Vitodens 100-W b1he-150 piped "backwards"

formy

For some unexplained reason my plumber has decided to pipe the unit "backwards" (supply/returns flipped). In my case looking at the front from left to right, heating return, DHW return, NG, DHW supply, heating supply.
I expressed my concerned that it's not in accordance with the manual and all I got is it's going to be fine and not to worry.

Asking the experts for advice if this is fine and I am worrying too much? The unit is not operational yet, it's going to be fired up later today.

Thank you.

GGross

You need to ask them to fix it. Can you post some pics of the overall install

formy

Sure. Here are some pics.

GGross

is it possible to get a pic where you can see the connections under the boiler? it almost looks like one of your space heating pipes is connected to a DHW port on the boiler but it is hard to tell

GGross

Your hydraulic separator (the big brass thing that is attached to strut on the wall near boiler) should be connected to A and D on this chart. The top pipe coming off the separator should go to A and the bottom one should go to D

From your water heater you should have pipes going to B and C

If this is not the case, then just as you expect they have not piped it correctly. It must be changed

DJD775

@formy From your pictures and a quick scan of the manual it looks like it is plumbed correctly up to the hydraulic separator. In your initial post you mentioned the heating return was on the left but according to the manual that is the supply.

formy

Thanks for your comments @GGross . I'll ask my plumber to redo the piping. I can confirm that the space heating pipes are indeed connected to A and D and not to B/C.

@DJD775. I see. Instead of redoing the piping on the bottom of the unit, maybe he can just swap the pipes to the left of the hydraulic separator. Thanks.

Ironman

The pipes on the left of the separator are backwards; they’re correct on the boiler side. In other words, the supply must connect to the top of the low loss header and the return to the bottom on both sides.

JUGHNE

Are the combustion air inlet pipe and the exhaust pipe on the opposite sides of the house?

Sometimes approved....sometimes not.

Usually both to be in the same pressure zone on the exterior of the house.

GGross

@JUGHNE
Viessmann is generally OK with this arrangement of venting

formy

@JUGHNE Exhaust goes up thru the relined chimney, intake thru the side of the house.

pedmec

requirements for intake/exhaust venting being in the same pressure zone has been dropped by a lot manufacturers but not all. Installation manual needs to be read for proper installation.