Time it takes to heat the house by 5 ?

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Old 01-08-15, 11:49 AM
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Time it takes to heat the house by 5 ?

Hi everyone, have a question to the knowing public.

I have a Peerless Oil Furnace, WBV-03 and with an indirect water heater.
The temp outside was around 10 degrees, thermostat set to 67, the control is set to 160 Lo, 180 Hi with Diff 10. The oil tank is outside.

I woke up to a temp being at 61 degrees and furnace was running full tilt. I do have a variable circulator with a Lo/Med/High settings and it was set to Low - circulating the hot water at low speed.

I set the circulator to medium at 7am when the temp was at 61. Now, 6 hours later of the curculator running non stop and furnace running enough to keep the temp at 170 degrees, the temp crept up to 64, so 3 degrees in 6 hours.

Now there are two questions - any alternative answers are welcome.

- Why did the temp drop?
I'm guessing either the fuel got too thick at night since the tank is outside and furnace stopped working for some time or because the circulator was set to Low, the water wasn't being circulated quickly enough to heat the house with outside being so cold.
- Should it take that long to heat the house back up?
It's not often that I see it being 10 degrees outside but i think it always took at least an hour to get the temp up by one degree. Is that too long? The furnace is operating within spec as i can tell so not sure where the issue is.
 
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Old 01-08-15, 12:16 PM
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I moved your thread from the furnace forum to the boiler forums.
A furnace is hot air.... a boiler is hot water.

I doubt your boiler stopped working last night. My guess is that you have a lot of heat loss in an older home and not enough emitters (baseboard) to replace the heat fast enough.

In my old retail store I had a lot of glass frontage and not enough area to install more baseboard so I used an outdoor temperature reset control. This device increased the water temperature as the outside temperature went up.

Trooper... the forum pro.... will stop in and add his opinion.
 
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Old 01-08-15, 12:23 PM
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I moved your thread from the furnace forum to the boiler forums.
A furnace is hot air.... a boiler is hot water.

I doubt your boiler stopped working last night. My guess is that you have a lot of heat loss in an older home and not enough emitters (baseboard) to replace the heat fast enough.
That would probably be my guess as well. Would be curious to know your dT from supply to return with the low and medium settings on the circulator. Your boiler must by cycling a lot as well. Depending on your heat loss, and the amount of emitters you have, 180 may not be hot enough. You may have to bump that up to overcome the greater heat loss due to cooler temps. But on the other hand, if this is a once or twice a year temperature, and everything works fine every other day of the year, maybe it's better to just deal with it.
 
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Old 01-08-15, 12:46 PM
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I've found that night time set backs greater then 2 or 3 degrees isn't very cost effective. I run 170 degree water temps in my system and have no issue maintaining indoor temps, but if I try to recover more then 2 or 3 degrees it take a few hours. Don't forget, everything inside the house, furniture and even walls and floors has to heat back up.

FWIW - I set back to 66 at night, up to 67 at wake up, 68 at noon and 69 at 4:30, then back to 66 for the night. The recovery as you can see is minimal and gradual over the course of the day. I take full advantage of any solar gain from the daytime sunlight and make sure the house is nice and warm for our evenings.

It was a very cold night last night, you may have to bump up the water temperature a bit if you want a faster recovery or cut back your set back a deg. or two. When you're recovering, keep in mind you're battling the heat loss of the home, heating up the cold items inside as well as the interior structure. When we're down at design temps, recovery is more difficult then maintaining.
 
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Old 01-08-15, 12:56 PM
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I agree that the issue here was the recovery. I concur with only 2 or 3 degree set backs. With very cold temperatures, it makes it even harder to recover any kind of loss.
 
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Old 01-08-15, 01:18 PM
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In my opinion you should set the high limit to 180f and the pump on medium , or check the return water temperature against the boiler temperature for the delta T should be 20f .
 
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Old 01-08-15, 02:35 PM
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I'm in New England, and have a very similar setup. My system (setback, recovery, etc) works fine down to overnight temps in the low teens. After that, recovery takes a very long time. Last night, it went down to minus 4, and my system was huffing and puffing this morning!

I would chalk this up to a very cold night. The experts here can help you fine tune, but I'm not sure there is anything grossly wrong with your system.
 
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Old 01-08-15, 03:55 PM
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I think it comes down to the cold...

There are basically three things to consider:

1. Your home has a certain heat loss. Of course when it's super cold out, the heat loss goes up.

2. Your boiler can output a certain amount of heat to the heat emitters in the home.

3. The heat emitters move that heat from the boiler into the home.

For the home to be able to maintain temperature, the boiler output has to meet or exceed the home's heat loss.

AND... the heat emitters have to be able to move that heat into the home.

I agree that the pump should probably be on MEDium.

Your boiler is probably big enough...

How many square foot is your home? How many BTU is your boiler?

What type of heat emitters do you have? I'm thinking that you have 'fin-tube baseboard'?

One thing you can do that will probably help...

It doesn't take much dust buildup on the fins of the baseboard units to cut their heat output way down. Removing the covers and brushing and vacuuming the dust from the fins of the baseboard will increase the heat output into the home.

When it's really cold out and the boiler can't keep up, it would be permissible to increase the high limit to 190F temporarily.

Saves asked about the 'delta T' being 20F. What he means is that the water returning from the baseboards back to the boiler should be about 20F cooler than the water leaving the boiler.

Do you have a way of measuring this?

A bare hand can be used for the 'OUCH! test'... briefly touch the supply pipe leaving the boiler. Note how long you can touch it. Do the same for the pipe returning. Is it much cooler?

If you do find (or feel) that there's a 20F difference, and the boiler outlet water is at 180F, the only other reason the house would cool off is that there isn't enough baseboard installed to replace the heat that is lost.
 
