Weil-Mclain ECO 70 cycle rate.

djc2232

Hey everyone. Searched around the forum to find the answer but i just couldnt. I may be thinking into this more than i should but Id thought Id ask.

Recently had a WM ECO-70 installed that heats 2 (2 thermostats) zones of radiant infloor (staple up). Previously had outdoor wood boiler which I got rid of and replaced with the propane boiler.

To me, the cycle times are a lot longer than i thought. The thermostat will kick on one of the zones, take about 15-20 min to reach target supply temp. Usually like on a day like today 20-25F out, it would fire for about an hour and a half give or take and then shut off. Thermostat wouldnt make a call for heat for another 2 to 3 hours due to the house holding the heat the the residual heat from the heating tubes/floor. Sometimes overshoot by 1 degree. (Set at 71 in the main living room zone).

Here are my settings, Supply max set at 170 degrees, supply min set at 120, boost interval set at 45 minutes.

To me the house is warm and comfortable. Wife is warm and comfy too so thats a plus. Havent really gone through a lot of propane gas at this point but its a little early to tell.

Any help/input would be greatly appreciated. If there is anything else i missed, ask away. Thanks!

Leon82

It's alot Better than firing for a minute and a half a bunch of times per hour.

Floor radiant is not usually fast response heat

It also means that is is around the correct size too if it runs for 1.5 hours without cycling

Jamie Hall

The absolutely ideal arrangement for a radiant floor setup is with an outdoor sensor, which will control -- depending on the settings on the unit -- the target temperature of the circulating water and also, I believe, controls the firing rate of the burners to maintain that temperature. If all that is set up well, the boiler may -- particularly in colder weather -- never turn off at all, but will modulate to maintain the space temperature.

Do you have outdoor reset? If not, it will behave pretty much as you are describing.

djc2232

Jamie Hall

Yes, the boiler has an ODR. Still monkeying around with the settings to find out whats best. This system is totally new to me. Ive always lived in homes with forced air so thats what Im used to.

House in a single story ranch, 1620sq ft, with a 4ft crawl space. Floor joists are insulated very well underneath the tube runs and the crawl space itself is insulated all the way around the walls. All the floors are 3/4in ply sub floor either tile, luxury vinyl tile, or laminate. Only place with carpet (no no for in floor heat) is in the bedroom. Other than that the house seems pretty well suited for this type of system.

djc2232

Leon82 said:

It's alot Better than firing for a minute and a half a bunch of times per hour.



Floor radiant is not usually fast response heat



It also means that is is around the correct size too if it runs for 1.5 hours without cycling

Leon, yes radiant does not have a very fast recovery. Which is a little why its running longer. The boiler will be on standby for quite a while, lose heat then have to regain that just to satisfy the thermostat. But hey, the house is warm.

Leon82

Some run constant circulation with the boiler running nonstop sometimes. You can drop your odr curve or remove the boost to test gas consumption.

Don't forget happy wife happy life so don't do anything drastic. Lol

djc2232

That was my next step when i get home from work. I may leave the max supply temp where its at and lower the minimum a few degrees and raise the boost temp time. Right now my max is at 170 with 120 min. Boost is set at 45 min. I may increase that to 50 minutes and lower minimum temp a few degrees.

djc2232

The other thing i should mention, especially with these colder temps, the only time the boiler is condensing is when it first fires up, running on max getting to the supply temp. Since I am running higher temps. Manual shows recommended settings for my set up as 90f supply min temp, and 160 max supply temp.

flat_twin

The example you gave with 25 degrees outside and the boiler running 1.5 hrs then off for 2 or 3 hours and repeat sounds to me like you have a lot of room to turn down the supply water temperature. Instead of having your floors gain lots of heat and then losing that heat over a couple hours, It's much more efficient if it runs at lower temperatures non stop. Plus you have a better chance of running in range of condensation.
I would turn off the boost completely and try lowering the max and min boiler temps gradually.
I have an Eco 110 with cast iron radiators. The recommended temperatures in the manual for a given radiant system are just a starting point. Don't think that you have to be close to those settings to be doing it right. The manual said I should run at 180 max / 120 min. My house is nice and warm with 128 max and 86 min, and I'm condensing all the time.
Dial it down until it can't keep up and then adjust up just enough to satisfy the thermostat. Be aware overcast windy days will require a little more and sunny calm days a little less.

djc2232

Thanks. My set up runs off of two 100 gallon propane tanks. I also have a tankless water heater and a gas range. I raised the temps and put the boost on thinking if it always on it would suck me dry.

Ill start dialing down in small increments tonight and see how it does. I just cant get over the fact that it should be running at such long intervals like that. Ill be leaving town tomorrow night for Thanksgiving and returning Saturday evening so I wont be around to really see how it performs.

