UK Heatrae Sadia Electromax boiler not powering up at all

blacbabo · Jul 3, 2024

Hi all,

The boiler, a Heatrae Sadia Electromax, is connected through a Timeguard timer. It's programmed to run between 20:30 and 22:30 every day and has been working fine until last night. I noticed there's no hot water coming out of the shower. Upon checking, the timer seems to be working fine. I can see the status changes on the display when the preset time is reached. However, the output LED did not light up, and the boiler is not powering up at all. Nothing is lit up on the boiler control panel. No power, no alarm, nothing.

Could someone give me some advice, please? It would be really appreciated.

Avo Mk8 · Jul 3, 2024

If the Timeguard output green LED never lights up, have you checked the 13A fuse (with a meter), or tried a replacement fuse?
The timer and switch precede the fuse, which is on the output side of this device.

Otherwise you could try resetting it according to the instructions:

https://dam.epim.online/timeguard-19abbd57-b7f1-4088-baa7-bbe453c25a37/Product%20Instructions/Time/Immersion_General%20Purpose%20Timeswitches/FST24_FST77_instructions_135x85_issue_3_web_ready.pdf

blacbabo · Jul 3, 2024

Avo Mk8 said:
If the Timeguard output green LED never lights up, have you checked the 13A fuse (with a meter), or tried a replacement fuse?
The timer and switch precede the fuse, which is on the output side of this device.

Otherwise you could try resetting it according to the instructions:

https://dam.epim.online/timeguard-19abbd57-b7f1-4088-baa7-bbe453c25a37/Product%20Instructions/Time/Immersion_General%20Purpose%20Timeswitches/FST24_FST77_instructions_135x85_issue_3_web_ready.pdf

Hi Avo,

Thanks for the reply. I tried resetting the timer a couple of times and even cutting the power, but no luck. I thought it might be a blown fuse, but I googled it and found out it’s probably not that since the timer still turns on. I think this is beyond what I can fix, so I guess I'll call an electrician.

Thanks again for your help

Avo Mk8 · Jul 4, 2024

blacbabo said:
I thought it might be a blown fuse, but I googled it and found out it’s probably not that since the timer still turns on

I'm sorry I wasn't clear. The instructions for the Timeguard include a block diagram clearly showing that the 13A fuse is on the output of the unit, so the timer should continue to work (except the output light may not light) even when the fuse has blown (assuming their diagram is correct!).
I urge you to at least try another fuse! If I've misunderstood I apologise, but for the price of a fuse it might be worth a try.

[ElectriciansForums.net] Heatrae Sadia Electromax boiler not powering up at all

Of course if the fuse has blown because of a new fault, you will need the electrician.

blacbabo · Jul 4, 2024

Avo Mk8 said:
I'm sorry I wasn't clear. The instructions for the Timeguard include a block diagram clearly showing that the 13A fuse is on the output of the unit, so the timer should continue to work (except the output light may not light) even when the fuse has blown (assuming their diagram is correct!).
I urge you to at least try another fuse! If I've misunderstood I apologise, but for the price of a fuse it might be worth a try.

View attachment 117093

Of course if the fuse has blown because of a new fault, you will need the electrician.

Thanks for the clarification. I'll check the fuse before calling an electrician. By the way, do you happen to know how to access the fuse? The closest information I found online suggests inserting a screwdriver into the slot near the 'FUSE' label and gently turning it counterclockwise.

DPG · Jul 5, 2024

blacbabo said:
Thanks for the clarification. I'll check the fuse before calling an electrician. By the way, do you happen to know how to access the fuse? The closest information I found online suggests inserting a screwdriver into the slot near the 'FUSE' label and gently turning it counterclockwise.

Yes, switch off and then carefully use a screwdriver to prise the fuse holder out.

Might take a jiggle or two (technical term that)

blacbabo · Jul 6, 2024

DPG said:
Yes, switch off and then carefully use a screwdriver to prise the fuse holder out.

Might take a jiggle or two (technical term that)

Thanks for the confirmation. It turned out it was indeed the fuse. However, the fuse holder has melted, so I think it's beyond repairing. I guess it's time to call an electrician to have the timer replaced and hope it won't trigger again.

DPG · Jul 6, 2024

blacbabo said:
Thanks for the confirmation. It turned out it was indeed the fuse. However, the fuse holder has melted, so I think it's beyond repairing. I guess it's time to call an electrician to have the timer replaced and hope it won't trigger again.

Yep, looks like there has been some poor contact between the fuse and the holder at some point that has caused the overheating. Glad you found it.

Avo Mk8 · Jul 6, 2024

blacbabo said:
Thanks for the confirmation. It turned out it was indeed the fuse. However, the fuse holder has melted, so I think it's beyond repairing. I guess it's time to call an electrician to have the timer replaced and hope it won't trigger again.

Definitely best to replace the timer. May have been due to a fuse with slightly oxidised contacts, or the spring clips in the timer a bit weak, and they will be weak now they've been heated up! One sees this from time to time on immersion heater switches because the load is high for a sustained period.

Just to say a like for like replacement of an accessory like this can legitimately be done as a DIY job if competent to swap it out. I'm not encouraging you to do it - if you don't feel confident, it's best to get an electrician in.

blacbabo · Jul 6, 2024

DPG said:
Yep, looks like there has been some poor contact between the fuse and the holder at some point that has caused the overheating. Glad you found it.

Thanks for the info. I'll have an electrician replace the timer and take care of it.

blacbabo · Jul 6, 2024

Avo Mk8 said:
Definitely best to replace the timer. May have been due to a fuse with slightly oxidised contacts, or the spring clips in the timer a bit weak, and they will be weak now they've been heated up! One sees this from time to time on immersion heater switches because the load is high for a sustained period.

Just to say a like for like replacement of an accessory like this can legitimately be done as a DIY job if competent to swap it out. I'm not encouraging you to do it - if you don't feel confident, it's best to get an electrician in.

Thanks for the explanation. I did feel the timer getting warm (or even hot), so that could be the cause. I think I'll play it safe and let a professional deal with it. Appreciate the tips!