Viessmann VitoCal A2WHP , running!

hot_rod

Viessmann has good training vids on sizing, piping, and wiring. I didn’t find a control programming video? The manual is a bit uncharacteristically slim for Viessmann on the control portion. A few tech support folks got me through the error screens, thanks . More to lean on the control functions,

It is very quiet, inside and out, maintaining tank temperature, 115F through the 30 degree evenings. Including the 20 gallon buffer in their package helps with piping options. I put a HX between the outdoor unit and buffer. So only about 3 gallons of glycol needed. The control has a relay to wire the HX pump to. Also contacts to call on the boiler for extreme cold back up.

Not the prettiest insulation job on the piping 🥴

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mattmia2

Is the thing that looks like the gas tank from a 70's honda engine the expansion tank? You made the copper bends and the drawn tee fittings?

Kaos

Nice! That first bit of hot water is very satisfying.

The manual on most of these units need a lot of work. I'm pretty good with figuring stuff out but it took me an afternoon to get hot water out of mine. Some of it was basic stuff like the pump priming function simply would not work.

I can't see anybody not specifically trained on these getting a unit installed and working. It really doesn't have to be this way though.

hot_rod

https://forum.heatinghelp.com/discussion/comment/1821617#Comment_1821617

yes it is a flat, or pancake style tank. There is one just like it inside that Viessmann indoor unit. They save a little space. The diaphragm is front to back, so I believe they can be mounted in any position.

Yes all the bends and the pulled tees I did in the shop.

JakeCK

Sweet! You should install one for me next?!

Joking!

Kinda.

hot_rod

It is a fairly simple install compared to a boiler. No fuel piping, venting, combustion adjustments, yearly HX cleaning and combustion analysis.

If you isolate it from the system, the small 3 gallons glycol at low temperatures should not be a maintenance issue. I used all copper and brass piping on the HP/ glycol side.

I'd like to see a non ferrous, composite pump inside the module. I think it is a Wilo. And a DHW type expansion tank. Then it would be 100% ferrous free.