Plumb into hot water line?

Water analysis, treatment, and mineral recipes for optimum taste and equipment health.

#1: Post by mountmustache »

I sit here on a beautiful Sunday morning in the mountains, drinking a locally roasted SO Costa Rican americano, contemplating life and, more importantly, coffee.

I'm currently plumbed in with a water filter/softener and bypass valve to get the appropriate minimally scaling water. Everything's great and I'm not changing anything in the foreseeable future. But what I've always wondered, is why not plumb things in to the hot water line? My thought is that the hot water heater taken the brunt of the scaling and is sending out pretty clean water. I haven't tested any of my hot water, but was wondering what the downsides would be. What am I missing?


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#2: Post by ragdoll serenade »

I would guess that your hot water heater removes only a tiny fraction of the minerals that cause scale that are present as water flows through it. The remainder are left to go and deposit (in small amounts) inside your espresso machine. Scale is something that forms and accumulates over time....If you have a TDS measuring device, check the numbers of the hot and cold side of the tap and see what you get. It's a nice idea....


#3: Post by lagoon »

So much to unpack here. I'd caution against.

What does the water from your HWS taste like?

Your filtration cartridge before your coffee machine will almost certainly be incompatible with hot water.

Parts of your machine not designed for a hot water feed may fail or expand or both.

If you get a leak, it will be hot water instead of cold.

Hot water taps tend to have wild temp variation, especially if unused for an hour or more. They will run cold for the first litre or so, and then slowly warm up.

In other words, shot 1 of the day the machine is fed with water at 20C. Shot two 60C. That's a big ask of the machine.


#4: Post by Ciaran »

Prior to PID controllers becoming common, feeding a commercial espresso machine with hot water was a way to increase stability in the heating system. You have to install the heater after the water filters, as they can't tolerate high temps. The common practice was to install a Bosch 4 or 6-gallon point of use water heater right before the machine. A commercial machine isn't going to be damaged by feeding it hot water.

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#5: Post by JohnB. »

If you have a tank style hot water heater you never want to be drinking that water. There is a reason you are supposed to flush the entire tank yearly.

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#6: Post by Peppersass » replying to JohnB. »

Really? Yikes. I didn't know that. We've had our gas-fired hot water heater for 24+ years and have never flushed it.

[It wouldn't be unreasonable for people to chime in here with advice to replace the hot water heater to avoid the high probability of a leak from a tank that old, but ours is glass-lined and seems to be holding up well. That said, I'm keeping a close watch on it, as I am with our 27 year-old gas furnace and 24-year old A/C compressor...]

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#7: Post by JohnB. » replying to Peppersass »

Never too late. Hook up a hose to the tank drain, shut off the feed & open a few hot water faucets. Should look pretty clear until you get down to the bottom. My Buderus indirect hot water heater has a sacrificial magnesium anode rod that slowly dissolves in the tank to protect the fittings from corrosion. Drained the electric hot water tank in my shop after many years of use & the bottom was nothing but black mucky water. Took a few flushes to clear that out.

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#8: Post by Randy G. »

An old water heater that has not been regularly drained will weigh a lot more than when it was new from the sediment that can collect in the bottom. With a gas water heater that is problematic enough, but with an electric that can possibly, eventually cause the bottom element to fail.

Be sure to turn off the water heater before draining.
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