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Viessmann B2HB 200 & vitocell indirect tank -no hot water

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mtorsen
mtorsen Member Posts: 5
edited February 2016 in Domestic Hot Water
hi all.

We recently installed a Viessmann B2HB 200 series boiler and a Viessmann vitocell indirect hot water tank. The heating side has been online and working for the last month. We commissioned the hot water tank yesterday, it worked fine for 24 hours. Now, when there is a DHW call on the boiler nothing happens. There is no fault on the boiler and it says the DHW tank temp is 5 degrees C, so it should be firing. The boiler fires perfectly for heating. We have bled and refilled the lines a few times to no avail. We have checked the time programming and every other conceivable setting as well. The DHW circulation pump runs fine.

Any input or suggestions would be greatly appreciated.

Thanks in advance


T.



Comments

  • JharrisSeattle
    JharrisSeattle Member Posts: 26
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    Is the dhw pump downstream of the low loss header? If so, change address 5b from 0 to 1. If directly connected to your boiler you are most likely not proving the internal flow switch. Possibly a backwards pump?
  • JharrisSeattle
    JharrisSeattle Member Posts: 26
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    Nevermind on the backwards pump. Jest reread that it was working for 24 hrs.
  • CMadatMe
    CMadatMe Member Posts: 3,086
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    Pictures please. What size boiler B2HB19,26,35,45,60,57? What size VitoCell?

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  • mtorsen
    mtorsen Member Posts: 5
    edited February 2016
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    It is directly connected to the boiler. The weird thing is that it worked fine for 24 hrs. Lots of hot water. We had to shut down the water to the house for a bit and drain the cold water lines, when we recharged everything (we didn't drain the heating loops but the hot water tank was drained)that is when the problem started but like I said the heating side works fine.
  • GW
    GW Member Posts: 4,700
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    Did you double check your clock settings? Those Germans don't use hw on weekends (opinion)
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    gary@wilsonph.com
  • CMadatMe
    CMadatMe Member Posts: 3,086
    edited February 2016
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    What size boiler and what size tank? What size is the supply/return piping from the tank? There's a menu now for Mon-Sun..

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  • mtorsen
    mtorsen Member Posts: 5
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    Hi. We checked and rechecked the time settings. It is on the Monday to Sunday 00:01 - 24:00 hours.

    It is a 92 gallon tank connected by 3/4 inch lines to the 119,000 BTU version of the 200 B2HB.

  • GW
    GW Member Posts: 4,700
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    Ok good, did you check your system type? If your programming is similar to the WB2B vitodens 200, you need to check this in the coding set up. Does your boiler tell you what the temperature is? Or is there no temp reading for the water heater?
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    gary@wilsonph.com
  • mtorsen
    mtorsen Member Posts: 5
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    We did check the setup, a few times, everything looks good. The boiler is reading the probe in the DHW tank. The tank is about 5 C (41 F), so according the the boiler programming, it should be firing.
  • gennady
    gennady Member Posts: 839
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    how tank is piped? directly to the boiler or after separator?
    It looks like boiler is not configured properly.
  • CMadatMe
    CMadatMe Member Posts: 3,086
    edited February 2016
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    3/4" Is WAY TOO SMALL. DHW Pump can't make the flow switch so boiler is more then likely just sitting there looking at you. Minimum pipe size for a 119 is 1" supply/return for B2HB35.

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  • mtorsen
    mtorsen Member Posts: 5
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    Hi Chris, I am not disagreeing with you but I am curious, where did you see that spec? The boiler's factory connections are 3/4.
  • CMadatMe
    CMadatMe Member Posts: 3,086
    edited February 2016
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    Flow rate sir... Pump should be a Grundfoss UPS15-58 if you have a EVI-119 (Stainless Tank). Page 4 of the Viessmann Tech Data Manual. But the 1-1/4 is based on the btu/hr output required plus they are assuming a bigger boiler. Doesn't matter what the outlet size of the taps are. You size piping for the gpm required to move and you aren't moving 5.9gpm (flow rate needed across the heat exchanger at high fire) through 3/4" pipe. Needs to be a min of 1". You are also not getting the recovery as listed because you can't flow 28gpm across the coil. You can move 280,000 Btu/hr across a 119 Coil with minimal pressure drop.

    If the boiler is standing there just looking at you its generally 1 or 2 things. You are either air bound, can't make the flow switch or condensate is backed up. But since the boiler fires on heating, take condensate out which leads me to believe the indirect is either air bound and/or you can't make the flow switch. Also check the check valve in that pump. Never know, something could have got hung up in it. Always remember in the Viessmann world. No Flow, No Go and No Fault Code.

    http://www.viessmann.ca/content/dam/vi-brands/CA/pdfs/tanks/vitocell-v_300_tdm.pdf

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