BLR: SETPOINT MET message?!? (lochinvar)

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Old 09-28-09, 07:59 PM
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BLR: SETPOINT MET message?!? (lochinvar)

I have a new Lochinvar Knight 080 (80K BTU/hr) boiler.

Night time temps are in the low 50s. Daytimes mid to high 60s.

The message I see on my boiler a lot is
BLR: SETPOINT MET which according to the owner's manual, means "The unit has met the water temperature set point, but is still receiving a call for heat from either a remote thermostat or a DHW thermostat."

Now, the installer told me something about how if the outdoor temperature is over 60, the boiler will not heat my house. (I could have understood this wrong). To me this means that my house is calling for heat but my boiler won't come on since it's over 60 outside? Is this right?

Problem is the darn boiler pump runs often, usually at night. Now, these pumps/boiler are NOT silent. They run even though "set point met" (and wake/keep me up!) Of course, I can shut it off by pressing the shutdown key but then I have to remember to turn it back on in the morning, which I can't always rely on my morning brain to remember.

I would like my boiler to do one of two things:
1) Heat my house or hot water to the desired temperature;
AND THEN/OR
2) Shut off and be quiet.

It bothers me that if I want my house let's say 75, my boiler may or may not comply, but it WILL run anyway and use gas and electricity. (I mean, if there is a call for heat, it should heat IMO). I liked my ancient boiler where if my house was less than 75, it would come on, but if it was >= 75 it would shut off. I don't care if the outside is 72, if I want my house at 75 my boiler should come on.

Any way to get the "good old days" back? In other words, are there any settings I can change so that my boiler will do steps 1 and 2 above?
 
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Old 09-29-09, 02:34 PM
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I'm not real familiar with the control on your boiler, but can offer some insight as to what is happening...

First, the bit about the boiler not heating above 60 or whatever... that setting may (should?) be adjustable, or even able to be turned OFF. Tekmar controls call that WWSD (Warm Weather Shut Down). In general, it is set at the temperature at which your home should not need heat. If 60 is too low for your comfort, take a look and see if you can bump it to 65 or even higher.

The control uses what is called a 'heating curve' to determine the temperature of water required to heat your home, based on the temperature outdoors. SETPOINT MET means that the water is at or above that water temperature, and indeed, the circulators will probably still be running. That's normal operation, but the 'curve' may not be tuned in properly.

As for the pumps being noisy... they should not be at all noisy! You should barely even know they are running! What kind of noises are you hearing?
 
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Old 09-29-09, 05:40 PM
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So not that you can answer this... but I wonder what the point is of having the circulators running all the time even when the boiler has decided your house is warm enough? It's circulating cool water...

So you are saying that if I want my house to be a certain temperature, I need to set BOTH my thermostat AND the outdoor reset?

The boiler (or circulation pumps, not sure which) and condensate pump (if I turn the light on) sound like a vacuum cleaner. Kind of like a whining noise when they are running.

Here is what I found in the manual about set point.
Originally Posted by manual
Outdoor air reset
With outdoor air sensor connected, the control module will calculate the set point based on the programmed reset curve. The installer can change the slope of the reset curve by several adjustable parameters. The user can limit the maximum set point for the system using the space heating set point.
I know how to set the space heating set point (it's in the menu) - if I set it to something high like, 68, will that affect the boiler's performance? Or does the system just automatically calculate it and I can only set the maximum.
 
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Old 09-29-09, 07:54 PM
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i have same lochinvar. The control module is run by a very complex algorithm, and you will need to study the install and service manuals in detail to comprehend all its aspects.

"set point met" means the control module knows the house isn't hot enough( still calling for heat) but it figures that based on its various inputs( esp the outdoor temp) that the water is hot enough to make the house warm enough if you just wait. This is to avoid overheating the water for a small heat need, and then overshooting.
I actually disconnected my outdoor reset bcs. i also believed it was too smart.
 
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Old 09-30-09, 05:54 AM
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Sounds like you have a poorly-set reset curve. We can fix that.

What is the heat loss of the house?

What is the design temperature of your location?

What kind of heat emitters do you have? (e.g., copper fin-tube baseboard, cast iron radiators, etc.)?

If you assume a supply water temperature of 180F, what is the output of the radiation of the house (or of each zone, or even each room)? Or, how many feet of finned element in each zone or room (assuming baseboard)?

When properly set, this boiler will rock.
 
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Old 09-30-09, 03:05 PM
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Knight Boiler Question

avatar, I have seen a couple of these units and I believe I can offer some assistance.

It sounds like there are several issues at work here and it sounds like they should be easy to resolve.

I would also like to advise anyone that troubleshooting and repairs on any boiler or system should be performed by a licensed and qualified service professional.

1. The first issue is the boiler having a call for heat from an external source and will not come on. There is a setting called Outdoor Air Shutdown within the control that tells the boiler when the outdoor temperature is above a certain temperature no further heat is needed. It sounds like yours is set at 60 when the outdoor air temperature is at or above 60 degrees the unit will not respond to any calls for space heat.

There are two ways to resolve this issue.

A. You can remove the outdoor sensor and the unit will default to the User SH Setpoint temperature and run as needed on a call for heat. This is easier but you lose the systems desgined energy efficiency.

B. Reset the Outdoor Air Shutdown temperature. This can be found in section F of your control, look on page 19 of the service manual for step by step set up.

