Reluctant Riello

[Baz2126]

I have a Grant 50/70 with a Riello RDB1 burner. For over 10 weeks now we've been trying to resolve a lockout problem that occurs at start-up. Normally the boiler will have failed to start and the lockout light will be lit. When the reset button is pressed it will run a full 40 second sequence but then lock-out again. At a second pressing of the reset button the boiler will fire up normally after 12 seconds. It is then something of a lottery as to how long the system will run before the same thing happens again.

So far we have changed the oil pump, two stems, two solenoids, two photocells, a motor, several nozels and substituted a new control box which made no difference so we replaced the original. I've also added a Tigerloop, checked and removed water from the tank, verified the supply to the burner and checked the baffles for any obstruction and checked and cleaned the filters at least twice. All to no avail.

Help please! any hints, tips or advice will be greatly appreciated.

Baz

 

[Roger Welton]

Is the fuel pressure stable when it locks out or fluctuating?

I take it the photocell was replaced at the same time as the control box.

Are the flue and fleets clear?

 

[SimonG]

How old is the boiler? Fitted a new nozzle?

 

[PlumbBobBob]

How old is the boiler? Fitted a new nozzle?

they say several nozzles

 

[SimonG]

they say several nozzles

Missed that in the op. Cheers steve.

 

[SimonG]

What are the combustion settings like? Oil press., co2, air?

 

[Baz2126]

What are the combustion settings like? Oil press., co2, air?

Oil pressure has been read at 7.2 bar and stable at that time, no other figures taken. The 50 volt 'white' supply to the control box was verified as were flues clearance.

Boiler is just 9 years old and serviced every year...

Thanks folks

Baz

 

[Best]

Sounds like you have been changing everything! My first thought is that the burner needs set. The air adjustment is an issue with the Grant 50/70. Especially on colder days. If the burner tends to start on second go, or when boiler is warm, then this is classic problem, very common. Nozzles that are 60 degrees are also more likely to cause ignition trouble.

 

[Roger Welton]

Have you tried blowing through the oil line to prove its clear?

 

[dontknowitall]

Have you tried blowing through the oil line to prove its clear?

This is my thought too. If you disconnect the flexible oil line and let it run into a container (e.g. Tesco's 1 litre Lemon Sorbet ice cream tub) you can see how the oil is coming through. Might be some sort of blockage on the line, especially if the boiler's run out of oil at some stage and the dirt from the bottom of the tank has worked its way into the line.

Might be worth checking the oil filter at the tank too.

 

[Best]

That should have been done in a service, - especially given the fact the boiler has been locking out.
Since the burner is supposed to be doing everything but igniting, by the sounds of it, then either the nozzle is partly blocked, or the setup is not right, most likely, IMO.
If it was a blockage in the oil line, then the boiler may actually start okay, but give trouble when drawing the reduced oil, later, so probably not that, though it def should be flushed through anyway, & oil filters checked.

 

[WHPES]

Is the tank below the level of the boiler? If it is then you probably have a leak which is allowing air into the line and the oil to start to slowly run back down into the tank, causing the lockout when the air starts to get drawn into the burner on startup. If you press reset a couple of times you will probably clear the air to get the burner started, but when it stops you will be back where you started the next time it tries to fire.

You can find such a leak using a plumbers hydraulic pressure test pump.

 

[Roger Welton]

(e.g. Tesco's 1 litre Lemon Sorbet ice cream tub).

I use Morrisons vanilla, best bit is emptying a new tub ready for use 🙂

 

[Best]

I use Morrisons vanilla, best bit is emptying a new tub ready for use 🙂

....and remember, if you have oil heating yourself, to keep all the small drops you flush through, let it settle & pour the clean stuff into your own tank. Like gold now, heating oil!

 

[Baz2126]

Hi Gents,

Oil delivery has been proved and I have a new Tigerloop fitted so you can see the head of oil. We haven't blown the pipe through because the flow is good. Both oil filters have been checked and cleaned at least twice.

Temperature does not appear to be an issue as the fault started (suddenly) when the temp was below freezing and has continued when the temp was at +15 degrees the other week.

I presume we'd need analysers to set the air mixture up?

Baz

 

[Best]

Yea, need an analyser to properly do it. I assume it is the standard eff 50/70 grant? They are critical to be set right, - a little too much air & they don't start easy when cold start.
An engineer could set it well, using a smoke pump & an oil gauge only, though, but good to have it fully checked.

 

[WHPES]

I presume we'd need analysers to set the air mixture up?

By that I assume you aren't technicians if you don't have an analyser? Get a pro in to do the work. Don't tinker around with combustion appliances if you aren't qualified - could end in tears (or worse).

 

[Best]

By that I assume you aren't technicians if you don't have an analyser? Get a pro in to do the work. Don't tinker around with combustion appliances if you aren't qualified - could end in tears (or worse).

Agree, you will just waste your time & money on parts - & extra oil used if burner not set up!

 

[WHPES]

Potentially dangerous in the hands of the inexperienced and untrained.

 

[Roger Welton]

Agree, you will just waste your time & money on parts - & extra oil used if burner not set up!

A qualified chap would have probably sorted it out on first call and saved you all the you've parts fitted!