Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 22

Thread: Pump overrun

  1. #11
    Automated Home Jr Member
    Join Date
    Nov 2016
    Posts
    43

    Default

    Quote Originally Posted by victorp1612 View Post
    Interested to hear their feedback as I have the same setup as you
    Hi, are you running overtherm as well?

  2. #12
    Automated Home Jr Member
    Join Date
    Nov 2016
    Posts
    43

    Default

    From Viessman :

    The Europe market boilers do not have the facility to change the overrun time parameters.

    Pump overrun on all Vitodens 100-W boilers is temperature controlled, and it is optional on the open vent version. It may be used or not as you see fit. The boiler is unlikely to be harmed if it is not connected.

  3. #13
    Automated Home Jr Member
    Join Date
    Jun 2016
    Posts
    24

    Default

    Quote Originally Posted by Norfolkboy View Post
    Hi, are you running overtherm as well?
    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.

  4. #14
    Automated Home Jr Member
    Join Date
    Nov 2016
    Posts
    43

    Default

    Quote 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.
    Thaks for that, what is the lowest temp you have seen it modulate at, my system sounds indentical to yours but im see it modulate at 28-33C which seems too low, also viessman just told me -"I would not use Opentherm myself, it's a bit like fitting a BMW automatic gearbox to a Mercedes-Benz"

  5. #15
    Automated Home Jr Member
    Join Date
    Jun 2016
    Posts
    24

    Default

    Quote Originally Posted by Norfolkboy View Post
    Thaks for that, what is the lowest temp you have seen it modulate at, my system sounds indentical to yours but im see it modulate at 28-33C which seems too low, also viessman just told me -"I would not use Opentherm myself, it's a bit like fitting a BMW automatic gearbox to a Mercedes-Benz"
    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.
    Within approx 5 mins ( didn't time it ) , the temp had dropped back to 31 and the same process repeated.

  6. #16
    Automated Home Jr Member
    Join Date
    Nov 2016
    Posts
    43

    Default

    Quote 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

  7. #17
    Automated Home Jr Member
    Join Date
    Jun 2016
    Posts
    24

    Default

    Quote 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 )

  8. #18
    Automated Home Jr Member
    Join Date
    Nov 2016
    Posts
    43

    Default

    Quote 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

  9. #19
    Automated Home Legend
    Join Date
    May 2014
    Posts
    1,000

    Default

    Quote 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!!

  10. #20
    Automated Home Jr Member
    Join Date
    Jun 2016
    Posts
    24

    Default

    Quote 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 )

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •