Fixed vs Portable Thermostat

[uksoup]

Hi Folks,

I’m having a Worcester Bosch 37 CDi installed. I’ve (eventually) decided on fitting a Honeywell CMT927 controller which offers a number of benefits to me including portability. I’ll also have a Worcester Bosch DT20 fitted to time the preheat function.

//www.diynot.com/forums/viewtopic.php?t=226686

I have shopped for a portable controller because I expect to use the thermostat in my sitting room, however in early autumn and late spring I get a substantial imparity between my sitting room and bathroom. I have a large south facing window in the sitting room, a few hours of sunshine warms the room up considerably but the bathroom is still pretty cold with its two outside walls. I measured the difference in the earlier part of May while there was still the odd frost about; no heating.

0830 hours
Sitting room = 20.5 degrees C
Bathroom = 15.5 to 16.5 degrees C

I expect to locate the thermostat in the bathroom for two or three weeks at each end of the heating season, this is why I have gone for portability.

It’s been pointed out that the Worcester Bosch FR110 might be a more effective controller for the 37 CDi as it can do “load compensation” (thank you ianniann), it has many features and it can also store a number of separate weekly heating programmes which is especially attractive to me as a shift worker, however, it’s fixed wiring.

If I was to change my thinking and go for a fixed wired thermostat, I guess I’d have FR110 in the sitting room, could the system deal with the cold bathroom?

Thanks Again,
soup

 

[Axel]

Wireless stat is a good idea - they are 50 quid if you shop around.

But, one would not put it in the bathroom, because of dramatic temperature variations whenever someone has a bath or shower, or opens bathroom window to ventilate. Also, excessive moisture condensing on the sensor might give a false reading.

The room it is in should have no TRV in it.

I suppose the best place to put an RF stat sensor would be implanted inside the body, switching on the central heating if you personally felt cold!

 

[oilhead]

Portability is great, except it doesn't work too well when you hold it in your hand!!!!
I'm not being plummy, I actually had to attend such a call when the woman couldn't understand why it didn't work.

 

[ianniann]

Personally I think the wireless feature is far less useful in practice than you expect, and the more intelligent it is the less useful it will be getting moved about. The single biggest thing going for a wireless controller is ease of installation.

Perhaps more thought about a permanent location for a thermostat? Somewhere that won't be subjected to sporadic heating by the sun or your morning shower, but is still relevant to your living arrangements?

 

[Boilerman2]

Don't expect an electronic thermostat to last very long in the humid atmoshere that is the average bathroom the whole point of wireless stats is to make installation easier, NOT to allow the householder to place the stat where he pleases after Part L1 Building regs has very definate ideas of just where the room stat should be placed!!

 

[D_Hailsham]

I have shopped for a portable controller because I expect to use the thermostat in my sitting room, however in early autumn and late spring I get a substantial imparity between my sitting room and bathroom. I have a large south facing window in the sitting room, a few hours of sunshine warms the room up considerably but the bathroom is still pretty cold with its two outside walls. I measured the difference in the earlier part of May while there was still the odd frost about; no heating.

0830 hours
Sitting room = 20.5 degrees C
Bathroom = 15.5 to 16.5 degrees C

So, when the thermostat is in the sitting room, the thermostat is turning the boiler off before the bathroom has got up to temperature. That's to be expected if there is heat coming through the window.

The idea behind wireless thermostats is to make installation easier, not so the user can carry it around from room to room. Locate the thermostat in a relatively cool area, e.g. the hall and set it to the desired temperature. The rad in the hall should not have a TRV as the thermostat controls it; other rads should have a TRV. If you find that the hall thermostat shuts the boiler down before rooms get up to temperature, close the valve on the hall rad a bit. You will have to experiment a bit to find the correct setting.

 

[uksoup]

Thank you all, everybody is in agreement that moving it around is a bad idea and, placement in the bathroom is a no no.

I’ll have to scratch my head and come up with compromise I think.

Thanks all for your time and thoughts yet again.

soup

 

[muggles]

Sounds to me like your system just needs balancing, if the room with the roomstat in is getting up to temperature and shutting off the boiler before other rooms are warm, then the lockshield in that room may need winding down or others may need opening up, or maybe both. Look at the FAQs on system balancing.