Nicholas, you think it looks good now, wait until you get these in the mail




I love having a wood shop.

*snap*

This just keeps getting more and more awesome. I'm really looking forward to seeing this thing completed.

Thanks, Dave!

Well, here goes a requested update for Tom and Mark... photos of my pump outboarding.



It's a little complicated. I use filtered water at the tap next to the machine, so that adds a bit to it. However, I've done some work toward simplifying the setup, and I think that it's more or less paid off. Here's a quick explanation of how this works: In the center, you can see the inlet from the mains. It elbows, and there's a gate valve (main shutoff for the setup) and enters the top fitting of the softener. Softened water exits the bottom fitting, and enters the carbon filter. From there, it goes through the regulator, and over to the main junction on the right: Accumulator, sink line, and pump inlet. That tee right after the pressure regulator serves to bleed pressure into a container when I shut things off, and also serves as an inlet for a water tank when I want to descale the machine.

For now, the pump is mounted by zip-tie to several layers of melamine foam wrapped in a plastic bag, and held against that rubber mat. It rocks around a little on startup, but there's actually surprisingly little of that. It works very well for a temporary setup. In a few weeks I am hoping to make my own mounts for the pump--I can't find a place that will sell me a motor mount without a motor, alas. Another detail: you can see that my check valve is installed right prior to the pump. Stefano is sending me a brass check valve that is intended to go on the pump's outlet. This will be good, because the pressure on the line actually hovers at 7-8 bars when the pump is off, and I'd rather avoid having that pressure on the pump's sealing bearings all the time.



As for wiring, I ran wires from the brain box out to the control side of a SSR, which you can see mounted above. I wired an extension cord to the load line of that SSR and connected it to the original plug assembly of the pump. That works pretty nicely, one plug to disconnect the pump. For now I have mounted the SSR to the wall of the cabinet, but I am planning on putting that all in a project box and wiring it with no exposed wire. I mounted it to the wall to keep it out of any water, of course.



Up inside the machine, I hooked up the braided hose line to the main inlet junction for the machine. I got a 1/4" F BSPT to 3/8 M BSPT adaptor to do this, and it worked relatively without a hitch, other than some stupid leaks on the boiler inlet valve assembly... I actually ripped out some threads on the junction (far up it) trying to tighten down the nut that's used to set the thing, so I replaced it with copious amounts of Teflon tape. This looks a little tacky, but I'm OK with it for now.



Pretty simple inside the machine, eh? I bet it's ventilating a lot better, too. It's really nice to have the pump put far away from this environment. Hopefully that will extend its life. You can also see my zip-ties holding the hose and pump wiring together in the photo above.

I guess that's it for now... comments welcome.

Hi Nicholas,

and you said it looks bad:) good job, even though it's not completed.

I would love to be able to mount stuff to the inside of the cupboard, but as it is not mine I can't do that. Instead I used adhesive cable tie bases which hold the power cable 60cm above the bottom of the cabinet which is more than enough for protection.

That's some bad news with those threads on that junction, but I know that threaded joints can be tricky. I recently bought some Loctite 542 thread sealant to get rid of teflon tape for good and hopefully will have clean nice leak-free threaded joints on the pump.

Regards,
dsc.

I like how much space you have in there. Have you installed the new handles yet?

Mark

shadowfax wrote:the pressure on the line actually hovers at 7-8 bars when the pump is off, and I'd rather avoid having that pressure on the pump's sealing bearings all the time.

I initially was thinking that was due to the line locking up after a pump cycle occurs, but I'm not sure. Does the line from the pump to the solenoid always have that much pressure after the pump shuts off? That's a lot of pressure on that hose!

Honestly, it didn't do that before I outboarded the pump. I had suspected it had to do with the ~1/60 s switching delay on the SSR I added, as well as the increased volume of water "after the pump" (in the hose), but these ideas seem less and less reasonable the more I think about them. Perhaps it's that the hose flexes much more than copper pipe does, and it holds the pressure longer than can be relieved between the pump shutoff and the closing of the solenoid valve. I assume it also has something to do with thermal expansion, since the line is fully open to the heat exchanger. I was actually seeing it drift up over 12 bars the first night, but then I took apart and descaled my thermal expansion valve (aka the OPV that shouldn't open during brewing), which I forgot to do when I originally descaled everything else. Now it tops out at 8 bars at idle now.

Anyway, I have seen very similar behavior to this on a Synesso (pump pressure remaining high after a shot pulls), so I am not hugely worried about it. I believe these braided hoses are rated for quite high operating pressures.

Sounds compelling. I was mostly curious as I have somewhat the same problem on my GS3. The brew boiler gauge will sometimes crawl above 12bar, even though the expansion valve is set correct - well set correctly as far as I can tell. I was told to set it at initial power up on a cold boiler, and as the machine warms up.

I wonder if a short delay on closing the solenoid after the pump shuts off would relieve the pressure. I know those lines can hold some pressure, but if that line blew, the place would be flooded.

Sounds like your GS3 has the same anomaly that I witnessed on my friend's Synesso. I think delaying solenoid shutoff could help, but that's easier said than done, and it would suck to get backflow of coffee water into the water line (the risk of delaying the shutoff). If I were you, I would try adjusting the OPV down when heated up. Even if it does open a little bit during brewing, it's easy enough to turn it back up, and the flow rate of a rotary pump is so high that even if the valve does open up it will still be able to hold the brew pressure.

As for lines blowing: that is extremely rare, and I believe it's more related to crappy fittings shearing than anything else. What's much more likely is springing a small, slow leak. You could end up with a big puddle, but the chances of flooding your house are pretty low. If you're concerned, you should look for one of those systems that shuts off the water supply if it detects a leak. IIRC, there's a thread on HB about it.

I already have a leak detector. To be honest, I was just trying to show concern about the line bursting. Granted it's pretty unlikely, but it's also worth our few words discussing it. I usually see those types of lines burst at the joint between the fitting and the tube itself, as you said.

Wouldn't the check valve keep the water from flowing backwards? I would assume the pressure after the pump stops would continue to flow forward, through the solenoid, and out the OPV, or just overfilling the boiler slightly given it's a HX.

I was going to mess with that expansion valve this weekend. As it sits, it's not impacting the spro, so it's been a low priority.