Well if you have recently done the block as you say, you will surely have changed the little O rings on the NRVs they come as part of the kit. However the guide cone on the NRVs does get a lip on it, that sometimes sits on the seat making the valves weep air. Do the test of NRV1 as described earlier. Any air coming from exhaust port when compressor is stopped and system is up to pressure is more than likely a leaking NRV1. The violet coded pipe from block to tank is the only connection that takes air to and from the tank. If both ends are sound and not leaking, way to test for leaks in pipe is to disconnect it from tank and block end. Then suck on other end and seal with your tongue, you should be able to get it to stick by vacuum. If it won't and the end is properly sealed there will be a pin hole in it. Unlikely though. Get it up to pressure spray with soapy water look for bubbles is the normal way of leak detection.
