Are my cycle times too short?

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Old 12-12-13, 01:51 PM
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Are my cycle times too short?

Peerless WB-3
3 heating zones (circulators) - thermostats set to 3 CPH (on or about...)
4th zone is indirect DHW


Recently disabled the tankless and installed a Beckett Aquasmart. High limit is 185, with a high differential of 12. Low limit is disabled.

I now have the ability to see the last nine "events" in the Beckett's log. It logs the trigger and time for burner-on, burner-off, and average water temp during the cycle. I'm seeing burn-on times in the 3 minute range, plus/minus 10-15 seconds over the period of many cycles (I've been checking the log for a few days). Based on what I've read in this forum, I'm thinking the burner-on times are too short. If you agree, what should I do to increase the time?

Of course, let me know what else you may need, and I will post back. Thanks in advance.
 
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Old 12-12-13, 02:07 PM
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Those do seem like short cycle times. I had a similar issue, installed a Heat Manager also.
One of the issues with my system was the overall size and firing rate. It, like most other boilers is over sized. What I was able to do was down fire it a bit, according to the mfg. instructions. After the down fire and the Heat Manager I've got cycle times way up. Sometimes, depending on the load, I can get 10+ minutes of burn time. With that set correctly, and water temps lowered slightly, I've managed to save quite a bit on fuel over the past few years.
 
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Old 12-12-13, 02:26 PM
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high differential of 12.
I would start by using a wider differential... say 20
 
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Old 12-12-13, 02:29 PM
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Thanks tomf63. I'm assuming that I need a pro to change the firing rate. I can certainly look into that. If you have any specifics on HM settings, let me know. Is 185 too high? Should I increase the high diff?

I have two zones on the first floor, and one upstairs. The problem is that they sometimes overlap (first thing in the morning, after dinner), and sometimes only the first floor zones are calling for heat (during the day). I warm up the upstairs for a bit before hitting the sack, but only enough to get the chill off. I'm not smart enough yet to know how the zones' on/off cycles (via setback thermostats) affect how the boiler behaves v-a-v cycle time. Not at all?
 
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Old 12-12-13, 02:36 PM
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NJT - will do. 185 ok for now? the original temp was set at 190, but i thought that was too high. went down to 180, and now at 185 (for no apparent reason).

I forgot to mention that the house does take a bit to heat up after an 8 degree setback. While I was thinking that a higher water temp would help with recovery time, I guess a smaller setback is also a possibility.

I have so much to learn!
 
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Old 12-12-13, 05:57 PM
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185 ok for now?
I'd roll it back to 180 for now and see how that goes. Unless you can't heat the home with 180, there's no other reason to turn it higher.

house does take a bit to heat up after an 8 degree setback
Is that when you are seeing the short cycling?

If so, what you are describing makes perfect sense... and the wider differential will absolutely help with that. I might even suggest a WIDER diff in this case. What's the max on that control? 30 ?

Run with 20 for a while and see how that goes too.

While I was thinking that a higher water temp would help with recovery time, I guess a smaller setback is also a possibility.
Hotter water would dump more heat into the home more quickly during recovery from setback, but an 8 degree setback is a bit extreme in my opinion. If you instrumented the home with temp sensors, and the boiler with fuel use measuring device, and mashed all those numbers together you would find after experimenting endlessly that there is a 'balancing point' of fuel saving versus t'stat setback.

How far you can set the thermostats back and still save money depends on so many factors... how fast the home loses heat, etc...

I usually don't recommend more than THREE degrees. My own thermostat says "HOLD" at all times and is set to 70F. I don't bother anymore with setback. I actually took all that data... for months... and did the comparisons... and I honestly did not see any savings.

Remember... when you set back, EVERYTHING in the home cools off. When the system goes into recovery, you will burn nearly everything you saved during the setback period trying to get EVERYTHING in the home back up to temperature.

I know that you will read everywhere that setback saves tons of money, but I've done the tests, crunched the numbers, and can say that IN MY HOME, the savings are NIL... so small as to be nearly non-existent.
 
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Old 12-12-13, 06:06 PM
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NJT,
Yes, that's when I see it. Differential can be 5 to 45.

