a knightly error message

Landry Mechanical

Ran into a 3 month old knight whn080 boiler that locked out on ahl and mhl one after another. I replaced the primary circ and bled the system thinking there was a flow problem. Now a week later the boiler is locked out again. Has anyone run into this?I am thinking maybe the board is bad and not calling the pump on??

Mark Eatherton

Sound like...

No time delay on the pumps. The pumps (all 3 of you are doing DHW) have a programmable time delay that can be programmed for anywhere between 0 and 10 minutes of run time AFTER their call for heat has been satisfied. If you have them set to zero minutes, and the boiler is running full out during a call for heat, and that call expires, you have an extremely hot combustion chamber with some heat to dissipate, and if you don't dissipate it, you WILL hit the MHL and AHL settings.



Access code to this section is 5309 on the on screen settings, which is in the I&O manual.



Check your pump settings.



The control on this boiler is THE best that I've ever seen on the market, and although I've not seen all of them, I have seen a LOT of them and none of them comes close to this system for flexibility and contractor access/control capabilities.



Ramping up, ramping down, time delays, boost over rides, time of day set back, offsets and on and on.



THE BEST, bar none. And it just keeps gettin' better.



If you get the manufacturers software and interface cable, you can go to the field with a lap top, and connect it to the boilers computer, and see EXACTLY when, where and why you are experiencing these issues. Not many manufacturers can make that claim. Don't forget to set your lap top such that it doesn't fall asleep while its data logging, or you will have wasted your time (don't ask me how I know this...)



Good luck and get back to us.



BTW, I've had one (1) bad circuit board on all of the Knights I've installed, and I suspect, based on the 50 cent piece of missing board and charring, that it was hit by a major electrical spike or some other condition beyond control. Very robust board IMPO.



ME

Steve Whitbeck

WHN

Do you have an indirect water heater connected. You have a smaller boiler than I had this problem with ( WHN285 and SSU 60 ) when the boiler was heating the indirect it would ramp up too fast and overshoot the max temp. You can limit the speed of the blower thus limiting the BTU's in indirect mode. I cut mine to 50% firing rate. Solved the problem.

Landry Mechanical

thanks guys

Thanks Mark and Steve, I do have post purge set up on both my dhw and space heating demands. I donmt think its an energy absorbtion isue since the boiler is so small. Mark I do really like this boiler I have probably installed about 20 and have only had a few issues. One time one of the two averaging flame sensors failed. Another time the ohms reading on the supply sensor on an install went bad tripping the boiler on delta t and have oddly had two bad indirects (squire 40s) fail in. Under two months. Nothing two major other than the indirects but that's part of the game we play. I had already gone to this job once a week ago and talked to tech support, they told me to raise the ahl and mhl and if that didn't work to change the board I think that's the direction I will go.

Mark Eatherton

Follow the factorys lead...

They know what they are talking about.



As with any piece of equipment, its not a matter of IF you will have issues, but more a matter of WHEN, and then it boils down to their response to the situation.



Keep us posted.



ME