Boiler Cut Out

[BlueZulu]

I have a one year old oil fired boiler sited in my garage supplying central heating and a megaflow. I have no handbook and its starting to play up. Its manufactured by a scottish company called Rhino - Model BHS 90 - 120 fitted with a Riello RDB120 Burner unit.

I have it set up to come on twice daily and works fine cutting in and out as thermostat requires. More frequently now though, It locks out either at the end or start of the timed period and have to go out to the garage to reset it.

Cut out set to 90 (max)
Expansion vessel set to lift at 2 bar working fine at about 1.5 bar
Self Bleeder fitted and all radiators are fine
Plenty of fuel (tigerloop fitted)
Same symtoms in hot or cold weather
I have also started to notice the exhaust is getting a bit smoky so suspect a dirty nozzle?

Since I have no handbook and live out in the sticks I don't want to strip the unit down and be without heating while I wait for spare parts to arrive. If I knew what I needed I could order it in and then strip it down.

Any advice would be greatly apreciated.

Neil


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[ChrisR]

Phone them up and get a manual?????

 

[BlueZulu]

Phoned them up first thing and they said they will post out a manual.

I did however notice that the exhaust manifold was a bit discoloured and felt extremely hot. I had someone look at it and sure enough had high flue gas temps. Opened up the unit and apart from the usual deposits everything was exactly as I would have expected for a one year old boiler. The best we could get the temp down to was 500 degree c.

The burner had a 1litre/hour nozzle so perhaps a smaller one may be better but wont know that until I get a manual. In the meantime the temp setting was reduced from 90 to 75 so we will see how we get on.

 

[Agile]

My favourite wine is called Dumisani which is a Zulu word meaning "its right" !

I dont understand your temperature setting of 90*C. It is normal to have a heating flow temperature of a maximum of 82C.

An elevated flue gas temperature of 500*C is dangerous and implies that the water flow through the heat exchanger is far too slow or the power output is set far too high. Or that the HE is seriously scaled up!

The oil pressure to the burner can usually be set with an innoculous looking hex socket screw but this should usually be done by an OFTEC registered person ideally with a flue gas analyser.

Tony