Hi Dana, I have read many of your excellent informative knowledgeable posts. Thank You
On another site PeterNH did some math:
"3x50, 150 gallons of water to heat up.
I can't imagine, even with a boiler that big, especially throttled down by ODR, that you would have any need for a time delay.
Besides as far as i understand it, short cycling, refers more to short on cycles, not necessarily a short time between reasonably long on cycles.
At full 130k output, 150 h to 130 low:
Without any load at all, it would take about 12 minutes to heat up the 150g's of water.
With a 20k btu load it will take about an hour and 13 minutes to drop 20*
A 40K load, will take, 37 minutes to cool off 20*.
But then with a 40k load it will take 37 minutes to heat the tanks up again.
Not exactly short cycling, imo.
Additionally.
Presumably, the ODR wouod also widen the differental as needed, in warmer weather, thus extending the cycle times."
My response:
"Thanks Peter for doing that math.
I'm unsure of the AM10 ODR controllers algorithms.
Time delay relay cost only $22
When it comes to boiler cycles "longer IS better"
My goals:
1. Heat this LARGE house, with its pex & manifolds already installed, with this boiler as efficiently as reasonably possible, while minimizing expense, using parts on hand.
2. Determine how to manage a large buffer tank, using ODR as high temperature limit and how to call for heat from boiler using its T-T input.
3. Prevent boiler short cycles, when small low mass zones call for heat, which is exaserbated in shoulder weather conditions. Draw buffer temperature down without firing boiler when possible."