K6 boiler won’t stop heating

Hey all new here,I have a K6 boiler and I have 4 zones. 3 zones run off from circulator relay and zone controller. The 4 th runs off from triple aqua stat. That one we have wire so that when it calls for heat it turns on the main circulator pump to the boiler and turns the boiler on. My problem is that the first 3 zones heat as follows: run#1 heats concrete in basement, run#2 heats mud room kitchen living room, run #3 heats 3 bedrooms and 2 bathrooms. The fourth zone runs to a heat exchanger which is 19”x22” with 3/8 tubes that is duct into multiple rooms with about 1200 sq. ft. The 3 zones never call for heat because for some reason it’s always 78 degrees in there, I can’t seem to get those zones to cool down. The 4th zone calls for heat and in fact does heat. Also, I have the triple aqua stat set at 140 and 160 but the boiler continues to run even above 180. I hope it’s not too confusing any help would be great, sick of sweating all night!!

Check valves anywhere...
Sounds like a ghost flow...
Open some windows first...
The boiler stops running at what temp...
Does it go over 210*...

If the stoker and fan are running above 160, you either have a bad triple aquastat or you are backfeeding the b1 terminal somehow. It should never fire above the high limit except possibly on the timer. Has it ever ran correctly or is this a new system?

Sound like you are getting gravity convection through the 3 zones when the 4th one is on. Hot to cold convection can be a problem if not piped properly or zone valves are leaking by.

It doesn’t ever go over 210, all valves are open and solenoids are working properly. It worked correctly for a few days and then started acting up.

I currently have the valves off to the first 3 zones just to help cool it down

Hello Aecarl,

Does your kaa-6 have a hydrolevel triple aquastat??

Aecarl wrote: ↑

Sun. Nov. 10, 2019 12:10 pm

It doesn’t ever go over 210, all valves are open and solenoids are working properly. It worked correctly for a few days and then started acting up.

Welcome to the forum.

Is this a new install??? Or has it been in place for many heating season and just started having this problem??? This is very important to know if we are to figure out if it is a failed part or an install problem.

-Don

This is a new install. I think I attached a couple of pictures

You may have multiple things going on. Wiring issues, ghost flows, etc.

I would start by checking the high limit functionality on the aquastat.

So, I am going to order a new aqua stat but, I have had 3 zones off all day. I just went and turned them on and got flow through the manifolds, do I need to install a solenoid on the inlets as well? None of the zones were calling for heat except zone 4.

Mixing valve for zone 1 garage floor likely needs check valve(s)...there is pressure differential from other zones passing through there somehow.
You should be able to use your hand and feel that there is heat flow even when zone 1 is not calling for heat...

Aecarl wrote: ↑

Sun. Nov. 10, 2019 8:50 pm

So, I am going to order a new aqua stat but, I have had 3 zones off all day. I just went and turned them on and got flow through the manifolds, do I need to install a solenoid on the inlets as well? None of the zones were calling for heat except zone 4.

Before you order a new one I would just troubleshoot the one you have. Remove all but the incoming power wires in the aquastat, and with the boiler at a known temperature, adjust the high and low limits with a voltage meter (or wire up a light bulb) across the B1 & B2 terminals.

Aecarl wrote: ↑

Sun. Nov. 10, 2019 8:50 pm

So, I am going to order a new aqua stat but, I have had 3 zones off all day. I just went and turned them on and got flow through the manifolds, do I need to install a solenoid on the inlets as well? None of the zones were calling for heat except zone 4.

+1 on troubleshooting your triple aquastat. Most of the time when this comes up, it's a wiring issue.

Also, do all of your taco circulators have integrated flow checks? If not they can be added into any newer taco circulator (newer housings are all machined to accept the IFC). They are sold separately and are just press fit by hand in the end of the circulator.

You should post a picture of how the 4 th zone is plumbed. I think that you have set your system up that a call for heat from the 4th zone is pressurizing the supply on the other three zones. Post more pics showing the piping from the three zones to the boiler. Nice pipe job by the way. Did you do that?