Thermostat

[Tomo72]

Hi all,

I'm looking at replacing our rather dated Potterton room thermostat that controls our Potterton Suprima (30 I think it is) boiler like this one;

https://www.plumbcenter.co.uk/product/potterton-prt100st2-room-thermostat-spst/

With one like this one;

https://www.amazon.co.uk/FLOUREON-T...d=1507539987&sr=1-3&refinements=p_89:FLOUREON

Can anyone tell me if this is ok and will work properly?

 

[stem]

The Floureon thermostat is designed for electric underfloor heating with a remote sensor. The link to the website that you have posted tells you it is not suitable, when it states, in not too brilliant English, that it "Not Fit air conditioner, water boiler"

 

[Tomo72]

The Floureon thermostat is designed for electric underfloor heating with a remote sensor. The link to the website that you have posted tells states in not too brilliant English, that it "Not Fit air conditioner, water boiler"

Thanks Stem, I did read that part after I'd posted the question here, my bad. But having said that, the thermostat is effectively a switch that switches the boiler on and it says that it is capable of switching 16A. I'm an electronics engineer but not a plumber or heating engineer but I wouldn't have thought that switching whatever it is in the boiler to come on wouldn't be more than 16Amps, would it?
Perhaps I should look at something else? Any suggestions that look like this one? We really like the look of that and will fit our decor nicley.

 

[Doggit]

It'll depend on how the thermostat is powered. Most boilers use a volt free theremostat/programmer that has a battery, but if the thermostat is powered by 240v, then it'd burn out the boiler pcb.

 

[stem]

With underfloor heating thermostats, it depends how the remote sensor is used. I'm not familiar with this model, but with most underfloor thermostats, as well as controlling the room temperature, the remote sensor is in the actual floor and it is there to prevent the actual surface you are walking on getting too hot. So it's different from a basic switching thermostat.

As to a replacement, that's really a personal choice, but you need to check what wires are actually run to the existing thermostat and this can depend on the original installer.

 

[Doggit]

Well done stem, didn't think about the remote floor stat bit.

Looks like a no on both aspects then.

 

[stem]

Your existing thermostat should have:
1. A live supply that is provided from some form of time control.
2. A switched live that controls the heating
3. A neutral.

Sometimes the installer omits the neutral which may be a problem if a replacement thermostat needs mains voltage to power its display.

You may also need a permanent live for the same reason. Because the live to the thermostat is usually switched by a timeswitch / programmer and so is not permanent.

It'll depend on how the thermostat is powered. Most boilers use a volt free theremostat/programmer that has a battery, but if the thermostat is powered by 240v, then it'd burn out the boiler pcb.

The existing PRT100 doesn't have potential free contacts, so you won't need this.

The Potteron Suprima uses 230v for its control

Most (but not all) new thermostats have potential free contacts anyway so that they can be wired to suit either 230v and 24v

 

[Tomo72]

Your existing thermostat should have:
1. A live supply that is provided from some form of time control.
2. A switched live that controls the heating
3. A neutral.

Sometimes the installer omits the neutral which may be a problem if a replacement thermostat needs mains voltage to power its display.

You may also need a permanent live for the same reason. Because the live to the thermostat is usually switched by a timeswitch / programmer and so is not permanent.



The existing PRT100 doesn't have potential free contacts, so you won't need this.

The Potteron Suprima uses 230v for its control

Most (but not all) new thermostats have potential free contacts anyway so that they can be wired to suit either 230v and 24v

Yes there is a timer mounted just beneath the boiler for hot water (tank) and heating. I've not looked inside the existing thermostat yet.

 

[Tomo72]

The existing PRT100 doesn't have potential free contacts, so you won't need this.

The Potteron Suprima uses 230v for its control

Most (but not all) new thermostats have potential free contacts anyway so that they can be wired to suit either 230v and 24v

Do you mean by this the same as 'volt free' I've seen online? Does volt free mean it doesn't have an actual output voltage of its own, it outputs whatever is inputted?

 

[stem]

Yes, it refers to two switching contacts that are isolated from anything else, so they can be used to switch any voltage applied to them. They can be referred to as 'potential free' or 'volt free'

 

[Tomo72]

Thanks Stem,

Could you please point me in the right direction for a suitable alternative replacment for the PRT100? It doesn't matter what website it is.

 

[stem]

As you don't have a permanent live, any of the battery powered room thermostats with potential free contacts would be fine. (the batteries last for several years) These tend to be more accurate than the old mechanical type.

Examples would include a Drayton Digistat or a Honeywell DT90

If you want an easy straight swap, don't get an RF thermostat which has a separate receiver and a remote thermostat, or a programmable thermostat that also controls the on/off timings as you have those functions in a separate timer already.

If you do have a neutral connection to the existing thermostat, then you could fit a traditional dial mechanical thermostat if you wanted to.

If you find a thermostat that you like the look of and you are not sure if it will be suitable, post details of it back on here and someone will be able to confirm its suitability.

 

[Tomo72]

Thanks Stem,

I was hoping to be able have the heating switched to constant and be able to get a programmable thermostat to set different temperatures throughout the day, would this be possible?

 

[Tomo72]

So, this is what I’ve got in the existing thermostat. Doesn’t that make it a 240V? If I were to use a battery operated thermostat, I’d just use two wires? Which ones? Would this do the job?

https://www.amazon.co.uk/dip/B074M8RV45/ref=cm_sw_r_sms_c_api_Si62zb8SYHSD9

 

[stem]

I was hoping to be able have the heating switched to constant and be able to get a programmable thermostat to set different temperatures throughout the day, would this be possible?

Yes, if the existing time control allows the heating to be set to be permanently on 24/7. and has separate control for the hot water.