Weil-Mclain ECO 70 cycle rate.

djc2232

Found a chart and design day temp shows -15 for St. Lawrence County. Right now I have mine set at -5.

djc2232

Well just a quick update over the past few days. Its been pretty mild. low to mid 40's during the day. High 20's to low/mid 30's at night.

Max supply 166, Min supply 105, boost off, max ODR 70f, min ODR -10f, blower speed at factory default 4150.

Changed both thermostats now over to the "slow" or hydronic heating system cycle speed. Temp differential now cycles on and off around 1.5f. Fast setter on both was just below 1f. Found both zones would kick on and off rapidly on occasion. Seems to run much better on the slow or larger differential setting.

Tough to tell as I work 3pm to 11pm. But when i check the boiler when its running it seems to be 1: Running/modulating down to a lower percentage and supplying a lower water temp than it has been before (granted it has been mild the past few days). 2: Cycle time does appear to be shorter. I think.

Still unsure of fuel usage. Im hoping over the past few days with turning the boost feature off and lowering the max and min supply temps and lowering the ODR range has helped. Next fuel delivery will be sometime next week.

Will keep the settings where they are at now. Supposed slowly get warmer with a high of 49 on Tuesday but turn bitter cold this weekend into next week with lows in the mid single digits over night. Coldest temps so far this heating season. See how she runs. So far so good.

flat_twin

The cold snap next week will be a good test. Post your outdoor temp, target, supply , return temps, output % one of those cold nights. I'm curious to see how it's working. Thanks!

djc2232

It's been mild and I've seen supply temps around 129 with target around 132 or so and she's chugging along at 35 percent or so and as low as high 20s. That was around mid 30s temp. So not too bad so far. Making good headway.

djc2232

Just got home from work. Outdoor temp is 28. Target is 136f supply is 136 f. Boiler in shows 132f. Output is at 43%. Ok I think.

flat_twin

Heading the right direction. Keep going. Lower boiler return temps mean less propane consumed

djc2232

Dropped max supply down to 164 and min supply to 102 with min ODR at -10 this morning. Boiler won't be running today or much at all the next two days. Mainly at night. High 40s and sunny all day today. Previously when I had boost on and higher supply temps, at around 28 degrees outside, supply temp was close to the 150s and 68-69% output. Now it's putting along in the mid 130s around 43% no problem keeping the heat.

mikeg2015

Ideally, I'd get a thermostat with adjustable cycle rates.

I'd still use 1F. 1.5F is just such a wide swing. I think a system that's designed well should control withing 0.5F, with exception to steam in mild weather unless you have a heat timer with ODR.

Just keep adjusting the reset curve. Really, the thermostat should only come in to play to prevent from overheating the space. Use minimal setbacks (2-3F at most) at night and start recovering 2-3 hours before you want it warm.

I would use 65F for the high setpoint and set water temp lower, maybe 100F. Then use -5F for the low point and use 160 for that.

See if the thermostat still cycles.

A second option might be to use a 2 stage thermostat, and set up and 2nd "zone" in the boiler controls using W2 and use a separate ODR curve that's more aggressive, maybe 5F higher. This would keep it at a cooler water temp most of the time and if done well, almost never shuts off except on sunny days or when cooking for example.

djc2232

I've looked at other thermostats and with my system I have now I really couldn't find one I liked. Prior to putting both thermostats on the slow cycle setting when a call for heat comes on, boiler would fire and heat up only about halfway before thermostat shut off. Would stay off for like 10min then kick on again. With both on the slow now neither do that.

I don't set my thermostats back ever. With my radiant heating in the winter a few degrees temp recovery would take way too long.

I've been slowly turning down the temps and may drop ODR max temp a little lower and see how that works. Because if it's anywhere above 40 and sunny the boiler won't fire. My home gets sunlight from sun up to sun down.

djc2232

47 outdoor. Target 119, supply 116, return 112 on panel but showed lower on my analog gauge on the manifold, output percentage 22%. That's as low as it can go I think. Well 20%. Not sure how long it had been running for, by the time I got up 815ish. It shut off at 830 or so.

