Skip to main content

Troubleshooting our Buderus Logamatic 4000 based heating system, part II (manifolds)

In the last part of this series, I've outlined the heating system in our newly acquired house, which had some issues: namely it was not warm enough.

As a  software engineer I was trying to find the problem by modeling the components in the system, then by coming up with a theory that could be the root cause, then either prove or disprove it by doing measurements. Even if the theory is wrong, I learn something about how the stuff works. If I am right I get closer to solving the problem.

The first theory I had was about water flow. I was kind of sure that the boiler produces enough heat, but if the hot water is not flowing through the pipes in sufficient quantities our rooms will remain cold.

So I was trying to find how I can find the flow information. The answer lies  in the heating manifolds:


I have one of these on all floors of the house, their role is to distribute the incoming hot water into multiple downstream pipes (under the floor heating or wall heating) and then collect them back. You can see the red one which is the hot side, and the blue one is the cold side.

As you can see, I have 8 circles in this manifold, each of which can be opened/shut using an electronic motor (driven by temperature control). The flows of the circles are shown on the cold (blue) side.

Those plastic thingies on the top of the collection  side show how much water per minute is flowing though a specific circle.


There's a yellow plate in these that move up as water flows, but there are versions that move down. You will find a scale there to show the amount proportional to the movement of the plate.

The water that needs to cross is measured in litres/minute, but I have seen the use of cubic meters per hour as well.

The minimum you need depends on how much wattage you need in a room to heat it. This is typically specified in the heating designs of your house. I needed somewhere between 2-5 litres per minute. This is important as the wattage depends on how much water you pump in a room and how much degrees it cools down while in there.

If you need 2kW per hour, water cooling down 4 degrees, you will need roughly 120 liters per hour, eg 2 liters every minute. (Basic physics).

I actually had much less than that 2-5 litres (in some cases 1-1.5), especially when more rooms were heated, that  was one issue that needed fixing, so at this point I decided to eventually check out the pump that drives the water flow in the pipes.

Interestingly, the flow measurements weren't entirely conclusive as one of the bathrooms was pretty warm even though it's flow was only a trickle, and I had to find out why.

So next, I decided to check out the thermostats, as I suspected their settings were customized by the previous owner. Since the house has a KNX based smart home infrastructure,  to check out these adjustments I needed to set up access to the KNX bus as well as install the software needed (ETS). But more on these in the next episode.


Comments

Popular posts from this blog

syslog-ng fun with performance

I like christmas for a number of reasons: in addition to the traditional "meet and have fun with your family", eat lots of delicious food and so on, I like it because this is the season of the year when I have some time to do whatever I feel like. This year I felt like doing some syslog-ng performance analysis. After reading Ulrich Deppert's series about stuff "What every programmer should know about memory" on LWN, I thought I'm more than prepared to improve syslog-ng performance. Before going any further, I'd recommend this reading to any programmer, it's a bit long but every second reading it is worth it. As you need to measure performance in order to improve it, I wrote a tool called "loggen". This program generates messages messages at a user-specifyable rate. Apart from the git repository you can get this tool from the latest syslog-ng snapshots. Loggen supports TCP, UDP and UNIX domain sockets, so really almost everything can be me...

syslog-ng OSE 2.1 released

I have just uploaded the first release in the syslog-ng Open Source Edition 2.1 branch to our website. It is currently only available in source format at this location: http://www.balabit.com/downloads/files/syslog-ng/sources/2.1/src This release synchronizes the core of syslog-ng to the latest PE version and adds the SQL destination driver. This is an alpha release and thus might be rough around the edges, but it basically only contains code already tested in the context of the Premium Edition. The SQL functionality requires a patched libdbi package, which is available at the same link. We're going to work on integrating all our libdbi related patches to the upstream package. If you want to know how the SQL logging works, please see the Administrator's Guide or our latest white paper Collecting syslog messages into an SQL database with syslog-ng. The latter describes the Premium Edition, but it applies to the Open Source one equally well.

syslog-ng 3.2 changes

I've just pushed a round of updates to the syslog-ng 3.2 repository, featuring some interesting stuff, such as: SQL reorganization: Patrick Hemmer sent in a patch to implement explicit transaction support instead of the previous auto-commit mode used by syslog-ng. I threw in some fixes and refactored the code somewhat. Configuration parser changes: the syntax errors produced by syslog-ng became much more user-friendly: not only the column is displayed, but also the erroneous line is printed and the error location is also highlighted. Additional plugin modules were created: afsql for the SQL destination, and afstreams for Solaris STREAMS devices. Creating a new plugin from core code takes about 15 minutes. I'm quite satisfied. With the addition of these two modules, it is now possible to use syslog-ng without any kind of runtime dependency except libc. The already existing afsocket module (providing tcp/udp sources & destinations) is compiled twice: once with and once withou...