Just makes me wonder a lot when i hear it running. It sits in our "Utility" closet now boiler room which shares a room with our bedroom. You can hear it kick on. Not loud but its there.

kcopp

I would not use the boost feature. Are you using a programmable T-stat? If its radiant floor heat you should really just find a temperature to set it at and forget about it. Let the boiler and floor maintain the set point . Because of the mass of the system it will take time to get it up to temperature as already stated... long run times are indicative of the zone temp being played w/ too much.

djc2232

Not using a programmable. Bedroom zone is a simple heat only. Living room is a 1h/1c that controls the central air as well. Both are rarely ever changed. Bedroom at 69 and living room zone set at 71. Once up to temp, boiler has no problem maintaining those temps.

Jean-David Beyer

Yesterday, my boiler ran 12 hours 58 minutes continuously. It was keeping my radiant slab at grade just hot enough so my downstairs was 69F. I run supply temperatures between 80F when it is 50F outside or warmer, and up to 130F when it is 0F outside with a mod-con with outdoor reset. I use higher temperatures in my upstairs that uses fin-tube baseboard. If I want to change the downstairs temperature more than about a degree, it takes about 24 hours to stabilize at the new temperature. Changing the temperature of a slab is a very slow process. I do not use setbacks.

djc2232

I don't use set backs either. Thermostats have remained unchanged for over a month now it's gotten colder. With my system I can raise the temperature by a degree In under two hours if it's not too cold. I've set my temps back a few degrees and it seems to be fine. Will set them back a couple more and see what happens.

MikeG

What type of staple up, plates no plates, hanging pex, ultra fin? is there a mixing valve involved or is there the potential to actually run 170 degree water through the system? Wouldn't that be a bit high for the floor most of the time?

NY_Rob

Disable Boost, it's not needed and is screwing with your ODR curve, that's why you're overshooting setpoint. Boost is good for baseboard (if absolutely necessary), not for slow reacting radiant.

You are fortunate to have long burn times vs. short cycling.

djc2232

> @MikeG said:
> What type of staple up, plates no plates, hanging pex, ultra fin? is there a mixing valve involved or is there the potential to actually run 170 degree water through the system? Wouldn't that be a bit high for the floor most of the time?

Staple up on entire. Insulated with a layer of reflectex with r19 batt underneath. Holds heat very well. Only place I have extruded plates is at the bedroom because there's carpet. Yes there's mixing valves for both zones. So I believe with those I can only push a max supply of 165 I think.

djc2232

> @NY_Rob said:
> Disable Boost, it's not needed and is screwing with your ODR curve, that's why you're overshooting setpoint. Boost is good for baseboard (if absolutely necessary), not for slow reacting radiant.
>
> You are fortunate to have long burn times vs. short cycling.

I have noticed a short cycle a few times but it was due to the fact the thermostats were set on the fast setting. Would turn on run for 10 min then shut off for 10 min but that was due to the thermostat not the boiler running over temp.

djc2232

Well since I've been back home I've dropped the max and min supply temps by 5 degrees each. Running more at a lower percentage and seems to be condensing more now. Cycle times still seem to be about the same time. I haven't turned boost off yet. Raised it from 50 minutes to 65 minutes. Will continue to lower temps int eh coming days to see how it runs. So far so good.

flat_twin

Mixing valves. Help me understand how ODR affects a circuit with a mixing valve.
For example, If the mixing valve is set at 130, the ODR has no affect until the SWT drops below 130. Producing boiler water higher than 130 for space heating is a waste because it will be mixed down. Is this correct? And the ODR will now actually range between the min boiler water setting and the mixing valve setting.

Were you using mixing valves when the wood fired boiler was connected?

djc2232

> @flat_twin said:
> Mixing valves. Help me understand how ODR affects a circuit with a mixing valve.
> For example, If the mixing valve is set at 130, the ODR has no affect until the SWT drops below 130. Producing boiler water higher than 130 for space heating is a waste because it will be mixed down. Is this correct? And the ODR will now actually range between the min boiler water setting and the mixing valve setting.
>
> Were you using mixing valves when the wood fired boiler was connected?

Yes. The house was built in 2008 and my wife and I bought it summer of 2016. Used the wood boiler one winter before having an HVAC contractor do the propane boiler. Still have the mixing valves used previously but he competent re built the manifold out of copper and insulated underneath the pex better than previously.

The wood boiler put out water temp anywhere from 185 to 195 into the house.

I'm not an expert by any means and dont really understand these systems. My mixing valves are turned all the way up. I think max temp on those says 165F on the little green cover cap. It will definitely be another learning curve for me this year to get it dialed in.

I'm running off two 100 gallon propane tanks. Filled two weeks ago today. Just checked this morning. One was just about 60% and the other was about 55%.

flat_twin

When the boiler is running and you check the diagnostic screen for water temps what does it say? What is the target temp and outdoor temperature. Also what is the output % at that time? While I'm at it, what are the set points for ODR? I think the factory defaults are 0 and 70.

