Tekmar 363: boil fire * 60 / boil cycle is small

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  #1  
Old 03-05-18, 07:17 PM
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Tekmar 363: boil fire * 60 / boil cycle is small

Hi
Have Tekmar 363
If I retrieve Boil Fire and Boil Cycle
multiply Boil Fire by 60 and divide by Boil Cycle I get the number 4.6
Which I think means cycle average is 4.6 minutes
However
if I watch boiler fire for heating it is about 12 minute
if I watch boiler fire for hot water heating it is about 8 minutes
So why is Boil Fire * 60 / Boil Cycle so short?
Thank you
 
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  #2  
Old 03-06-18, 06:34 AM
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It looks like those counters can be cleared independent of each other. I don’t see how they could have gotten out of sync since you have to hold 2 buttons at once to clear a counter. But maybe somehow one counter was zeroed out and the other wasn’t.

If it were me I would zero them both out and start another monitoring session.

(well, it didn't occur to me that maybe you did in fact clear them out before you started)
 

Last edited by zoesdad; 03-06-18 at 06:46 AM. Reason: added last sentence
  #3  
Old 03-06-18, 08:37 AM
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Hi & thanks
I did clear both at the same time
and overnight
Boil Fire went up 2 and Boil Cycle went up 31
2*60/31 is 3.9
 
  #4  
Old 03-06-18, 10:20 AM
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Even assuming the hour counter was very close to but less than 3, that still would only bring the average cycle time up to about 5.8 minutes – yet as you say you observe much longer cycle times. Do you think you have done enough random observations of the cycle time to be pretty confident they are up around 12 minutes average for heat and 8 minutes average for DHW?

Otherwise it does seem like something is really crazy there. It doesn’t seem like there are any other menu items that could confirm or deny short cycle times. I guess you could also clear and look at the OUT HI and LO and ROOM HI and LO temperature fields, over the same period of time, but I guess that would just have some remote possibility of showing something a little crazy is going on in the control, if in fact that were the case.


This would be a case where it would be great to have an actual log that showed start and stop times for the burner, but it looks like this control doesn’t have any type of log. Bummer!

Just thought of something. I don't think that hour counter includes FIRE DLY. I think that might make a difference since FIRE DLY would be added to every cycle - I think lol! But that value FIRE DLY might actually be very small.
 

Last edited by zoesdad; 03-06-18 at 10:29 AM. Reason: added just a thought
  #5  
Old 03-06-18, 01:46 PM
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Ok, thanks
might be time to query Tekmar tech support
 
  #6  
Old 03-06-18, 04:26 PM
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actually, it might be correct
was in garage today and heard pumps running so went over
Boil Trg was 167 and Sup158
boiler ran 3"40s
outside temp is near 50, tstats set on 55
maybe when outside temp is near the tstat values it only runs 3-4 minutes to accomplish the goal
and this could happen often during the day and bring the average down, especially if only one zone wants heat
I suppose could test by setting tstats to 68 and see what Boil Fire * 60 / Boil cycle is after house is 60
or
since all seems to be working, and nothing has changed for "years", simply cease and desist

is a 4 minute run short cycling? bad? really bad?
 
  #7  
Old 03-07-18, 07:06 AM
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is a 4 minute run short cycling? bad? really bad?
Thatís a good question. Iím no expert for sure. My understanding is that each burner start/stop has some inefficiency due to ramp up time after start to bring the system up to temperature. But I think there was a thread here not long ago where the opinion (expert I think) was that in some of these smarter systems (like yours) frequent short run times of a few minutes was fine.

But Iím not absolutely sure. Hope the more knowledgeable people jump in and answer that good question.
 
  #8  
Old 03-07-18, 08:44 AM
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But I think there was a thread here not long ago where the opinion (expert I think) was that in some of these smarter systems (like yours) frequent short run times of a few minutes was fine.

Heat guy here also said short run of 5" is not bad save it wears out parts faster. But lotsa parts are 10/15 years old so cannot be too bad.
 
  #9  
Old 03-07-18, 09:17 AM
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You can increase the cycle time by setting a larger differential temperature. I'm not sure what it is called on a Tecmar, but it is the temperature drop from the high limit setting for the burner to refire. I have my Burnham ES2 high limit set for 150 with a differential of 30 so the burner will not fire until the boiler temp drops to 120. My cycle time averages 6.7 minutes. On a conventional boiler you need to keep the low temperature above the condensing temperature to prevent problems. My boiler can go as low as 100. Other boilers may have to stay above 130. Condensing boilers have no such limits.
 
  #10  
Old 03-07-18, 09:30 AM
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Heat guy here also said short run of 5" is not bad save it wears out parts faster. But lotsa parts are 10/15 years old so cannot be too bad.
It seems like your savings from a smart system will more than pay for the parts.
 
  #11  
Old 03-07-18, 11:19 AM
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You can increase the cycle time by setting a larger differential temperature.
I thought about that. But heat guy said best to leave it on "auto" so I did. But I could try a diff of 20 and see if anything changes.
 
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