How To Set A Timer On A Boiler – An Illustrated Guide

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Have you moved into a new house with a mechanical boiler timer, and don’t know what you’re doing with it? Don’t worry, I have a mechanical timer, so let me show you how to set a timer on a boiler. I’ve got a step-by-step photographic guide to make things as easy as possible for you.

I’ve written about setting the timer on your boiler in the past in order to save energy. But the other day it dawned on me: what if you don’t know how to set a timer? Don’t worry. Let me show you how to set a timer on a boiler.

I have a combi boiler and it has one of those mechanical timers on it. Being used to digital timers I’ll admit I was a little flummoxed by the timer when we first moved into our house. I did a bit of internet searching and found this useful video about how to set a mechanical boiler timer. 

Video Guide on How to Set Your Boiler Timer

YouTube video

The video should appear above. If you can’t see the video in your browser, then here’s a direct link to the video 0n YouTube.

Although it is made for Worcester boilers, this video is actually really useful for most makes of boilers. It certainly did the trick for our Valiant boiler. This is because almost all mechanical timers work exactly the same, regardless of the make.

Step By Step Boiler Guide With Photos

dog sleeping next to a radiator with a blue text box that reads how to set a timer on a boiler.

If you can’t get the video to work, or if you would prefer a step-by-step guide that walks you through setting a timer at your own pace, then let me run you through exactly how to set a timer on a boiler. You’ll soon have yours working in no time:

1. Set The Time On Your Boiler

First of all, ignore all the little tabs for now. What you need to do first is set the clock to the right time.

You can do this by turning the dial around clockwise until the arrow points to the correct time in the inner portion of the dial.

It’s important to bear in mind that boilers work on the 24-hour clock. So make sure you’ve set it to 24-hour clock time, otherwise, your heating will come out at odd hours of the night! If it’s 1:30 pm (13:30 in 24-hour clock speak) then you want the arrow to be halfway between the 13 and 14.

2. Now Set The Time When You Want Your Boiler To Come On

Once the time is set correctly, you can now set the times that you would like your heating to come on and go off.

This is where the little tabs come in. These tabs on a mechanical boiler timer can be overwhelming as there are so many. However, I promise you that they are not as confusing as they look. All that they do is represent 15-minute periods of time. 

To set what time you want your boiler to turn on, simply push those tabs in for the times that you want your heating on. Let me talk you through this, in case this sounds complicated.

After you’ve set the time properly on your boiler, you’ll notice that each tab lines up with each 15-minute segment of the 24-hour clock. So, to tell your boiler that you want your heating to come on between 5:45 a.m. and 7:30 a.m. you are going to want to push in all of the tabs that represent that period of time.

Once you’ve done this you should have all 7 consecutive tabs pushed down between 5:45 am and 7:30 am. All of the other tabs should be up.

Confused? Here’s a picture of my boiler timer so you can see exactly what I mean.

how to set a timer on a boiler

When I took the photo, the time was 1 pm so you can see that the arrow points to 1 pm (13). You can also see that my heating is set to come on twice a day. Firstly between 5:45 am and 7:30 am (we are early birds!). And secondly between 6 pm and 8 pm.

If you look closely you’ll notice the tabs are down at these times, and all of the other tabs are up. It can be quite tricky to see so I have annotated the photo to make this a bit clearer.

It’s quite easy to accidentally twist the dial and change the time when you’re adjusting the tabs. Therefore, you may have to readjust the time at this stage! Just something to be aware of.

3. Next Steps

Now you need to tell your boiler that you want it to run to your scheduled programme.

To do this, simply turn the switch that you would normally switch the boiler on to point to automatic scheduling. This may take the form of a picture of a clock or of a stopwatch. It will depend on your boiler – mine’s a stopwatch.

Your boiler should now come on and then switch off automatically at the desired times! And that’s how to set a timer on a boiler!

Energy Efficiency Tips

I always love a two-for-one deal. So as well as telling you how to set the timer on your boiler, do let me share my top energy efficiency tip for your boiler.

It typically takes about half an hour for your house to warm up once you’ve switched your boiler on. It then takes around half an hour for your house to cool down again once it’s switched off. So, with that in mind, if you get up at 7:30 am and leave the house at 8:30 am, it’s most energy-efficient and comfortable for you if you set your boiler timer for your heating to come on at 7 am and off at 8 am.

Looking for more energy-saving help? You can find lots of energy-saving tips here if you’re looking to save money on your heating bills!

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  1. Hi i have just had a alpha e-tec 33 installed.i want to turn off all the timers so i just turn it on as and wen i need..there must be timers set as the heating comes on by itself and i dont want this..i have a wirless box thing but cant seem to figure how to turn off times that have been set ..please help me

  2. Hi dear
    I have got a main Eco elite and there is no time on it and tharmomiter as well can they even be able to fixed it or what should I do

    1. Hey, if there is no timer on your boiler then you can get a smart thermostat like Hive or Nest. Our boiler in our new house doesn’t have a timer, so we use Hive. You can set your boiler to come on and go off when you want it, and control it from your phone or the thermostat.

  3. my boiler was off due to work in the house; it is now back on but the clock is not working. When I manually move it to the time to come on it fires up but the clock is not working so I guess it does not know when to turn off…any ideas.

    1. Our clock stopped working on our our boiler at our old house – we were able to buy a replacement clock from the manufacturer for not much money as it was a separate component and that did the trick for us. If it’s not separate then I would get your boiler serviced by a professional and they should be able to fix it.

  4. Hi please help I managed to set my timer last winter but this time I can not get the times to match up ?i have got my centre clock at 19.00 or 7pm but my pointer is at 17.00 hours ?it doesn’t matter how many times I turn the clock ,clockwise I still can’t get it to match the pointer !where am I going wrong or is there a problem with my timer ?thankyou .

    1. Normally if you set the time on the 12 hour clock, you can then just turn the dial on the 24 hour clock so that they match up. If turning the 24 hour clock makes the 12 hour clock out of sync, try readjusting the 12 hour clock as adjusting that shouldn’t affect the 24 hour clock!

  5. My clock isn’t on the boiler its detached in the hall. Does this same rules apply with the ones attached to the boiler. Timer!?

  6. Hi, thanks for great tips. I have one problem though (mine is a water heater timer I had fitted). The clock hands don’t go round, it still shows same time however it did heat up the water during the set times. Hope someone can help please.

  7. My centre clock and 24 hour one do not match up. Example I was trying to set the time as 11:30pm but the 24 hour click arrow was pointing at either 2:30am so turning it again it ended up at 14:30! I decided to ignore the 12 hour one and try set it with 24 hour, so put it to 23:30 mark and the centre clock was saying 9:30! Any advice?

    1. HI Mary,

      Normally if you set the time on the 12 hour clock, you can then just turn the dial on the 24 hour clock so that they match up. If turning the 24 hour clock makes the 12 hour clock out of sync, try readjusting the 12 hour clock as adjusting that shouldn’t affect the 24 hour clock!