2. The boiler pump never shuts off. This sounds like the pump is wired to run continously. This can be corrected by using the internal contacts and control settings supplied with the boiler. The control will turn the pump on and off. The pump will only run when there is a call for heat.

3. The pumps/boiler is really loud. I agree with an earlier comment that you should have the operation of the pumps and piping checked. My first thought would be to see if there is entrapped air in the system. Air transiting through piping, the pump, and the boiler can be very loud. I would look at the velocity of the water this can sometimes cause harmonics.

I agree that sometimes older technology was and is easier to understand. I liked being able to tune my old truck, but I love the gas mileage of my new car, there are always trade offs.

Finally, the product you have installed is a cutting edge, state of the art, peice of heating equipment. The control is very flexible and can be adapted to many different operating conditions, depending on the installed system. It sounds like the contractor is trying to give you the most energy efficient set up possible, but it may need just a little tweeking to meet all your needs.

If you or your contractor need more help the folks at Lochinvar will try thier best to assist you just call 1-800-722-2101.

Good Luck, John
 

Last edited by NJT; 09-30-09 at 04:32 PM. Reason: great reply, just needed some 'white space'
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Old 09-30-09, 04:30 PM
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Thanks John! good info... I've taken the liberty of 'formatting' your response a bit to improve readability...

Reset the Outdoor Air Shutdown temperature.
The 'default' setting for that, according to the manual is 80 F, so if it's at 60 now, your installer may have been a bit over eager to get the most out of the control. 65 or 70 might be a better choice.
 
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Old 10-01-09, 08:12 PM
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Wow thanks everyone, I got some really great replies here. I'll try and address things that need addressing.

Heat loss is around 40,000 BTU/hr. Design temp is -5F. Heat emitters are convectors - they have some pipes running through with fins on, so copper fin tube? I have absolutely no idea how many feet of pipe I have (heat loss was done professionally and I don't have the numbers he used), but the main floor of my home is 735 sq ft (approx) and upper floor is around 350 sq ft and I have a full unheated and uninsulated basement, if that helps.

So far I'm happy with this boiler. Last night was 38F and my boiler said it was running at 20%. And my house is warm. I have to admit I was a bit worried having a boiler installed that was so much smaller than what all the contractors recommended. I'll post back in the spring and let you all know how my winter went!

1. If I do step B which is reset the outdoor temp control, will this allow the boiler to respond to calls for heat when the house is cool but outside is higher than 60? I do not have a service manual, but I will try to find one on Lochinvar's site or call them. I have an owners/installers manual, though - I'll read through it again.

2. The boiler pump doesn't run continuously. There are times when the boiler is happy and all is off. However, it appears that oftentimes when the outdoor temp is right around the 60 mark, that it gets calls for heat that it refuses to answer and then the pump runs for nothing, a lot. As the temp last night was much lower, the boiler ran but it was heating, and if the temp inside is high enough that my house isn't calling for heat, it does shut off. Hope that makes sense. So this is the problem: the house calls for heat, the boiler does not heat because SET POINT MET but runs its pumps anyway.

3. I would like to clear something up since I gave everyone the wrong impression: I did not mean to imply my boiler is excessively loud. It isn't. It's just that I can hear it running from the basement on the other end of the (small) house during the night, which would be fine if it was actually doing something (i.e. heating) but since it's just circulating tepid water, I'd like it to not do that when I'm trying to sleep. I'm not even exactly sure which part is making the noise, but I believe it's the boiler unit itself. Sounds a bit like a small vacuum cleaner motor running, maybe a bit quieter.

I like the new car vs old truck analogy. My old boiler was anything but efficient and at the end of its life, didnt heat all that well either. I guess I am just used to setting my thermostat and always having my house at that one temperature no matter what was happening outside. This one even has a night setback feature which I am going to learn how to use.... later

[[In all fairness to the installer, I had a very lengthy discussion with the estimator on why I did not want a huge 150+ BTU/hr boiler and how much more efficient a properly-sized boiler would be. Although we were on the phone, I could feel his eyebrows raising more than once, LOL. (He actually said I was the first customer to ever raise the concern of oversizing the boiler). This was the only company that actually listened to my concerns and agreed to install a teeny tiny boiler that I requested. I guess the installer decided that I was all about efficiency and therefore set my outdoor setting to 60. LOL....]]

Again, thanks for the replies and helping me configure my new boiler.
 
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Old 10-05-09, 03:09 PM
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1. Yes. Setting that outdoor shutdown temp higher will allow the boiler to heat when the outdoor temp is below whatever you set it at.

2. It sounds as though the bottom end of the heating curve may be a bit too low.

Any progress on fine tuning the settings?
 
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Old 10-12-09, 08:01 AM
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Originally Posted by JPemerton View Post
B. Reset the Outdoor Air Shutdown temperature. This can be found in section F of your control, look on page 19 of the service manual for step by step set up.
Thank you very much.. I have found the service manual (http://www.lochinvar.com/_linefiles/KB-SER-07.pdf) and it seems that is one setting I am able to change, so hopefully Outdoor Air Shutdown is the only thing I need to fiddle with. (Is this the "bottom end of the heating curve?")

I had been waiting for the installer to come and fix certain issues on the install but it is "busy season" and he hasn't come yet.

Should I set "Outdoor Air Shutdown" to 70F? Do I need to change the "Outdoor Air Shutdown Differential" value?
 
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