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**howson** · 02-22-2023, 09:53 AM

Have you seen this recent thread? https://gdrvowners.com/forum/operati...on-for-a-310gk

Brandons32 's been on the hunt for a replacement, too.

**TheNescios** · 02-22-2023, 11:21 AM

I did see that thread and have been looking at the Dometic 320. Seems like Dometic & Thetford are the main brands, are there any others to consider?
Like the looks & style of the Thetford, but the headaches haven't been fun?
Next week will be my sewer side of things focus, dump valve on the forward black tank stuck in the open position so going to do a thorough flush and repair the valve - I'm still working full-time so hired a local mobile repair person to do the heavy lifting and I'll be the assistant as needed. Says he runs a 2000 psi pressure hose into the tank to flush everything out before pulling the valve off and I was thinking after he did that I'd replace the toilet while he did the valve.
Thankfully I've been adding in-line shutoff valves on the water supply side of things as part of replacing the soft supply hose so am able to operate the toilet manually.
Never a dull moment!

**Cate&Rob** · 02-22-2023, 11:23 AM

Hi Chris,

The Thetford pedal actuates several different things that have to be in the correct pedal cavities. The pedal can be snapped into place without everything in the right places . . . ask me how I know this

. I had ours apart several times shortly after we got the trailer, but once I got misc construction shavings out of the valves and the pedal installed correctly it has been trouble free other than needing grease on the main ball valve seal as a maintenance item.

Rob

**TheNescios** · 02-26-2023, 11:56 PM

First Dometic 320 didn't have all the right parts in the box so after contacting the Dometic Tech Support line returned it on and got a replacement.
Received and installed the replacement today and so far no leaks.
Couple of notes:
Water supply line will need to be move about 3.5" horizontally - I'm still replacing all the Flex lines with PEX so had all the components to modify where the water supply attached. It's really nice having spare fittings and such on hand, but if you don't make sure you're prepared to make modifications?
Still like the look of the Thetford, but after doing my research with several sources chose the Dometic for its ease of maintenance/repair over the issue of needing to get multiple components in exactly the right place - time will tell if this was the right choice?
Will update when I have a bit of time with the new toilet.

**Lonestar** · 03-02-2023, 12:40 PM

Originally posted by Cate&Rob View Post

Hi Chris,

The Thetford pedal actuates several different things that have to be in the correct pedal cavities. The pedal can be snapped into place without everything in the right places . . . ask me how I know this

. I had ours apart several times shortly after we got the trailer, but once I got misc construction shavings out of the valves and the pedal installed correctly it has been trouble free other than needing grease on the main ball valve seal as a maintenance item.

Rob

How and what did you use to grease the main ball valve??

I'm not a big fan of the Thetford as in my previous trailer the foot lever fell off after normal use. I guess it was not fully seated at the factory and after a few years of use the small hole where the spring seated into the foot lever was enlarged and would not allow the lever to be re-used. The replacement lever cost about 50% of what I found the entire toilet for, so I ended up just replacing the toilet.

My point is: be very careful when repairing the valve in removing and replacing the foot valve. The more you remove/replace the lever the more wear you will induce where the spring seats.

**TedS** · 03-02-2023, 02:06 PM

To grease the main ball valve I use Vaseline.

**Cate&Rob** · 03-02-2023, 08:19 PM

Originally posted by Lonestar View Post

How and what did you use to grease the main ball valve??.

I use silicone lubricant intended for water valves and faucets. It comes in small quantities in the plumbing section of Home Depot or similar and is rather expensive. (I have never been able to find larger quantities). Turn off the water, open the ball valve and apply a light film of the silicone grease to the seal.

Rob

**Lonestar** · 03-02-2023, 10:01 PM

Originally posted by Cate&Rob View Post

I use silicone lubricant intended for water valves and faucets. It comes in small quantities in the plumbing section of Home Depot or similar and is rather expensive. (I have never been able to find larger quantities). Turn off the water, open the ball valve and apply a light film of the silicone grease to the seal.

Rob

Yes, I have some. Believe it's called plumber's grease. Don't know why but I've never done this before, but makes sense.

I'm sure Vaseline would work. Just might have to apply it a little more often.

**TheNescios** · 03-02-2023, 11:24 PM

First time someone mentioned "plumbers grease" on YouTube when I was researching whether to repair or replace the Thetford toilet I thought it was something made up or the person was in need of therapy..... then it turned out it's a real thing.

Have the replacement Dometic installed now in the main bathroom, bunkhouse toilet is still the Thetford that isn't leaking past the foot valve - but from what I've found it's just a matter of time until it does.
Dometic has a nicer foot valve assembly from the mechanical aspect that should be easy enough to service and overall seems well made and I like the lip to keep "splash" in the bowl but the water flow during flushing isn't great. They have holes around the rim to supposedly increase the flow but I keep the water pressure at 40 psi and the only way the toilet will work as advertised would be to turn the pressure to probably 60 psi - and I'm just not comfortable with that.
Thetford in the bunkhouse has a better water flow characteristic at 40 psi and I like the foot pedal ergonomics better, but the mechanical aspects aren't great.

With less than a week with the Dometic, if I had it to do over again I'd stay with the Thetford and deal with the foot valve issue - maybe time will change my mind?

**Cate&Rob** · 03-03-2023, 07:35 AM

Lonestar

Be cautious with “plumbers grease” . . . some is specifically labeled with a caution NOT to use it on O rings and seals. The smaller containers of silicone grease are labeled for O rings and seals.

Rob

**Jlawles2** · 03-03-2023, 12:35 PM

Waterproof silicone grease is not cheap. https://www.amazon.com/dp/B0B2KSNWHH...NrPXRydWU&th=1

**Lonestar** · 03-03-2023, 06:07 PM

Originally posted by Cate&Rob View Post

Lonestar

Be cautious with “plumbers grease” . . . some is specifically labeled with a caution NOT to use it on O rings and seals. The smaller containers of silicone grease are labeled for O rings and seals.

Rob

I did not know that. This is the only brand I've ever used, and I see it is no longer stocked:

https://www.lowes.com/pd/GUNK-Gunk-P...Grease/3350380

It looks like Petroleum based formula products are not recommended on O rings like this one:

https://www.homedepot.com/p/OATEY-1-...0620/203489444

So would that rule out Vaseline?

**TheNescios** · 03-04-2023, 12:23 AM

Well.... Puddy Taters!!.... put a bit of the "plumbers grease on the floor seal to make sure everything sealed when I installed the Dometic toilet.
And I just grabbed the stuff from the local Ace Hardware in Florence AZ - what do you want to bet the "house" Ace brand isn't for seals & O Rings???
Hopefully things will hold up for a few weeks - am off to Mexico this next week and then heading for WA state late March.
At least I'm hearing about this potential issue before flushing the toilet sometime in the future and wondering where the water came from?

**Raven's Roost** · 03-04-2023, 06:22 AM

I have used food grade silicon grease on many an o-ring. Just put some on the toilet ball valves.
https://haynesmfg.com/products/hayne...ease-4-oz-tube

There is also Magic Lube for pools. Pool stores should have tubes available. There are two flavors: Silicon and PTFE.
https://www.poolzoom.com/magic-lube-...lubricant.html

AZ should have LOTS of pool stores.

Steve

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