Lochinvar mod/con boiler question
I had a lochinvar KHN-110 and indirect water heater installed over the summer. As I was reading this forum and learning about heating in general I came across Gumby77 thread about system temp probe in his lochinvar. That made me look closer at my setup and I noticed that It was not installed during installation. Its funny but I found the plastic bag wrapped around the inlet pipe. So I called the installers back and they got it connected.
Before system sensor installation outdoor reset was controlling the outlet water temp. As you can see in this not so great picture. In this screen shot below outlet temp is 130 currently and (149) is the target temp based on the sensor.
After system sensor
got installed it seems that outlet temp is no longer controlled by the outdoor reset and outdoor reset now controls the system temp as you can see in the screenshot below outlet temp is now 192 (max for Space heating is set at 180 plus 10 offset in the settings) and system temp is now showing 176 based on outdoor reset.
So I'm confused as to which way is correct setup. Is the boiler and outdoor reset controlling the outlet temp or is it suppose to control system temp? I'm very new to this and been reading and learning past few weeks as much as i can.
Thank you
Alex
Comments
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The sounds like they made an adjustment to some of the parameters0
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Although if it's extremely cold outside and it was warmer when the first picture was taken that can explain the difference in temperature.
It looks like there's a 12 degree difference so maybe your outdoor curve is pretty steep0 -
The outdoor reset should be controlling the system temp, so that is correct. I am a little troubled by such a high system temp and much higher outlet temp when the boiler is only running at 36% though....do you know what the outdoor temperature was when you took the second picture?
How big is your house? How many zones do you have? What kind of radiation is it, radiators? baseboard? in-floor (hopefully not)?
Can you take some pictures of the near boiler piping? stand back and get a good picture showing as much of the piping near the boiler as possible, a few pictures from different angles would be good. Also show us how they installed the system sensor as well.
I suspect that your boiler may be over-sized, or that there is an issue in the piping.0 -
@delta T
Thank you for helping out everyone.
At the time of that picture outdoor temp was 36 degrees.
I'm in Northern NJ 07010 zip code. Picture was taken at the end of the cycle. It was at 100% fire until it got to about 180-185 on outlet temp then started modulating down.
House is about 2200 square feet, 3 floors. Built in 2012, contractor special. Each floor is one heating zone for a total of 3. All heating is done via baseboards. No radiant in-floor.
Boiler is oversized, although it has 10:1 turndown so should help a bit. By the time I learned about this it was too late
I tried to see if we can get KHN-085 but sales guy said it might not be enough and afterwards i figured out that he was sizing it by indirect specs. Now I know better.
I took a bunch of pictures and made an album. You can find it here:
https://photos.app.goo.gl/Gt1dwMYPuRnwPuJj1
System sensor is located after the red pump and before the shutoff valve going to the zones. Its wrapped in insulation tape and white zipties in the back. So expansion tank, red pump, system sensor.
I also included Screenshots from Con-X-US app with the settings.
Let me know if you need me to explain anything better. I can also post them here if needed
Alex0 -
The system sensor is in the secondary loop which is correct but.
The close tees have a valve and not enough straight pipe near them
The temps indicate the boiler is cycling water back thru the boiler instead of the system.
What speed it the boiler pump set to?
It should have had a label from the factory which speed to run it0 -
You can limit the firing rate of the boiler using the ramp delay settings.
But I would post your outdoor reset numbers. I'm in CT and mine stops at 160 with fin tube. It's 30 according to my sensor here now and my setpoint is 121.
Turn the knob to the sh cycles and sh hours and see what they say.0 -
Which pump? Red one in the back?Leon82 said:The system sensor is in the secondary loop which is correct but.
The close tees have a valve and not enough straight pipe near them
The temps indicate the boiler is cycling water back thru the boiler instead of the system.
What speed it the boiler pump set to?
It should have had a label from the factory which speed to run it0 -
I think the black one. The one that pumps into the boiler. It should be a grunfos 3 speed0
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That’s definitely a pretty steep odr curve. Generally speaking we don’t do 180f supply water until 14f out side in NJ. I always try’s to push it down as low as possible. Like 160 or 170 at 0F outside temp.0
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That's probably the correct speed.
