Central Heating randomly coming on

[david891]

Good morning,

Recently my boiler has started coming on at random times for central heating, heating the radiators up and making the place feel like a sauna. Woke up a few times during the night realising what was happening.

My thermostat control is a Salus RT300RF and boiler is a Greenstar 25Si Compact Combi Boiler located in the kitchen.

My thermostat is always set to 17 degrees but the boiler keep firing up the heating even when the thermostat is reading 23 Degrees.

I have checked the boiler setting and there is no additional on/off times set its all working from the thermostat. I have also noted when the boiler is firing up the central heating the "heating" symbol on the thermostat doesnt display.

The boiler temperate indicates 32 degrees so it doesnt appear to be frost protection.

Any ideas what the problem could be?

Appreciate everyones time.

 

[dilalio]

https://salus-controls.com/uk/videos-support/rt300-rt500-faqs/#

4th article in faq's

 

[ericmark]

I had the same problem with a Horstmann HRFS1 wireless thermostat, as the problem developed it became clear the frequency of one of the units had drifted, and since there is no fail safe once boiler was switched on, it could fail to get the switch off signal, the unit does have a code set so it will not interfere with other devices using same frequency, but it was not interference which was real problem, it was the units failure to hand shake, so if remote sends off signal it simply assumes the base will get the signal, and the base does not confirm the signal has been received.

More expensive thermostats like the Honeywell Y6630D repeat the signal and if no signal received in ½ hour auto shut down, but the price is a lot higher and it is not programmable, the problem is unless you down load the instructions for each thermostat there is nothing in the adverts which say if they fail safe or not, clearly with a wireless thermostat at some point the batteries will fail, so there should be a fail safe built in, but also clearly this is not always the case.

Even hard wired battery powered thermostats can have problems, my old Horstmann DRT2 has a battery indicator which did not show until the batteries were below the voltage required to work relay.

So first thing swap batteries, could be as simple as that, you can also try swapping the code as shown in video that @dilalio has linked to, but it may need a new thermostat, you can try putting thermostat closer to the base, that worked with the Horstmann HRFS1 but in my case yes in kitchen facing the base across the entrance between oven and wall in kitchen the unit did work, but that was not really where I wanted to measure temperature.

 

[dilalio]

Older Salus units are notorious for interference... As I've said before, they often have more chance of picking up radio Caroline than a signal from the RF stat

 

[ianmcd]

Salus are very poor but changing the RF address sometimes works its very easy to do, it shows how in the installation manual

 

[dilalio]

Salus are very poor but changing the RF address sometimes works its very easy to do, it shows how in the installation manual

And in the video I linked to above!

 

[CBW]

Could it be the preheat? https://www.worcester-bosch.co.uk/support/literature/download/release/8716115660/12690 sending it down rads if sticking diverter/motor?

 

[dilalio]

Recently

And it wouldn't...

making the place feel like a sauna.

Edit: ha! Just saw you edited your post to include diverter fault .
I'd say unlikely mate.
Suspect the Salus is still my go to on this

 

[ianmcd]

And in the video I linked to above!

sorry mate never seen your link