Interesting you bring up setback temps, as I've struggled with nothing more than anecdotal data, such as the long recovery times. You have the data that backs up my suspicions!

We are up at 5:15 each morning, and I have the thermostat turn on at 4:30. I've barely gained a few degrees - even after an hour. We're out of the house by 7:15, and we never "enjoy" a warm house before the daytime setback temp kicks in.

At some point, I need to consider "comfort" into the equation. Saving money or not, if we're sitting around in a cold house, the whole point of why we're heating gets lost.

Here's my plan. Holler back with edits.
Increase setback floor. I do like a cooler temp to sleep, so I can't quite eliminate it yet...
Set high limit to 180
Set differential to 20

One last question....what target burn time should I shoot for? If it's still short of the target, do I increase the differential a bit more?

thanks again to everyone that responded.
 

Last edited by cdbma; 12-12-13 at 06:25 PM.
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Old 12-12-13, 09:52 PM
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At some point, I need to consider "comfort" into the equation. Saving money or not, if we're sitting around in a cold house, the whole point of why we're heating gets lost.
I always tell the treasurer of the house, if I don't spend my money, I forget why I'm working!

I do like a cooler temp to sleep, so I can't quite eliminate it yet...
Agreed about that... my system is one zone, thermostat downstairs... all the baseboards upstairs where bedrooms are have the damper on top SHUT and the valve that I can adjust water flow to upstairs is only open enough to keep the pipes from freezing! (well, not quite... but pretty far closed!)

Set high limit to 180
Set differential to 20
Sounds good as a starting point.

what target burn time should I shoot for? If it's still short of the target, do I increase the differential a bit more?
I dunno... say 5-7 minutes minimum... maybe 10-12 OFF

How much time is burner OFF, between the 3 min burns, during the recovery period?


Yes, I would experiment with the differential... I don't think I would go to 45F though! I might try as high as 30 or so.

One thing to keep in mind is that after the burner cuts out at 180, the circulating water will start to cool... with 20 diff, down to 160 when the boiler refires. Lower water temp means lower BTU output which means somewhat LONGER recovery. But I honestly don't think you will notice that much of a difference.
 
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Old 12-13-13, 04:59 AM
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How much time is burner OFF, between the 3 min burns, during the recovery period?
I'm listing my last 9 log entries (9 is the max) - from this morning back through last night. It was very cold last night (low teens), so I'm certain we hit the setback temp many times. First time is burner-on, second is burner-off, third is the "average water temperature over burner off-on cycle." (from the manual)

[first is most recent]

3:47 7:09 169
4:24 4:07 170
5:11 12:32 177
3:52 24:58 176
4:47 22:14 172
4:44 22:21 171
3:52 18:11 174
3:28 7:44 169
3:48 11:55 169

I agree that the larger differential will lead to a longer recovery time. The lower average water temps seem to bear this out. I'm tempted to make the differential a little smaller. Also, the HeatManager could be dynamically lowering the high limit - impacting the average. Will continue to monitor.
 
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Old 12-13-13, 06:41 AM
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Trooper - He had a DHW Coil, his a-stat diff shouldn't effect the high setting, only the low which he disabled. The high should be fixed at 10 deg. unless he swapped out a different a-stat.

Correct me if I'm wrong here....

The heat manager should increase his swing.
 
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Old 12-13-13, 07:49 AM
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... installed a Beckett Aquasmart ...
...unless he swapped out a different a-stat...
That's what I got from the quote above yours...

His HeatMangler is integrated into the AquaSmart.

I though the DIFF on the HM was AUTOMATIC... not real hip on the AquaSmart or the HM settings... been a while since I've looked at that manual.
 
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Old 12-13-13, 08:00 AM
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the diff settings on my "heatmangler" (love it!) default to 10. high diff range is 5-45, low diff (not used) is 10-45.
 
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Old 12-13-13, 12:19 PM
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I dunno... say 5-7 minutes minimum... maybe 10-12 OFF
Trooper, is this "steady state," after the house has reached temp? Would the cycles be different (shorter?) as the boiler warms the house from the setback temp? The reason I ask is that I'm still not seeing anything over 4 minutes.
 
