K6 Feeding Above Hi Limit

I posted this on another topic where I received a great deal of much appreciated help. It might not really apply to that topic though so I hope it's alright that I post it as a stand alone.

Everything seems to run fine on the install except the stoker keeps feeding at and above the high limit.

Hi is set to 180. Low to 160. Diff at 10. My understanding is that in this case, if I am not calling for
heat (thermostat is off or way down) then the feed and my pump should stop except as set on the timer, until the water cools to 150, then kick on and heat to 160, then cease again. If I am calling for heat, it will only feed up to 180 then cease until dropping to 170 even if I am still calling for heat. As long as I am calling for heat the feed should cycle off at 180 and on at 170, but if no demand it should cycle on at 150 and off at 160. Is this correct?

When we first got it hooked up with the pump wired in the temp had fallen to 145. We turned the system on and the feed started but not the pump. Pump kicked on when temp hit 160 which seemed to make sense. But then it kept going to 185 without shutting down. We tried shutting off the thermostat and it still didn't stop feeding. Turned power off, hubby double-checked the thermostat wires (we did install a new simple dial thermostat) turned it back on, turned thermostat on, gave it a minute, turned it off, feed kept going. After maybe 5 minutes the feed stopped and I thought maybe there's just a delay. Temp was only at 175 so I wasn't overly concerned. Then the timer kicked it on for the 2 pins every 7.5 minutes that the man we purchased it from had in it, and after the pins had passed it just kept feeding through 30 minutes even though it was at 175 still.

Troubleshooting in manual said disconnect TT terminals and if motor stops the thermostat or wire is bad. Thermostat is brand new. Wire not so much. Motor did stop when red was disconnected but it seems like it can't be the wire because it will turn on the motor by calling for heat, and when we turn it down the little magnet thing in the aquastat clicks, but the motor just keeps on going.

Anything that could be imagined as a possible cause here would be a big help.

Timer stuck will do just that. And wired up backwards hi limit 4006 or 6006 would too. How many terminal screws are in the H/L?

Look for the direction on how to post pics to a thread...we are severely handicapped without your pics.

Getting to a computer to upload a couple pics. But I want to update: Feed just stopped 16 minutes after stopping demand from thermostat. Is this the normal delay? Maybe I'm just accustomed to a more instant response?

Pics here I hope

Jrhughes wrote:Getting to a computer to upload a couple pics. But I want to update: Feed just stopped 16 minutes after stopping demand from thermostat. Is this the normal delay? Maybe I'm just
accustomed to a more instant response?

Depends on how far the boiler temp had gotten drug down by the heat call...but 16 mins. is pretty long for a 130K btu/hr boiler to catch up...I'd be concerned if the boiler temp was drug down too far. Circ. pump may be too high flow volume and pulling it down too fast. What model circ. pump?

McGiever wrote:Timer stuck will do just that. And wired up backwards hi limit 4006 or 6006 would too. How many terminal screws are in the H/L?

Look for the direction on how to post pics to a thread...we are severely handicapped without your pics.

4006 has red to red and white to white so I don't think there's a problem there. The timer clicks off and the little lever pops up like it should. I have since removed two sets of pins so it only triggers every 15 instead of every 7.5. I definitely suspected the timer since twice it was off but when the timer kicked it on it just stayed on. Is there anything not visible right there on the timer that could be getting the circuit stuck closed even though it appears that the metal switch is popping like it should? Sorry for the inaccurate descriptions

McGiever wrote:

Jrhughes wrote:Getting to a computer to upload a couple pics. But I want to update: Feed just stopped 16 minutes after stopping demand from thermostat. Is this the normal delay? Maybe I'm just
accustomed to a more instant response?

Depends on how far the boiler temp had gotten drug down by the heat call...but 16 mins. is pretty long for a 130K btu/hr boiler to catch up...I'd be concerned if the boiler temp was drug down too far. Circ. pump may be too high flow volume and pulling it down too fast. What model circ. pump?

Hmmm. I'm not sure I understand, sorry. The temp is staying really high. 175-180. I thought if I turned down the Thermostat when it was that hot, the motor would shut off until it got 10* below my low limit of 160*. But it never drops nearly there. I've had the thermostat off for most of the day and haven't seen lower than 170.

Edited to add: Circulator is a Taco 007-F5. New this year.

Jrhughes wrote:Hmmm. I'm not sure I understand, sorry. The temp is staying really high. 175-180. I thought if I turned down the Thermostat when it was that hot, the motor would shut off until it got 10* below my low limit of 160*. But it never drops nearly there. I've had the thermostat off for most of the day and haven't seen lower than 170.

Edited to add: Circulator is a Taco 007-F5. New this year.

Temp staying high is due to the timer cycles repeating and no loads large enough to drop boiler temps below set points.

Ok. There's a distinct possibility it's oversized for the system currently online. Someone stole half our cast iron rads and we haven't been able to replace them yet. Heating about 2800 sq ft right now on rads that I calculated at a total of 97,000 BTU using height, columns, fin count. It keeps house pretty toasty. Is it dangerous to be tuning it on this small of a system? Pressure stays around 17-18 psi so it seems ok. Can I ease the issue by cutting back the timer? Right now I'm on 4 pins every 15 minutes.

Ugh. I was so hopeful. It was off for 53 minutes. Just kicked on 4 minutes before timer triggered and with thermostat off. Water temp 190. 4006 set to 200. What in the world is activating it?!

Also, because the thermostat isn't calling for heat the pump isn't running. I'm starting to worry that this is a serious safety concern. Turned up thermostat to get pump circulating but the dang motor seems to just kick on randomly.

I had feed nut at 5 turns back. will taking it back til I have a smaller fire help any?

Let's not be too hasty w/ the 4006 being alright. Previous owner of boiler were heating their swimming pool, true?
Does the 4006 have a 3rd terminal screw which is not used?

Again, we need pics...help us help you.

McGiever wrote:Let's not be too hasty w/ the 4006 being alright. Previous owner of boiler were heating their swimming pool, true?
Does the 4006 have a 3rd terminal screw which is not used?

Again, we need pics...help us help you.

Yes they were. We opened it up and don't see a third terminal but I've posted pics of it here and there are pics of the triple and timer above.

Thanks so much for your patient help. It's really appreciated.

This is a very simple system, so it has to be a simple problem. Get yourself a multimeter, and you will soon have your answer. Either something isn't wired correctly, or one of the controls is not working properly...maybe both.

When the stoker is running (and you don't think it should be) see if there is power at the N/O terminal in the timer. If there is, and the pins in the timer are not touching the switch/lever, the timer is either faulty or not wired properly. Also check for continuity across the terminals on the 4006B. It is possible that the 4006B is causing a call for heat when it shouldn't be, either because the contacts don't break properly, or the aquastat is way out of calibration. Lastly, it is possible that the triple aquastat itself is messed up.

Not having a bypass on the boiler is going to cause stratification in the boiler when the circulator is not running, so the temperature gauge, triple aquastat, and 4006B in the top of the boiler may be sensing different temperatures. There really isn't a good solution for this other than running the circulator all the time.