Wind is starting to pick up, got a front coming in with snow in the forecast for late tonight into tomorrow. Temps will continue to drop from here. Boiler settings are going to remain unchanged over the next few days. She how she runs when the temps start to fall.

flat_twin

Just to ease any concerns about turning it down too much I'm posting screenshots from a few days ago when it was 49 degrees here in OH. For reference this is in a 1874 sq ft house built in 1850. Slant Fin app says 65k btu heat loss. Fuel based calc from when we burned fuel oil says 49k btu heat loss. I have 9 cast iron rads downstairs, 1 upstairs.



Minimum fire for me is 22k btu and on this day the house didn't need that much so the boiler ran 30 minutes on, 30 minutes off. When outdoor temps are below 32-35 degrees, it runs non stop as the house is able to make use of 22k btu or higher. In hind sight I could have gotten by with the Eco 70 and taken advantage of the lower minimum fire. Still, the cycling in warmer weather isn't severe and condensing all the time is a big plus.

The coldest temp I saw last winter was -3 late in December. Boiler supply was about 125 and had no trouble keeping the house warm.

A peek down into the heat exchanger. 20% output

NY_Rob

^ the cast iron rads are keeping your cycles/hr down on warmer days when you can't drop your output below 22K BTU's. They seem to work really well with mod-cons. You'd probably cycle 2-3x more/hr with fin-tube.

Replacing fin-tube with cast iron baseboard in my shortest zone has completely eliminated mod-con cycling there.

djc2232

Nice. Contractor didn't do a heat loss calc. Old school guy been doing HVAC since 1969. Highly regarded in my area great guy too. My pellet stove is around 38k btu. Ive had that running when we had the wood boiler in temps around 20 outside and it would heat the house to 76 no problem. That was too warm for me. Will get one done in the spring so I have an exact number. My place is 1620 sq ft built in 2008. So I'm taking a wild guess at no more than 45k btu heat loss.

Today it kicked on for about 30min then off for another 30 and it was condensing entire time. Making progress.

flat_twin

If you keep track of your propane usage this winter you can calculate your heat loss. Assuming you don't use the pellet stove or other heat sources.

djc2232

I checked the tanks today, actually used less than i was expecting.

Solid_Fuel_Man

Nice! Keep dialing it down until you can't maintain indoor temps, then back up a couple of degrees every few days. You'll find the sweet spot and reap the benefits of fuel savings and equipment longevity. You'll be surprised how low you can go.....

Jean-David Beyer

"For some reason I just can't get over the fact that it would run continuously and not burn a lot of propane. "
If your boiler is a mod-con with outdoor reset (as mine is), they it will run a long time (many hours), but not burn much fuel unless it is very cold outside. What happens is that the boiler lowers the firing rate so that it is burning just enough to overcome the heat-loss of your house. My slightly oversize boiler will fire at 20% of its maximum firing rate all day if it is not too cold outside.

djc2232

Solid_Fuel_Man said:

Nice! Keep dialing it down until you can't maintain indoor temps, then back up a couple of degrees every few days. You'll find the sweet spot and reap the benefits of fuel savings and equipment longevity. You'll be surprised how low you can go.....

Right not my max is at 166 and min is 102, ODR max is at 68 and min I dropped to -10. I may drop min temp to 100 and let her be for a while, while dropping max temp down 1 degree every so often. Tonight is only supposed to get down to low 30's, But then its all downhill from there with the low single digits next week over night and mid teens during the day. At this point I have seen decent progress with more room to drop the temps.