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Old 12-13-13, 12:55 PM
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I don't know if you could really call it 'steady state' or not...

After the house has been reheated, and everything is back to temp, then the boiler will only fire up to replace any heat loss since the last time it fired.

Would the cycles be different (shorter?) as the boiler warms the house from the setback temp?
How to most easily explain this... there's several different 'conditions' we're talking about here...

First, recovering from setback...

When the thermostat alla sudden bumps up eight degrees, it means that it will be calling for heat continuously for a long period of time. The boiler will fire continuously until the water hits the high limit setting and the burner will shut off but the pump continues to run and move heat out of the boiler and into the home.

The FIRST burn cycle after a setback is likely longer than 3-4 minutes because it is likely heating the water from a cooler condition.

So now, the burner is off, pump running, and the boiler water is cooling off.

When the water hits the temperature of the setpoint MINUS the differential setting, the burner will fire again, up to the high limit.

This activity will continue as long as the thermostat continues to call for heat.

We call this "Bouncing off the High Limit".

With a SMALL differential, the burner cycles will be SHORTER because the water will not cool as much before the burner refires to reheat.

With a 180 HIGH and a 10 DIFF, the boiler would heat to 180, burner off, cool to 170, burner on.

With a 180 HIGH and a 20 DIFF, the boiler would heat to 180, burner off, cool to 160, burner on.

Which case would result in a longer burner cycle? If you said the 20 DIFF, you would be correct because you are heating the water from a cooler temperature.

The larger DIFF also means a longer burner OFF cycle, because the water has to cool more before it refires.

Theroretically, the NET FUEL USED will remain the same. Between the two, the AVERAGE time the burner runs during a given time slot would be the same.

Once the home is up to temperature, the boiler AND circ will shut down and wait for the next heat call.

OK, that's what happens on recovery from setback... you can see that in this condition, the LARGER the differential, the LONGER the burner cycle, and the LONGER the off cycle.
 
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Old 12-13-13, 12:57 PM
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His HeatMangler is integrated into the AquaSmart.
I stand corrected, missed that part!
 
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Old 12-13-13, 01:21 PM
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Next, when house is up to temperature already and boiler fires to replace lost heat.

Thermostat calls boiler, which dutifully starts up...

In this case, only enough BTU need to be added to raise the house temp maybe 1/2 to 1 degree.

So burner fires, water starts to get hot and flow, and in just a few minutes the thermostat is satisfied and the boiler shuts down.

This is a COMPLETELY different scenario to the recovery from setback one.

In this case, the boiler may never get near the high limit. It's very possible that the heat call may end before the boiler comes up to high limit.

The length of this type of burner cycle depends on the BTU output of the boiler, the amount of connected radiators, and the heat loss of the home.

If the boiler water does NOT HIT THE HIGH LIMIT, the DIFFERNTIAL HAS NO AFFECT!

more later maybe...
 
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Old 12-14-13, 04:30 PM
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quick update: burn times are a little bit longer, but not yet 5-7 minutes. However, it is brutally cold in the Boston area this weekend (didn't even hit 20 today), so my boiler is working overtime. Increasing the setback floor temp has helped a bit - my wife said the bedroom felt warmer in the morning. Just a few degrees seemed to do the trick.

Now I'm trying to figure out why one of my zones (the one were we "live" during the winter) seems to be pokey. We came home at 3pm, with room temp at 64. I turned up the thermostat to 68, and at 6:30, the room temp is 66. Everything feels hot and all three zones seem to be working fine. Yes, this zone is heating the largest amount of space, but 3+ hours seems excessive. Stay tuned!
 
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Old 12-14-13, 05:05 PM
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Yes, this zone is heating the largest amount of space, but 3+ hours seems excessive.
Yes... it does seem pokey...

If the baseboards are all HOT and the room is still not coming to temp, it would indicate to me that the room could use more baseboard.

Does that large room have lots of windows?

What is the square footage of the room, and how many feet of baseboard are installed in that room?
 
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Old 12-14-13, 06:40 PM
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Before I answer your question, I don't recall that the temp increase has been this slow. Maybe it has, but I never noticed. Since all the changes, I been watching and measuring everything.

