Motor Shaft Seal--Vacuum or Pressure Side?

[Scowman]

Greetings.

I have searched but cannot find an answer on this. I am running down a vacuum leak in the plumbing (I have read all the threads) but I cannot determine if the pool motor shaft seal is on the pressure side or the vacuum side. Said another way, could the motor shaft seal be the source of bubbles in the pool return? To me it seems like it would be on the pressure side, but something is nagging at me telling me that it could be vacuum as well be cause it is on the exact opposite side of the impeller as the inlet. The impeller seems to create pressure tangentially and not longitudinally like a boat motor.. Just thinking out loud here.

15k in-ground cement pool, Intelliflo VSP, Sand Filter, etc.....

Thanks in advance.

 

[Bill1974]

Pressure side, but it's not much pressure. This is why we see leaks when the pump is running, otherwise it would be sucking in air. When the pump is off it will see vacuum, but not much, unless your pump is below water level. Ideally these types of seals like to see pressure or vacuum only and need to lubricated with water/fluid at all times. Grease, finger prints, anything else on the seal faces just make it fail sooner. One side is a ceramic and the other is graphite. The graphite is easily damaged. There are other materials available, harder ceramics and even diamond coated silicon carbide instead of graphite. These are many times more durable, then can grind down sand. I only know this because I worked on improving the seal performance used in liquid ring pumps used in dental applications. FYI the cost for the better seal is not worth for a pool pump IMO (a couple of bucks for the ceramic/graphite compared to ~$40+ for a better ceramic/silicon carbide) unless your never check on your pool equipment and/or a leak would cause a lot of damage.

 

[1poolman1]

Greetings.

I have searched but cannot find an answer on this. I am running down a vacuum leak in the plumbing (I have read all the threads) but I cannot determine if the pool motor shaft seal is on the pressure side or the vacuum side. Said another way, could the motor shaft seal be the source of bubbles in the pool return? To me it seems like it would be on the pressure side, but something is nagging at me telling me that it could be vacuum as well be cause it is on the exact opposite side of the impeller as the inlet. The impeller seems to create pressure tangentially and not longitudinally like a boat motor.. Just thinking out loud here.

15k in-ground cement pool, Intelliflo VSP, Sand Filter, etc.....

Thanks in advance.

Do you feel/see water below the pump right a the back of the sealplate. As counterintuitive as it seems, a bad seal can cause enough of a suction leak to stop a pump from priming. On your pump, replacing a #1000 seal is not too difficult, nor costly (don't forget the impeller screw is left-hand threaded). A standard US Seal, PS-1000, will last a long time. A description/picture of the rest of your equipment would help

 

[Scowman]

I bought a saltwater seal kit from inyo. Going to replace all those. Then wotk my way out from that. I will inspect the housing too. Could be old glue fitting too. Or a cracked lid... might just get a new one.