The stoker will always run during a call for heat once it falls below the HI limit minus the differential. The Lo limit controls the pump between the Lo limit and the Lo differential. Turns on pump at 160 and above then turns off pump at 150 to protect DHW temp and boiler protection so it does not drop below 140 or so. Once call for heat ends, stoker shuts off at LO limit.
HI limit will shut off stoker during a call for heat for overfire protection. Then let it turn back on once it falls below HI minus differential. I've never had that happen on my system. If the pumps are on, temp is dropping
Mine is set at 200/170 with the dump at 220. I use 170 simply because I have a converted gravity system with almost 150 gallons of water. 170 helps with boiler protection when I have 3 or 4 hours between calls for heat.
Let's Install a Keystoker K-A6
- CoalisCoolxWarm
- Member
- Posts: 2323
- Joined: Wed. Jan. 19, 2011 11:41 am
- Location: Western PA
- Stoker Coal Boiler: Keystoker KA-6
- Hand Fed Coal Furnace: old Sears rebuilt, bituminous- offline as of winter 2014
- Coal Size/Type: Anthracite Buckwheat
- Other Heating: Oil Boiler
Here's a decent graphic that explains what could be the confusing operation of a triple aquastat. Maybe it will help you understand it's function, like it did for me a while back.
- StokerDon
- Site Moderator
- Posts: 7486
- Joined: Mon. Nov. 11, 2013 11:17 am
- Location: PA, Southern York County!
- Stoker Coal Boiler: Gentleman Janitor GJ-5, Van Wert VA-600, Axeman Anderson130 X3.
- Hand Fed Coal Furnace: Harman SF3500 reduced down to 3 grates connected to its own plenum
- Coal Size/Type: Rice, Chestnut and whatever will fit through the door on the Harman
- Other Heating: Noth'in but COAL! Well, Maybe a little tiny bit of wood
I like that diagram CoolX. It even explains the LO limit adjustable differential.
-Don
-Don
- CoalisCoolxWarm
- Member
- Posts: 2323
- Joined: Wed. Jan. 19, 2011 11:41 am
- Location: Western PA
- Stoker Coal Boiler: Keystoker KA-6
- Hand Fed Coal Furnace: old Sears rebuilt, bituminous- offline as of winter 2014
- Coal Size/Type: Anthracite Buckwheat
- Other Heating: Oil Boiler
Yeah, there are differentials in there that are fixed that will sneak up on you, LOL. One of the things I learned on this site, then found that graphic a couple of years ago that showed the details.
Passing along a good thing.