No PTO pump pressure

[CMR]

Where is the filter at? Between the tank and the TEE? Or between the TEE and the pump?

Between T and pump as I said before

 

[LD1]

If the filter is between the tee and the pump it's a suction filter and you are fine. This is the first time you have given an accurate enough description we know where it is. Fluid is only flowing one way across it. No problem.

No, it is not logical thinking to believe that the line between tee and pump is both suction and return.

Again, your lack of understanding the terminology, then not accepting the correct terms when told is adding to confusion.

The pipe or hose....from the tank all the way up to and including the tee is simply an extension of the tank.

You have two distinct likes, suction and return. They are not the same, never the same, and no part you your setup can be called both.

Using your logic....you could call the return line a pressure line. Since all of the fluid on that line was once in the pressure line. Hell you could call the pressure line a suction line by the same logic.

One your return hits the tee....return ENDS. From that point forward, no part of it is return

 

[LouNY]

A lot of Peeing in the coffee cups today.
The OP's system wasn't unusual 40 years ago.
Today it would not be made for a few reasons. The filter being located between the tee and pump is a suction filter.
Suction filters or screens are usually used in a good system a return line filter is also used. The suction screens or filters filter out the coarse
contaminates that will rapidly damage the pump and valve often being a 50 mesh screen or 50 or 25 micron filter. At the same
time the return line filter can be a 10 micron filter to catch the smaller particles and maintain a cleaner oil.
One issue commonly found with the single line tank setup is moisture contamination of the fluid as much of the fluid lies stagnate in the tank,
the other issue that is quite common when one of these older systems gets worked hard is the temperature rise of the pressurized fluid as it is not circulated through the reservoir which also acts as a heat sink to cool the oil over temperature conditions can occur.
Also the top of the reservoir should be vented other wise pressure and vacuum conditions will be created in the system,
this will cause either vacuum leaks into or pressure leaks out of the system or both.

 

[wdchyd]

FWIW, I have seen some old Gresen spin on filters that were actually 100 mesh screens internally when opened up. Maybe someone down the line mistakenly replaced one of these with a paper type normal everyday return line filter element.
That said I don’t like paper element filters used on the suction lines of any circuit, though it may work sometimes it usually ends up with bad mojo when it gets cold.

 

[CMR]

FWIW, I have seen some old Gresen spin on filters that were actually 100 mesh screens internally when opened up. Maybe someone down the line mistakenly replaced one of these with a paper type normal everyday return line filter element.
That said I don’t like paper element filters used on the suction lines of any circuit, though it may work sometimes it usually ends up with bad mojo when it gets cold.

Like I said before, I used a hydraulic filter, Napa 1551. I suspect it is up to the task

 

[CMR]

A lot of Peeing in the coffee cups today.
The OP's system wasn't unusual 40 years ago.
Today it would not be made for a few reasons. The filter being located between the tee and pump is a suction filter.
Suction filters or screens are usually used in a good system a return line filter is also used. The suction screens or filters filter out the coarse
contaminates that will rapidly damage the pump and valve often being a 50 mesh screen or 50 or 25 micron filter. At the same
time the return line filter can be a 10 micron filter to catch the smaller particles and maintain a cleaner oil.
One issue commonly found with the single line tank setup is moisture contamination of the fluid as much of the fluid lies stagnate in the tank,
the other issue that is quite common when one of these older systems gets worked hard is the temperature rise of the pressurized fluid as it is not circulated through the reservoir which also acts as a heat sink to cool the oil over temperature conditions can occur.
Also the top of the reservoir should be vented other wise pressure and vacuum conditions will be created in the system,
this will cause either vacuum leaks into or pressure leaks out of the system or both.

 

[CMR]

I’m looking for a vent with the 3/4 NPT I have, I think it will prevent condensation and evaporate water. I really haven’t had any leakage except from infrequent repairable seals. It only gets fluid by gravity, so there’s not much pressure inside that tank. Next to none. You haven’t said how an unventilated filler cap increases pressure

 

[CMR]

I’m looking for a vent with the 3/4 NPT I have, I think it will prevent condensation and evaporate water. I really haven’t had any leakage except from infrequent repairable seals. It only gets fluid by gravity, so there’s not much pressure inside that tank. Next to none. You haven’t said how an unventilated filler cap increases pressure

Oh ok you said pressure increases as the heat increases the volume of the fluid. That’s not much pressure. I appreciate the suggestion to get a line filter for the ten micron filter instead of the 50. I’ll look into that.

 

[CMR]

If the filter is between the tee and the pump it's a suction filter and you are fine. This is the first time you have given an accurate enough description we know where it is. Fluid is only flowing one way across it. No problem.

No, it is not logical thinking to believe that the line between tee and pump is both suction and return.

Again, your lack of understanding the terminology, then not accepting the correct terms when told is adding to confusion.

The pipe or hose....from the tank all the way up to and including the tee is simply an extension of the tank.

You have two distinct likes, suction and return. They are not the same, never the same, and no part you your setup can be called both.

Using your logic....you could call the return line a pressure line. Since all of the fluid on that line was once in the pressure line. Hell you could call the pressure line a suction line by the same logic.

One your return hits the tee....return ENDS. From that point forward, no part of it is return

I don’t see how I could attempt to claim a pressurized supply line could pass as a suction line, you’re really grasping at straws there aren’t you? Let’s just say the only return is from the valve to the T then, and anything with suction is just suction line. That’s fine. So the filter is on a suction line. But you have to agree that the fact remains that some of the fluid, probably 90% of it, is not going to the tank, and IS being suctioned through the filter, right?

 

[CMR]

I don’t see how I could attempt to claim a pressurized supply line could pass as a suction line, you’re really grasping at straws there aren’t you? Let’s just say the only return is from the valve to the T then, and anything with suction is just suction line. That’s fine. So the filter is on a suction line. But you have to agree that the fact remains that some of the fluid, probably 90% of it, is not going to the tank, and IS being suctioned through the filter, right?

I get the 90% estimate by virtue of the fact that the return from the valve is entering the T while the pump is sucking on the T, so why would return fluid instead go into the bottom of the tank. It’s primarily circulating in a pump to valve circuit. Which includes the