Worcester Bosch- Temperature - Get the Balance Right !

[tesla2014]

Ok, I live in a three bed house, new install of Worcester Bosch Greenstar 29CDI Classic with TRVs on all new Stelrad rads apart from one in the hallway where a Danfoss RX1 digital thermostat sits. Reading 59, bar 1.5 when off. Here's the rub, setting the thermostat at 22 dc kicks in the boiler, reading drops from 59 to 32 and then rises to 70 and bar rises from 1.5 to 2.0, nice and toasty but too warm and more then 22 dc, boiler switches off as a result. Room cools down but thermostat still shows 22 dc(actual temp, not target temp) and doesn't kick in the boiler. I need to then raise the temp on the thermostat to have the boiler kick in again..... but all of this causes a wide swing of either being too hot and waiting for the room to cool down significantly. Any help appreciated please? thanks.

 

[D_Hailsham]

The RX1 is just the receiver for a wireless thermostat.

Which user control do you have?

How far apart are the user control and the receiver?

Have you checked that the user control is communicating with the receiver?

 

[ALEC1]

you are talking about hysteris, the band width of operation of the thermostat...

you would be better of getting Bosch's own compensation controller...

 

[D_Hailsham]

you are talking about hysteresis, the band width of operation of the thermostat.

I could accept that if the OP was using a mechanical stat without an anticipator. But a digital stat using a NTC sensor? The hysteresis on one of those is normally less than a degree.

 

[tesla2014]

The RX1 is just the receiver for a wireless thermostat.

Which user control do you have?

How far apart are the user control and the receiver?

Have you checked that the user control is communicating with the receiver?

quite right. thermostat (RET-BF) fitted near front door but not fitted near rad, about 3.5 metres apart from receiver which are paired as can see signal lights flash when changing temp. was told 29CDI kicks in after 3 degree drop by WB and this can't be altered.

 

[tesla2014]

you are talking about hysteresis, the band width of operation of the thermostat.

I could accept that if the OP was using a mechanical stat without an anticipator. But a digital stat using a NTC sensor? The hysteresis on one of those is normally less than a degree.

a bit new to this but thermostat set to six cycles and chrono sync.

 

[ALEC1]

Uneven heatloss with a poorly sited room stat will give huge hysteris everywhere but at the stat..

compensation contols keep the pump running and vary the flow temp...a mich better solution..

 

[tesla2014]

Uneven heatloss with a poorly sited room stat will give huge hysteris everywhere but at the stat..

compensation contols keep the pump running and vary the flow temp...a mich better solution..

so... you're suggesting the sat should be situated somewhere else then? lounge maybe?

 

[D_Hailsham]

What are the four small switches set to on the back of the user control?

 

[tesla2014]

What are the four small switches set to on the back of the user control?

set to heat, chrono, 6 cycles, centigrade.

 

[ALEC1]

This is a really good example of how poor on -off control technology wastes gas...a stable temperature is far more comfortable than a changing one, and does enable people to lower their set points and make savings.

Seriously bin this stuff and treat yourself to the Bosch compensating controller, you will wonder why you did not do it earlier....