It sure looks like the pumps are pumping away from the water feed line, which means they're pumping out of the return tapping, which would mean that you're pumping into the supply tapping, which makes me think it looks like the pumps are backward? Might just be the way I'm looking at the in/out of the pumps. Because if they are pumping into the return tapping, that would mean you're pumping toward the water feed line, which I guess would be OK if you turned the valve off. Am I seeing this right? Or explaining what I see right?
A friend just had a modular home built and here are pics from the boiler room (located in a "walled in" section of the garage. House is 2x6 construction. 2 floors. Approx 2500sf. Boiler is oil fired, direct vent. Comments/questions are welcome and I will be happy to get more/better pics if needed.