Viessmann pump overun

[sammymeir]

Hi, Looking for help with moving into my new house, I have 2 Viessmann boilers as a cascade system 200-w controlled by a 300-k panel and 200-H. It doesn't appear to be set up how I would expect, when calling for heat Id expect the valve to open and then the heating pump and boiler pump to start and the boiler to fire. They all operate at the same time meaning the water cant pump anywhere because the valve isn't open yet is this normal? When the heating goes off the boiler pump stays on with the valve closed, but because there is nowhere for the water to go it won't cool for such a long time meaning the pump is constantly running, how can I overcome this.

 

[Brambles]

I would start by looking at the Benchmark Certificate and contacting the system installer for advice.

Background:

There are a multitude of ways to configure the 300k controller. The installer will have / should have prepared a hydraulic schematic of the system - which will include the designated heating / dhw pumps and their respective temperature sensors. The document is probably with the installation manual and service record book.

Thereafter, thoroughly read through the 300k installation manual - to get a good understanding of the product and how it works. The 300k is not a wiring centre it is an installer configurable external control interface.

If you have not got the system specific schematic, the only way is reverse draw it out from the installation as installed.

Thereafter you can work through the control philosophy and how it interacts with each boiler and the assigned priorities.

I would not make any configuration changes unless you are confident that you know what you are doing and the impact it may /could have.
In my view, it is unlikely that this ( the 300k) was installed and configured by someone who did not know what they were doing.

 

[sammymeir]

I would start by looking at the Benchmark Certificate and contacting the system installer for advice.

Background:

There are a multitude of ways to configure the 300k controller. The installer will have / should have prepared a hydraulic schematic of the system - which will include the designated heating / dhw pumps and their respective temperature sensors. The document is probably with the installation manual and service record book.

I would start by thoroughly reading through the 300k installation manual - to get a good understanding of the product and how it works. The 300k is not a wiring center it is an installer configurable external control interface.

If you have not got the system-specific schematic, the only way is to reverse draw it out from the installation as installed.

Thereafter you can work through the control philosophy.

I would not make any configuration changes unless you are confident that you know what you are doing and the impact it may /could have. It is unlikely that this ( the 300k) was installed and configured by someone who did not know what they were doing.

Hi, thanks for your reply, I don't have any drawings as such but do have the manuals. I do have a good understanding of wiring boilers as I'm an electrician and regularly do s and y plan systems. This seems just a bigger scale and with lon connectors instead of the boiler. I've spent many weeks getting familiar with the pannels and how to set things up, but not having much luck with the pump overrun issue. Also, there are several zones with my heating, and 1 of them id like to change the stat to a programable one. I'm struggling to see how this can be done as there doesn't seem to be a connection on the panel that fires the boiler, only connections that become live depending on which heating circuit you select.

 

[ShaunCorbs]

Hi, thanks for your reply, I don't have any drawings as such but do have the manuals. I do have a good understanding of wiring boilers as I'm an electrician and regularly do s and y plan systems. This seems just a bigger scale and with lon connectors instead of the boiler. I've spent many weeks getting familiar with the pannels and how to set things up, but not having much luck with the pump overrun issue. Also, there are several zones with my heating, and 1 of them id like to change the stat to a programable one. I'm struggling to see how this can be done as there doesn't seem to be a connection on the panel that fires the boiler, only connections that become live depending on which heating circuit you select.

havd you tried phoning Viessmann’s tech up ?

 

[Brambles]

Hi,

We installed a system with a Vitronics 300 controller in November 2019 in Oxon. The control equipment and bits and pieces was £430 net and it took our controls man 11 hours over two days to install and commission.

The boilers were existing and the pipework modifications flushings, new pumps filters et al a further 2 days work.

Looking at the detail, it would be difficult and time consuming to draw out the schematic from looking at the installation. There are three control blocks - each of the boilers internal controllers and modified settings and the Vitronics box.

I think that contacting the original installer for information would be my starting point.

One other point that often emerges in these type of domestic installations is that are just not required. In most cases the system can be served by one boiler, if a second boiler is required it is often best as a stand alone system, feeding a floor / annex or pool area et al.

Very rarely do we come across domestic situations where multiple linked boilers are required.