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Convotherm 4, E05.1.8
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I guess it’s possible.
Just wouldn’t know what to do about that.
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Okay, so here is what I am seeing.
I pulled the burner, igniter gap is good, not much wrong, cleaned the burner, swapped modules and here is what I see.
The top burner is loosing its MA signal, or its growing weaker and weaker by the minutes. It starts out at 30 on full heat, then slowly drops down and keeps dropping, it went down to 8 MA whereas the bottom burner stayed strong on 30 or above and didn’t waver. I was monitoring gas pressure at the same time as this, it was holding 7″ W.C strong and the MA signal was still dropping.
When I originally changed the igniter the first time (in this chain of events) the MA signal was doing the same thing and kept dropping until it hit 0 and the burner would relight and start over, that’s why I changed the igniter again but It’s doing the same thing it seems.
This is reminding me of the last time with the faulty igniters, I believe we were seeing similar things.
Tried to use the combustion analyzer but the 02 sensor is used up and doesen’t work so it’s not much good.
CO is 18 PPM for both top and bottom burner, not much good without all the other measurements but that’s all It’ll do right now.
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Clean bright connections. cotton gloves when handling the electrode. Especially the outer 90 degree one to prevent body oil from making a track or oxidation point. Fresh screws and star locks help. It has to ground through the burner, so it to has to be clean at retaining points.
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Just got off the phone with Convotherm, apparently they now have a Gen III igniter and I am using Gen III so they are advising I change to the new style and update my software and that should take care of it.
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Makes sense, I’ll keep it in mind.
This igniter only has 1 wire, I wonder how it travels back to the ignition module. Could they be using the same wire for spark ignition as they are for monitoring MA signal?
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Normally the sensing is done through the burner ground. But, this machine has a dedicated special built burner control. Wiring diagram on it is a bit vague.
Now I noticed that the electrode wire has a either resistor or diode in the middle. Be nice to know which it is. If you have a old one yet you could cut off the heat shrink to see. It should have a NEC number or colored bands. Ohm it out and check vs. a new one. Semiconductors are very sensitive to heat, So routing of that wire may be critical if a diode..
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Right, figured as much. The former model has 2 wires coming off the igniter, I wouldn’t even really know how to check for MA on this igniter if it wasn’t for the feature in service that does it for you.
Here is the shrink tubing cut off.
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22 ohm resistor. They must have had some interferance to there controls at some point.
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Could very well be.
Got 2 of the Gen IIII igniters coming from Convotherm, will be here tomorrow morning. I’ll snap a picture of them so you can see the new one.
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Well, got the new igniters today. They are a bit different but not by a whole lot.
So there ya go, hopefully its going to last this time.
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