Honeywell CM907

[ollie3686]

For those of you that recommended the Honeywell CM907 programmeable thermostat - THANKYOU VERY MUCH! What a decent bit of kit.

Unlike my old one (the Timeguard), its accurate to half a degree and actually turns off when the air temperature falls below. However i do have a couple of questions if anyone could help.

- Firstly (and most importantly), do i leave my programmer on 'on' constantly now? Unlike my old one, it turns of completely when the programmer states it.
- Secondly, should i leave 'omptimisation' on? i;ve head some bad things about it such as the heating turning on redicuously early
- Thirdly, there's an option to connect an external thermometer to it. Anyone know how to do this?
- Lastly, it says about telephone override. It looks quick flash and we'd actually find it useful. Does anyone know how to use this?

Not too worried about the answers to the two but i would really appreciated a quick response on the first question would be appreciated.

Thankyou in advance

 

[Tibbot]

Yes- leave the programmer on, set CH by the prog-stat.

 

[MJN]

- Secondly, should i leave 'omptimisation' on? i;ve head some bad things about it such as the heating turning on redicuously early

Whilst they may call it optimisation it does in my experience seem to be somewhat pessimistic in its forecast of how long it'll take to reach target temperature. It's worth trying it out for yourself however as you may find it works good for you (it must work well for some as they've been offering this functionality for years now). Do give it chance to sort itself out (i.e. over several days) as it needs time to assess the achievable rate of rise.

- Thirdly, there's an option to connect an external thermometer to it. Anyone know how to do this?

It simply connects into the terminal blocks in the 907. Note that there are two such thermometers that could be described as 'external' - one ('outside temperature sensor'l) used purely to give an indication of temperature outside (i.e. it doesn't play any role in the control function), and the other ('remote temperature sensor') used as part of the control loop i.e. you can have the 907 in one room but it functions against the temperature in another - handy if your 907 is badly located in terms of being able to capture a representative temperature reading (although the wireless versions are the usual mitigation for this scenario).

- Lastly, it says about telephone override. It looks quick flash and we'd actually find it useful. Does anyone know how to use this?

You'd need the external telephone interface which would then give you the ability to set/unset a pre-defined target temperature over the phone.

Mathew