Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length.

[pettyofficernick]

Hi Folks, I am in need of a bit of advise, the gas burner in my Maccsteam 3.5 inch boiler has taken to 'striking back' it works normally for a while but as soon as things get heated up the flame seems to go to the wrong side of the ceramic insert and the noise it makes changes, The boiler then takes for ever to raise steam, if I turn off the gas supply and then relight, it almost immediately strikes back again, ( I hope striking back is the right term, it is what school chemistry bunsen burners did).I am also using a Forest Classics attenuator valve, but I have double checked the instructions and all the pipework is in the correct places. Any suggestions would be most appreciated.
Regards,
Nick.

[KBIO]

Good evening Nick;
Interesting! But hard to give an answer staight away. Some pics will help us to figure out.
First thing I would do,  is to ensure the jet is clean by passing a guitar string inside it (smallest one).
Second one is to make a test with the burner out of the boiler. Directly from tank to burner.
Tell us also, what is your gas pressure all along the process.
by eliminating the suposed problem one after the other, we'll find the solution!
Regards.

[pettyofficernick]

Hi there Kibo, I have no means of checking gas pressure at the moment, I will however do as you suggest and check that the jet is clear. How critical is the position of the jet in the tube, the reason I ask is I may have disturbed it when tightening the gas feed pipe, at the moment, the face of the jet is level with the back edge of the air holes. I shall post a photo shortly.
Many Thanks,
Nick.

[pettyofficernick]

Heres some photos of offending burner, not to clear I know, taken with phone.

[TAG]

Hi Nick
Only got time to quote from an O level chemistry book, chapter on flames, section headed "striking back". "Striking back is always liable to happen if the air supply is too great"
Suggest you have a play with the volume of air being pulled in by the venturi, jet position might also be worth adjusting.
Hope this helps
Must dash
Tim 

[kiwimodeller]

I would suggest you email Mike at Maccsteam. He is always very approachable and helpful. There will be a standard setting for the jet position as a starting point. On a Cheddar burner it was from memory 4mm from the edge of the airhole to the face of the jet. Final tuning of the mixture was usually achieved with the jet only a little either side of this initial setting. When in doubt ask the man who made it. Cheers, Ian.

[KBIO]

Good evening !
Hello Nick!
I would say that your jet is probably too much in, and does not allow enough air to go in. I may be wrong, but I would suggest that you pull it out a bit and check.
The best way to see if your burner is functioning good, is to pull it out of the boiler and to check if the flare is fairly strong and blue (no yellow in the flare exept (eventually) at the tip). Also, if the burning gas out of the chemney is picking your eyes , it means that you have not enough air.
I shall try to get a photo of my mcSteam boiler tomorrow to compare with yours.
The right solution (as Kiwimodellers says) is also to contact Micke from McSteam who is always of great helps.
Last, I won't keep the gas tank insulated. It needs heat exchange to keep some pressure inside. Your problem may come from there also. You may have enough pressure at the begining to supply gas to the burner, but the tank cooling down, the pressure drops, and there is only a weak blow to the burner.
Last: a McSteam boiler works good and your will do as well. 
Reagrds;

[livesteam]

Hi Nick!
I had exactly the same problem and emailed to Mike. He answered that he had a burner series that had a problem with the ceramic materials. He changed my burner for free and very quickly. Great service! 
Kaspar

[pettyofficernick]

Many thanks to all for all the advice,phoned Maccsteam this morning and a new redesigned burner is on the way, excellent service!