I am going to go under my mobile home and check the both lines, they are covered in pipe Insulation,to check what fittings the previous owner used. I thing the test set up is leaking, put it together with Teflon tape, I will use pipe dope next time. also I will get a 1/4" tee for a vac test at the fuel pump. I did not want to have to go under my home as it is 17 degrees out right now. 1 good thing it is on a concrete slab, I use a mechanics creepier to slide down to where the lines are and I have permanent lights installed under there, just have to plug them in.
OK that was the test to see if the pump seal is leaking or if the fuel pipe is leaking. The running vacuum test is taken with all the valves open and the burner operating. The gauge should be as close to the pump as possible. A tee like this in the pump inlet (where the valve was installed)will do nicely. 1/4" street tee.
By the description of the fuel line, you have a normal vacuum near 8"Hg or higher. The fuel deaerator will fix your problem. but there is little room for that in a mfg. housing heater. "tight space" So I would recommend the 2 stage pump to guarantee the noise is eliminated.
Ed I did the vacuum test....I put the vac gauge at the oil tank after the filter, Shut the valve at the tank Vac went up to or down to -25", after 5 Mins it read -21". I have 43' of Horizontal run, 10' Vertical = -14". I did make the mistake of using Teflon tape on the gauge set up, I will change it tomorrow, Should I put the Firomatic valve back in at the pump. I also closed the valve on the test set up to see if it is leaking there.
Ed. Cleaners should really not be in the system more than 1 week...10 days Max. Power flushing is highly recommended. When the stuff is flushed out typically the sanitary sewer in fine. What did you figure on for a boiler? Need to look at the fine print especially if it is a Bosch/ Buderus. They can void warranty stuff when it comes to Non- barrier tubing. Where are you located?
Ed, I don't know of any studies that have been done only the jobs that I have been to. That is upwards on 20 that have Onix tubing installed. I have flushed out the systems, power flushed out 4-5 and saved some of the fluid. After it settles out (and it is a suspension) I have run a magnet through the material left. It sticks to the magnet. If the tubing was what was breaking down it would not stick to the magnet. This suggests that its all the ferrous parts of the system... Cast iron boiler, expansion tank, air scoop and circulators. In those cases the tubing appears intact. I have swapped out as much of the ferrous components and treated the system w/ an inhibitor. I have used Fernox and Rhomar. Both will help.... I actually think Rhomar is a bit better. Hope this helps. kevin