All the baseboard gets heat correct?0 -
Here is the outdoor reset curve settings from the Con-X-US board. does this help?Leon82 said:You can limit the firing rate of the boiler using the ramp delay settings.
But I would post your outdoor reset numbers. I'm in CT and mine stops at 160 with fin tube. It's 30 according to my sensor here now and my setpoint is 121.
Turn the knob to the sh cycles and sh hours and see what they say.
My outdoor temp is showing at 28 now.
EDIT: SH runtime is at 12 and sh cycles are at 49. Just started using heating this past week.0 -
Yep all baseboards get heat everywhere. No issues with heat.Leon82 said:That's probably the correct speed.
All the baseboard gets heat correct?
You mentioned earlier "The close tees have a valve and not enough straight pipe near them"
Which ones are you referring to? Sorry fairly new to this so bare with me please 0 -
I'm sure. Guy who came over to do start up wasn't in talkative mood. I tried to ask and he basically said "This is how we do it to everyone". Did his thing and left.njtommy said:That’s definitely a pretty steep odr curve. Generally speaking we don’t do 180f supply water until 14f out side in NJ. I always try’s to push it down as low as possible. Like 160 or 170 at 0F outside temp.
What would you recommend? I can set these via the app0 -
I think mine is set a 7 degrees 154 for the high end and the bottom is 115. I'll look after if finishes it's running now and when you exit it restarts.
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I would turn the min out door air temp to 12-14f. For now. Make sure the house is still able to hold temp. With the new odr curve. And as we get into colder weather you can keep adjusting it down. This will help your system efficiency. You really want to try and keep the boiler condenseing as much as possible. To do that the return water temp needs to stay at 130f and below.0
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Here are outdoor settings from the boiler:
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I'm guessing the supply sensor isn't making good contact. And definitely use the last ramp delay to limit the boiler output during space heat calls.DIY'er ... ripped out a perfectly good forced-air furnace and replaced it with hot water & radiators.
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Follow the pipe from the black pump left and up. This is where the primary and secondary loop converge. The tees need to be close within 4 pipe diameter which you have. But the schematics want a certain length of straight pipe on each end.
It may not cripple your system but it may be less than optimal0 -
System sensor seems to be making good contact. its attached via zipties to the pipe and wrapped in few layers of insulation tape with zipties on top. I checked it with Fluke thermocoupler probe and they were within few degrees of each other.Boon said:I'm guessing the supply sensor isn't making good contact. And definitely use the last ramp delay to limit the boiler output during space heat calls.
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These ones?Leon82 said:Follow the pipe from the black pump left and up. This is where the primary and secondary loop converge. The tees need to be close within 4 pipe diameter which you have. But the schematics want a certain length of straight pipe on each end.
It may not cripple your system but it may be less than optimal
0 -
The problem is the 20 degree difference in between the outlet and system temp.
What happens when all zones call for heat?0 -
See if the system and outlet come closer together0
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Please post your numbers when you can. I'll try them and see how they work. If you can, please post the numbers so a dummy (me)Leon82 said:I think mine is set a 7 degrees 154 for the high end and the bottom is 115. I'll look after if finishes it's running now and when you exit it restarts.
can follow them and adjust
Does this look right?
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My low is actually 7 degrees at 148
My high was 68 at 81.0 -
You can try that curve but you may find it’s not hot enough it really depends on how much baseboard in each zone you have and your heat loss. You be good in 1 zone but not the other.
See how it goes tonight and move it around tomorrow if need be.
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> @njtommy said:
> You can try that curve but you may find it’s not hot enough it really depends on how much baseboard in each zone you have and your heat loss. You be good in 1 zone but not the other.
>
> See how it goes tonight and move it around tomorrow if need be.
Yea before I understood it fully I used set point 2 to make a flat curve at 120 so it overrides the first setpoint. One-day I'll fix the first one to stop at 120 on setpoint 1. It's been really good so I didn't want to change it0 -
Was the inderect calling for heat when you took that picture? It would explain a lot0
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You can set set point 2 as well? how does it kick in?Leon82 said:> @njtommy said:
> You can try that curve but you may find it’s not hot enough it really depends on how much baseboard in each zone you have and your heat loss. You be good in 1 zone but not the other.
