TRV with timer?

Do any of you know if the normal TRV action is powered by a thermostatic element as in an ordinary TRV? With the battery only switching the valve on/off ?

Or, as I had expected, that every TRV action requires the battery to provide the motive power for every turn down of the flow as the room warms up?
The battery will need to make every adjustment Tony. It's only a minute amount it needs to move the valve though.
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I have now fitted 5 Rondostat 20E's digital TRV controllers, bought from Klimalex in Germany. not cheap at 38 Euros each (or 108 for three), plus tax and postage, and I will have great difficulty getting the costs back in savings. However, because I have recently had a Viessman Vitodens 200w fitted, they give me the local room control which is not available with the standard Viessmann control panel, (it has weather comp and no room thermostat).

For anyone thinking of fitting Rondostats, they work very well, perhaps the only drawback being that they only have two on/off periods per day, sufficient for my needs for bedroom and lounge.

Further, the units come supplied with adapters to fit several Danfoss TRV's, but none fitted any of mine, which were all of different types. However their site offers the units supplied with 8 other types of adapter (none were of use to me).

To resolve my problem, I bought Honeywell Angled TRV bodies, as used with their CM Zone, which I guessed would take the Honeywell Rondostats, and so it proved, adding a further £8 or so to the cost of each unit. However, the finished setup is extremely satisfactory, and I am at a complete loss as to why they are not available in the UK, or as Honeywell curtly told me " Not supported"!

gcol, the OP, was very helpful in my project.
The Rondostat is not made by Honeywell, but another company called Caz. Honeywell badge and market it in some regions.

The only disadvange we have found is the display is upside down when fitted to UK pattern radiators. The valve is most compatible with honeywell V117E or VH200E rad valves; other rad valves tend to have a longer 'stroke' and the batteries can be depleted sooner.

Honeywell make a 40 series electronic rad valve, using a similar casing to the HR80 Hometronic/CM Zone valve, I believe this has the display correctly orientated.

The HR40 is not a UK supported product either. Honeywell UK say there is no market for it, and it is fair to say most of my customers have not been impressed when I get a sample unit out of the van. Many customers don't understand the principle of a basic TRV so it is difficult communicating the benefits of an electronic one. Perhaps Honeywell marketing appreciate this.

I think the average German is more engineering minded and therefore they would sell better in their native country.
Hi Simon,

I too was concerned at the HR 20 display orientation, until I received the units and found that the display section is easily removed, and then can be easily adjusted as required.

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apologies if my post has been misinterpreted. I did not mean that the orientation can be altered, only that the timer can be easily adjusted with the head removed.

What is the difference between the rondstat/honeywell 20 and 40 independant radiator timer besides the position of the display.

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