Getting used to a cold start boiler.....are they really better/more efficient?

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  #41  
Old 12-27-15, 07:50 PM
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So you say I should open both valves fully? What impact will that have on the water temp? What is the ultimate goal in terms of adjusting the valves?
Yes run them full open. The bypass alone should fix your temp issue... Youll have to post boiler temps and how long to get to 180f on a call for heat...

The bypass is interesting because it seems to go against the goal of raising the return water temp. In reality it actually lowers it a bit, right?
Not really. The goal is to get the boiler up to temp so it dont condensate...

Sure you will have lower temps in the shoulder season out of the rads but in the winter youll be getting hotter temps out the rads..

This is a poor mans outdoor rest... ( Google it)

You dont need 180f water temps at the rads when its 50f out...

I just want to know on a call for heat with all valves open how long now does it take for the boiler to get to 180f or over 150f...?
 
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  #42  
Old 12-27-15, 08:32 PM
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I should time it from the boiler being stone cold (usually around 75 degrees or so)?
 
  #43  
Old 12-27-15, 08:51 PM
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Sure why not...

Compare it to this...

I just timed the boiler it took 25 minutes to go from 73 degrees to 136 degrees. I gave up counting at that point. I guess that seems rather excessive I assume?
Turn economy knob all the way up... ( Ill read up more on that..) Not sure where you left it set at......
 
  #44  
Old 12-27-15, 09:19 PM
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At the moment the economy setting is turned all the way down/off. I will time it tomorrow. I will use the digital temp read out on the front of the boiler.
 
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Old 12-27-15, 09:28 PM
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And take return temps and feed temps from the gauges at 5 min intervals...

You can try it with economy off for now...
 
  #46  
Old 12-29-15, 12:25 PM
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Well I went to the house today but I was pressed for time so I only was able to observe it for a short time.
The first thing to report is from my mother who lives there, she said the heat is great now. It heats "nice and even".
When I initially observed the boiler it was already warm/hot because they had the heat on. So I could not time a cold start to 180. Based upon the way they had the valves throttled, the boiler seemed to struggle to get beyond 150 quickly, so I adjusted the valves.
The way I have the valves throttled now is the following: bypass valve is fully open and the supply valve is partially closed. With the supply valve partially closed, the boiler temperature rose from 144 to 180 in 4 minutes and 20 seconds.
Based upon what I have described, do my "adjustments " sound good?
Also what purpose is served in partially closing the bypass valve? What temp would be increased with that valve partially closed?

Thank you,
Zack
 
  #47  
Old 12-29-15, 12:35 PM
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Also is there any danger in closing the supply valve too much? I guess I mean will closing it too much allow the boiler to heat too quickly thereby cycling on off more often?
 
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Old 12-29-15, 01:49 PM
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the boiler temperature rose from 144 to 180 in 4 minutes and 20 seconds.
Seems ok but maybe too fast... Let me think about it some. Others will chime in..

Also what purpose is served in partially closing the bypass valve? What temp would be increased with that valve partially closed?

As I stated bypass should be fully open. probably the feed valve too.. Closing the feed valve would be the right thing... But the boiler needs a certain flow through the heat exchanger. Closing it too mmuch can cause overheating of the heat exchanger I would guess.

The temp that increases is the flow aross the boiler. This allows the boiler temps to rise quicker..

But I think with them both open fully should of been the way to start. Then as you monitor the boiler for the heating season you can make adjustments..

As I said run them full open and economy setting all the way up..

Also is there any danger in closing the supply valve too much? I guess I mean will closing it too much allow the boiler to heat too quickly thereby cycling on off more often?
Having not enough flow and in turn the boiler will cycle more...

And as stated the bypass alone should sufficiently of fixed the issue.. The valves are there just incase adjustment is needed..
 
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Old 12-29-15, 02:14 PM
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From comfort calc .com...

Remember reducing boiler flow the water gets hotter. I would than adjust the flow in the boiler until I get a 30 - 40f rise through the boiler. If that causes the boiler to short cycle, open the valve slightly until the short cycling stops

So you check the temp at the return gauge on that back pipe and compare it to the gauge on the the supply side at top of boiler . ( The black one)


But you will probably get that 30-40F delta T rise with the valve fully open...



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Old 12-31-15, 02:59 PM
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Hi everyone,
I had a chance to spend some time at the house today and I was able to time the boiler. The results are as follows.

