British Gas 330+ boiler - Flashing SE

18 Nov 2018
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United Kingdom
I moved into my property about 3 years ago and it has a British gas 330+ condensing boiler.

Every year, around this time, I wake to a freezing house and no hot water. Heating system is calling for the boiler but when I go to the boiler and look at the LCD I see it flashing and alternating between the temperature (something like 16 degrees) and SE (or 5E I guess it could be).
Tapping the mode button 4-5 times brings the radiator symbol up and the allows me to set the temperature back to 72 degrees and everything works again. This will happen again and again randomly.

Looked in the manual for the 300 version and it mentions nothing about a flashing 5E/SE symbol. Just mentions F codes which I don't get.

At first I thought it was to do with Servicing, although I think that's pretty dumb for a boiler to stop when it needs servicing, because it happens the same time every year.
Every service engineer I had out (not British gas) said they don't no what it means and can't get rid of it.

The other thing I have noticed is that the heating/hot water demand, powers the boiler? Looking at the wiring diagram the boiler is suppose to have a separate live and neutral supply. I haven't looked at the wiring yet but the LCD is never on when the heating/hotwater demand is off. Pushing buttons does nothing either.
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it is indeed the service due indicator and you are correct this boiler requires a permanent live
That is really dumb!. I have a baby and I was woken at 4 in the morning and she was cold. Her room was freezing, like the rest of the house.
Why couldn't they put a buzzer or something on the boiler to notify you rather than turn off the hotwater/heating.

Anyway, how do I get this switched off/disabled or change the date? I had this boiler serviced in March (2018) so it shouldn't need servicing until March next year.
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I don't know your system, but there are some heating programmers that are deliberately designed to inconvenience the householder when they reach the service interval. They are mostly found in rented homes to incentivise the occupier to have it serviced.

In the event that you have one of these, get it replaced with an ordinary one and smash the SI model with a big hammer. Some people sell them second hand on ebay and they make some other poor sod miserable.

Some photos of your heating controls may help.

I am not a heating engineer.
The heating controller is one that I have installed and is a Honeywell Evo home.

The issue is not related to the controller it is the boiler itself.
The boiler should have a permanent live going to it, but the central heating and hot water share a common call for heat. Your thermostat/controller should control a couple of valves in the systems which opens/closes a couple of valves to ensure it only services what requires the demand (HW, CH or both).

I'm not a plumber, but just have one of these installed in my house. I've got the manuals (install & user) for the BG 330+ direct from the manufacturer, send me a message if you would like a copy of them.
I found some manuals online thanks, I just can't see anywhere about the SE/5E flashing and, if it is service interval, how do I get rid of it.

I have a Honeywell wiring centre and for the boiler terminal I only have live, neutral and earth wired in. 2 thoughts I have here.

1) I am going to need a 4 core cable installed as I need a wire for heating/hotwater demand.
2) If the boiler is wired to the boiler live on the terminal block in the wiring centre then surely I should be seeing the opposite of what I have? i.e. I should see the boiler powered 24/7 but no demand for heating/hotwater.
You need four cables going to the junction box on the boiler as you state, E/N/L and switch live. We have mains by the boiler that goes directly in, then a four core cable that goes out to the programmer which provides the mains and switched live. Switching off power to the boiler turns of the power for everything linked to the boiler. Having the power run this way round allows the boiler to run without a programmer, with some overrides in place.

Does your system have mechanical valves on it? to turn the HW/CH on off?
The call for heat from the programmer for both CH/HW needs to use the same switched live to the boiler.

If you have separate power available to the wiring centre/programmer and the boiler. You use one of the existing cores for the switched live to test and confirm that you can get things working properly, then run in a four core cable and do properly.

Though, to the letter of the law, you can't even take the cover off the boiler, you'd have to get a registered engineer in to do that for you.
The Mains goes into the wiring centre and this powers everything from there.

Yes there is a 3 port valve with actuator.

The part that is really bugging me now it the fact that the live to the boiler is wired into the live of the boiler terminal in the wiring centre, yet the boiler is still being switched off. That says to me the wiring centre is not right either.
When it comes to Y plan a significant number are not wired properly...a missing cylinder thermostat satisfied wire being the most common fault.
I had to completely re-wire our ones, who ever installed stuff had got all of the cables wrong for the valves, not sure how it was working before! I had to map everything out to work out what was what and then work through what changes were needed. I'd suggest getting a pen and paper and working out exactly how it is cabled now (trace all cables). Refer to the manufacturers documentation for all the valves/controllers etc. and work out what is cabled right and what is wrong. Obviously, turn the power off whilst you do that.

That is the only way you can confirm that stuff is wired correctly.

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