Hi,
I have a ceramikX (9"x2.5") filter hooked up to my Elektra T1. I noticed that the flow rate is .75gpm. Is that enough flow to supply my machine? It seems they're all really low flow. Is that the flow rate for max filtration? I don't want to starve my machine of water.
Thanks,
Joe

If I've done my math right, it's fine for espresso extraction rates: (0.75 gallons / minute) x (128 ounces / gallon) x (minute / 60 seconds) = 1.6 ounces / second. However, the pump may cavitate while refilling the steam boiler. I would consider an accumulator to buffer the flow since filters get slower over time.

HB wrote:However, the pump may cavitate while refilling the steam boiler. I would consider an accumulator to buffer the flow since filters get slower over time.

Dan is right. When drawing water through the group, the flow is limited by an 0.9mm jet that restricts the flow to < 1 oz/s. I can't remember the exact rate off the top of my head, but I am sure about that. During the steam boiler refill, there is no such flow restrictor, and the flow rate is extremely high. This is bad from two perspectives... First, your pump may cavitate from low-flow filters or a low-flow water line, and second, pumping that much cold water into the boiler that fast causes the boiler temperature to drop much faster than the heating element can recover, which can be a pain if you want to steam anytime soon.

My pump also cavitates just a little bit when the steam boiler fill is activated. For my part, this is because the water flow rate in my apartment is not up to snuff. They're supposed to fix that soon enough. Another possible solution to this problem is to fill the steam boiler without turning on the pump. You would need to do some rewiring, I think, to accomplish this. I've been considering doing this. The main problem with it is, you will want to make it so that you can re-activate pump-filling the boiler for descaling, etc--when you draw citric acid from a bucket.

Yet another option would be to put a flow restrictor on the boiler fill line. This shouldn't be too hard, but of course you'll have to find and fit the restrictor somewhere.

Anyway, if you get an accumulator, get a darn big one. I have one of those Shurflo accumulators that they use in RVs, and while it helps a little bit, the Elektra pump sucks it empty and begins to cavitate again on the more significant fills (the rare occasion that you draw 12 oz. of water, which I do when I am soaking my baskets, or doing the weekly boiler flush to keep the mineral level in the boiler down).

Thanks for the replies. Can someone tell me what an accumulator does, where I Can get one and how to hook it up? Maybe I should look at a different type of filter instead. Might be cheaper. What flow rate should I look for?

My system consists of 3/8" line. Their supply comes from the water line to a barrel type softener, to the filter to a pressure regulator to the machine. I'm thinking the flow of the softener might be restrictive too.

Thanks,
Joe

An accumulator acts as a buffer so the pressure doesn't drop precipitously. It's nothing more than a water storage tank with a pressurized rubber bladder. They're needed for reverse osmosis water treatment systems, so Google finds quite a few options: reverse+osmosis+accumulator.

I understand now. Thanks! I have a very large one for my house supply. Since I have a booster pump to raise the psi I also have a tank that supplies 10 gallons of water at 60psi so the pump isn't continuously running. How big of a tank do I need?

I think a 1 gallon accumulator would be more than adequate for just the Elektra. The little Shurflo I have isn't half that. Still, if you can fit the 3 gallon one OK, it's probably better.

I think that's more cost effective than large, high-flow filters. They can get expensive.

shadowfax wrote:I think a 1 gallon accumulator would be more than adequate for just the Elektra. The little Shurflo I have isn't half that. Still, if you can fit the 3 gallon one OK, it's probably better.

Keep in mind that, at least for the ones I've seen, the size refers to the total volume of the tank. You usually pump the bladder up to 7 psi, so that sets the pressure of water at which the tank volume is entirely filled by bladder. Depending on the pressure drop you're willing to tolerate, the usable volume may be considerably less than the stated one.

Best,
David

Could I use this,
http://www.lowes.com/lowes/lkn?action=p ... 8324-LPT-2

Its the same brand I have in my house now and way cheaper than the Shurflo 2 gallon model (by about 2/3)

Thanks,
Joe

Sure, why not. If you want to save a few more dollars, it may be worth searching online or eBay.