Help choosing a new boiler (Part 3 - the Results! and more questions :)

RandomLady

https://forum.heatinghelp.com/discussion/comment/1827197#Comment_1827197

Thank you!!! Yes, that sums it up very nicely, thanks for doing that.

For number 5. I am still trying to figure out if the outdoor reset is something I actually want or not.

The installers should be coming by tonight to fix the DHW mixing valve, and I will ask about the circulators being set lower and doing something about the heat recovery time like increasing the water temperature.

LRCCBJ

and I will ask about the circulators being set lower

…………………just the circulator for heating……………..NOT the one for the indirect.

EdTheHeaterMan

I have been following this @RandomLady

You probably want the ODR feature to be connected, just in case there is a setting that will allow you to offset the ODR curve to allow for a higher water temperature that will allow for faster recovery. For now, you may be able to use ODR with the parameters set to higher temperatures for all times. 

The company that I sold my business to has a ModCon they like to sell to all boiler customers.  One customer was a 85 year old lady with poor blood circulation. She wanted her home to be 80 degrees in the winter because of har condition.   The new boiler was set up with ODT that allowed the inside temperature to stay at a comfortable 69 to 71 degrees.   Perfect for you or me but not so for the women with poor circulation.   The service technicians returned 4 times under the warranty to tell the customer that the boiler was operating properly.  On the 3rd and 4th warranty visit the company charged her over $400.00 for something in order to discourage these nuisance calls because the boiler was working as designed..

The customer told the CSR on the phone that she was interested in central air conditioning but will purchase it elsewhere because they couldn’t get the heater right.   Lucky for the customer, that CSR made up a lead sheet for a central air estimate as a result of the customer's comment.   That lead came to my desk and I made an appointment to visit the home.  I sat down with the customer and listened to her story. While at the home, I called the Tech Support for the boiler and they walked me through the steps to allow the boiler to make the home 80°.  Problem solved!  This customer clearly did not need ODR with her condition.   But no one at the contractor level would listen because she was an “old woman that did not understand” how the new heater would save her $$$$

Maybe it will take a person that is above the pay grade of the technician who is going to come today, to get what you want. But that tech is a good place to start.

EdTheHeaterMan

I have just read the entire I/O manual and there are no instructions on how to program the controller. There must be a different manual for the controller. If I can locate that manual, Perhaps I could see if the ODR curve is adjustable so you can get a faster recovery from setback. IBC does not make it easy to find that booklet.

RandomLady

https://forum.heatinghelp.com/discussion/comment/1827210#Comment_1827210

Wow, thank you! These seem to be the manuals for my boiler: Manuals

My paper copy of the controller manual looks like the one labelled "enhanced screen"

EdTheHeaterMan

Thanks. that will help.

RandomLady

Update! The installers came back and the following happened.

1. DHW temperature is fixed. (yay!) The mixing valve just needed adjusting because it was not, for some reason, set at the factory default of 120F (which the installers, I suppose, assumed it was?) Also, they had actually left the special Allen key tool for it on top of my boiler and forgot to tell me. 😅
2. The outdoor reset was installed. They normally do not install them, so we had a discussion about how it works because I wasn't too sure if I wanted it either. We discussed that if the boiler senses the outdoor temperature is warmer, it will set the boiler water to a cooler temperature. This should, in theory, keep the recovery time from a setback more consistent. I noticed that when it was -10C (14F) the recovery took 4 hours, but when it was 0C (32F) it took around 2-2.5 hours. Which makes sense if there is a difference in outdoor temps on different days, but the boiler supplies water that's the same temperature every day. I will most likely need to play around with the curve myself (😥) until I am happy with the recovery time. So they have set it up for now and I will need to see how it goes. I asked, and it is easy to uninstall if I hate it. 😁
3. I asked about the supply and return temps being so close and being concerned about the boiler not condensing. The technician said that the boiler is measuring the supply and return temps from the "primary loop" and not from the rest of my house. Apparently that's how the manufacturer recommends it be set up. So the temps on the home screen are misleading and don't necessarily reflect if the boiler is condensing. (Does this resonate with anyone? Not sure if I understood it completely).

