Boilermate 2000 with Glow Micron 40ff causing reset

I cant run the Glow Worm Micron 400ff boiler on full with out it reseting. It works fine at half heat, but when it is run on full it resets and the LED indicates a "non volatile lockout"
The sequence of events to the boiler is;
1. The boiler will be running fine on full heat.
2. Once the store is heated it stops
3. Then the store asks for heat again after a short period, say if the hot tap has been running
4. Boiler fan starts
5. Ignitor sparks
6. Then the Micron 40ff doesnt start
7. LED sequence indicates "non volatile lockout"

This ONLY happens when running boiler on full heat.

I have changed the Thermistor, Safety Temperature Limiter, and PCB. Glow Worm have suggested that it is an external fault. The strange thing is that the Boilermate is obviously calling for heat, the boiler starts its iginition sequence but never iginites. I have checked power to the gas solenoid, and during the sequence there is no power provided to this. So from this i presume the Solenoid is ok, as i would expect to see power to this during in the process, so for what ever reason the PCB doesnt provide power to it.
Just wondered it this could be some sort of over heat problem caused by a malfunctioning pump.
Any advice greatly appreciated.

Just an idea.
Try running at half heat.
And if the boiler pump on the BM 2000 is on 3.
Try it at 2 or even 1.
This may induce the fault whilst running at half heat with the micron.
If it does, then you may have a boiler pump on the BM getting lazy.
Or restricted flow due to sludge from boiler to BM pipe work.
Worth check that the BM takes water when draining.
And also try draining boiler at doc to see what you get.
You may find the doc is blocked.
Which will indicate a system either untreated with inhibitor or not enough.
I will add though that the micron can be trouble.
I know because I have one!
Try looking on Google ref micron, you'll see what I mean.
Mike
MGC/H2O
Norfolk

I agree with Mike. This sounds like the classic Glow Worm Micron fault, nothing to do with the Boilermate, Googling will reveal the extent of this Micron problem!

The 'non-volatile lockout' is Glow Worm techy gobbledygook for 'overheat lockout'. Sometimes fixed by a new thermistor on the glow worm, sometimes a new control board will fix it, on other Microns the fault persists despite changing both. There are no other part of a Micron that control the temperature. If the problem persists on a Micron after changing both these parts it is likely to be products of corrosion accumulating in the heat exchanger in my opinion. I've yet to prove this though. Better to cut your losses and change the boiler I suggest.

Thanks for the advice.

I took the front of the Gledhill to check the pump, and noticed that the system was leaking from the base of the front of the unit on the joint. After checking through other threads on here, i see that basically it is a sealled unit, and probably needs replacing.

Anyway I checked the pump to the boiler, it was working fine on speed 3 and 2, speed 1 lagged a bit, it probably could do with changing but not really worth it if i have to change the unit. The water wasn't excessively dirty.

I wondered if the Gledhill may be calling for heat if the store wasn't satisfied, but not initiating the pump, I had read somewhere this can be caused by a PCB fault. So i wired in the pump to the switch live to the boiler, so when the Gledhill calls the boiler the pump should run.
So far the Micron has not reset and it has been 48 hours.
I say this seems to have fixed it, but now the pump runs constantly, which would indicate that the store is perminatley asking for heat as it is never satisfied. The Gledhill gives a Max store temp of 77C, when taking a reading off the boiler return pipe it reads 72c before the boiler turned off.
I wonder if the boiler is never man enough to heat the store, i read the Gledhill is self learning and i cant manully bring the MAX store temp down. Does anyone know a good way to bring the store temp down?
I think i will be replacing it in the next 2 -3 months, for a new boiler and a non vented pressured hot water tank. Any other suggestions appreciated.
Cheers

The store may well be 77 c
And the return 72 c
What was the boiler flow temp ?
What was the temp reading at the store sensor pocket?
But if the unit is leaking, then waste of time going further.
But I have a Micron 50 ff and it has been running ok for a few weeks now.
But one day soon it will not light.
And yes I will admit the 40 ff is a bit optimistic on a BM 2000.
AS in the winter if the store temp is not 60 c or above the heating will NOT work.
So have a big hot bath and no heating till unit has heated.
If you want to replace the BM 2000
You could use the Boilermate BP unit.
You can Y plan or S plan it.
Programmer required.
Hot water is via blending valve so adjustable.
Would recommend putting on a plinth giving access to pipe work below and also enables crossing of pipe work easier.
BM 2000 to a BP unit is NOT a straight change over
You will need to add a cold feed to the heating and vent.
The configuration inside the unit whether Y or S plan is not easy as tight.
If the cupboard is large enough it is possible to locate the pump ( only one!) outside the unit.
Another one to look at would be the Albion Mainsflow which comes as a package.
Mike
MGC/H2O
Norfolk