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I actually had a similar scenario a couple of years ago for a friend. he had an ultimate oil fired boiler with tankless coil. it was way oversized for his house. did a heat loss and needed 85k and change for heat. they had it firing at 175k in. the 3 loops were piped back seperately so i installed 3 zone valves. changed it to primary/secondary with a 256. then used an 80 gallon storage tank for domestic off of tankless and changed out triple aquastat.
problem was with zoning it, even at lowest firing rate i could go. on heat calls the burner would fire for say 30-60 seconds and the call would satisfy. this would be near the end of the entire call on odr. so yes a buffer tank would be ideal, but my buddy squeaks. so a couple tdr's were installed and all is good the world. he wouldnt drop the $ for the 260. never would have had the issue if he would have. 260 has the adjustable fire delay built in.
so i'm in on dob and dom timers.

This is how I set up outdoor wood boilers plus a rib to shut off od circ

Originally Posted by billygoat22

how about-

two stage tstat. first stage cycles pump only, so any residual heat left in boiler from last cycle heats house, until cool enough that stage two kicks on burner.

Is the OP trying to sell something?

Originally Posted by techwizard007

OK so you asked how we would do it and stay under $ cost ,but never gave a real real cost to stay under, so I've been this field for over 20 yrs and know for a fact that you can have one problem but can resolve it by over 100 ways to fix it..So as long as it works properly no answer would be wrong..Regards

He did give a real cost. And said it was the whole sale cost. Since this is an open forum, I removed the cost/price. Cost/pricing is only allowed in the restricted Pro forums, the OP is not a Pro member.

OK so you asked how we would do it and stay under $ cost ,but never gave a real real cost to stay under, so I've been this field for over 20 yrs and know for a fact that you can have one problem but can resolve it by over 100 ways to fix it..So as long as it works properly no answer would be wrong..Regards

how about-

two stage tstat. first stage cycles pump only, so any residual heat left in boiler from last cycle heats house, until cool enough that stage two kicks on burner.

Merry Christmas all.

Anytime pulse modulation is discussed I think voltage regulators as that was a big part of my previous day job. I

In this case a TI UC1825 pulse width modulator chip, a few resistors and capacitors and thermistors and you have a state of the art control. Use the UC1825 to control the boiler on-off functions, and instead of the feedback circuit regulating on a voltage, use the thermistors as the control element. Since the 1825 is a current mode device, you can use that inner control loop for a continuous operation type control with the inner control loop running an inverter driving a variable speed pump. Thus burner almost never turns completely off, just the fuel and water flow are regulated in a pulse width modulation scheme.

OP probably wanted something to buy off the shelf though, eh?, not a design tutorial?

Originally Posted by butternut

Looks like a Logomatic. Is it cheaper than the logomatic?.

Don't know, don't know what a logomatic cost.


And since this is an open forum, prices aren't allowed.

Originally Posted by butternut

DWH?...

DHW, can't you read minds yet lol. What the purpose for the pulse setup? To get the boiler hot before any water is pumped.

Originally Posted by Joehvac25

I'm thinking of various ways but I'm not getting the question completely. A Teckmar could keep a set temp plus with ODR modulate the temp. A bypass would let the boiler heat fast also.

Bringing the boiler up to temp before allowing that water to exit. This is a pulse supply where the flow is started and stopped and the burner runs continuously until the aquastat set point is made or the call for heat is satisfied. Generally the aquastat is set 20 - 40 degree's above the Purge point setting.
The cross over would be needed to either assist in tempering the return side in order to eliminate shock and increasing the rise within the boiler. It would also be needed on a pulse system to minimize pump stress while the boiler was making, prior to the purge.
The final stage purge would come after the call for heat was satisfied.

Got to go

Originally Posted by Joehvac25

I don't remember having to describe how to prioritize DWH loop so you win a cookie or a slap in the face which one? Lol that's a joke we use to use when I was younger.

DWH?...

Originally Posted by beenthere

Weil McLain BCP 3. Its simple fast and easy.

It will run the circ anytime the outdoor temp is below the heating point, and regulate boiler temp based on outdoor temp.

Looks like a Logomatic. Is it cheaper than the logomatic?.

I don't remember having to describe how to prioritize DWH loop so you win a cookie or a slap in the face which one? Lol that's a joke we use to use when I was younger.

Lets hear more about these three stats.

Originally Posted by techwizard007

Ok 60sec go , you need three stats , a bypass ,holding take and a solenoid. When a boiler is turned off some heat remains in the mass of the boiler. If the flow through the boiler is stopped at the same time the boiler is shut off, the residual heat is lost. Therefore, after operation of the boiler the residual heat in the boiler should be purged to the system in order to decrease standby losses. This is accomplished by turning the boiler off but keeping the system pump on for a period of time. This function increases system efficiency by minimizing standby losses.

You win for the explanation of the purge cycle but what if you don't have a DHW tank?. Remember.... no waste (by design) and $. limit on parts.

Ok 60sec go , you need three stats , a bypass ,holding take and a solenoid. When a boiler is turned off some heat remains in the mass of the boiler. If the flow through the boiler is stopped at the same time the boiler is shut off, the residual heat is lost. Therefore, after operation of the boiler the residual heat in the boiler should be purged to the system in order to decrease standby losses. This is accomplished by turning the boiler off but keeping the system pump on for a period of time. This function increases system efficiency by minimizing standby losses.To ensure that the DHW tank is up to temperature after the DHW Setback period the control must raise the tank temperature before the setback period ends. This can be accomplished automatically by using a control that has an optimum start / stop function. This function increases comfort by ensuring the DHW tank is up to temperature at the beginning of the occupied period.DHW priority allows the DHW tank to recover faster by temporarily suspending the heat supply to the heating system. All of the available heat is provided to the DHW tank for a period of time. This function provides more comfort by ensuring faster DHW pick up times and increases system efficiency by often allowing the use of a smaller heat source. OK what did I win....???? lol

I'm thinking of various ways but I'm not getting the question completely. A Teckmar could keep a set temp plus with ODR modulate the temp. A bypass would let the boiler heat fast also.

Weil McLain BCP 3. Its simple fast and easy.

It will run the circ anytime the outdoor temp is below the heating point, and regulate boiler temp based on outdoor temp.

Won't bring the water temp up fast, as what purging the boiler is counter productive to doing that.

The rest of you are just as funny... HAHAHA

Originally Posted by ammoniadog

Does everything have to be automatic, or can we have some guy stand there operating manual "modulate" and "purge" valves?

LOL!~I scared the cat half to death with the snarf I made when I read this Beer all over the floor...which I have to clean up now

Seriously though, what do you mean by modulate and purge? Are you talking about a primary/secondary setup where the primary maintains a steady temperature while the secondary modulates somehow? Does purge mean an auto air vent? Is labor and piping materials included in your price?

Modulate the out going water at a set temp (lets say whatever you like between 140 and 180) and then purging the remaining water out of the boiler after the call is satisfied.
Reason for doing this is to bring the boiler to temp fast without chilling the element or causing the boiler to shock and then getting all the water top side after the stat is satisfied, rather than losing it to standby.
Material only

Place someone next to the boiler with his/her hand on the on/off switch and a thermometer & turn it on. When the thing, whatever your are measuring) reaches 110 degrees have that person turn off the on/off switch.