Honeywell CM907 Installer menu questions

[vetinry]

Evening All

I switched on the UFH in the Kitchen at the weekend and initially had problems. Found that the Grundfos pump was buzzing. So dismantled it and the impellor had seized but thankfully not seriously. Once freed, all now appears to be working ok.

However, last year, when I initally installed the floor, I wired in the Honeywell CM907 but didn't set up all of the options.

I've just been into the installer menus to switch on Optimum Start and noticed 2 other options that I hope people might understand.

In the second installer menu, there are some options for using thermostat for specific applications. It says that if using a gas boiler or zone valve, you should leave at default settings of 6 cycles per hour and minimum on time of 1 min, but if you are controlling an oil boiler, you should change to 3 cycles per hour and 4 mins minimum on time.

The CM907 in the Kitchen is controlling a zone valve, which then switches an oil boiler.

Do you think I'd be better to change to the oil boiler settings or leave? The boiler is quite old (Camray 5) and so might prefer longer run times?

And then, in the final setting of menu 2, there is control for pump exercise, which is default off. Is this as it sounds and occasionally spins the pump to stop it seizing. If so, I will switch on. Any idea how often it does this?

Hopefully someone can help. Whilst I am happy with Honeywell controls, they are not always great at explaining functionality.

Thanks

Steve

 

[Dan Robinson]

Leave the pump exercise feature off and change the rest to suit the oil boiler.

 

[vetinry]

Thanks Dan

Doesn't the pump exercise option do what I thought then?

Steve

 

[Dan Robinson]

Yes.

 

[vetinry]

So why wouldn't I switch it on then, since I've just had to dismantle and reassemble a sticking pump?

 

[Dan Robinson]

Largely because it isn't really needed, but if it will help you sleep at night...

 

[ChrisR]

Afaik it'll make the pump go briefly about every 24 hours. So if you're on holiday with the heating left on low but it doesn't come on cos it's too warm, it might stop your pump sticking.
It might not depend on whether the heating has been on or not, I don't know. If it ignores that, it might just spin the pump at 3am , so NOT help you sleep at night!