Seal plan for condensate extraction pump

[Karam Al Battat]

Hi everybody
We have flowserve virtical condensate extraction pumps in our power plant.
API 13 in combination with API 32 are used for supporting the mechanical seal of the pumps.
There is a problem on the sealing lines (API 32) on the both pumps, the check valve allows backflow through it, so water flow from seal chamber of the running condensate pump to the seal chamber of the SB pump.
What is the reason of the two check valves are damaged?
What is the effect of the problem on the running pump and the SB pump?

 

[Pandeyji]

For Condensate extraction pump only Plan 13 should be sufficient. No need of Plan 32.
In case there is chance of vapourisation due to pressure drop created by Throat bush, use Plan 14.