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Old 01-08-15, 08:36 PM
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Boiler

Thanks everyone, here's some more info:

It's a 1950's house, around 2,000 sq ft. I did quite a bit of insulation updating in the attic, with several layers of R30, also plastic wrapped my vinyl windows. The boiler is 110,000 BTU boiler with a Riello40 burner set for .6 GPH.

I have convectors in most rooms (7 total) - just under the window, our bedroom and downstairs are hot water baseboards. I did vacuum most of them out within 6 months when a circulator had to be replaced and i had to open all of them to bleed the air out so that's not a concern.

The return water is about 6 degrees colder coming back than going out - according to the infrared thermometer - it's around 160 leaving and 154 on the return line, that's with the circulator running with a call for heat.

The boiler kicks in every 4-5 mins or so mid cycle, the water cools off from 170 to 160 in the boiler and that takes around 5 mins so it kicks back in to get it up to 170 and shuts off. The circulator runs non stop during the cycle.

With the circulator set on High, the water temp cools off even quicker, forcing the boiler to kick in more often.

Do i need to allow more range, e.g. allow the water to go from 170 to 150 while ciruclating before kicking the boiler back on? if so, what settings do i change?
 

Last edited by GeneBerg; 01-08-15 at 08:56 PM.
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Old 01-08-15, 09:08 PM
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the control is set to 160 Lo, 180 Hi
kicks back in to get it up to 170 and shuts off.
You've got the HI set on 180 but the temp is only going to 170?

You could try juicing the HI setting up to 190 during this cold spell, and set back to 180 when it warms up a bit.
 
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Old 01-09-15, 10:20 PM
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You'd be surprised how quick the dust can collect especially on the bottom that is harder to see, nevermind if you have pets. I've seen some people clean it with a spray bottle and water also (towel under it). If carpeting is close it blocks a lot of the flow in also (as well as furniture close to it).

I have a WBV-04 with indirect and had in another thread that my aquastat shuts down at 180 (mine has digital display) BUT I'm also only getting 170 max out to zones according to newly installed strap on temperature sensor for a new controller.

I'm still working on that for some ideas. But it almost appears that the larger water capacity area for tankless coil heats up faster than what the dial gauge show (as well as output). The Flir E4 I have for a couple days showed my black pipe manifold to be at 162 (strap sensor showed 163, dial gauge about 160+) Aquastat showed 177.
 
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Old 01-10-15, 06:34 AM
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FWIW: I have used my compressor, along with my shop vac, to clean the fins. You have to be careful not to have the pressure up too high, as it can create a cloud of dust (I know this from experience!). I do this because just straight vacuuming does not always do the trick. I am careful not to touch the fins, to prevent damage to them. I have also used cans of compressed air on lengths where I can't get my air hose. A bit more expensive to use canned air, but the results are satisfactory. I live in a house with no kids, and no pets. Still, I can attest to the amount of dust that accumulates in a short amount of time. Recall that these work by convection, so all that airborne dust is dragged across the fins by design.
 
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Old 01-10-15, 09:39 AM
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I'm going to add to this a little. Been having a jelling issue with my oil and lost the burner again last night. The house dropped down to 61 by this morning. I blew out my oil line and had the burner back up and running at 8am. It's now 11:40 and I've just about made it back up to 68. So that recovery is taking me 4 hours. It's currently 19 degrees outside.
 
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Old 01-10-15, 08:59 PM
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I'm wildly speculating that i had something similar, recovery took a bit longer, I went from 61 to 67 at 2 pm that day so just over 6 hours to make that climb. I bought an 80oz bottle LINK and dumped about a 1/3 of a bottle into 100 gals or so I had remaining in the tank. It is a bit warmer now, 20 instead of 10 it was that night but so far so good, temp is holding and burner is running.
 
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Old 01-14-15, 07:20 AM
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With the ODR setup, I find that on the relatively colder days/nights like we have been having the past few weeks, I am able to gain about 1* per hour. I lose at about the same rate, maybe a hair quicker.
 
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Old 01-14-15, 06:03 PM
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Ran a test tonight. 20 deg out, ODR calling for min (150 deg), took 1.5 hrs to raise my dining room 2 deg. Heated it from 66 to 68. Room is like 14x14 or so, has 2 3x5 windows, and like 10' of baseboard. Was seeing 3:30 burns and 7:30 idle times which works out to like 5 cycles per hour or so.
 
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Old 01-14-15, 09:33 PM
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I've been taking notes since mod/con install and over the last 30 hours (8*-20* outside in that span) the boiler has been running for 29 hours with 3 cycles. I'm at 140* for my 5* design day, last night dropped to single digits and the house lost 1.5*, recovered well and has been comfy.
 
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Old 01-16-15, 05:27 AM
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New stats I put in have a timer that record when it is calling for heat. Only been a few days, but it seems like it averages around 12 hours or so.
 
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Old 01-16-15, 05:43 AM
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which stat is that, that sounds like a good feature.
 
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Old 01-16-15, 06:47 AM
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I got the LUX TX9100U. I had originally purchased the Honeywell RTH7500D, but realized the "swing" was fixed, but on the LUX, you can adjust the swing up to 2.25* I think it is. I have it set to 1* right now. Stat set to 68, kicks heat at 67, heats till 69 then off. With the adjustable swing, I figured I could try different values out until I get a happy balance of heat call and boiler run times. Haven't tried anything but 1* yet though.
 
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Old 01-16-15, 08:29 AM
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Just read the LUX manual, that energy timer is a nice feature. That was on my top 3 list when I replaced mine in Oct. For $42 I may just try the LUX next winter.
 
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Old 01-16-15, 10:34 AM
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Ya, it seems to be working well so far. Like I said, it's only been installed for a few days but.
 
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