The timing was done with both valves totally open (bypass and supply) and the economy setting turned down/off.

Cold start of 82f - 140f - 12 minutes

@ 13 minutes -143f
@ 18 minutes - 149f
@ 26 minutes - 159f
@ 30 minutes - 161f
@ 35 minutes - 168f
@ 43 minutes - 174f
@ 47 minutes - 178f
@ 49 minutes - 180f
@ 50 minutes - Shut off because it hit 180f

When the boiler shut off, the boiler dropped down to 157f before it started up again. When it started up again, it went from 157f to 180f in 3 minutes and 48 seconds.

How do the numbers sounds? Based upon the numbers, should I leave both valves totally open? Also the Delta T seemed to be about 40 degrees - 140f-180f. I don't know for sure because I am not positive that the strap on thermometer is totally accurate. According to the Comfort Calc site, a 40 degree Delta T is acceptable with a high volume water system, like cast iron. Is that correct?


Thank you everyone,
Zack
 
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Old 12-31-15, 03:34 PM
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I just timed the boiler it took 25 minutes to go from 73 degrees to 136 degrees. I gave up counting at that point. I guess that seems rather excessive I assume?

Cold start of 82f - 140f - 12 minutes

So we cut that time in half..

I would wait till TOheating or Rbeck take a look at those #'s..

But you did not tell us the delta t... Return temp vs supply temp...


Also...


Your water heater vent looks back pitched in the pic.. And not a fan of the flex pipe.. Were permits taken out for that.. It would have never passed.. As well as a ell is not allowed as the first fitting off the draft hood....


Co issue for sure. Make sure your detectors are working.
 
  #52  
Old 12-31-15, 04:22 PM
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Well the Delta T seemed to be just about 40 degrees......140f return - 180f going out of the boiler. But I am not 100% sure that the strap on temp gauge on the return is accurate.
 
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Old 12-31-15, 04:25 PM
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The water heater pipe was done by the liner company
 
  #54  
Old 01-04-16, 01:05 PM
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Bump....has anyone else had a chance to look at the numbers as lawrosa suggested?


Thanks,
Zack
 
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Old 01-04-16, 03:33 PM
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Cold start 82-140 seems good..

50 minutes is not too bad either from cold to 180.

As the link from comfort calc.com stated you want a delta tee of 30-40 degrees. You said you have 40...

Throttle the boiler out valve to get a 30f delta tee and retake your temp readings.

Dont go crazy and restrict too much flow through the boiler..
 
  #56  
Old 01-04-16, 03:40 PM
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How do you adjust the bypass valve?


This is normally is done after the system water temperature gets above 140f. If there is a valve on the boiler bypass it is wide open all the time. Some people do not even install it. Do not partially close it, as there has to be a lot of water passing through it. There could be as much as three times the water going through the bypass as going through the boiler. The best way to adjust the valve on the boiler is install thermometers on the supply and return pipes near the boiler or use temperature probes strapped onto the pipe and insulated. I usually adjust the delta T through the boiler as follows. Low water volume systems whether zoned or not 20f to 25f rise. Large water volume systems such as cast iron radiators and radiant heat 30f - 40f rise through the boiler


Comfortcalc.com
 
  #57  
Old 01-05-16, 04:12 AM
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I don't live in this house, but my mom does so I need to rely on her thoughts. Since the bypass was done she claims the house is more comfortable and seemingly heats evenly. Since I have not experienced this first hand I can't expand on what she exactly means with her description. But it seems to be making her happy, so that is good.
 
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Old 01-05-16, 07:23 AM
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Also I will try to get to the house today since it is very cold out to check the delta t. Quick question related to the delta t, does raising the boiler temp to say 190f have any effect on the delta t? Or does it not matter what the boiler temp is because it will lose a defined amount of heat passing through the cast iron radiators?
I spoke with my mother this morning and she noted that once again the house was warm and comfortable with the single digit temps we had last night.
 
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Old 01-05-16, 01:03 PM
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Wrong style valves for throttling!!!! They should have used globe and not ball valves. If they are going to leave it running like that, I'd make them put the correct valves in.

https://controls.engin.umich.edu/wik...TypesSelection

As info, I used a Danfloss ESBE valve to regulate the bypass loop on my oil fired cold start. Works great.

pete
 
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Old 01-05-16, 07:31 PM
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What is the harm in using the valves currently in place?
 
