Mansfield Toilet System

[MMills]

After searching the existing threads, I am having trouble finding information on my Mansfield Toilet System that seems to pre-date most.
The system does not build up, and "hold" a vacuum, rather when you flush the head, you push a little silver button on the back of the toilet, which starts the remote vacuum pump. The pump runs until a green light comes on, then you step on the "flush" lever.
The system was working great, then out of nowhere, it is struggling to build a vacuum on the tank. (The discharge hoses run direct from the toilets to the holding tank)
I can unhook the discharge hoses at the tank, (which isolates the system to the pump, and tank, eliminating any issues with the toilets themselves) put my hand over the fitting and feel the pump sucking vacuum, and bleeding off over and over. I have checked all of the tank fittings, and they seem solid. I am curious if there is some kind of vacuum pressure switch built into the pump itself??? Any ideas??
Thanks in advance, I appreciate it!

[oil&water]

I had a similar issue with a Vacuflush system. It ended up being a stuck vent valve that wouldn't seal. Check the overboard vent first.

[Big D]

It should be similar to the Vacuflush system in that there's likely a pressure switch to control the level of vacuum, and check valves/duckbill valves. If it's not actually building vacuum and the pump runs continuously, chances are the check valves need to be replaced as they are a regular maintenance item or you have solids stuck in one of the valves keeping it open thus preventing the system from creating a vacuum. The valves are located on both sides of the pump in a Vacuflush application, I suspect it's the same in yours.

[MMills]

I had a similar issue with a Vacuflush system. It ended up being a stuck vent valve that wouldn't seal. Check the overboard vent first.

That would make sense... I will check that out.. Thanks!

[MMills]

It should be similar to the Vacuflush system in that there's likely a pressure switch to control the level of vacuum, and check valves/duckbill valves. If it's not actually building vacuum and the pump runs continuously, chances are the check valves need to be replaced as they are a regular maintenance item or you have solids stuck in one of the valves keeping it open thus preventing the system from creating a vacuum. The valves are located on both sides of the pump in a Vacuflush application, I suspect it's the same in yours.

I could be wrong, but I believe this system does not use duckbill valves... the vacuum pump hose goes direct to the blackwater tank. I can unhook the waste lines from the toilet, which should eliminate the vacuum switches on the heads themselves. The tank doesn't "hold" a vacuum, rather it developes a vacuum each time you flush by pushing a button on the back of the toilet, which activates the pump.. I am not sure if there is a vacuum pressure switch on the pump or not. It has two electric motors with drive belts that work bellows at the base of the pump to create the vacuum.

Thanks for the info, I appreciate it!

[MMills]

I had a similar issue with a Vacuflush system. It ended up being a stuck vent valve that wouldn't seal. Check the overboard vent first.

Right on the money!! Problem solved! Thank you sir!

[oil&water]

Right on the money!! Problem solved! Thank you sir!

Awesome! Glad to hear it is fixed! That's why I love this board.