I think it could be normal, if the pool is not losing water. On my filter and pump, I have a valve, that when open, causes bubbles to come out of the low end jets, simulating the jets of a jacuzzi. When closed, there are no bubbles. If the pool is losing water, then the appearance of bubbles in the pump, or coming out of the jets could be due to air from from the outside which would mean a leak in one or more of the lines or at the fittings. Also, I'm curious as to how one would "pressure check" a return line from the skimmer, the main drain or vacuum line since these wouldn't be under pressure from the pump. If your pool is blowing air back into the pool through the return lines, it is caused by an air leak, on the suction side of the pump. Because the pump is above the water level of the pool, you will not lose any water. To check to see if you are sucking air at the pump, turn the pump on and take some dish detergent and squirt it along each Plumbing fitting in front of the pump. Watch to see if any soap bubbles form in the pump housing. If so, you'll probably need to to replace those fittings, one of them is leaking.
The leak discussed above could involve both in and out fittings on the pump or it could be a leaking pump seal or a loose pump lid or lid gasket. The probable cause of this leak at the fittings is that the pump ran dry at some point in time causing the PVC fittings to become hot and shrink.
Pressure testing of the return lines involves plugging those lines at the pool and and pump. The people who do this sort of thing have a tool or tools to insert in the system and introducing air into those lines monitoring pressure loss in each particular line through a process of elimination.
Yes, pressure and return cooler lines.
The elastic makes marks that take time to return to normal.
Pressure and return lines that goto radiator and or transmission cooler to keep the ATF chilled off.
A leak on the return or supply lines and the automatic feeder is not working
turbos are cooled with oil and that oil is supplied from oil pressure lines. check out the turbo and trace the lines; they should return to the oil pan.
the fuel return line is on your fuel rail. it is part of the Pressure regulator assembly. Please view my Bio for access to my Saturn help site. in the fuel folder, go to Fuel pressure lines. the return line is highlited in green for you
a return address should have 2 lines
The transmission cooler lines are located coming from the radiator on the bottom. One is for the sending and the other for return. The lines are high pressure, just as your radiator hoses are when the car is running. The lines go from the radiator to the top of the transmission.
There are 2 fuel lines. One is a pressure line to the injectors and the other is a return to the tank.
the return lines are 99% of the time the ones with the smallest diameter.(also are not bolted down like the high pressure one)
Lines of Barometric pressure
The lines on a map for pressure stands for Isobars which they are lines on a map around areas with the same pressure readings to indicate highs and lows.
The 3800 engine (fuel injected) has a pressure feed to the fuel rail (smaller line) and a return from the pressure relief valve (larger line). All fuel lines use the O-ring fuel connectors.
with the ignition switch OFF, break the fuel lines loose slowly. there may be some fuel leak out, but that is normal.
Supply is above and return is under.
This can be tricky with several variables involved. How many skimmers? Are they independent lines? Any idea what clogged it? Toy? Acorns? Leaves? Concrete?
Pressure is shown with white curvy lines. The closer the lines are to each other in a certain area, the higher the pressure is. The farter apart they are, the lower the pressure is in that area.
Isobars, lines of equal pressure
The low pressure port is the one on the accumulator (the canister). The low pressure lines are the bigger lines and the high pressure are the small lines.
Pressure by the hydraulic pump is made​​.
It should not matter as one is pressure and the other is return from the transmission oil cooler.
Usually the leaks are at the high pressure line or the return line of the power steering pump. Tighten all the lines at the pump.
Fuel starvation, replace diesel filters first, then check lift pump for proper operation and fuel pressure.Also check for leaks in the fuel lines, and return lines...common problems on diesel engines.
isobars lines of equal pressure
normal lines or normals