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Old 01-05-16, 08:06 PM
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As the temps get colder out the boiler will cyle more, hence the rads will get hotter.

As the shoulder season comes the boiler will cycle less and rads will be not as hot. You dont need hotter rads in the shoulder seasons.

This is why the boiler bypass is called an poor mans outdoor reset..


I used a Danfloss ESBE valve to regulate the bypass loop on my oil fired cold start. Works great.

I dont like them as they keep flow through the boiler untill 140f. The OP's boiler gets up to 140 in 12 minutes. Thats fine IMO..

does raising the boiler temp to say 190f have any effect on the delta t?
No... No sense raising the boiler to 190 IMO..

On the coldest day of the year if that boiler was sized right and the rads where sized right for the heat loss, the boiler should run non stop and maintain 70-72 in the home.. Boiler water temp should be near 180f on that day...

Coldest day in NJ is 5F on average... more or less on where you live...

From comfort calc.com..

There are benefits to a boiler bypass. When the water bypasses the boiler and goes into the supply, the supply water temperature drops slightly before going to the radiation. This will increase the comfort level of the home as cooler water is circulated through the system. The temperature change in the living area is slower thus more comfortable. Another advantage is you are not heating all the gallons of the water in the system through the boiler that saves fuel.


The boiler bypass will vary the system water temperature as outside temperatures change. I call it the poor man's outdoor reset. It works better with larger water volume systems but just as important with other systems.


A boiler bypass is more about flow and delta-T than return water temperature.

A boiler bypass will reduce the flow in the boiler and increase the flow around the boiler. As we slow down the flow through the boiler the average water temperature in the boiler gets above the condensing temp in the boiler as the delta-T is increased in the boiler.




I would leave the valves as they are for this winter... You already reduce the time it takes for the boiler to get to 140F which is above the condensation level...

12 minutes now vs 30 minutes before...

And remember the boiler got to 180f in 50 minutes but that was from cold start.. In real world scenerio that would only happen on shoulder season.. Plus the boiler may heat the home without reaching 180 during those times.. You may only need 120f to the rads..( 150 boiler water)


And again in the winter the boiler will be starting at a much higher temp as its cycling more often... So those times of 50 minutes to 180F are mute...
 

Last edited by lawrosa; 01-06-16 at 03:18 AM. Reason: changed op's boiler gets to 140 not 160
  #62  
Old 01-05-16, 08:09 PM
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What is the harm in using the valves currently in place?
Nothing.. They are used all the time..

But as I stated just leave them both open... Your doing fine.. The valves are inplace for when some boilers dont react as yours and need adjustment...

Again the bypass should always be wide open and never adjusted.

Its the boiler supply side that needs adjustment sometimes in certain applications....
 
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Old 01-05-16, 09:14 PM
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I dont like them as they keep flow through the boiler untill 140f. The OP's boiler gets up to 140 in 12 minutes. Thats fine IMO..
I used the 110 degree version.
 

Last edited by lawrosa; 01-06-16 at 03:18 AM. Reason: changed op's boiler gets to 140 not 160
  #64  
Old 02-21-16, 07:15 PM
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Update....
I just wanted to give everyone an update on the heating system performance. Since my last update we had very seriously cold temps here in NJ. In fact last weekend the temps dropped to -5.
I am happy to report that the system has been working perfectly and keeping the home warm and comfortable. On the coldest day of the year thus far, my mom had the thermostat set at 74 and it maintained that temperature without any issues. Without question the bypass solved the issues that we originally had when the boiler was replaced, without the bypass. Thank you everyone for your expertise to make my family happy!

Going forward, what kind of maintenance should we have performed of the new Weil-McLain CGA-4? Does it need yearly service? I guess it does not have a pilot light, so during the summer should I raise the thermostat every once in a while to dry out any humidity in the boiler? My boiler knowledge is based on my oil boiler, which NEEDS yearly service.....natural gas is new territory for me! Is the CGA-4 an easy boiler to clean/service?

Thanks,
Zack
 
  #65  
Old 02-21-16, 07:42 PM
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Happy all is well....

NG needs no maintainence really.......... Vacuum burners every few years.....

Check pressure and expansion tank yearly is all......


I leave mine off all summer......
 
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