open therm compatible wireless modulating room thermostat?

[D_Hailsham]

At the moment I have a Honeywell CM907 which performs well. The only prob I have sometimes is when its mild outside but cold indoors, it takes ages for the house to heat up unless I shut off the weather comp and crank the temp right up.

So the inside of the house is colder than the outside? In which case heat should be flowing into the house through the walls!

Have you tried experimenting with the Proportional Bandwidth setting of the CM907.

What happens if you turn Optimisation off?

I'm interested in that Honeywell modulating stat but so far can't find any info on it.

The Honeywell modulating stat needs an OpenTherm compatible boiler, which the Ariston isn't.

 

[mehran]

Interesting reading.

I have a Ariston Genus 30 HE combi that is 2 years old (very good boiler so far, touches wood!)

I have fitted the 'weather comp' sensor on north facing wall....this works a treat after experimenting with the curves!

I have 'range rated' the output down to about 18.

At the moment I have a Honeywell CM907 which performs well. The only prob I have sometimes is when its mild outside but cold indoors, it takes ages for the house to heat up unless I shut off the weather comp and crank the temp right up.
.

I think this is the man difference between simple and advanced weather comp. the advanced you can chance the way the curve is shaped as well as how steep it is.

but I would try and turn off the honeywells Optimisation and see if that helps.

 

[Fleeting Glimpse]

Ok Guys...thanks for the reply s

Regarding the bandwidth of the cm 907, I have checked it and it is set to 1.5. I don't actually understand the function of this setting...whats it for?

Will try turning off the optimization.

Ariston do make 'modulating' stats for there boilers...would on e of these be worth investing in?

 

[D_Hailsham]

Regarding the bandwidth of the cm 907, I have checked it and it is set to 1.5. I don't actually understand the function of this setting...whats it for?

It determines the temperature at which the thermostat starts cycling the boiler.

Say you set the stat to 20°C and the bandwidth is set to 1.5°C. If the temperature is below 18.5°C the boiler will run flat out. When the temperature reaches 18.5°C the boiler will start cycling say 90% on and 10% off over the time determined by the number of cycles per hour (six for a gas boiler, i.e 10 minute cycles) as the room temperature gets nearer to 20°C the on/off ratio will change e.g 80/20, 70/30 etc until, at the set room temperature, the ratio is about 50/50.

The purpose of this is to prevent overshoot, i.e the room temperature continuing to rise after the thermostat has turned the boiler off. This will happen with normal thermostats which just keep going until they turn off. The radiator will continue pumping out heat, so the room gets hotter. So you turn the thermostat down a bit. Which means that the room cools down too much before the stat turns the boiler on. So you turn the stat up again and the vicious cycle starts again.

By changing the proportional bandwidth, you change the temperature at which the boiler starts the cycling. So with a bandwidth of 3°C it will start at 17°C. The purpose of this is to be able to fine tune the system to take account of the heat loss characteristics of the house.

One question: have you checked the accuracy of the thermostat against another thermometer? Sometimes you find that they do not agree. There is a parameter, Temperature Offset, which can be changed so the thermostat displays the same temperature as the thermometer.

 

[Fleeting Glimpse]

Ah...thanks for that.

It will not under 1.5 so I'll maybe try raising the set temp a little.

Yes I have checked it with a thermometer when it was fitted and it was about 1 degree out.

Any thoughts on the ariston modulating stat?

 

[erki]

Hi Johnnynuffin

Did you come up with a solution - wireless modulating thermostat for your remeha? I am seeking the same thing and I could only find the vokera 611 at about £150. I wrote to both Vokera and Remeha asking about compatability - it uses Opentherm so should follow the same protocol ; both replied that they couldn't guarantee compatability.

 

[D_Hailsham]

Did you come up with a solution - wireless modulating thermostat for your remeha?

Remeha make a wireless version of the iSense, which is not available in the UK. This is because the boilers sold in the UK do not have the latest circuit boards. However you can buy it direct from Holland. Try

http://www.cv-sanitairkorting.nl/product_info.php?cPath=96_110&products_id=3119

You have to specify the 'International' version, then you get the option of English.

You also need to purchase, from Holland, the Remeha SmartPower adaptor that provides the 5V supply needed for when the boiler is using the latest circuit board.

You will also need the outside weather sensor, which is available in the UK.

 

[mickyg]

funny this has been resurrected. Im still waiting for honeywell to release the stats they promised us in 2009
Only UK wireless modulating stats are from vaillant but only work with vaillant boilers .
In actual fact I only know of 3 genuine opentherm controls available in the uk full stop and yet manufacturers are advertising boilers as "opentherm compatible" like thats much help without a damn stat !

 

[erki]

That's good info D_Hailsham, thanks. It looks like the adapter needs an external 240V socket. Is that the case? Thanks again[/quote]

 

[dumbrill]

That's good info D_Hailsham, thanks. It looks like the adapter needs an external 240V socket. Is that the case? Thanks again

Yes a USB 5V 'wall wart' supply is what you need. Just cut the end off and make sure you test the polarity before wiring it in.

