H2O mixing station dry fit- am I good to glue?

[SallyWho]

This is a very preliminary dry fit for the plumbing of my water mixing station- not everything is cut exactly to size and I need to exchange the threaded fitting on the bulkhead of the left barrel, but I'm on limited time today. I'll make it all pretty and even this weekend. What I want to know is whether I have all the fittings where they belong. Do I have the unions and valves in the right places? Am I missing anything? The end goal is to have the right barrel fill with RODI, be able to pump it over to the left barrel, circulate and mix the saltwater, and be able to pump either RODI or saltwater as needed out the barbed fitting.

And here's some novice plumber questions. Do I glue the pvc pipes into the unions, or by screwing them tightly enough, they don't leak? Also, on these threaded fittings on the barrel bulkheads (preinstalled) and the pump intake/output, do I need to use something like thread sealant, glue, or that plumber's tape?

Thanks, guys! I know I've been asking a lot of questions lately, and I really appreciate how helpful everyone has been. I'm probably within a few weeks of being able to kick off build thread!

 

[aherre07]

Might want to put the ball valve going up from outlet of the pump after the T so that you can shut off the feed to the tank if you are using the hose side to fill.

 

[SallyWho]

Might want to put the ball valve going up from outlet of the pump after the T so that you can shut off the feed to the tank if you are using the hose side to fill.

Oh, that's a good point. Thanks!

 

[SallyWho]

Might want to put the ball valve going up from outlet of the pump after the T so that you can shut off the feed to the tank if you are using the hose side to fill.

Like so?

 

[Brew12]

Like so?

That will work better!

I would also add a union above that top valve "just in case".

 

[SallyWho]

That will work better!

I would also add a union above that top valve "just in case".

Roger that! Glad I picked up extra unions. I do wish I'd noticed earlier that I had the wrong sized threaded fitting in that left hand barrel, though- another trip to the store! God help me when I have to plumb the actual tank! [emoji28]

 

[SallyWho]

Anybody have insights on my amateur plumber's questions? Do I glue the pipes into the unions, and do I need teflon tape/thread sealant/glue on the threaded fittings at the bulkheads and pump?

 

[Brew12]

Anybody have insights on my amateur plumber's questions? Do I glue the pipes into the unions, and do I need teflon tape/thread sealant/glue on the threaded fittings at the bulkheads and pump?

Yes, the pipes should glue into the unions.

No not use teflon tape on a PVC joint! You will want a non-setting thread sealant safe for PVC such as this one.
https://www.homedepot.com/p/RectorSeal-T-Plus-2-4-oz-Teflon-Pipe-Thread-Sealant-23631/100201204

 

[SallyWho]

Yes, the pipes should glue into the unions.

No not use teflon tape on a PVC joint! You will want a non-setting thread sealant safe for PVC such as this one.
https://www.homedepot.com/p/RectorSeal-T-Plus-2-4-oz-Teflon-Pipe-Thread-Sealant-23631/100201204

Thank you!

 

[Ocelaris]

Yes, the pipes should glue into the unions.

No not use teflon tape on a PVC joint! You will want a non-setting thread sealant safe for PVC such as this one.
https://www.homedepot.com/p/RectorSeal-T-Plus-2-4-oz-Teflon-Pipe-Thread-Sealant-23631/100201204

I'm going to have to respectfully disagree. I just don't think there is a strong case either way for tape or sealant when done correctly. Instead of painting the problem as black and white, let me give my opinion on worst to best fittings by effort, cost and ease of use.

Leakiest ---------> no leaks

threaded no sealant < threaded, teflon tape < threaded, pipe goop < compression fittings < Glue < Sweat/weld

Hard to use --------> not hard to use

Sweat/weld < Glue < pipe goop < threaded teflon tape < threaded no sealant < compression

Cheap -------> expensive

threaded no sealant < threaded teflon tape < threaded pipe goop < glue < sweat/weld < compression fittings

As for the chemistry, both tape and goop are basically inert, so it's a non-issue. I think the thing people run into is more on the mechanic/physical side. The taper of threaded PVC is often less than metal threads, so it can be a bit more challenging to seal, and over tightening can lead to cracking plastic. I think this is especially true as we often use smaller manufacturer's of plastics which may not hold themselves to the highest standards; as opposed to the general home building industry which probably has tighter standards. I just know off the top of my head how many "irregular" fittings from the aquarium industry I have lying around.

In practice both can work fine when applied properly, and for someone new to plumbing the goop may be a nice compromise between leaks and using silicone, which IMHO is like bringing the nukes. At the point you're using silicone, just glue it with a slip fitting, it'll have less internal resistance.

 

[Brew12]

I'm going to have to respectfully disagree.

I won't say that you cannot be successful using teflon tape. However, this is what a large manufacturer says.

http://www.lascofittings.com/threads

 

[Ocelaris]

That's a strong argument! Thanks for that. I can't say I'll change, but makes sense.

 

[Erica-Renee]

I almost never use Teflon Tape and when i do its because of loose fitting threads. I use sparingly and always use it with Thread Sealer.. I do at least 3 plumbing jobs a week Usually repairing a leaking shut off valve ,Changing out a sink while installing new Counter tops to sometimes Moving fixture locations on Kitchen and Bath renovations.. I find the Yellow gas line Teflon to be best.. you just have to use MUCH Less of it...

I am not a Professional plumber , I am a Home Renovation Contractor.

 

[Sleepydoc]

When I’ve done research, there are a whole lot of people who say ‘I’ve always used...,” but a significant majority (I.e all except for perhaps one) of the manufacturer recommendations I’ve seen are for thread sealant, not tape, and those that say you can use tape stress that it’s important to use it correctly.

I used to use Teflon tape and switched to thread sealant, and I have to say it’s both easier to use and more reliable. The only downside is you sometimes need to wipe the excess off.

 

[Sleepydoc]

As far as the mixing station goes, you might want some method of directing flow towards the bottom of the saltwater tank - either a powerhead or a pipe angled down. That will help keep the salt stirred up when it settles on the bottom and let it mix faster/better.