Boiler coming on when everything is off

N

Neil jones

Joined

14 Oct 2021

Messages

10

Reaction score

0

Country

• 26 Oct 2021

• #1

Hi everyone

Just moved into house. i have a potterton promax SL conventional boiler. Less than 5 years old.

There is an unvented hot water cylinder upstairs.

i have the hot water cycliner coming on between 7 and 730am each day.

i went outside in the garage earlier, around 530pm and heard snd saw the boiler firing up. Checked Gas for today and since around 8am had used 0.4 of a unit. The heating has been off allday?

i suspected it was using gas during the day, even though everything is off. Can’t understand why???

Cheers
Neil

 

Attachments

• 
  B701F50F-F930-4E2D-846E-FC5B378F1C38.jpeg

  214.2 KB · Views: 55

Last edited: 26 Oct 2021

S

Swwils

Joined

2 Jul 2020

Messages

1,202

Reaction score

244

Country

• 26 Oct 2021

• #2

The boiler is likely servicing a request from the hot water cylinder thermostat.

The cylinder isn't perfectly insulated so it will lose some heat by itself

 

muggles

Joined

28 Oct 2005

Messages

14,161

Reaction score

3,616

Location

Daventry

Country

• 26 Oct 2021

• #3

Assuming your "0.4 of a unit" is 0.4m³, that's not very much gas at all and would be consistent with reheating a smallish hot water cylinder

 

N

Neil jones

Joined

14 Oct 2021

Messages

10

Reaction score

0

Country

• 26 Oct 2021

• #4

Thanks.

in that case, is it worth having the system so it doesnt come on at 0700? If it is going to keep it at temp, then what is the point of it coming on at all? I thought the point of having it on a timer, was so that it goes completely off other than the times you want it on?

cheers.

 

S

Swwils

Joined

2 Jul 2020

Messages

1,202

Reaction score

244

Country

• 26 Oct 2021

• #5

Neil jones said:

Thanks.

in that case, is it worth having the system so it doesnt come on at 0700? If it is going to keep it at temp, then what is the point of it coming on at all? I thought the point of having it on a timer, was so that it goes completely off other than the times you want it on?

cheers.

Click to expand...

It might be that in your case your hot water control is a simple ON/OFF and is separate from the heating timer.

You can have it so both hot water and heating are on seperate timers if you desire, but you might not see any practical benefit since you will need to reheat the cylinder for whatever the loss happened when the hot water was off.

 

N

Neil jones

Joined

14 Oct 2021

Messages

10

Reaction score

0

Country

• 26 Oct 2021

• #6

Cheers.

the hot water and heating are on seperate timers (downstairs on the wall) The heating is off, so too is the hot water timer and it still fires up. So if i am reading you correctly, the hot water cylinder is either on or off. In my case on (which is why it is firing up) so the hot water timer on the wall downstairs is completely useless!

 

T

terryplumb

Joined

8 May 2017

Messages

9,407

Reaction score

2,339

Country

• 26 Oct 2021

• #7

If your programmer is set for hot water to ONLY come on between 7 to 7.30am ,then the boiler shouldn't be firing up at all to heat the cylinder outside those times. Check your programmed settings ,it may be set to come on at other times.

 

N

Neil jones

Joined

14 Oct 2021

Messages

10

Reaction score

0

Country

• 26 Oct 2021

• #8

Cheers

Double checked the hot water programmer and its defo only set to come on at 0700 to 0730hrs

 

T

terryplumb

Joined

8 May 2017

Messages

9,407

Reaction score

2,339

Country

• 26 Oct 2021

• #9

Show us pics of both of these " timers"/ controllers/ programmers or whatever they are together with any motorised valves in or around the hot water cylinder. The boiler is obviously getting a live supply from somewhere.

 

N

Neil jones

Joined

14 Oct 2021

Messages

10

Reaction score

0

Country

• 26 Oct 2021

• #10

Here you go. Top programmer is for hot water, bottom one is for heating (its on now, but wasnt earlier) Hot water cylinder top pics

 

T

terryplumb

Joined

8 May 2017

Messages

9,407

Reaction score

2,339

Country

• 26 Oct 2021

• #11

Your DHW programmer is set to OFF, I assume you usually have it set to something else ,what would that be ?

 

N

Neil jones

Joined

14 Oct 2021

Messages

10

Reaction score

0

Country

• 26 Oct 2021

• #12

It was set to “Auto” which trigers the programme. I then have 1 which is on at 0700. 2 is off at 0730. 3 is on at 0730, 4 is off at 0730. 5 is on at 0730, 6 is off at 0730. Same for each day.

 

T

terryplumb

Joined

8 May 2017

Messages

9,407

Reaction score

2,339

Country

• 26 Oct 2021

• #13

You appear to have the programmer being used as it should ,so there may be an issue with it. Best to engage an engineer to check it out ,unless you are proficient to do some voltage testing at the wiring centre. Could also be the motorised valve stuck ,if the boiler is coming on and off permanently

 

N

Neil jones

Joined

14 Oct 2021

Messages

10

Reaction score

0

Country

• 26 Oct 2021

• #14

Thanks for all your help. Appreciate it

 

L

Londoner2

Joined

24 Jul 2018

Messages

480

Reaction score

61

Country

• 27 Oct 2021

• #15

Looks like the boiler is in a cold area where it will be subject to cold temps if insulation is not up to scratch, expect the boiler to come on at night and day when outside temp drop off, you have a pipe thermostat that is designed to call for heat when temps drop.