Anyway, the zone is a bit complicated. It's the family room (3 large windows and a double-wide slider with insulating drapes), mudroom with doors outside and to the garage, a laundry room, and a kitchen (with kick space heater). Lots of places for heat to exit. Figure about 600 sq. ft.

After all the finagling an tweaking, the boiler hi temp is probably 5 degrees lower than when I had the H'well aquastat. Maybe that's the difference. dunno.

Once the room gets up to temp, the boiler seems to calm down and the room is quite comfortable. I really don't have any drafts that I can feel.

I'll keep an eye on things and take some notes over the next few weeks. Thanks again for your wisdom and insight. I'll report back when I have some more info that you can digest.
 
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Old 12-14-13, 07:33 PM
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Figure about 600 sq. ft.
A ballpark amount of baseboard for that space would be about 30 feet... but you say you've got a kicker in the kitchen... so whatever btu that is rated at divide by 550 and that would be the equivalent baseboard length give or take.

I'll report back when I have some more info that you can digest.
OK, good... I'm pretty full right now, but I will never turn down dessert.
 
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Old 12-15-13, 05:08 AM
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About 34', not including the kicker. It's been real, real cold, with daytime temps staying below 20 degrees. I know from experience that the system does well when temps are above 25, but struggles a bit if we have prolonged temps below that.

I don't believe I have air in the system and the pipes are hot, so I'm certain the circulator is functioning properly. I'll continue to poke around.
 
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Old 12-15-13, 09:17 AM
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About 34', not including the kicker.
Seems like it should be enough...

If you figure a 'ballpark' of 30 BTU / SQ FT as a SWAG, then you should need 18K BTUH of emitters to maintain... 30 BTU/SF is a pretty high number, so represents possible 'worst case'... it could actually be more or less, but given that you've mentioned sliders and doors to exterior... I used higher number.

Even if you go with a low number of 500 BTU / foot for the baseboard, you are at 17K, and add the kicker into the picture and you should be well over what you need. Baseboard is usually rated at 180 AVERAGE water temp, at 4 GPM, and with those numbers I believe that SlantFin 30 is like 600 BTU/FT. This would mean that you would need 190 going in and 170 coming out to get that BTU rating. Again, I've used a lower number, but perhaps it's even lower than that...

Do you know the entering and exiting water temps for the area?

Is there other baseboard 'upstream' on this zone that could be pulling the water temp down before it arrives?

How is the kicker piped in? Is it being fed by the same water in the baseboard loop, or home runs to the boiler?
 
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Old 12-15-13, 09:57 AM
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Do you know the entering and exiting water temps for the area?
No. I don't think I have the correct thermometer. I do have a very accurate one, but it's a probe type.
If you have ideas on how to measure without having to buy an expensive device, I will attempt.

Is there other baseboard 'upstream' on this zone that could be pulling the water temp down before it arrives?
The water moves out of the boiler to a small mudroom (fins on one wall), then the front of the family room (fins across the entire front), then make a left and enters the powder room (small section of fins) in the middle of the house. It then travels to the back of the house, where there is a T for the kick heater. The back of the family room has a slight bump out, and there are fins on both sides. Finally, there are fins in a small laundry room. The water then heads back to the boiler. I have a separate loop for the LR/DR on the other side of the house.

How is the kicker piped in? Is it being fed by the same water in the baseboard loop, or home runs to the boiler?
See above!
 
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Old 12-15-13, 10:25 AM
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cdbma,
with the aquasmart you might want to try the medium or low setting on the heat manager also. I just re-piped my whole boiler a couple weeks ago (Peerless WBV-04, Riello w/ 1gph nozzle), added a zone for room being converted (not hooked up yet), added 40gal superstor indirect, eliminated the tankless coil and put the Aquasmart on). The Heatmanager on mine came default on High/aggressive, 180 HL with 15 degree diff. It says in manual to change if comfort is an issue. So far mine is working well and heat and hot water are no issue. I'll try the log later for you to give my burn times etc. I have been watching it as I'm doing other things and the "economizing high limit" is on a constant change. an hour ago it said EHL of 145 degrees, burner won't fire until 130. I've seen it all over, short burns as it goes from 130-145, then as it cools EHL says 151 and kicks in at 136, it continues doing this until A) call is satisfied or it eliminates the EHL and runs to 180.

