Any doser you buy will need servicing this is correct, 3 months is a max based on high useage but 6 months cleaning and annual replacement for any doser peri tube is recommended. The APEX is absolutely no different and if "any" manufacturer told anyone they did not need replacing I will be very concerned with that advise
No manufacturer made that claim, I beleive the DOS has a quick snap release for the one piece replacement tube....no fuss just pop out and replace. The others require motor head disassembly and alignment of rollers etc. the apex just seems easier to maintain.
Rollers
NEVER need replacing there is no service part for them or price as you literally cant buy them
No you can't buy the rollers seperatly, had to buy the $60 replacement head because I was made to think that there was not enough grip on the motor shaft caused by degrading rollers.
If a doser loses prime its near impossible due to the design for it to be the pump itself, (im talking German and or other quality units, GHL etc, not cheap chinese units like BM etc where tolerances are very poor) all dosers use rollers which squeeze the pipe in either two or 3 locations, prime loss is always an issue with air seal of the pipe from the dosing container to the dosing unit itself.
I have replaced the lines, the connections the vessels every possible thing I could think of and still the motor runs but pulls nothing. If I switch the intake to my one functioning pump head it will draw liquid, so I'm not sure about air seal problems.
These are important things to remember for anyone investing in a doser, service is key dosers are mechanical and will need intervention, this is 100% normal.
Agreed, the DOS just seems like an easier to maintain
The screen with the old doser went through a
limited batch run where the pins would lift from the doser board, this was rectified in 2013. The new doser has no screen - no problem
Still leaves me with a twice busted screen that will cost me additional money to now replace.
The new GHL doser 2 uses German built high grade stepper motors
not small brush driven DC motors you find in older style units and in other manufacturer units also. Having said that the older GHL doser used German motors and were pretty bullet proof.
They sure look like the same small brush motors with the same small diameter tubing.
Hope that helps more so when looking for new dosers and the requirement for servicing, this is important for any doser someone buys.