Ideal Mini HE boiler on LPG

[alexmack]

My Ideal combi boiler on LPG seems to have an ignition problem! The ignition procedure runs as it should, but on some occasions the gas fails to light. The problem only seems to occur when the outside temperature is pretty cold, perhaps low single figures. After repeated re-sets it lights and then works normally. Once running it is okay. It seems to relate to the cold?
The boiler has just been serviced, and the engineer said all was okay.
There is a 6metre run of gas supply pipework above ground outside before the pipe enters the building, is it possible that the cold is affecting the gas?
Any suggestions would be much appreciated.

 

[transam]

You might need to get your engineer to check your boilers ignition gas pressure , on an ideal/biasi H.E , the suggested ign pressure is 13 mbars , we have come across several boilers were the ign pressure has had to be adjusted up wards , due to probs with ignition , L.P.G can be effected by sub zero temps , e.g it will cease to flow at approx minus 45degs C .

 

[AlanE]

minus 45degs C .

That could be a real problem in Devon.

 

[transam]

butane will be effected at approx' minus 2 degs C , now that could be a problem in devon !

 

[alexmack]

Thanks for your information. Is it therefore possible for the boiler to have problems igniting at low, but above freezing temperatures, yet to work normally when the temperature is say 10 degrees C?

 

[transam]

L.P.G, propane is not adveresley affected by cold weather conditions , which makes it ideal for outside storage , the temps you are quoting should have no effect on propane , what I have found is that at times the gas does not light cleanly across the entire burner , if I am correct I beleive the burner should light centre left centre right ,almost instantly ,& at times intermittently this did not happen causing ign lockout , hence adj ign' gas pressure , I beleive Ideal state 13 mbars Suggested ign pressure I assume that all other gas press are O.K .

 

[alexmack]

Thanks again. Is it possible that if the ignition gas pressure is currently set below 13 mbar (as you suggest could be the case), it would light normally when the ambient temperature is high, but with a cooler temperature, a resultant slight drop in pressure is therefore sometimes causing the failure to ignite? This would help to explain why failure to ignite only happens in the cold.
With regard to other gas pressures, I can only assume that the engineer who recently serviced the boiler would have checked and adjusted these, as I understand that this is normal practice after any servicing.

 

[transam]

its possible , but you may need to up the ign pressure beyond the 13 mbars , propane can be a ' lazy' gas , this ign pressure is only maintained by the boiler for secs ,note ideals wording 'suggested' ign pressure , dependant on what boiler you have , e.g 24 kw , or 28 kw , ( combi ?) but the max burner press ' would be 35? 36 mbars , min' approx 8 , ign suggested ! 13
the C.H would be range rated for a combi to suit your property , via seperate gas pressure adjustments .e.g on a 28kw boiler , 16 mbars would equate to approx 61,000 B.T.U's