Rayburn 499k MX Lock out on both burners

ightenhill · 3 Jan 2020

Our 499k MX with the Nu way burners has been running faithfully heating and cooking over the years.. Every now and again it throws a tantrum and needs Blaster Tubes replacing but this time Im mystified..

On the cooker side its starting its sequence with a small charging sound from the ignition unit before going straight to lock out.. At first I though it was the usual blaster tube problem until I noticed that the boilerside had also locked out. This sequence starts as usual with the fan starting plus an electronic noise which I presume is the boilers ignition charging up and then lock out..

I have checked that fuel is available by disconnecting the pipe so its not the fire valve on the oil line. I can also see some fuel if I unscrew the bleed on the oil pump..

My suspicion then since both sides are locking out is that the oil pump has gone or the 1st solonoid after the pump but is there a way to confirm this or does anyone have anyother ideas?

Thanks

oilboffin · 4 Jan 2020

Are the blast tubes wet if so then oils getting through check ignition then pressure from pump. Bob

ightenhill · 4 Jan 2020

hi - No its totally dry. Both ignitions have just been replaced.

ightenhill · 4 Jan 2020

One thing has occured to me - All though boilerside I can hear the fan kick in before it locks out... Cooker side Im not hearing the motor start at all.. (its obviously not starting when the boilerside tries to work either bu the noise of the boilerfan is louder and disguising its absence)

I presume then my first checks should be the pump drive motor - its power and the coupling to the fuel pump..

oilboffin · 4 Jan 2020

It's strange that every so often you need new blast tubes these should last for years. Bob

ightenhill · 4 Jan 2020

The 499ks blast tubes seem to me to have a terrible design fault and always seem to slowly tear over a year where the fold is..

Just looking at the motor when I removed the capacitor cover there is a little brown liquid on it? Never been much good with the voltmeter though so not sure how I check its the motor.. Im 99% sure of it due to the fact I cant hear it on start up.. It should start up regardless and before any lock out

oilhead · 4 Jan 2020

Check the solenoid valves after the pump. Sounds like one of these may have failed. If you're lucky, it may be one where you can get a new coil.
Blast tubes on the Nuway burner are absolute pants. As far as I'm aware, they are no longer available.

ightenhill · 4 Jan 2020

IM pretty sure it the motor as I did a resistance test and its way to low... 46ish

Also backtracking the start sequence the motor would still try to start (I think) even if the solenoid after the pump had failed... Oddly both Aga and Nuway still supply the blast tubes (probably because they are so poor that they have a constant demand for them

ightenhill · 4 Jan 2020

Just had an OMG moment - started it whilst the unit is outside the body of the rayburn (why I didnt do this in the first place I dont know - visions of it jet racing across the room like a drag racer) .. Motor not even starting .. My logic tells me it should start regardless of the solenoid condition because the boiler fan doesnt make such a check and starts as normal, but with no cookerside motor there is no fuel pumping round..

The only other thing I can think that could do no sequence lock out is the air pressure switch but not sure how to test that

Burnerman · 4 Jan 2020

With the burner unit withdrawn from the Rayburn, look at the boilerside photocell.....pull it from its housing, clean it then completely cover it so it cant see any light before you test again.
Am I right in saying the burners are soft start, and cookerside has its own fan motor?
By the way, if the capacitor is leaking, brown or distorted, replace it.
John

oilboffin · 4 Jan 2020

By the way all stove spares have now shot up in price. Bob

ightenhill · 4 Jan 2020

Burnerman said:
With the burner unit withdrawn from the Rayburn, look at the boilerside photocell.....pull it from its housing, clean it then completely cover it so it cant see any light before you test again.
Am I right in saying the burners are soft start, and cookerside has its own fan motor?
By the way, if the capacitor is leaking, brown or distorted, replace it.
John

I see the logic as its now outside the body of the rayburn - will give it a go though the resistance test on the motor does seem to indicate the motor has died (but looking at the engineering manual would the PEC fail even come before starting the motor as it seems to be the first call from the control box).. Im coming to the conclusion Nu way and Rayburn built this "engine" out of spare parts and fingers crossed.. Yes its soft start (though even this is done/designed oddly)

oilhead · 4 Jan 2020

A faulty P/cell will lead to lockout with a false flame signal.

Burnerman · 4 Jan 2020

If I recall, this Nu Way / Rayburn combination only lasted a couple of years before switching to Eco Flam burners....I don't know if they were an improvement or not.
Anyway, at least the control boxes and photocells are the same and therefore swappable......personally I'd go for getting the boilerside up and running first and sort the cookerside later - the chances are it will behave anyway.
A dud photocell could give your symptoms too.
You'll really need a pressure gauge screwed into the pump P port, and for the soft start it kicks off with around 100 psi before switching over to 140 psi after half a minute or so. This is done by the solenoid bank in the unit.
Personally I think the capacitor and motor need replacing, but that's easy enough to test on the bench and parts are available.
Have you managed to remove the boilerside baffles for cleaning? Accessible through the top left side they are a pig to remove and clean - but clean they must be, and that includes the flue path to the chimney at the back right.
John

Burnerman · 5 Jan 2020

I forgot to mention....ensure the boiler overheat thermostats are manually reset - on the front panel. They don't reset automatically and can be pushed in with either a match or a cocktail stick etc.
John

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Rayburn 499k MX Lock out on both burners

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