Jean-David Beyer said:

"For some reason I just can't get over the fact that it would run continuously and not burn a lot of propane. "
If your boiler is a mod-con with outdoor reset (as mine is), they it will run a long time (many hours), but not burn much fuel unless it is very cold outside. What happens is that the boiler lowers the firing rate so that it is burning just enough to overcome the heat-loss of your house. My slightly oversize boiler will fire at 20% of its maximum firing rate all day if it is not too cold outside.

Yea, its a new system to me. Ive never lived/owned a place that had a hydronic heating system so its definitely been a learning experience (again) this heating season. Ive already noticed the boiler running at lower percentages since dropping my temps. Min has been dropped about 20 degrees and max supply has been dropped about 8 with boost off. Seen a big difference.

djc2232

Jean-David Beyer said:

"For some reason I just can't get over the fact that it would run continuously and not burn a lot of propane. "
If your boiler is a mod-con with outdoor reset (as mine is), they it will run a long time (many hours), but not burn much fuel unless it is very cold outside. What happens is that the boiler lowers the firing rate so that it is burning just enough to overcome the heat-loss of your house. My slightly oversize boiler will fire at 20% of its maximum firing rate all day if it is not too cold outside.

Ive had multiple people, including a former landlord who put the same boiler into a new duplex he built in 2014, HVAC workers here at the school i work at say the same thing. Gotta find that sweet spot where it will just chug along at a low percentage. Its the constant on and off that will burn more fuel in a boiler and shorten the life span of the internal components. Boilers here at work (granted they are commercial and anywhere from 800k to over 1 million BTU boilers) NEVER shut off all winter.

djc2232

I keep turning down the temps. Currently max is at 163, min is at 96. Running good, heating at a lot lower temps and condensing more.

Now how will this affect the way it runs when the temps get much lower? It's going to be -4 Wednesday night. At this point in the low 20s up to the mid 30s it's running great. Will it be affected at all or will the ODR curve be Ok that low.

I've set my ODR low temp to -12. Design day fory area is -15.

flat_twin

It's a gradual curve between your selected set points, -12 to 70 degrees. The boiler max is set at 163 which occurs at -12 outside. So when it's -4 your boiler is going to produce something close to 155. You may not even need that much heat and still have room to turn it down.

djc2232

Gotchya. I haven't hit the point where it can't keep up. Since turning down the temps it hasn't been below 25.

Previously I was heating at 25f outdoor with 140-150. Now it's around high 120s-130. Still have plenty of wiggle room.

I've stopped lowering my max supply to 161. Min is at 96. Should I lower them both evenly?

flat_twin

"I've stopped lowering my max supply to 161. Min is at 96. Should I lower them both evenly?"



How much heat can your floors produce with 96 degree water. How about 90 or 85 degree water? How much heat do you need when it's 70 degrees or 60 degrees outside? That's what you need to consider regarding where to stop lowering the warm end of the ODR curve. You also mentioned your home gets full sun so thats something to consider as well. A sunny 60 degree day may not require much at all. I would stop lowering the min at 90 for now. Do continue lowering the max boiler temp until you find that point where it just barely keeps up.

The curve shown in the middle of this diagram is just about where you are now. Notice it shows the ODR curve bottoming out at 0 degrees. Drag that set point over to the right to -15 or -20. Draw a new line down to 90 degrees. See how it changes the rest of the curve. I would put the ODR set points at 60 and -20.
I doubt your house need much more at 70 than it would at 60 degrees outside. Setting the bottom at -20 is a bit of insurance against temperatures colder than design day.

Leon82

if it overheats when it is colder outside drop the max temp side and vise verse

flat_twin

Just curious, how accurate is the reading on your outdoor temperature sensor? From the factory mine reads 3 or 4 degrees higher than my other two outdoor digital thermometers, even with the sensors placed side by side with the boilers outdoor sensor. There's a place to compensate for this at the bottom of the boiler settings screen. I've got it set at -4 to correct it.

Gordy

Sometimes we need to look at the emitters connected to the boiler. You will be far better off running as low as possible supply water temp to just maintain set point in your zones with near constant circulation verses banging setpoint with high water temps.

