Programable TRV statagy with cast iron rads?

Orionaut

Orionaut

Orionaut

Soldato
Joined
2 Aug 2012
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As above.

I have old cast iron rads (400Lbs each)

I have programmable TRV's

The problem is massive overshoot when the heating first comes on!

(Anybody who has a similar set-up will know what I mean but I will explain for anybody who doesn't if necessary)

I am trying to figure out a strategy for reducing the impact of this, but was just wondering if anybody else had already worked one out?

:)
 
FlyingFish said:
Overshoot?
Click to expand...

Rads fill up with hot water fairly quickly and then become massive storage heaters. By the time the TRV's have an opportunity to respond the amount of heat stored in the rads will make the rooms get up to 25C or more!

They have been "off" for two hours now but the rads are still hot and the room is still at 23C which is wayyyy to hot for me despite the TRV's being set at 17C. :(
 
I wouldn't have programmable trv's on CI radiators,all sorts of problems, as mentioned they hold the heat, better to have a room stat, some peeps actually have seperate zones, ground floor & first floor with seperate stats, this allows for separate areas to be controlled.
 
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You might be in for a bit of trial and error :)

You could try slowing the flow down into the radiator with the lockshield valve, if you can live with the possibility they may make more noise. Slows down how fast they heat up, so gradually heating up the space without turning into a heat store. You may need to run the heating for a longer period.

Turn the temp down at the boiler, so the rads don't get as hot.

Depending on what boiler you have, you might be able to turn down the energy output of the central heating. Has it been set right to start with? You can use an app to work out heat requirements (or Mears calculator if your old school) for each room and house, then set your boiler accordingly.

Mick
 
What I am tempted to try (The terrier valves are quite versatile) is to aim for a burst heat at switch on (Say 19C at 18:00) but with a shut down to 5C shortly after (say after 30 Min) , then a lower switch on value, say at around 17C at 19:30/20:00 Hrs.

As I said to begin, I am just wondering what others have done. I am sure I am not the only person with CI rads. :)
 
turn down the lockshield or the thermostat on your boiler.. if your ci rad gets too hot doesnt it make sense to turn down the heat ? pretty simple really..
 
FlyingFish said:
You can use an app to work out heat requirements (or Mears calculator if your old school) for each room and house, then set your boiler accordingly.

Mick
Click to expand...

Mears calculator.:eek:

Your old enough to remember them, do they still use them?
Having a clear out the other day, I found one I was given over 30 years ago, was in BTU's.:o
 
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