7900 cleaning cartridges

I have a 7900, and a set of cleaning cartridges from your company. I had another 7900, a "reclamation " job, in which I installed the cartridges, and did get the cleaning fluid to come through on nozzle checks. I had to abandon that one, for reasons not related to your cartridges.
I have another used 7900, which had been using your cleaning system since new. I tried the cartridges, and did several initial fills, but saw no cleaning fluid. I let this go for about a year, as the printer was responding to regular cleaning with ink in the lines.I now a stubborn blockage, on two black nozzles, and I have tried to use the cleaning cartridges. I have done around 8-10 initial refills, and did some “junk paper” printing; still no fluid. Is this normal? AND…the VLM channel is still showing the previous VLM Epson Ink cartridge level,- not the cleaning cartridge. I did spill some ink , upon filling, on the label of the cartridge, but nowhere near the chip. I assume it is a chip problem.
The main goal at this point is to put the printer in hibernation for two months while I am away. The Epson repairperson I have used for other printers has said that one a two blocked channels would not be a problem. I have read on your website that these blocked nozzle would eventually damage the head.
Any help would be appreciated.
Loy

The first thing I’d like to ask you is did you prime the cartridges before using them? This is very very important. That carts should be full of piezoflush (not half full) and they should be primed before doing the initial fill. If no ink flows that either the head or dampers are so blocked that there is no way to pull fluid through the nozzles, or the cleaning assembly vacuum motor is failing (this does happen).

-Walker

Walker
Yes, I did prime the cleaning cartridges, but no, they were not all completely full. I will try again with full cartridges. Since I wrote to to you, I have done a number of initial fill cycles, perhaps ten or twelve, and fluid has begun to come through on the nozzle checks. All the black ink channels are now pink, but the other channels are not, although they seem to be fainter then they were before the introduction of the cleaning fluid. I assume that it would be good to try more cycles to work the fluid into the remaining channels. I did have a stubborn blockage in the LLK channel, which is now gone. Sometimes, the printer will not recognize the ink cartridges. Turning the printer off and then on again seems to help. Also, I read your post about using the cartridge locking handles, and I will try that.
The cleaning cartridge for the VLM channels is still showing as a nearly empty ink cartridge. Do I need another chip or cartridge?
Finally, what I am deducing from posts and your replies about 900 series printers is that their useful life isn’t that long, even if they are well cared for, and that major replacements are routinely needed after a few years. Do you think that the new P series will be less troublesome, and that it might be better long-term to just replace a an older 7900 then put money into repairs? It is a matter of how much improved the new ones are, and I have to assume that nobody really knows for sure yet.