Boiler outside temperature compensation sensor - worth the hassle?

leo738

Hello All,

I was looking at installing one of these on my Vokera boiler:

http://www.plumbingforless.co.uk/heating/gas-boilers/vokera-boiler-controls/vokera-outside-weather-compensation-controlsensor-2359259

It's claimed they increase efficiency. However after speaking to a rep in Ireland he has advised that the signal must be cut if the hot water is being heated, otherwise it won't come up to temperature during the warm(-ish) summer months.

Has anyone any experience? Are they worth fitting?

Thanks,

Leo

Dtp1979

leo738 wrote: »

Hello All,

I was looking at installing one of these on my Vokera boiler:

http://www.plumbingforless.co.uk/heating/gas-boilers/vokera-boiler-controls/vokera-outside-weather-compensation-controlsensor-2359259

It's claimed they increase efficiency. However after speaking to a rep in Ireland he has advised that the signal must be cut if the hot water is being heated, otherwise it won't come up to temperature during the warm(-ish) summer months.

Has anyone any experience? Are they worth fitting?

Thanks,

Leo

I have one on my own boiler and it's great. I've no idea how Vokera wire there's or how their one interacts with the hot water controls

leo738

leo738 wrote: »

Hello All,

I was looking at installing one of these on my Vokera boiler:

http://www.plumbingforless.co.uk/heating/gas-boilers/vokera-boiler-controls/vokera-outside-weather-compensation-controlsensor-2359259

It's claimed they increase efficiency. However after speaking to a rep in Ireland he has advised that the signal must be cut if the hot water is being heated, otherwise it won't come up to temperature during the warm(-ish) summer months.

Has anyone any experience? Are they worth fitting?

Thanks,

Leo

Outdoor sensors work very well in environments suitable for them but like anything if fitted incorrectly or in a unsuitable environment then they can have a negative impact on a heating and hot water system.

If you are heating hot water with your perticular vokera system boiler then a outdoor sensor isn't for you, if you had a combi boiler and it was practical to fit it then the outdoor sensor is perfect add-on for improving efficiency.

Dtp1979

gary71 wrote: »

Outdoor sensors work very well in environments suitable for them but like anything if fitted incorrectly or in a unsuitable environment then they can have a negative impact on a heating and hot water system.

If you are heating hot water with your perticular vokera system boiler then a outdoor sensor isn't for you, if you had a combi boiler and it was practical to fit it then the outdoor sensor is perfect add-on for improving efficiency.

Would it be a terrible idea to use the immersion in conjunction with the weather comp? Have the immersion set to heat the water twice a week up to 65 and let the gas heat it to whatever it can depending on the weather.

Dtp1979

Dtp1979 wrote: »

Would it be a terrible idea to use the immersion in conjunction with the weather comp? Have the immersion set to heat the water twice a week up to 65 and let the gas heat it to whatever it can depending on the weather.

The best systems are the simplest:D

I find most home owners I speak to don't wish to take ownership of their home heating/hot water controls so unless you could put a 7day programmer on the immersions I couldn't see it working also as the temperture leaving the gas boiler isn't a constant (as you know) so the home owner would have to check their weather app to see if they have to set the immersion timer for the next day if the sun is out, you'd end up with costumers who'd be the only people in the country cursing because it's a fine day.

murphaph

I presume controls that access weather forecast information are available for gas boilers as well, right?

murphaph

murphaph wrote: »

I presume controls that access weather forecast information are available for gas boilers as well, right?

No that I know of, outdoor sensors are like a room thermostat but outside.

murphaph

I was familiar with controme, a German heating controller aimed mostly at underfloor heating users. It works with our heat pump but apparently also with gas boilers. It gets predicted temp data from the internet and can adjust the system based on it. This is especially important for underfloor as it reacts relatively slowly. Not sure if it's available in Ireland though.

leo738

My understanding of the effect of these type of compensation sensors is limited.

I had presumed that they improved the efficency of the boiler by having a more accurate temperature of the incoming air & so improve the extraction of the latent heat during operation. But from the replies it seems that the sensor actually causes a refinement of the water for radiators (ie lower in warmer weather).

Is that correct? If so I can understand how it may have an undesirable effect when hot water is required.

murphaph

murphaph wrote: »

I was familiar with controme, a German heating controller aimed mostly at underfloor heating users. It works with our heat pump but apparently also with gas boilers. It gets predicted temp data from the internet and can adjust the system based on it. This is especially important for underfloor as it reacts relatively slowly. Not sure if it's available in Ireland though.

Gas boilers with inbuilt outdoor sensors are a different animal to external programmers not made by the boiler manufacturer, you could use this type of technology with a gas boiler(I haven't seen one though) but you wouldn't be using the inbuilt controls of the gas boiler

leo738

leo738 wrote: »

My understanding of the effect of these type of compensation sensors is limited.

I had presumed that they improved the efficency of the boiler by having a more accurate temperature of the incoming air & so improve the extraction of the latent heat during operation. But from the replies it seems that the sensor actually causes a refinement of the water for radiators (ie lower in warmer weather).

Is that correct? If so I can understand how it may have an undesirable effect when hot water is required.

Outdoor sensors when used correctly on a suitable gas boiler can have a massive effect on efficiency.

The sensor will take into account the outside temperture and adjust the output of the boiler accordingly ie.. A boiler set to run at 65c can often have a flow temperture below 55c on a nice day.

Dardania

murphaph wrote: »

I presume controls that access weather forecast information are available for gas boilers as well, right?

The nest version 3 has access to weather data, and can communicate using open therm with suitable boilers, to modulate. That for me is the ultimate in joined up control...

It is also capable of controlling hot water, so I guess it should be smart enough to set the flow temp to 60c when there is hot water demand...

leo738

Hello All,

Just to let you know I fitted the module. Not too difficult but as advised by a Vokera engineer it's input to the panel must be cutout if the hot water cylinder motorised valve is energised. I accomplished this by using a mains relay. Not complicated but difficult to run the wires.

I found without the cutout relay the cylinder temperature wouldn't reach a decent temperature in warmish whether.

I got the attached circuit diagram from Vokera. As mentioned I used a separate mains relay rather than using the onboard relay (already in use).

Hope this helps someone!

Leo

Dardania

leo738 wrote: »

Hello All,

Just to let you know I fitted the module. Not too difficult but as advised by a Vokera engineer it's input to the panel must be cutout if the hot water cylinder motorised valve is energised. I accomplished this by using a mains relay. Not complicated but difficult to run the wires.

I found without the cutout relay the cylinder temperature wouldn't reach a decent temperature in warmish whether.

I got the attached circuit diagram from Vokera. As mentioned I used a separate mains relay rather than using the onboard relay (already in use).

Hope this helps someone!

Leo

That's a really smart way to get the right output temp - I would never have thought of that...

How's it working for you - do you see the boiler running longer etc.?

leo738

Well,

I wish I could take some credit for the solution but it came from a Vokera engineer!

Very difficult to know if there's any substantial difference to efficiency or run time of the boiler because of the changes in weather, effect of thermostats on radiators, amount of sunlight through the day etc etc.. Any opinion would be more aspirational than scientific! However the house continues to heat quickly & is comfortable throughout.

Regards,

Leo