Switching radiators off properly

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Hi, I'm a complete newbie when it comes to these things... just bought a flat and learning as I go. So I need some quick advice about radiators here in Germany. I want to switch a radiator off properly, i.e. at the pipes.

 

Here's the radiator in the bathroom:

post-26963-13981995609617_thumb.jpg

 

Am I right in thinking I need to turn one (or both) of these? Which way?

 

Also what does this regulate on the side?

post-26963-13981995735877_thumb.jpg

 

Cheers for any advice!

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Don't mess around with anything except the big white knob, which should be turned to 0 or the * symbol. That'll shut off the inlet valve.

 

The one on the side, if opened, will lead to copious amounts of system water pouring out!

 

The 2 lower ones look like lock shield valves that you could isolate the radiator with, but if the system has been balanced then these valves will be in a "half open" position that should not be tampered with or your radiators might become unbalanced.

 

Normally you'd only have one lock shield valve on the radiator return, the other one here (on the flow) seems to be there just to make maintenance easier (ie, allow complete isolation of radiator so it can be removed without needing to drain down entire system)

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I've turned the main knob completely off, and I'm finding that the meter reader "thingy" is still increasing in value (I have no idea what these units mean, it's completely obfuscated IMO). My impression is that when the radiator is switched off properly, these values should not be going up.

 

This radiator is in the bathroom which has a main chimney next to it, the side wall is usually warm anyway... hence no need to have this one on.

 

Cheers.

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The previous owners of the flat apparently didn't use much heating at all, yet they had a heating bill of >€1100. So I'm trying to get to the bottom of it.

 

The meters were recently changed over and I have no idea if the increase in value is something normal or not. I've checked on the ISTA website but have yet to find an explanation of what the values mean.

 

Here's a pic (excuse random sheep :P )

post-26963-13984347507427_thumb.jpg

 

The meter flicks between 2 values when you press the button. I will post these later

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The large white knob on my radiators have a zero symbol as wll as a snowflake symbol. All summer I had most of my radiators set to the zero symbol, so as to minimise the heating cost. I am assuming setting them to zero as opposed to snow is what really completely turns them off.

 

These days, the temp in the night drops off to around 5C. So I am wondering if I should change the setting. I am travelling for a week, and dont want the pipes to freeze or anything. At the same time, I dont want the heating to be on, since I am not there.

 

What is the difference between the zero symbol and the snowflake symbol anyways?

 

Any suggestions would be appreciated.

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The snowflake symbol means - as you correctly deduced - the radiator isn't completely turned off. It's opened just a fraction (the heating effect is almost nonexistent) so water very slowly moves in the pipes, and hopefully does not freeze in the winter.

It's the recommended setting when going on a winter vacation, or when nobody is living in the house.

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How come months after i turned the big white knob to zero (not the snowflake symbol, but beyond it) the radiator is still hot?

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That probably means that the big white knob (room temperature thermostat) is either not seated properly on the valve, or is broken. The former is more likely. If it's broken you can get replacements in all good hardware stores for around €20.

 

Another possibility - the valves themselves (metal bits that sit under the big white knob) eventually wear out, though good ones can outlive the radiator the cheap ones can be useless in 5-10 years. While replacing big white knobs is child's play, replacing the valves is beyond your average DIYer.

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so i guess going away for a week this month, when the temp shouldnt fall below a few degrees, its not any risk to put the radiator to zero symbol?

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replacing the valves is beyond your average DIYer.

 

Yup. Im my rented flat 8teh one I rent out) the valves regularly jam in the "closed" position (another good reason for using "*" rather than "0") and although a couple of taps with a plastic mallet generally loosens them, last season one jammed solidly and had to be replaced. as this is a old-fashioned central heating system, they had to ice up the pipes to replace the valve. Not a DIY job.

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0 means 'OFF'

* means 'Frost Protection' (Usually set at around 7 degrees so basically the house and the pipes don't freeze. If you're away for a week or weekend, either leave as is or just drop to 1. If you plan to vacate for weeks or months maybe consider frost protection setting)

 

Many German thermostats go from 1 through 5 with 1 being ~12C and 5 being ~28C. The middle setting is usually around 20C. As these things aren't digital they can vary by a little (+/- 1C) but are usually pretty good. Some models have the ability to set max and min values by the landlord, so you can't go too hot or cold. Don't be surprised if you might not be able to switch yours off or all the way up to 5. If it's an issue talk to the landlord.

 

As scoffer suggested, the little pin in the middle can wear down over time which would result in them running a little hotter from reference (as the pin pushes the radiator valve in less) but they should still be consistent across the range, so just set a little cooler.

 

In days of internet just try looking online for a user manual of your particular thermostat and you will likely find an exact answer. Example here for Oventrop.

 

https://www.oventrop.com/en-NG/productssystems/articledetails/1011464

 

As murphahp said don't touch the valves at the bottom. They're set by the plumber at time of installation to balance the rads in the flat and you will mess everything up if you play with them.

 

If your rad is always cold, especially at the top and maybe warm halfway down, you likely have air in the rad that needs bleeding out. You were either given a radiator key or speak to the landlord.

 

Hope this helps

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