20A surge protector: http://www.google.com/products?q=panamax+max+2+20+amp

I have also been using a 15A surge protector on my Bricoletta and so far it is functioning normally. I have a Kill-a-watt and I believe the current draw while the heating element is on is at around 16.6A, and the power usage is at around 1960w. If the pump is operating at the same time as the heating element it increases to around 16.8A and 2000w. My surge protector/timer are both rated at 1875w, so that is within 10% of the rated operating capacity... I think that is probably "good enough". YMMV though.

Since people in this thread known a lot about plumbing (everything I asked about earlier works now, by the way, so a big thanks!), I'll try to tack on another question. I'm trying to adjust the inlet pressure to match the machine's specs, and was wondering about pressure loss.

I run plumbing for the machine in the basement (filter, etc.) and then up through the floor into the dining room where the machine is. My pressure gauge is in the basement (after the filter and regulator) and reads around 45 PSI. The entire system is 1/2'' PEX tubing, and after the water runs through the PSI gauge it goes through about 30 feet of tubing, 5 feet rise (from basement ceiling to machine on 1st floor), and a few sharkbite fittings (elbow, shutoff valve, tee [to tee off some extra tubing to another valve that lets me draw water next to the machine ... sort of a makeshift faucet], 1-way valve, and a fitting to reduce the 1/2'' to the 3/8'' machine hose.

I'm wondering how much pressure I lose in this setup. The 5 feet elevation would by my calculation cost me about 2.5 PSI, the fittings and tubing maybe a little more (though I don't have a good sense how much, esp. whether the 1-way valve leads to PSI losses). And my main question: what happens to PSI when the line is reduced from 1/2'' to 3/8''? Common sense tells me that pressure increases (water flow gets compressed into smaller space), but at the same time, there's added friction in the reducing fitting that might actually decrease pressure.

I could hook up a second gauge close to the machine, but before I go buy one of those, I wanted to see if anyone knows how to calculate (or estimate) pressure losses. Even with a second gauge it'd be nice to know how water pressure behaves in these common plumbing setups

Essentially zilch. Of course, anytime there is a flow of fluid through a piping network, there is a loss of pressure in each segment BUT, in your particular case, the velocity of the water through this network is very low and thus the pressure loss is small. There is a small pressure loss in the 1/2 to 3/8 transition but, of course, an increase in the water's velocity.

If you really want to delve into it further, here is a good practical reference - http://www.craneco.com/Category/200/Purchase-Flow-of-Fluids.html

So would it be safe to say that beyond the PSI loss from moving water up about 5 feet (roughly 2.5 PSI), the various fittings and about 30 feet of PEX will result in at most 1-2 PSI loss (i.e., nothing substantial)? I guess I don't have a good sense of just how fast the water is running through these tubes, but if it's fairly slow, that makes sense.

Yes, no substantial pressure loss. You could even read it on your machine's gage with the pump disabled but with line pressure water flowing through the group.

Just out of curiosity: how would I get line pressure to flow through the group without engaging the pump? I thought that's something that most home E61 machines can't do.

Disconnect one of the wires or both depending on the connector configuration. Do all of this WITH THE MACHINE UNPLUGGED.

Hmm....thanks, but I think I'll just measure the pressure before the water goes into the machine . Haven't owned it long enough yet to unplug wires inside.