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.
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.
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.
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?
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.
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
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.
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.
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.
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Originally Posted by beenthere
