Dometic Toilet Water Pressure Pump Not Working

[Area45]

Hopefully this is the right place to post this.

I have a Dometic toilet in our Four Wheel Camper. It's either the 970 or the version just before. The pump to pressurize the tank has stopped working. The lever comes up and can be pushed down, but it feels like something inside is not making a seal and not creating the pressure. Does anyone know if it can be replaced or serviced? I looked in my manual but I only see a part number for the entire pump assembly. I was hoping to see a replacement washer or something like a camp stove might have to pressurize the fuel tank.

Any ideas or help would be much appreciated. Thank you.

 

[camelracer]

I don't have any experience with the Dometic toilet but I had a similar problem with my Thetford toilet. It turned out to be a tear in the pump bellows. I found a replacement bellows on the internet (not too expensive) and it was an easy repair.

 

[Area45]

I don't have any experience with the Dometic toilet but I had a similar problem with my Thetford toilet. It turned out to be a tear in the pump bellows. I found a replacement bellows on the internet (not too expensive) and it was an easy repair.

Thank you. I'm going to try and open it up tonight or tomorrow. Hoping it's something like that.

 

[Old Crow]

My wife and I rented a campervan with what I believe was a 970-series potti in New Zealand a few years ago. The pump on that one kinda-worked but was awful. I wondered if putting lubricant of some type down the shaft might improve the seal so it would pump better. But if I read your post correctly, your pump isn’t working at all.

Like you, I'm not finding anything on rebuilding the pump assembly on the Web. I see what I think is the pump assembly on page 34 here and note that page 25 tells us it listed for $41.11 (in 2013). That seems like a lot but the best price I could find on a new 970-series potti (5 gallon) was $120 on Amazon.

If you can figure out how to remove the assembly, you might take a shot at repairing it but I'd think the odds are against you, especially if there’s a broken part inside. But who knows....

You might also call up a Dometic SaniPotti parts supplier (like these guys) and see what you can learn. Maybe you'll get lucky, perhaps with a good price, perhaps with a lead on how to to remove the old pump assembly when/if you do find one at a good price.

The other thought is Dometic customer support. The Sanitation Products number/email address would I’d think be better than the RV ones, depending on how they split their product lines.

When the bellows-style pump in my old Thetford broke years ago, I realized I didn't really like that pump anyway. So I switched to using a plastic sports-style water bottle to spray a few well-directed squirts into the bowl for wash-down. For me, that works better than the pump and lightens the potti quite a bit since I no longer need water in the upper chamber. But I did have to find the right storage spot for the squirt-bottles I dedicate to that purpose. Just a thought.

Good luck!

 

[Area45]

Ok, so I tore into it today. I was somewhat reluctant because as luck would have it, it appeared to be working again. I didn't want to make it worse since the pump was creating some pressure again, although it was quite sticky. So I figured it was still looking into.

I was able to unscrew the pump assembly and then, with some carefully placed flat head screwdrivers, worked the pump lever out of the body. I wish they would make it more user serviceable. Too much force on one of the tabs would make the pump assembly unusable. There is just a rubber o-ring inside there. The walls of the pump chamber were pretty sticky so I figured that's where the friction was coming from.

My guess is that the pump assembly wasn't working due to cold weather. When we first noticed it we were up north and the overnight temps were close to freezing. Maybe the o-ring shrunk just enough to not be contacting the walls? Then, when it was warmer again the pump worked, but there was too much friction. Would the cold weather affect whatever lubricant was already in there?

Anyways, I applied some silicone lubricant from the plumbing department to the o-ring and re-assembled everything. It works like a champ now! While it was out it gotta very thorough cleaning and topped with water. Plus a sticker from Joshua Tree National Park since it was used there.

 

[Wandering Sagebrush]

It was the sticker that fixed it .

Good work!! Did you by any chance photo document it? Might make a good 'how to'.

 

[Happyjax]

I like the idea of the squirt bottle. More efficient better control on usage

 

[Area45]

It was the sticker that fixed it .

Good work!! Did you by any chance photo document it? Might make a good 'how to'.

I only thought about it when I was typing up my post last night. Next time it fails I'll take pics. Hopefully it will be a while.

 

[Old Crow]

Glad to see you got it working, Area45!

Also:

Just attaching some Dometic 970-series related stuff to this thread for future readers. (I'm unable to travel right now and just keeping busy. If I got anything wrong, please let me know.)

Parts diagram. Note that it's a bit confusing because it shows the two holding-tank sizes and the optional marine sanitation device (MSD) fittings. Diagram is from here (where you can also see part numbers and nomenclatures). The o-ring Area45 lubed is in the pump assembly marked 1.



Another view of the air pump assembly (and a water-tank cap). Apparently the pump can be pried apart but requires judicious prying.



Intro video to the product. Interesting for those of us with other systems. Offhand, it seems the o-ringed air pump is not a great idea (if it tends to go dry and is difficult to lube). But it does have the benefit of not needing the batteries of an electric pump or the repeated pushing of a bellows pump.

Promotional brochure showing model numbers, capacities, measurements etc for both 970 and 960 series.