KA-6 boiler keeps going out

Hi, It has been a while since I posted to this forum as there are usually others that have issues with their KA-6 boiler that answer my questions. Anyway, this time I have an issue that has stumped me. My KA-6 keeps going out and when this happens, it appears to not cycle at all when the temp of the water drops below 160 and does not cycle even when the timer pins hit the switch. The primary fan and secondary fan are both working and under the grates are clear as well as the holes in the grates but the normal air flow from the fan motors will not keep the fire lit. I replaced the timer box last year. Thank god that the weather is getting warmer and I can switch to propane until I can figure this out. Anybody have any ideas what to look for next? Thermostat? Limit switch?

When the timer pins hit the switch and there is no cycle is your pinch point. When the timer hits the pin is the feed motor getting power? Basically you have a maintenance mode issue. I assume when there is a call for heat it is a non issue?

That is what I originally thought until I watched the temp on the water go below 150 and it didn't cycle either.

So either low water temp or time trigger a cycle of the feed motor? I would think then water temp does not matter if there is not a call for heat, kind of like a cold start bolier. Do you also have a hot water coil in the boiler? Which would change everything.

Not water coil in the boiler. I have an Amtrol watermaker hooked into one of the zones in the system. Thermostat is calling for heat but still no cycle. So no cycle on the call for heat and no cycle on the 15 min timer. What does that leave?

Hi Limit 1 is the control between the timer or the aquastat to the feed motor.

Since fans both run then that means all the limits and motors are good...maybe there is a shortage of coal being fed??? maybe a rock or something partially blocking the hopper outlet collar??? time to dig down and explore...

Keep adding new Coal and Air, that's all it takes!

New coal is going into the pan as the boiler keeps feeding, it just won't cycle with increased air to keep the coal burning. I have never had the boiler still feed coal but not increase the air to make the coal burn more. Is that a limit switch not working correctly?

I have a single blower for my KAA-4-1 combustion fan system and I have no trouble with the fire not making fine fly ash for me.

Have you had issues with this latest batch of coal not burning well??

Your problem sounds more and more like a bad triple aquastat OR the need for more pins in the hold fire timer to increase the hold fire time every thirty minutes.

I would add more pins to the hold fire timer first before I changed the triple aquastat though as a box of timer pins is less than $10.00

I got rid of my hydrolevel 3250plus triple aquastats "thank you keystoker, you get a big minus on that one" and replaced them with a Honeywell L8124L1011 horizontal triple aquastat from Patriot Plumbing Supply and a B+G/McDonnel & Miller RB-122-E low water cut off from TRIBRO supply in Vestal, New York I have had zero problems since then.

With this recent spat of warm weather I had my second outfire since last fall and I need to buy more pins for my Intermatic 30 minute timer to increase the hold fire time.

I would spend some time with a multimeter and make sure your controls are working properly.

Thanks guys. I had issues with this batch of coal burning this year and the only way I could get it to burn better was slowing the feed down and decreasing the air from the blower. I also added doubled the amount of pins in the timer so that hold fire timer would turn on every ten minutes instead of 30 earlier this year when we had a warm spell in order to keep the fire lit. I haven't checked control settings with a multimeter yet. Can you tell me what readings I should be looking for?

Are you saying the stoker is pushing coal but the primary blower is not blowing like it should? If so, they are both wired to the same place so I would be checking to see if that primary motor is bad...

Thanks, that is what I am going to check when I get home from work. I appreciate all your help!!

linkman2448 wrote: ↑

Mon. Apr. 01, 2019 12:08 pm

Thanks, that is what I am going to check when I get home from work. I appreciate all your help!!

Sorry, I was thinking of my kaa-4 (has separate motors). Your primary motor runs both the blower and stoker with the one primary motor. Very odd that you are pushing coal but not air. How far is the air shutter opened?

My KA-6 has separate motors as well. The secondary keeps running but the primary keeps shutting off when the boiler is cycling. I thought if I had a motor issue, it would trip out and need to be reset but it just stops running even though the thermostat is calling for heat.