My upstairs heat is set at 66 constant but is in my foyer area and sometimes makes bedrooms too warm as there is not much baseboard and far from t-stat. Main floor is 70 day, setback to 65 at night, but recovers quick. Definitely not a 3 hour thing.

I used to have an Intellidyne HW+ at old house and that told me what it economizing (30%) and was correct based on my fuel usage from before to after install. The Aquasmart I have no clue except after maybe I run for the next year. I do know that with the new setup with IWH it runs WAY less. I also installed (last year) a Field Oil Vent Damper which helps hold the heat in the boiler between cycles.

I'm not changing much yet as I have high shower demands with the rest of family so need the quicker recovery on the water.
 
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Old 12-15-13, 10:32 AM
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If you have ideas on how to measure without having to buy an expensive device
Even just knowing the boiler supply temp during a heat cycle is probably enough... have you observed it during your 'freeze-out' period at all?

I know you posted temps earlier, but I presumed that those were during a recovery from setback period when the boiler was in fact hitting high limit.

Are those temps also typical of what you see during a 'normal' heat call?

Where in that area is the thermostat located? Hopefully not above a radiator!
 
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Old 12-15-13, 10:53 AM
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One quick edit on my "run" description. The first set of fins is the front of the FR. The mudroom is at the end of the run. Two pipes crossed in the basement and I went the wrong way! So, presumably, the FR gets the hottest water first.

I taped the thermocouple from my DVM onto copper for the loop. I measured at the nearest to "boiler out" and then "boiler in". I got 180 out and 159 in.

The house is now warm, so I'll check the history in a bit. The other temps I listed were as the house was warming up.

Thermostat is on an inside wall, in the middle of the FR.

Sequoiasoon - I will read the manual again. Maybe I need to back down on the economizer.
 
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Old 12-15-13, 08:31 PM
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cdbma,
if you observe a couple cycles what does the economizing high limit say during some of those cycles? The "old" heat manager was done by Intellidyne but according to them the new version algorithm built into the aquasmart is not from them. The Intellydyne version I had prior had a set low limit of I think 135 during a heat call, once fired it would run to 180 unless heat call was satisfied so it would run for 45 degrees worth of change. If it saw temps dropping fast it would kick in earlier like 150 for example and run to 180.

This newer version tries to keep max temp lower and adjusts (based on what I read) how long the standby has been idle (off time). The longer the "off time" the lower the economizing high limit is. I watched mine earlier and had 4 shorter cycles and watched the EHL change. My boiler was idle for a while so EHL said 146, I got a heat call (for superstor) and with the 15 degree diff, boiler went to 131, fired and shut off at 146 (just that 15 degree change) which didn't take too long. It cooled pretty quick with the water demand and circulator was still running, EHL changed to 151, at 136 boiler fired and while it was heating, the EHL changed to 153. Boiler got there, shut off, EHL changed to 163, so boiler only cooled 5 degrees and fired again. This time there was no EHL limit message and boiler went all the way to 180.

I don't if it helps or hurts others to understand it's operation. Times during that:
On: 4:21 Off 1:31
On: 5:18 Off 8:18
On: 4:22 Off:65:26

I need to call Beckett myself because what seems strange to me is my "average" temps on those calls 418, 420, 405. On the last 9 events I also have in there avg temps of 144, 150, 173, 170 with some 412, 418, 419 thrown in the mix.

I also have burn times in the 2+ to 8+ minute range, and multiple (from past checks on warmer days and recent cold) in the 60+ off and warm days 350+ off.
 
