Pump overrun

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts
  • Norfolkboy
    Automated Home Jr Member
    • Nov 2016
    • 43

    #16
    Originally posted by victorp1612 View Post
    I've been reading your other posts , looks like you're having a hard time with your set up ...
    Just checked my boiler behavior : here's what I noticed.
    Current heat demand is minimal - the system is maintaining the existing set points.
    The boiler pump was running and temp was 35
    It fluctuated up and around 35 and when it dropped to 31 , the burner fired up ( 1 bar on the output display ) for approx 15 secs until temp reached 46/48. The burner then stopped. The
    Within approx 5 mins ( didn't time it ) , the temp had dropped back to 31 and the same process repeated.
    Thanks for this once mine gets going it does s a good job, just seems a little strange getting up to desired temp. Did you need the optional hot water demand box from viessman, to get max flow temp when hw is called, I didn't but read another member that did have to- gets me thinking if their are different versions of the software in the boiler

    Comment

    • victorp1612
      Automated Home Jr Member
      • Jun 2016
      • 24

      #17
      Originally posted by Norfolkboy View Post
      Thanks for this once mine gets going it does s a good job, just seems a little strange getting up to desired temp. Did you need the optional hot water demand box from viessman, to get max flow temp when hw is called, I didn't but read another member that did have to- gets me thinking if their are different versions of the software in the boiler
      No additional Viessman boxes , just the plain boiler and the evohome.
      Opentherm module attached to boiler and a BDR controlling the HW.
      As a matter of interest, do you have dials ( knobs ) on your viessman or is everything controlled through the touch screen ? ( wondering if we have the exact same model - I have the touch screen model )

      Comment

      • Norfolkboy
        Automated Home Jr Member
        • Nov 2016
        • 43

        #18
        Originally posted by victorp1612 View Post
        No additional Viessman boxes , just the plain boiler and the evohome.
        Opentherm module attached to boiler and a BDR controlling the HW.
        As a matter of interest, do you have dials ( knobs ) on your viessman or is everything controlled through the touch screen ? ( wondering if we have the exact same model - I have the touch screen model )

        I don't have a touchscreen, can you adjust the boiler setup on that? I am unable adjust anything on mine, which may help with the short cycling I'm seeing sometimes

        Comment

        • HenGus
          Automated Home Legend
          • May 2014
          • 1001

          #19
          Originally posted by victorp1612 View Post
          Yep , sorry I should have added that I'm using Opentherm with a Vitodens 100W. I have 9 Rads and the DHW kit on a S plan config - with a ABV installed.
          I definitely see Opentherm modulating as when the heat demand is low , average temperature demand is 40 ( would need to check again ) with 1 bar on the burner output displayed on the boiler.
          If the heat demand increases, so does burner output and water temp.
          When DHW kicks in , it goes full blast - up to 80deg . Once the DHW time is over , it closes the valve on the cylinder and the boiler pump will then stop. It will however kick in again for a few seconds as the temperature rises. It usually does this 2 or 3 times over a 10 minute period until the boiler temp decreases.
          Sorry to thread creep. I m looking at the Viessmann with O/T. How is the HW BDR configured to get 80c HW? I was told that the HW demand box is a must. Out-of-interest, what size of boiler do you have? I ask because I have a 5 bed modern property (15 years old) with an Ideal FF280 (24kW). One installer has suggested that I need a 32kW, and another a 24kW but I could go as low as 18kW!!

          Comment

          • victorp1612
            Automated Home Jr Member
            • Jun 2016
            • 24

            #20
            Originally posted by HenGus View Post
            Sorry to thread creep. I m looking at the Viessmann with O/T. How is the HW BDR configured to get 80c HW? I was told that the HW demand box is a must. Out-of-interest, what size of boiler do you have? I ask because I have a 5 bed modern property (15 years old) with an Ideal FF280 (24kW). One installer has suggested that I need a 32kW, and another a 24kW but I could go as low as 18kW!!
            I have a 14yr old house , 3 bed + converted attic - I've checked the label on the boiler and it's a 19kW.
            For HW, I didn't do any special config. The sensor attached to the cylinder is connected to the BDR , which is then bound on the evohome as Stored Hotwater.
            When HW comes on , the boiler fires up at 80 ( don't know why 80 ... I've checked the boiler config and see that HW temp can be set but it looks like the opentherm module over rides that setting )

            Comment

            • HenGus
              Automated Home Legend
              • May 2014
              • 1001

              #21
              Thanks - that's interesting. I was told that without the HW Demand box, the HW would just heat at the modulated boiler output temperature.

              Comment

              • Norfolkboy
                Automated Home Jr Member
                • Nov 2016
                • 43

                #22
                Originally posted by HenGus View Post
                Sorry to thread creep. I m looking at the Viessmann with O/T. How is the HW BDR configured to get 80c HW? I was told that the HW demand box is a must. Out-of-interest, what size of boiler do you have? I ask because I have a 5 bed modern property (15 years old) with an Ideal FF280 (24kW). One installer has suggested that I need a 32kW, and another a 24kW but I could go as low as 18kW!!

                As a fellow viessman owner, I have a 26kw version, 3 floors 14 rads in the 60 year old house. I also thought I needed the demand box so bought it, but then tried it without connecting it up and the opentherm upped the temp to 78c when hw demand. Can sell you my box if you need one!

                Comment

                Working...
                X