Zilmet mini buffer install and review

hot_rod · May 4

I am downsizing from a 20 gallon buffer to this Zilmet 7 gallon for my A2WHP.

The tank came from Supply House.com. They did an excellent job with packaging, 20' of bubble wrap!

I like the adjustable wall mount brackets. If they were a bit longer you could get to the mount screws easier.

It is nicely jacketed, connections protrude out so you can spot leaks on the threaded connections.

Labels were crooked, oh well.

My biggest grip is that the ports are not aligned well. You need to use swing ells, of bend the tube slightly, to get them all in alignment, and space out the wall bracket mount to get the side ports aligned parallel with the wall.

Easier said than done getting 6 ports aligned on a round vessel, plus two mount threaded connections.

HydronicMike · May 4

Very interesting. How did you size it to confirm 7 gallons would be enough or give you the performance you desire? Just asking as 7 gallons doesn't seem like much.

hot_rod · May 4

My radiant is only one zone now, and the cooling will be a single zone air handler also. So mainly it is a hydraulic sep and a reference point for the control sensor.

This Viessmann A2whp model ships with a 20 gallon buffer tank. it is designed to sit on top of their indirect tank, so large diameter and stubby.

Screenshot 2026-05-04 at 10.32.14 AM.png

EBEBRATT-Ed · May 4

When I did welded pipe (I am not much of a welder) you put a pipe in a pipe vise with a pipe stand on the far end and level the pipe.

Find the top center line on the pipe using a square and a level. For instance 4" pipe is 4 1/2" od so holding 1 leg of a framing square on top of the pipe and you plumb the other leg pointing to the ground then center punch the top center 2 1/4" from the inside edge of the square.

You only need 4 hands to do this. Then cut and weld in the tapping's by squaring and leveling them.

Don't know how they do tanks but it would have to be similar.

mattmia2 · May 5

you could probably punch them or mark them in a line before you roll it in to a cylinder

hot_rod · May 5

Certainly hand making a tank or vessel would/ should allow spot on taps and connection.

I suspect these tanks are robotically mass produced and whatever "jig" aligns the ports is not dialed in. Even the top and bottom ports are not parallel or plumb to the tank. So a total of 8 ports, none in alignment with one another.

To clearly see this you could screw a 12" long nipple into each connection and get a visual of the mis alignment.

GGross · May 5

https://forum.heatinghelp.com/discussion/comment/1895834#Comment_1895834

did you notice similar mis-alignment with the viessmann 20 gallon buffer?

hot_rod · May 6

https://forum.heatinghelp.com/discussion/comment/1895837#Comment_1895837

Funny you should ask, I'm using that 20 gallon as my drainback tank for this 42 gallon Vitocell. I installed a glass site gauge today and alignment was perfect, square to the tank, parallel and in the same plane.

Same for the other connections on the 20, and the connections on the Vitocell 42. So it can be done on a mass scale.

Zilmet mini buffer install and review

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