Solid_Fuel_Man

Just keep turning down the reset curve a few degrees every 3 or 4 days until you can't maintain temp in the house. I'm gonna take a stab in the dark that you'll end up with about 130 degree supply at around 10 degrees outside, just to give you an idea that you are way too hot now. Should be able to condense most of the time.

The main goal of a mod-con is for it to modulate the temp constantly to maintain indoor temp. Think of it like the throttle on your car, set the cruise and it maintains speed even up hills. Too hot of temps is like always speeding up....then letting off and slowing down.....then speeding up....then slowing down. Adjusting the reset curve to suit your house and your system is like learning how much pressure you need to apply to the gas pedal for nice constant speed cruising.

djc2232

> @flat_twin said:
> When the boiler is running and you check the diagnostic screen for water temps what does it say? What is the target temp and outdoor temperature. Also what is the output % at that time? While I'm at it, what are the set points for ODR? I think the factory defaults are 0 and 70.

Just kicked on about 15 min ago. Outdoor temp is 23f, target is 151f with a supply of 147f. Boiler in is 140f. Output % is currently at 69%.

Supply max currently set at 169f, supply min is at 114f. ODR max is at 70, ODR min is at 0. Boost I still have set on 72 minutes. Max blower rpm I raised up to 4210 from the default of 4150.

djc2232

> @Solid_Fuel_Man said:
> Just keep turning down the reset curve a few degrees every 3 or 4 days until you can't maintain temp in the house. I'm gonna take a stab in the dark that you'll end up with about 130 degree supply at around 10 degrees outside, just to give you an idea that you are way too hot now. Should be able to condense most of the time.
>
> The main goal of a mod-con is for it to modulate the temp constantly to maintain indoor temp. Think of it like the throttle on your car, set the cruise and it maintains speed even up hills. Too hot of temps is like always speeding up....then letting off and slowing down.....then speeding up....then slowing down. Adjusting the reset curve to suit your house and your system is like learning how much pressure you need to apply to the gas pedal for nice constant speed cruising.

I initially had the temps way down for some reason when it was first installed. To me it just seemed like it took forever to satisfy the thermostat so I turned everything way up. Just not used to having it running all the time. Always lived in a house with a forced air furnace.

Solid_Fuel_Man

The boost is messing with you. Try turning it off.

Solid_Fuel_Man

The amount of condensation you make is a direct indication of the fuel efficiency of the unit. If it can be allowed to purr all day long and condensate the whole time at like 10-20% modulation, you will use less fuel the if it runs for 1.5 hours and off for 2 hours. This type of system should have no similarities to the forced hot air you are used to. It will be constant and comfortable all the time. No hot/cold swings.

NY_Rob

As mentioned by several posters- disable Boost.
There's no way to "dial in" your ODR curve with Boost enabled.

No need to mess with blower rpm, the boiler will handle that and you run the risk of frying your HX if you set it incorrectly.

I'm not up on radiant, but your temps seem way too high... here's your present ODR curve.




In order to condense (and be efficient) your returns need to be below 130F...

djc2232

That's what I'm used to, so hearing the boiler on for long periods of time has me thinking its using a lot of propane and making me worried.

It just kicked off, so heating time was just about an hour or so. Granted it hadn't been on since 6ish in the morning. Currently moved max down to 168 min to 113. Boost turned off. That last cycle didn't reach boost so I think temps are getting close. See how it runs tonight. Supposed to be down into the mid to low teens.

djc2232

Another thing. I've noticed on both thermostats, "bedroom" and "living room" zone is that the temperature tolerance is set to fast or a half a degree. Both be noticed on these settings will turn on, fire the boiler for like ten minutes then shut off. Come back on for 10 then shut off. Eventually after one or two of those cycles the thermostat will stay on for a while before reaching temp.

Should I change the thermostats over to the "slow" setting to get the 1.5 degree or larger differential? Manuals for both state that the slow setting for larger differential is for hydronic applications.

NY_Rob

Once you get the ODR set properly with low supply and return temps you will see efficiency. Your boiler can modulate down to 14,000 BTU's, that's the same output as a single burner on a modern kitchen gas range.

By using too hot supply water, you're essentially creating a seesaw effect of overshooting/long rest/overshooting again. The ultimate goal is more or less a steady supply to offset heatloss.

NY_Rob

You need to establish a baseline, set your t-stat differentials to 1F and see how that works to stop cycling.
.5F differential will cause a call for heat if someone walks past the thermostat.

flat_twin

"Just kicked on about 15 min ago. Outdoor temp is 23f, target is 151f with a supply of 147f. Boiler in is 140f. Output % is currently at 69%.

