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Only getting 109F from my CombiPlus (Vitodens 100)

bhilton
bhilton Member Posts: 51
Hello everyone,

My Vitodens boiler gets up to 148 F on the digital display and my in floor heat, etc, all works great now that the Taco is wired properly.

I hadn't had a chance to test the CombiPlus DHW until the other day.

#1 My plumber has a temp guage directly on the outflow of the CombiPlus and it seems no matter what setting 4, 5, 6 or as far as the knob will turn to the right, I only get 108-110 F coming out of the CombiPlus. Is it possible to get 120 F or more out of the CombiPlus?

#2 I've tried following the instructions to set the COMFORT mode so the DHW is more immediately available, but the instruction manual steps aren't working. Any tips or comments on using the COMFORT mode? Any ideas why when I follow the procedure in the manual it ignores me? It says turn the DHW knob all the way to the right and in 3s it will.... and then COMFORT will show on the screen to indicate it's on. Seems to ignore me when I try!


Thank you guys!

Bill


Comments

  • bhilton
    bhilton Member Posts: 51
    Also note I have well water which is quite cold I've been told and the boiler does not have the outdoor sensor hooked up (yet).
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,450
    ODR has nothing to do with combi operation. I assume you have the 35Kw boiler? It's rated at 3.6 GPM at 63* rise. Get a bucket and a stopwatch and determine the flow rate. If it's more than 3.6 GPM you will get less than a 63* rise.
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  • bhilton
    bhilton Member Posts: 51
    Hi Robert, all my tests have been @ 1.1gpm - my water softener has an indicator showing the flow rate (live) and I can tell by just looking at the water coming out of the shower or kitchen faucet, it's not abnormally high - you can tell it's eco-flow restricted at the fixture.
  • bhilton
    bhilton Member Posts: 51
    Or wait, are you asking about the flow rate of the closed loop between the CombiPlus and the boiler?
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,450
    A 26 isn't a good choice with the combi plus, only 2.6GPM at 63* rise. The 26 requires a restrictor in the combi plus unit,is it installed?
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  • bhilton
    bhilton Member Posts: 51
    Just called to confirm, I was wrong, despite my heat loss paperwork which calls for a -26, he says I do have a -35, it says right on the side of the boiler. I've got a hold of my local Viessmann sales rep and he thinks it's either not programmed right or the jumper in the boiler to tell it the Combi is there was not removed. The fact that the COMFORT option is not accessible even by following the instructions to enable/disable it, he thinks the boiler does not know the Combi is there... my plumber is back this afternoon to go over it again (3rd time now).
  • bhilton
    bhilton Member Posts: 51
    Solved! The jumper was off, so that was allowing the combi to partially work. The boiler still needed to be programmed to tell it a Combi was there. Had to follow the instructions very carefully. :) Plumber left yesterday after not being able to do it - I tried it: turn both knobs to the dead center, then the DHW knob all the way to the right, etc. It took me a few tries but I got the ECO on the screen! Then I followed the steps to enable COMFORT mode. Everything works like a charm, had my first shower in my new place this morning!
    Robert O'Brien