and use a gasket in the cap, that’s the issue finding a ball valve. Having a valve on the red line and opening sink valves will drain the hot water tank. 7 gallons of water weighs 58#, that’s a little more than a pair of HeyDudes lol. We normally empty most remaining fresh water into black tank before driving to dump station but also drain fresh water before leaving, it’s a hassle reaching way underneath trailer to get to drain cap.

No so sure.
Opening the red low point drain will indeed remove the water from the hot plumbing lines by opening a faucet but once the water in the water heater gets siphoned to the level of the hot water outlet in the tank, no further draining will occur, leaving it about 3/4 full.

Now, if you open the blue low point drain... that's a different story... but... be cautious doing this! Better yet, don't!

Doing so will suck sediment from the water heater into the plumbing lines from the cold water inlet on the water heater (where some of the sediment remains even after draining) and will clog faucet aerators and toilet valves on repressurization.

When opening the low point drains, it is always better to bypass the water heater first. If you want to drain the water heater, remove the drain plug or remove the anode. (however equipped)

 

[5picker]

When you guys say "straight threads" not plumbing threads, do you mean it's threaded like a 1/2" bolt? Never see such a thing on a piece of pipe. Pipe thread is pipe thread, unless it's a compression fitting.

But it is a compression fitting. That's why the caps on the low point drains have a tapered gasket in them. That's what seals the cap, not the threads.

With that said, the difference in threads between a pipe thread ball valve and a straight thread low point drain fitting are different enough that the ball valve will indeed seal on the fitting, especially with a bit of Teflon tape/pipe dope.

 

[5picker]

Want to put valves on low point drains and fresh water tank drain and eliminate caps. Never used low point drains except when winterizing but now want to lose extra water weight towing and refresh water routinely. Plan is use 90’s and short pieces of tubing and put drains at outside edge and be easily accessible. What and where to get plastic valves? Don’t want to use brass to reduce weight hanging. Been to Lowes and HD, doesn’t seem to be anything available in the home market? Thanks

You could always continue the PEX line to the side of the R/V using plastic screw on ells and plastic shut offs. But that would likely leave a bit of pipe hanging under the R/V to be knocked off. I'd rather cut off the low points near the underbelly and plumb to the side from there.

Just keep in mind for those camping in cold weather, extending the low points to the side of the R/V creates additional plumbing that would need protected from freezing as opposed to the short stubs as they come from the factory.

 

[Willhound]

Ahh, ok. So if a compression thread, there are valves that have it, but yes, harder to find. Usually not hard to find a fitting that will adapt from CMP to MPT or FPT and then to valve.
Or, just cut off the capped fitting that is CMP and replace with MPT to Valve.

 

[5picker]

Ahh, ok. So if a compression thread, there are valves that have it, but yes, harder to find. Usually not hard to find a fitting that will adapt from CMP to MPT or FPT and then to valve.
Or, just cut off the capped fitting that is CMP and replace with MPT to Valve.

That screw on ell I referenced above is compression and uses a tapered cone washer. You can see part of the cone washer in this photo...