Central Heating coming on when timer is off.

Linda32

Hello, I wonder if you could help.

Worcester Digistat DT10RF Programmer and Greenstar Si Compact.

We have recently had this equipment installed and during the last month or so have switched the heating on. We are happy with the central heating timings.

However, we are finding that the central heating is coming on during the night and presumably during the day when we are out!

The timer gives 6 time slots (3 on and 3 off) So we have the heating to come on at 0600am off at 0700 at 19 degrees. On for five minutes during the day to take care of the unwanted slot at 10 degrees. (We don't want it to come on at all as we are out, that is why its set so low) Then on again at 1700 at 19 degrees and off at 2230.

We understand that the heating won't always be on. It will simply keep the house set at 19 degrees (even when the timer is on)

We understand that the heating will kick in anyway if the temperature drops below 7 degrees but it certainly hasn't done so far this year.

We simply don't understand why its coming on during the night when the timer is switched off, nor do we need central heating on during the night for obvious reasons.

We have tried searching on line and checking the manual but it seems only to state how to set the timer. Or if the heating is coming on at odd times then the clock is wrong. But it isn't.

TIA

Doozergirl

It sounds like it is kicking in 'anyway' at a higher temperature than 7 degrees. You said you understand this ; have you checked it

SGM1

Do all your radiators heat during the night? Have you got up to check what the timer/clock is doing? It could just be the preheat on the boiler firing but that shouldn't heat radiators

JohnB47

Agree that you should get up and check if the boiler us actually providing heat. It could just be the pump running. Our Worster Bosch runs it's pump for five minutes every 24 hours, to avoid the pump sticking during long periods of disuse (ie summer). I often hear the water being pumped around the rads when the heating is off.

Ianwzzz

Have you got a frost stat fitted, if so is it set to the correct temperature and is it working correctly.

Linda32

Hi, thank you for your replies.

We have not checked that the frost protection is set at 7 degrees we only assume it is because that's what it says in the literature. How do we check this?

We have not got up to check the other rads or the timer but the bedroom one does come on. We will get up next time. Last night we got over it by setting the off temp to 10 degrees which worked. The boiler isn't set to per heat the water it's set to off as we do not need pre heat we just demand the hot water. Is this causing a problem ?

I am not sure about a frost stat, the system was fitted in June and we have only used it during the last month for heating. The stat will kick in at 7 degrees according to the lit. How do we check this?

Ruski

The digistat isn't '3 on 3 off' its 6 times with individual temperature settings. i.e.


07:00 18'
07:30 5'
10:00 5'
12:00 5'
16:30 20'
22:30 5'


(as an example)


Is your belief that it's on/off confused you somehow?
Can you post up what the 6 time and temp settings are?


HTH


Russ

JohnB47

Linda32 wrote: »

Hi, thank you for your replies.

We have not checked that the frost protection is set at 7 degrees we only assume it is because that's what it says in the literature. How do we check this?

We have not got up to check the other rads or the timer but the bedroom one does come on. We will get up next time. Last night we got over it by setting the off temp to 10 degrees which worked. The boiler isn't set to per heat the water it's set to off as we do not need pre heat we just demand the hot water. Is this causing a problem ?

I am not sure about a frost stat, the system was fitted in June and we have only used it during the last month for heating. The stat will kick in at 7 degrees according to the lit. How do we check this?

I think you've sorted it. Your 'off' temperature is too high. It's very possible for the temp to fall below 19 degrees during the night. 10 is more sensible.

Also, you said something about setting it to come on for five minutes to take care of an unwanted time slot. On mine, I can simply set the on and off times exactly the same, so that takes care of one time slot without the boiler actually firing. Can't you do that?

Edit: I've just reread your first post and I'm confused about your on and off temperatures. What are they exactly? Your timer is obviously different to mine. I set on and off times with no temperatres - the room stat sorts that for the on periods. Yours seems to work like my electric underfloor heating where it's assumed you want a lower level of heating when in the off phase.