I have a 10-year-old Raypak 407 gas heater. Several months ago, I replaced the igniter and burners due to corrosion. While I had everything apart, I cleaned everything to make sure there was no sediment, leaves or dirt anywhere, either above the heat exchanger or below the burner tray. The rest of the heater is pretty much corrosion free.
While I was replacing these components, I checked the heat exchanger, which had almost no soot (I cleaned whatever soot was there), and found no blockages of any kind in exchange tubes.
For several weeks after that work was done, the heater worked perfectly. Over the last two months, the heater gets to about 92° and then shuts off automatically with a high limit#2 error. I tested the unitherm governor, which does open properly at about 100° or so, and replaced the bypass valve (which was stuck with some corrosion) and both limit switches, but the heater still trips with a high limit to error from between 88 to 92°.
I gave myself a $450 ceiling in terms of parts (I’m doing all the labor), before I pull the plug and think about a new heater. I’ve now reached that ceiling, but I can’t help but think that I’m missing something simple given the heater in all of the respects is now quiet and heats beautifully until the high limit error occurs.
Any ideas?
Many thanks in advance.
While I was replacing these components, I checked the heat exchanger, which had almost no soot (I cleaned whatever soot was there), and found no blockages of any kind in exchange tubes.
For several weeks after that work was done, the heater worked perfectly. Over the last two months, the heater gets to about 92° and then shuts off automatically with a high limit#2 error. I tested the unitherm governor, which does open properly at about 100° or so, and replaced the bypass valve (which was stuck with some corrosion) and both limit switches, but the heater still trips with a high limit to error from between 88 to 92°.
I gave myself a $450 ceiling in terms of parts (I’m doing all the labor), before I pull the plug and think about a new heater. I’ve now reached that ceiling, but I can’t help but think that I’m missing something simple given the heater in all of the respects is now quiet and heats beautifully until the high limit error occurs.
Any ideas?
Many thanks in advance.