>
> See how it goes tonight and move it around tomorrow if need be.
Yea before I understood it fully I used set point 2 to make a flat curve at 120 so it overrides the first setpoint. One-day I'll fix the first one to stop at 120 on setpoint 1. It's been really good so I didn't want to change it
I just checked 2 and 3 and they have
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Tomorrow is suppose to be cold day, I'm going to try your settings and see how it goes.njtommy said:You can try that curve but you may find it’s not hot enough it really depends on how much baseboard in each zone you have and your heat loss. You be good in 1 zone but not the other.
See how it goes tonight and move it around tomorrow if need be.
I measured baseboard before:
3rd floor has 46 feet total
2nd floor has 48 feet total
ground floor has 17 feet total0 -
Yes.
But I would bring the 81 degree up to about 110 minimum.
You can use the other 2 setpoint by sending the tt wire to the terminal on the boiler. You could set a curve for all 3 of your zones0 -
That’s a good amount of baseboard for a 2k sqft house. I would definitely dial all 3 zones in the same. If the ground zone can’t keep up you can change the odr curve for that zone.
If the other zones call at the same time as your ground zone then they will just get the same odr curve as the ground floor cause that one is set for the highest supply water temp. Once the the ground floor zone satisfies the other zones will drop to there odr curves.
This is going to take some time to get dialed in. Just stick with it and by the end of winter it will probably be dialed perfectly. For your comfort and efficiency.
It’s ok for the boiler to run a lot. Especially if you can get it to heat the house in the lower firing rates. The hardest thing a boiler can do is start. They are designed to run.0 -
MorningLeon82 said:Yes.
But I would bring the 81 degree up to about 110 minimum.
You can use the other 2 setpoint by sending the tt wire to the terminal on the boiler. You could set a curve for all 3 of your zones
Can you point out 81 degree to 110 part? I'm not seeing it in the picture.
Also the other 2 setpoints by sending tt wire - don't follow that one either yet
If i understand this correctly my current setup uses Setpoint 1 for all 3 zones. Did i get that right?0 -
Morningnjtommy said:That’s a good amount of baseboard for a 2k sqft house. I would definitely dial all 3 zones in the same. If the ground zone can’t keep up you can change the odr curve for that zone.
If the other zones call at the same time as your ground zone then they will just get the same odr curve as the ground floor cause that one is set for the highest supply water temp. Once the the ground floor zone satisfies the other zones will drop to there odr curves.
This is going to take some time to get dialed in. Just stick with it and by the end of winter it will probably be dialed perfectly. For your comfort and efficiency.
It’s ok for the boiler to run a lot. Especially if you can get it to heat the house in the lower firing rates. The hardest thing a boiler can do is start. They are designed to run.
My ground floor is the warmest one and its a small amount of space compared to the other 2 floors. So it should be fine.
I don't mind putting in the leg work to get it working correctly.
And I do understand now that boilers should be running and not short cycling. I noticed that if it short-cycles temp swings happen a lot. Goes from being hot to being cold. It also increases exhaust vent RPM which causes the fan to be louder vs when its firing at below 50% then its pretty much silent.
I also took these pics when all 3 zones were calling for heat. First pic was as I opened ground floor valve and cold water started moving from the zone.
https://photos.app.goo.gl/11IExetUzoGRVTRM2
and this one as fire ramped up and it started to delivery hot water
https://photos.app.goo.gl/mtQu2demMqBNDUbp10 -
> @kalex1114 said:
> Yes.
>
> But I would bring the 81 degree up to about 110 minimum.
>
> You can use the other 2 setpoint by sending the tt wire to the terminal on the boiler. You could set a curve for all 3 of your zones
>
> Morning
> Can you point out 81 degree to 110 part? I'm not seeing it in the picture.
> Also the other 2 setpoints by sending tt wire - don't follow that one either yet
> If i understand this correctly my current setup uses Setpoint 1 for all 3 zones. Did i get that right?
Yes there are 3 sets of terminals on the boiler for each of the reset curves.
I used setpoint two to make a flat curve at 120. I over think it and didn't realize I could make a graph and cut it off at 120.0 -
In the ramp delay settings you can limit the max firing of the boiler in the 6th slot.0
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