Short Cycling

Does anyone have an issue with the LL 110K short cycling. I am getting great heat out of the boiler. But I have noticed that sometimes when all zones are satisfied and the boiler goes into the idle mode, it fires back up within a minute ore two. My set points are as follows:

Low limit - 160
High limit - 180
PRV Aquastat - 180

The Aquastat to in the DHW loop is set to 130.
Today the house was satisfied and the boiler temp was 171F. The boiler went into idle then fired back up within a minute.

Also, I do not have a dump zone piped in yet.

Pictures of my install are attached.

The stoker may have fired on a timer cycle. My EFM does the same thing on occasion...the timer has no way to know if the stoker was just running.

Or it may just be that during a temperature fall from the hi limit setting once the differential is met that the boiler fires on a call for heat. When it does it, I'll bet the pump is running. Once the zone is satisfied the boiler will quit firing.

What do you have your idle settings adjusted to?

Rob R. wrote:The stoker may have fired on a timer cycle. My EFM does the same thing on occasion...the timer has no way to know if the stoker was just running.

The timer that Liesure Line uses does, and resets if the burner circuit calls. At least that is the way my boiler came wired.

coaledsweat wrote:Or it may just be that during a temperature fall from the hi limit setting once the differential is met that the boiler fires on a call for heat. When it does it, I'll bet the pump is running. Once the zone is satisfied the boiler will quit firing.

I agree, I've noticed that with my boiler as well. Same when I had oil.

PRV aquastat?

Ditto Plumber...as long as there is demand, once the temp falls the 10 degree differential from the HL setting, the boiler will fire..the dif setting is fixed at 10*..a user can not alter it...once the demand is met, off goes the boiler and circulator...unless, of course, for some strange reason your temps free fell to below the LL too, and then the boiler would continue to fire until temps rose to the LL, but the pump would be off..

stoker_RI wrote:unless, of course, for some strange reason your temps free fell to below the LL too, and then the boiler would continue to fire until temps rose to the LL, but the pump would be off..

Once it reaches the LL it should run until it hits the HL I would think.

coaledsweat wrote:

stoker_RI wrote:unless, of course, for some strange reason your temps free fell to below the LL too, and then the boiler would continue to fire until temps rose to the LL, but the pump would be off..

Once it reaches the LL it should run until it hits the HL I would think.

Thats true only if a demand still exists..otherwise, if the demand is satisfied, and the water temp is below LL-dif, the boiler will run until the water temp is up to the LL and then shut off...at least thats how this HW7224 control works..can't vouch for earlier of different brand controls...

stoker_RI wrote:Thats true only if a demand still exists..otherwise, if the demand is satisfied, and the water temp is below LL-dif, the boiler will run until the water temp is up to the LL and then shut off...at least thats how this HW7224 control works..can't vouch for earlier of different brand controls...

That's not what is described here.

http://www.forwardthinking.honeywell.co ... 9_1957.pdf

The 'flavor' of the control that comes with the boiler is the HW L7224C.... The information that you are referring to may be valid for the L7224U...

Please see pages 6 and 8 of the following...this *.pdf is posted right on the Leisure Line web site as documentation for the aquastat used on the boiler...

I see now. First one I've seen with dual differentials. Very interesting.

Honey well literature can be a pain! Yes..there is an abundance of literature available from them, yet its easy to walk away from it scratching your head sometimes....they found a way to never quite be concise, it seems!