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Old 12-16-13, 03:39 AM
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Good info. I need to take some more observations, but I just don't have the free cycles to do so. I can tell you that it has been brutally cold here in NE, so the boiler has been very busy. I guess I can see how I could be having the same incremental increase in the high limit, which would cause the boiler to short-cycle as it "climbs" up to the limit. The more I think of it, the more I'm leaning towards thinking that the economizer will only be effective in the warmer seasons, when it can truly set a lower high limit and still keep the house warm. For the winter, I'm wondering if it's better to just turn the economizer off and let 'er rip! When the temperatures are in the mid-teens during the day, and close to zero at night, there is no way my house will be heated effectively with 140-150 degree water!

Please share any insight that Beckett passes along. I know only what's in the manual, and that's not enough.
 
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Old 12-17-13, 12:33 AM
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I don't know on the Aquasmart but iirc when i had the Intellidyne it showed my best efficiency during the winter because it ran more than during the off months and had more residual heat. I didn't hear back from them yet.

In my current house/situation I've found that the bedrooms actually are warmer than prior to Aquasmart and 4 other people in house said the same. Downstairs feels the same to me. The only thing I can figure is that the water is circulating longer at the lower temps and not reaching the t-stat in foyer/hall area as well. Since the rooms have more baseboard it heats longer accordingly. I've seen mine start low and on these colder days it just keeps adjusting and going to the 180 HL as needed.

We have been in the 20's here nighttime with some warmer days. How is your insulation etc.? Any issues prior to the Aquasmart change on similar days in the past?

I also just bumped my differential to 20 today so we'll see if that changes anything on my run times. I do know that my second floor (bedrooms) seems to trigger often. It has an old T-stat that was line voltage with spring metal/mercury. I need to move it but now that it is 24V I might just tie into the electronic honeywell next to it that is for the central air (but has heat also)
 
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Old 12-17-13, 03:35 AM
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House is pretty well insulated. Lots in the attic and no drafts. Windows are ok, but I'm sure could be better if new ($$$).

Are you using any other custom settings on the AquaSmart, such as circulator on/off delays? I thought I would use the DHW priority feature, but I have plenty of hot water, and I really need the heat to come up quickly in the morning while we get ready for work, so I have that off.

I'm currently at 185, with a 15 degree differential. I continue to tweak and monitor! This morning, it's only a few degrees above zero, so the house is even slower to warm and the boiler is cranking!
 
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Old 12-17-13, 04:08 AM
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no custom settings for anything. I have 3 circulators currently working through a Taco SR506 controller. The Superstor zone/circulator is set on a priority zone so if it needs heat, the Taco won't let other zones circulate. I also need new windows but for now did the frost king stick on heat shrink plastic. That made a big difference in my kitchen. I have a bunch of drafts that are on the fix it list.

Maybe like NJT said try a less of a setback or even hold at temperature.

My friend just had his boiler not fire (water in fuel tank). we drained accordingly and refired and his house went from 58 to 68 in about 1 hour and it's 22 degrees here now. He has the Intellicon on his.

Anything blocking radiators? Last time covers removed and fins vacuumed? Mine were coated on the bottom with dust balls etc. when I removed them for doing the floors top was OK and hard to tell they were really dirty.

I'm not home in the AM when mine kicks in from setback but wife hasn't complained so can't be too awful on warmup time but 1st floor only has a 5 degree setback.
 
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Old 12-17-13, 02:56 PM
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Fins are squeaky clean. I vac and blow them out in the fall with compressed air.
 
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Old 12-17-13, 05:03 PM
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I figured out a better way to attach the thermocouple to the copper pipe. With the boiler set at 185, the temp on the outlet pipe about 3' downstream topped out at 191. I'm getting an overrun in the boiler; the AquaSmart shuts off the boiler at 185, but it keeps heating up to about 192. That all seems hot to me, so I dialed back to 180 (12 degree diff). As previously mentioned, I measured temps at the end of the run in low to mid 150s.

Run times are still in the 3-4 minute range, but outdoor temps have been consistently below 20 degrees - even during the day. I'm guessing that the boiler is struggling to keep up in this very cold weather.

The boiler is working, fins are squeaky clean. I am relatively comfortable in the house, and I can't complain about much of anything - except the cold weather! Good problem to have...So, I'll continue to read all the posts in this forum and continue to learn from the experts. I think it's time to find a new dragon to slay! Thanks to all for your insight and wisdom. Keep 'em coming!
 