Reason being your staple up design which is not my favorite for efficiency, has a delayed response. You have to remember it's trying to push btus through the subfloor, and what ever floor coverings are above. All which have r value. So it takes time for the btus to hit the room to satisfy the thermostat.

Your floor is the radiator emitting btus to the room. The more constant you can keep that floor to temp just enough to keep the room to desired setpoint is going to relate greatly to how hard the boiler, and emitters have to work.

Using high SWT is a vicious circle.

djc2232

> @flat_twin said:
> Just curious, how accurate is the reading on your outdoor temperature sensor? From the factory mine reads 3 or 4 degrees higher than my other two outdoor digital thermometers, even with the sensors placed side by side with the boilers outdoor sensor. There's a place to compensate for this at the bottom of the boiler settings screen. I've got it set at -4 to correct it.

I've set mine -3. It's right on with my two other outdoor thermostats. It's not directly on north side given the placement of the boiler and location but it's more like north east under my carport. Sun doesn't reach it.

djc2232

> @Gordy said:
> Sometimes we need to look at the emitters connected to the boiler. You will be far better off running as low as possible supply water temp to just maintain set point in your zones with near constant circulation verses banging setpoint with high water temps.
>
> Reason being your staple up design which is not my favorite for efficiency, has a delayed response. You have to remember it's trying to push btus through the subfloor, and what ever floor coverings are above. All which have r value. So it takes time for the btus to hit the room to satisfy the thermostat.
>
> Your floor is the radiator emitting btus to the room. The more constant you can keep that floor to temp just enough to keep the room to desired setpoint is going to relate greatly to how hard the boiler, and emitters have to work.
>
> Using high SWT is a vicious circle.

Yea it's not the best. It really wasn't installed the best. Contractor who did the boiler install re insulated and straitened out the runs before closing it up.

I'm slowing turning down the temps. Currently dropped min supply about 25 degrees and max supply about 12 degrees. I've dropped the ODR min to -12 and max ODR temp to 68. From where I started from I've already noticed a big difference.

We will be getting hit hard with cold temps next week. Low teens during the day and singles to around -4 for over night. Will leave settings where they are and see how it runs. Temps have been pretty mild.

djc2232

> @flat_twin said:
> "I've stopped lowering my max supply to 161. Min is at 96. Should I lower them both evenly?"
>
>
>
> How much heat can your floors produce with 96 degree water. How about 90 or 85 degree water? How much heat do you need when it's 70 degrees or 60 degrees outside? That's what you need to consider regarding where to stop lowering the warm end of the ODR curve. You also mentioned your home gets full sun so thats something to consider as well. A sunny 60 degree day may not require much at all. I would stop lowering the min at 90 for now. Do continue lowering the max boiler temp until you find that point where it just barely keeps up.
>
> The curve shown in the middle of this diagram is just about where you are now. Notice it shows the ODR curve bottoming out at 0 degrees. Drag that set point over to the right to -15 or -20. Draw a new line down to 90 degrees. See how it changes the rest of the curve. I would put the ODR set points at 60 and -20.
> I doubt your house need much more at 70 than it would at 60 degrees outside. Setting the bottom at -20 is a bit of insurance against temperatures colder than design day.

Anywhere close to and over 50 and the boiler wouldn't kick on all day. Granted the sun is out or if it's cloudy/windy. 60 degrees out I wouldn't need heat all all. I haven't dropped ODR min and max temps in a few days.

I've dropped everything quite a bit. Granted it's been mild I still feel like I have quite a bit of wiggle room. In mid 20s early morning I've recorded it's heating with high 120s to about 130f swt and around 42% output. Just haven't had that super cold day yet. She's coming though.

djc2232

Dropped ODR max to 62, min down to -16. Min supply at 93 and max at 162.

When I did that last night it was running, it dropped the target temp by about 5 degrees. It was running quite a bit longer. The thermostat kicked off just before I fell asleep then even before the pumps turns off the thermostat kicked on again. Very weird.