Thanks, all!

EdTheHeaterMan

I believe you made the correct choice. In page 34 of the control manual, you posted a link to, are instructions on how to adjust the boiler temperature if you don't use the ODR.

If you do use the ODR you can set up a lower temperature set back twice a day. Once in the evening to sleep overnight, and another for the daytime if you leave the home for work for several hours. The recovery to your normal temperature will automatically have a higher water temperature in order to get the home temperature to recover faster than if you changed the thermostat manually in the evening, and manually in the morning.

If you wake up at about the same time every morning, this feature may be exactly what you need. If you go to bed at different times, you can set the automatic lower temperature to happen at 3:00AM on the boiler’s clock. Then when you actually go to bed, you can lower the thermostat thru the IBC app, anytime before 3:00 AM when you want. The desired morning recovery is the important part of the scenero. Having the boiler do the "increased temperature for recovery" thing so you don't need to wait for hours in the morning when you awake and manually set  the thermostat. 

Does this make sense? or am I just babbling

RandomLady

https://forum.heatinghelp.com/discussion/comment/1827250#Comment_1827250

I think I get it 🤔 So you are suggesting that I can set some automatic setback and it will automatically adjust the temperature in the home? If I do that, does it mean it will ignore the thermostat?

In the controller manual, I see "Reset Heating" which I guess is what I have now, and "Setpoint" which I think is what I had when the outdoor reset was not installed. On Page 31 I see basic settings, which I believe I know what the values should be, and then on Page 32-34 I see more advanced settings.

RandomLady

On page 19, I see "IBC's controllers offer two reset heating methods for controlling the supply/outlet water temperature:

1. "Standard" reset heating (default) that uses a two-point reset heating ratio.
2. Advanced reset heating that uses a characteristic reset curve ratio."

I guess I am probably set up for the first one right now.

Edit: and I think the first one is the one I want, to get a consistent recovery time each day regardless of the outdoor temperature. I know the outdoor design temp (5F) I just need to figure out the max boiler temperature, I think. ..?

Kaos

The good news is by the time you are done with this, you'll probably know more about the boiler than your installer :)

Glad to see they are cooperative and installed the sensor which they should have in the first place. Makes me mad to see those missing on a new modcon install, it is wasting fuel for no reason.

They are wrong about the delta T. Delta T is your friend with a modcon since the efficiency of the unit is determined by the return water temperature not the supply temp. Higher delta T means higher efficiency for the same output temperature. Much like outdoor reset, this is free money. Reduces fuel use, reduces pump power thus electricity costs and reduces wear on devices. Pretty much the best win/win you'll get.

Once it gets cold, you want to adjust the pump speeds so you get about 20F delta on your boiler and also on your heating loop. You have to adjust both to get that. Sometimes with series baseboard heat, which sounds like what you have, if you run a 20F delta, the last couple of rooms on the loop might not get enough heat, something to watch.

EdTheHeaterMan

You are correct about the thermostat not being used for the night setback. You use the boiler reset curve (or strait line in most cases). Leave the thermostat at your daytime comfort setting and the boiler will automatically reset. to a lower radiator temperature that has no chance of getting that warm (like the old lady' home in my example above. No matter how high you set the thermostat all she could get was 71 max. Your system setback will be set to get no higher than 64°F, but it will take some trial and error to get that setting dialed in.  Once you get it, you can forget it and let the system run on autopilot forever.

Then in the morning, the boiler will go into recovery and allow a higher temperature to get the rooms up to 68° (or more) in short order (not hours). Then you will have the room thermostat to keep it from overheating, which can sometimes happen when there is an unusually large outside temperature change and there is a very sunny winter day that causes solar gain to overheat your home .