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Old 12-18-13, 04:25 PM
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more numbers...more data? more questions!

I'm back...you knew I would be! In a prior reply, I noted the "out" temperature on the pipe that feeds my family room zone. I forgot to turn off the DVM/thermocouple, and this morning, when it was quite cold - and all three zones were circulating - I noticed the pipe temperature was much lower - in the mid 150s - instead of the much hotter temp I reported earlier. This temp was observed right after the boiler reached high limit (180). Is this normal? Is my boiler just not able to supply the hotter water when all three zones are running? Almost seems that all the water running through the three zones can't pick up enough heat from the boiler as the water passes through it.

Also, I wonder if my Honeywell (RTH7500, 7600) thermostats are contributing to the short cycling. They advertise a very tight temp window, so I don't have to drop much below my setting before TT kicks in. I've noticed situations where the FR thermostat calls for heat, the boiler fires up, and a few minutes later the thermostat is satisfied and the boiler stops firing. I've read the Honeywell instructions a thousand times, and I've probably read every post in the other DIY forum dealing with thermostats. I have it set for the [DIY/Honeywell] recommended CPH. No idea what to do here, if anything.

As always, thanks in advance for your insight and suggestions.
 
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Old 12-18-13, 05:24 PM
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I noticed the pipe temperature was much lower - in the mid 150s - instead of the much hotter temp I reported earlier. This temp was observed right after the boiler reached high limit (180). Is this normal?
That TC is on the HOT SUPPLY out to the family room?

The boiler is reading 180 and only a few feet away you are reading 150?

The pipe that the TC is on has insulation all around the TC and at least a foot in either direction?
 
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Old 12-18-13, 05:26 PM
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I've noticed situations where the FR thermostat calls for heat, the boiler fires up, and a few minutes later the thermostat is satisfied and the boiler stops firing
Where is the thermostat physically located in relation to the baseboards?

Is there any chance that the heat coming off the BB is somehow influencing the thermostat into an early shutoff?

Is the thermostat indicating that the room has reached the t'stat setpoint?
 
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Old 12-18-13, 05:36 PM
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That TC is on the HOT SUPPLY out to the family room?
yes - I am going to test again to make sure I had good contact.
All my pipes carrying heated water are insulated. I know it can get to 180, because I measured it - as noted in earlier post.

If it is very cold, and all three zones are circulating, is it possible that the water coming in is on the cool side (remember, rooms are cold due to overnight setback) and the boiler just can't transfer enough heat to the circulating water before the water exits the boiler? Am I smoking something here?
 
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Old 12-18-13, 05:41 PM
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Where is the thermostat physically located in relation to the baseboards?
Baseboards run across the front of the family room. Thermostat is on an inside wall, in the "middle" fo the living space, and no closer than 10' from the nearest BB.

Is there any chance that the heat coming off the BB is somehow influencing the thermostat into an early shutoff?
I don't believe so.

Is the thermostat indicating that the room has reached the t'stat setpoint?
Yes

At some points in the day, I may have three thermostats (four if you count the DWH) all cycling on/off at the same time. I wonder if this is making the boiler go crazy. I tend to focus on the FR thermostat, but I need to remember that there are others in the mix.
 
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Old 12-18-13, 06:03 PM
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Am I smoking something here?
If you ARE, and are NOT sharing, BAD POSTER! :bad poster:

and the boiler just can't transfer enough heat to the circulating water before the water exits the boiler?
But you said the boiler temp is indicating 180 ? So how could a pipe just a few feet downstream show that large a difference? UNLESS, you are looking at the RETURN from the family room, in which case I would expect at LEAST a 20 degree difference.
 
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Old 12-18-13, 06:09 PM
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No, I'm certain it's not the return. Having said that, I'm on my way back downstairs to look at it again! I'll also take a peek at the temp.

The pipe I'm looking at is fed from the top of the boiler, where the main feed splits off to the zones, right after the expansion tank. I know, I know, a picture would help! I can do that if you want.

The system was designed to "pull" the hot water through the house, so the circulators are located just before the water enters the bottom of the boiler. Alas, another photo?

Stay tuned...
 
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