BWT Flex Head installation - Pressure regulator before or after water filter

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#1: Post by JDA1987 »


First time poster here but looking to get more actively involved.

I have a Marzocco Linea Mini that I'm installing with a BWT Flex Head water filter. For space and retrofit reasons, the filter is in my mechanical room in the basement and the machine is right above it. Say 7 feet higher, from filter output to machine input.

I'll be in the process of installing the filter head this week but before I have a few questions.

1) is the BWT pressure reducer meant to protect the coffee machine? Or the filter too?
2) based on the answer for 1) will dictate where the pressure reducer goes, if to protect the coffee machine I will install it after the Flex Head and if to protect both I will put it before
3) if installed before, so I need to account for the restriction created in the Flex Head to set my pressure reducer operating point? I know I'll have to manually adjust it for the 7 feet difference between the Flex Head outlet and the machine inlet
4) where does the flow meter go? Is it relevant if after or before the flex head? I would think not.

Thank you!

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BaristaBoy E61

#2: Post by BaristaBoy E61 »

BWT BestHead is specified for an inlet pressure of 2 to 8 Bar.

We have pressure regulator and flow meter turbine counter after the filter. This makes for easier filter flushing at full line water pressure easier. Flushing is not counted by the flow meter. Be sure to include ¼-turn cut-off ball valves before the filter in the mechanical room and in the kitchen before the espresso machine. Use 3/8in copper tubing and John Guest 3/8in fittings.

Unless you have water inlet pressure from the street higher than 8-Bar I wouldn't worry about it. You can set the pressure regulator for whatever pressure you want to see at your machine by reading the static pressure on the pump gauge. There might be some minor fluctuation that is not a great concern.

Our setup is almost exactly like yours. I have our pressure setup to give us the best line level preinfusion. Street level pressure above 11-Bar might cause leaking from OPV or steam boiler safety valve even when cold.

I would recommend purchasing the smallest size filter as it's likely to expire before it's exhausted unless you make a tremendous amount of coffee or unless your water is unusually hard.

I always recommend the installation of a Leak Detector with automatic cut-off to prevent a possible kitchen disaster!

"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

JDA1987 (original poster)

#3: Post by JDA1987 (original poster) »


I wanted to thank you for your input.

Why do you suggest copper lines? Unfortunately my plumber isn't a big fan of John Guest so we have two speedways 3/8 bsp to 3/8 compression on both sides. Both sides are connected to pex piping.

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BaristaBoy E61

#4: Post by BaristaBoy E61 »

JDA1987 wrote:Why do you suggest copper lines?
Our plumber prefers copper, as do I. Considering that our boilers are copper as is much of our machine's piping. There is no better piping, although you can use whatever you choose.

John Guest fittings are quick, convenient and so far have not leaked.
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"