Supply max currently set at 169f, supply min is at 114f. ODR max is at 70, ODR min is at 0. Boost I still have set on 72 minutes. Max blower rpm I raised up to 4210 from the default of 4150."



Thank you for the numbers. In this snapshot, 15 minutes into the heating cycle, the 69% output number tells me the boiler is working moderately hard to get the supply temp up to target after a long "off" cycle. This is the see-saw NY_Rob mentioned. Notice the return water is too hot to allow condensation at your current settings. Still lots of room to turn the boiler temps down.

As suggested, turn off the boost. Broaden the tstat temperature diff.
Keep turning down the boiler temp. I'd stop at 90 on the min temp but continue turning down the max until the boiler can't keep up. Then raise it a bit to cover cloudy or windy days. ( I think Solid_fuel_Man's stab in the dark is going to be close.)

When you get there you should find the output % is quite a bit lower, the boiler runs nearly continuously and hopefully the return water temps are 130 or lower to allow condensation and maximum efficiency.

About the ODR range. Is zero degrees during the winter likely for you? Any colder? How about -5 or -15? Design day for my area is 5 degrees but I set my ODR at -5 because it's normal to see sub zero temps for a brief period during the winter. The coldest I've experienced here is -22 but I wouldn't base my heating needs or boiler settings on a rare cold snap. Just saying you may want to nudge the ODR range down if sub zero temps are a reasonable expectation.

djc2232

I live in northern NY about 25 miles south of the Canadian border. 0 is likely. We do see temps down. Into the negatives. Coldest I've seen since I've been up here is -18. Seen plenty of temps from there on up to 0 but it's not like that all the time.

I probably could afford to drop my ODR range to -5 or even -10. I'm not sure what my design temp day is for up here. But right now it's at 0 and 70.

For some reason I just can't get over the fact that it would run continuously and not burn a lot of propane.

Right now I've turned down my max and min supply temps about 7 degrees each and turned off boost. Will let it sit at that for a few days and see how it does.

KC_Jones

What burns more gas in your car? Running for an hour at full throttle (if it will go that long on one tank) or running for 3 hours at 55?

You are trying to get that boiler to run as long as possible at the lowest setting possible.

It will be more efficient and more comfortable.

djc2232

> @KC_Jones said:
> What burns more gas in your car? Running for an hour at full throttle (if it will go that long on one tank) or running for 3 hours at 55?
>
> You are trying to get that boiler to run as long as possible at the lowest setting possible.
>
> It will be more efficient and more comfortable.

Good point. Just may take me a little while to get used to hearing it on for a while.

flat_twin

Design day for Albany is -1. Couldn't find any NY towns further north listed but around Burlington VT it's -7. Lowering your ODR range covers your butt if it gets colder.
As it is now the boiler is maxed out at zero outside and the indoor temps will sag if the outdoor temp falls further.

A graph like the one below helped me visualize what was going on. I made my own graph and kept track of how the boiler behaved vs the changes I made to the ODR and boiler temps.

djc2232

Nice. Burlington VT is pretty darn close as far as being north. Adjusting my ODR from 0 to -5 or even -7 may help a little. Ill do that later tonight when I get home.

Its going to drop into the mid to low teens tonight but will be almost 50 tomorrow. Ill see how that works and go from there along with dropping max and min temps every few days or so.

djc2232

Ok. So a few observations over the past day or so. Max supply temp down to 167, min supply down to 112. Blower speed set back to 4150 which is factory default. Boost remains off. Also set my ODR range min down to -5.

This morning I was up around 730 8am. Boiler kicks on around 830am or so just at the living room zone. Runs till about 938am and shuts off. Bedroom zone turns on and off a few times during that time frame. (Whoever decided to put carpet over staple up radiant is a bone head). Outdoor temp was around 23 on the panel. Sun out no wind.

Granted it was about 10 degrees last night and the boiler was on quite a bit, I believe I've dropped my cycle time. Prior when I had boost on and higher ODR curve I was over shooting and allowing the house to cool before it kicked in again. I was getting anywhere from 1.5 to two hour burn time. Now it's around an hour or so.

Just before it shut off I noticed a 144 target with 139 supply. Output percentage was at a mere 35%! (I may be making some headway here guys).

A little set back though. Went down to the crawl space and noticed a small wet spot on the concrete. Found a minor leak on my living room zone return. Just at the joint of the pex when it goes into copper and the return temp gauge. Contractor who did the Install is quite busy this week. Hopefully to get him in tomorrow or the next few days before it turns into a major leak.

So far so good. You guys have been a big help so far.

Terry O

Not quite sure where your located... I'm in Plattsburgh... If it is any help Clinton County design temp is -9F - Essex County -15F.

djc2232

St. Lawrence County. Canton Area.