I recently installed a iSense RF with my Avanta 18S. I had a few teething problems with the boiler settings, but once resolved it works very well. I like the way it works. The user interface is good and better than the CM927 I was using with my old boiler.

The good thing about the iSense is the option to use several varieties of weather compensation, but also to operate as a simple modulating room stat as well. This means that you install it and know that it will control OK as a room stat. Then you can experiment with the WC curve when you want, but switch back if needed. I've arrived at some settings that appear to work OK, but I should do some calcs to really get a good basis for the curve.

I coincidently bought mine from www.cv-sanitairkorting.nl. The only drawback is that you can only pay them via a GBP/Euro money transfer to their account. This adds an extra £25 to the cost.

The installation manual is available at http://uk.remeha.com/fileadmin/user..._Technical/iSense_Installation_Manual_vr1.pdf . This has better information than the User Manual.

I've also noticed that the volume of condensate the boiler has been generating is significantly greater since fitting the iSense and using WC. I know this because the only part of the installation that is not finished is the pipe from the condensate pump to the drain and so the pump is currently emptying into a bucket that I empty once a day (now I've got some longer hose I'll fix this tomorrow). I reckon that the boiler generates more than a litre an hour at the moment. This is only a guess, but it's probably double what it was doing with the CM927. Also the next door neighbour's condensing boiler billows out great clouds of vapour and mine just lets out a few wisps. Very satisfying on a cold morning

 

[D_Hailsham]

Yes a USB 5V 'wall wart' supply is what you need. Just cut the end off and make sure you test the polarity before wiring it in.

What's a "wall wart"? The spec (isn't Google translation helpful) for the Remeha power supply mentions thing like stabilization, so I wasn't sure if an off the shelf 5V power supply would be OK.

I coincidently bought mine from www.cv-sanitairkorting.nl.

Not really a coincidence. I remembered we discussed the earlier and found your topic "Control Options"

I've also noticed that the volume of condensate the boiler has been generating is significantly greater since fitting the iSense and using WC. ... Also the next door neighbour's condensing boiler billows out great clouds of vapour and mine just lets out a few wisps. Very satisfying on a cold morning.[/quote]
So much for for the "expert" who, when asked why there is steam coming out of the flue, says, "That shows the boiler is condensing, guv". I understand that you even get this when you phone manufacturers' help lines.

 

[dumbrill]

What's a "wall wart"? The spec (isn't Google translation helpful) for the Remeha power supply mentions thing like stabilization, so I wasn't sure if an off the shelf 5V power supply would be OK.

I coincidently bought mine from www.cv-sanitairkorting.nl.

Not really a coincidence. I remembered we discussed the earlier and found your topic "Control Options"

A Wall wart is a bit of american slang (I assume) that I came across for a plug in adaptor. It seems like a good description for all those chargers that we seem to have for everything - all different voltages of course.

I looked through the various specs in Maplin and most are stablised anyway. I put mine into an unswitched socket, connected into the fused spur for the boiler, so that the 5V can't be turned off independently of the boiler.

I can't remember that I had mentioned www.cv-sanitairkorting.nl before. Anyway they seemed OK, apart from the method of payment.

 

[Whitworth]

I too am interested in the opentherm idea,

In actual fact I only know of 3 genuine opentherm controls available in the uk full stop and yet manufacturers are advertising boilers as "opentherm compatible" like thats much help without a damn stat

Mickyg, could you let me know of the ones that are on the market so I can have a look at them?
Thanks

 

[dumbrill]

I too am interested in the opentherm idea,

In actual fact I only know of 3 genuine opentherm controls available in the uk full stop and yet manufacturers are advertising boilers as "opentherm compatible" like thats much help without a damn stat

Mickyg, could you let me know of the ones that are on the market so I can have a look at them?
Thanks

When I looked at this a few months ago I compiled the table below for controls:

Untitled

• dumbrill
• 28 Nov 2010
• 2

The only other information I can add now is that iSense RF works well with the UK Avanta, but you need to buy it from the Netherlands.

 

[dumbrill]

I too am interested in the opentherm idea,

In actual fact I only know of 3 genuine opentherm controls available in the uk full stop and yet manufacturers are advertising boilers as "opentherm compatible" like thats much help without a damn stat

Mickyg, could you let me know of the ones that are on the market so I can have a look at them?
Thanks

When I looked at this a few months ago I compiled the table below for controls:

Untitled

• dumbrill
• 28 Nov 2010
• 2

The only other information I can add now is that iSense RF works well with the UK Avanta, but you need to buy it from the Netherlands.

I've just remembered that there's also the RAMSES 786 OT Thermostat that I didn't to add to the table because I wasn't keen on it.