Not sure how much it ran last night, but I've been up since 8 or so. Target is 124, supply is 123, outdoor temp is 28. It's 9 now and output is at 25%.

Big thing is that it's running at percentages I've only seen before at above 40f outside.

flat_twin

How long are your on off cycles now? Mid 20s today

djc2232

> @flat_twin said:
> How long are your on off cycles now? Mid 20s today

Haven't been around a whole lot to notice. I'd say around the same. Off cycle time is less though now that I'm not over shooting with boost. I did change both thermostats over to the larger temp differential due to both cycling rapidly. Heating cycle time may be a little less.

I've been happy so far with the fact that it's maintaining temp and heating the house with about 15-20 degree less water temp than before. Lower temp and output percentage.

I haven't hit that spot yet where it can't keep up. I feel Im awful close though. I like the way it's running now at the moment. Going to let it be for a while and see how it runs with this week here. Low teens for highs and a low of -2 Wednesday night. Fingers crossed.

djc2232

Couple pictures this morning. Not the lowest temp this year so far but lowest I could get recorded since turning settings down.

flat_twin

The new ODR settings are a better match for your house and climate. Lowering the target five degrees in the process was a nice benefit.
Still, continuous running is the goal and you'll see that before you get to the point of not being able to keep up. Down, down, down...

djc2232

Dropped everything one degree. Only high of 20 today but sun is out. Hasn't kicked on in a few hours. But this morning when it bottomed out at 14 I didn't see any output over 45%. Most of the time in the mid 30s to 20%. It was running from 7ish when I got up to about 940 or so. And that was mostly the bedroom zone which usually is colder. Temps will continue to drop this week. Hopefully getting a fuel delivery too.

Terry O

djc2232 said:

St. Lawrence County. Canton Area.

That's funny.... my son lives in Canton.... Farmer St.

Small world!

djc2232

> @Terry O said:
> St. Lawrence County. Canton Area.
>
> That's funny.... my son lives in Canton.... Farmer St.
>
> Small world!

Nice! Yes very small.

Well we have officially plunged into arctic bitter cold. I've turned max/min supply and odr temps back up a little bit. Our bedroom zone thermostat is located in a bedroom which has carpet. Having a flooring company coming in to do an estimate to put something down that's better for the radiant. Looking at luxury vinyl plank. We have some in the kitchen are and the heat transfer is great on that. That may help as bedroom zone gets cold and takes a while to heat with the carpet.

She's running a bit longer now due to colder temps. Prior to it shutting down, at 8 degrees outside, living room zone had no problem heating with low 140s swt. Bedroom took a little while longer.

But hey, house is warm and I don't have to go outside to fill that dang wood boiler.

flat_twin

Not sure why you raised those settings. You need lower swt to achieve continuous running. The slow responding bedroom floor would benefit too.

djc2232

I've got max at 163 and min at 92. ODR max at 62 and min at -19. Just haven't been around much to see how it runs. At this point it seems pretty good to me and I'm comfortable with it. At 38f outside target was 115 and supply was 115. Output was 20%.

Previously it would have been over 120swt. I raised it a couple degrees due to the carpet in the bedroom. May pull it out and put something better and thinner down.

Bedroom zone kicked off then 5 min later came back on again. Not sure why. Wouldn't think a draft would have done that. Everything is pretty tight.

Much much lower swt and return temps from two weeks ago. I'm happy so far.

djc2232

Also, right before I left for work I noticed it hovering 1 degree above target at 20% output and not dropping below target temp. Only the bedroom zone running. Return water temp was within 2 or 3 degrees of outgoing temps on boiler control panel.

Would that mean that time with given outdoor temp, swt and rwt that that single zone didn't need the full 14,000btu my boiler is capable to firing down to? I've never seen that happen since turning the temps down. Even when it was above 40 a few weeks ago.