Gas boiler central heating and Danfoss timer query

[enna]

Can anyone help please?

I have an old gas back boiler with a Danfoss timer and thermostat. I often use the 1+hour setting to turn the central heating and water on and don't often use the auto setting on the timer. I went away early January for over a month. The heating and water were set to off. A friend was checking my house periodically. As there was a freezing cold week mid Jan, my friend came and set the heating to the auto setting which was programmed come on from 12.00am to 01.00am only. A week later she returned late afternoon to find the house unusually warm and the heating on (not at the programmed time). It seemed suggest the heating may have been on all that week (even though my meter reading shows significant usage but not as dramatically high as we had feared). Without anyone being at the house for that week I am unable to know for sure. As a check, my friend turned everything off and set the auto timer as before - and came back the next evening (late afternoon). Again it was on. After that she turned everything off as a precaution.

I returned home in the last couple of days and I have had the CH heating on (1+hour setting) and have tested the CH auto timer, such as in the morning e.g. 06.00 until 7.00 or 09.00am to 09.30am. No problems. However last night I put the CH auto timer on (12.00am to 01.00am), the setting as it had been set for when I was away. And it was still on at 01.40am. I did not keep it on to see if or when it would go off. As I don't want to increase my heating bill any higher. I have heard of some systems having a freeze setting, but I have not known of mine to. Also it would not explain the heating being on during the day.

It is a puzzle to me and forgive the long winded story, but I wonder if anyone can shed any light on my query please?

Thanks.

 

[jtsplumbing]

Is the setting on the timer , on timed or constant and what sort of timer do you have ? (Model No on timer) one with a dial or one with a digital clock

 

[enna]

Thank you for your reply. It is a Danfoss FP715 Si (below is a link to pictures of the model).



https://www.google.co.uk/search?q=d...k_XKAhWC2xoKHYCkCXEQ_AUICSgD&biw=1280&bih=673


It is digital, and has four settings for CH and HW: ON, OFF, AUTO, ALLDAY. It allows for three different times to be set in any one day. The setting I spoke of in the previous post was set to 12.00am to 01.00 and was the third and last one, and programmed to come on daily. All the other settings were programmed OFF.
Incidently I have had the heating on today on AUTO for each three settings. It went on and off as normal. So is the problem to do with the time of night it was set at? Or that it overlaps into the next days programme? Or something else?

Thanks, I hope you can help.

 

[stani]

12am dinner time 01-00 early morning = 13 hours.
Can't remember on these clocks exactly

 

[enna]

Hi,
thanks for your reply. It's 12.00 am midnight and 1.00am. The attached pictures should give you an idea.Thanks.

 

[jtsplumbing]

So you have it set from 12am = midnight to 1am total running time 1hr! why do you want to run heating at midnight for 1hr ?

 

[tamz]

All the other settings were programmed OFF.

Only way to program the other timings to off is to set them to the same time
eg
program 1 on 8am program 2 off 8am
program 3 on 4pm program 4 off 4pm

then set program 5 to 12am and program 6 to 1am

It will work that way if you do that (not that you'd want to)

 

[enna]

Hi,

Thankyou for your help. I had originally set the other timers to OFF the same as you suggested, although with a variation on the times..
E.g.
Program 1 on 6am then off 6am
Program 2 on 7pm then off 7pm

Program 3 to 12am then off at 1am.

I am going trying out some different times on the third setting tonight see if the heating continues to stay on after it is programmed to go off.

Thanks.

 

[enna]

Hi,

Thanks for youroquestion. In the original post I mentioned I was away from the house for a month. The auto setting at midnight for 1 hr was to stop the pipes freezing if the temperature dropped. I chose the time because it would be colder than the daytime.

 

[tamz]

Hi,

Thankyou for your help. I have done as you suggested, although the times varied.
E.g.
Program 1 on 6am then off 6am
Program 2 on 7pm then off 7pm

Program 3 to 12am then off at 1am*

I am trying out some different times on the third setting tonight see if the heating continues to stay on at nightime.

Thanks.

Doesn't matter much what times they are at as long as in a kinda order.
Btw if you have a room thermostat its easier to leave the heating on constant and turn the stat down to 10 or 12º. It will stay off all the time unless it drops below that which is unlikely and if it does will kick in for a bit before it gets too cold.

 

[tamz]

And remember, the coldest hour is just before dawn

 

[enna]

Thanks I will try the thermostat as an option.

Although it still doesn't explain why the heating system has been overiding the settings and continuing to stay on even when all the others timers were programmed OFF.

How would I know if my system has a freeze setting?

 

[tamz]

I don't know what your original timings were but the programmer will work in some kind of order so setting it as you have should solve that.
Having a back boiler you have no frost protection (freeze setting) as such unless you do as i said and set the heating to constant and let the room thermostat kick in if the temperature drops.
Back boilers were great machines in their day and would run for another 20 or even 30 years if looked after but my mk2 ford cortina was a great car too and i could get it running again with a 10mm spanner and a screwdriver and maybe a push down the hill but i can't remember the last time i saw one as they are all mostly scrapped.

 

[enna]

Thanks for your help and advice.