Some questions about a new Burnham install

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Old 12-07-11, 11:17 AM
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Some questions about a new Burnham install

Recently had a Burnham ESC5 installed during an oil to gas conversion and have some questions about it.

There are two circulators for two zones controlled by a Taco zone relay, and a Burnham outdoor reset. Technologically it's a very different beast than what we're accustomed to.

1) It cycles a lot. The boiler quickly climbs to it's setpoint and the boiler then shuts down leaving the circulator to run. The return water, being about 15 degrees cooler, quickly drops the temperature in the boiler. Because the differential is set to it's default setting of 15, it starts firing again after just a short pause. I'd envisioned it more like the old boiler; runs a bit and circulates a lot. The LED display reads 42 hours of use and 621 cycles. Is it typical for this model to cycle so frequently?

2) We've been enjoying the benefits of a hefty night setback, and the old beast had no problem recovering. The new boiler is a snail at recovering, even with it's "boost" turned on (the boiler setpoint climbs 10 degrees every 20 minutes if the thermostat has not been satisfied). Is there a way to make it recover quicker in the mornings?

3) Should the post purge be active with a boiler using a concentric vent out the side?

My mindset is from an ancient technology; what's the most economical way of running this?

Thanks in advance for your insight.
 
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Old 12-07-11, 12:47 PM
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Hello TBurr,
Sounds like an Alpine would have been the better fit.

140,000BTU firing is a whole lotta' boiler.
Does the house really have that big a heat loss?

If there is a way to increase the differential, i'd try it.

Likely it will cycle less whenever it really gets cold out this season.

As far as a "hefty"setback goes.. probably 2-3 degress is more workable.

What about starting the return from set back an hour or two earlier in the morning?

Does the post purge refer to running the circulator to move the heat out of the boiler?


Peter
 
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Old 12-07-11, 03:24 PM
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I agree that seems like a lot of boiler. How many sq ft is your home?
I also agree on getting away from such an aggressive setback due to outdoor reset. The odr will save much more than night setback will.
Increase the high limit differential.
Pump post purge will not help as the boiler is not controlling the pumps.
Have your contractor check the manifold gas pressure. I have seen many natural gas gas valves set on the high side from Honeywell. I put a furnace in mom my mother and her manifold pressure was 4.0 and it called for 3.5" w.c. It is not a huge deal but it all helps.
 
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Old 12-07-11, 04:30 PM
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Gee, unless something's changed the boiler is rated 120k. It does a good size two story home, although one zone (a mere three rooms) is kept much warmer than the other. With an empty nest now it's almost time to downsize.

What would you suggest I set the differential to? It's at the default setting of 15. I did increase the boiler temperature to settings of 145 low and 195 high. The default of 130 barely made the baseboards at the end of the loop warm. I thought it best to increase both ends at the same time, so I increased both by 15.

So with this boiler it's preferable to have the night setback at 62 while days is 65? In the past we've been able to effectively turn the heat off by setting it to 50. I'll try both ways and monitor the meter. That would be an unexpected luxury. All this new fangled stuff!

And yes, the boiler does not control the pumps. Could I disconnect the jumper between ZC and ZR on the Taco device, and feed the yellow wire in the boilers terminal box to ZC? It looks like ZC only supplies power to the the relay series. The rest of the box would still be powered by house current. Would that enable the post purge, or blow up in my face?

Will also look into the manifold pressure. I don't believe they did that, or any kind of testing.
 
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Old 12-07-11, 05:25 PM
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Is it typical for this model to cycle so frequently?
One thing that could affect the cycling is the fact that the old boiler was probably 2 or 3 times as much cast iron, thus able to store more heat in the metal itself... so the burner would fire (probably longer than the new one) but be off for a longer time as the heat was extracted from the cast iron.

The thing about replacing older boilers... back in the day nobody really thought much about installing the 'correct size' boiler. Fuel was cheap. They just slapped a 'big enough' boiler in and 'gotter done'.

I would say that nearly EVERY boiler that was installed 'back in the day' was 2 or 3 times the BTU output it needed to be. So, an installer comes in, looks at the old boiler and orders a new one the same size without doing an actual HEAT LOSS calculation on the building, and BAM! you're stuck with a boiler 2 or 3 times the correct size for the next 20 years or so.

Ideally, the boiler output should match the actual heat loss of the building on the coldest expected days of the year. This is known as the DESIGN TEMP.

As example, my home built in the 50's, a little under 2000 sq feet, has appx the same size boiler as the one recently installed in your home. 140K GROSS (check the specs on yours, you will see the gross rating is higher than the 120K figure)

Doing the heat loss calculation revealed that my home has a 'calculated' heat loss of around 65-70 KBTU. And the reality is that the ACTUAL heat loss arrived at by 'clocking' the amount of fuel burned is only a mere FORTY KBTU. The heat loss programs have a little 'windage' built in to them too.

Bottom line is that my boiler is about 3 times as big as needed!

So, how many square feet is your home?
 
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Old 12-07-11, 05:26 PM
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Hello TBurr,
So no heat loss then?

How many sq ft is the house?

140,00 btu if the firing input rate
120,000 is the output

I know my house is very well insulated.
At 3000 sq ft my 66,000 output btu boiler is too big.

So ya, 140,000/120,000 btu's is a whole lotta boiler from my view.

I'd set the differential at 30 degrees, and see what happens, unes RBeck has a better idea.

IMO it is an error to turn up the boiler temps.

Let the out door reset do it's job.

If the end room is cold, there are other ways to balance the heat.

Peter
 
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Old 12-07-11, 05:36 PM
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IMO it is an error to turn up the boiler temps.
I agree...

Read up some on how the OutDoor Reset does it's job. Once you understand the concept, it will be easier to let go of the past!

Start here:

Outdoor Reset Explained

Save on Your Heating Bills

then Google around a bit and see what else you can find.

Old habits die hard... trust me, I know about old habits
 
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Old 12-07-11, 05:42 PM
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Turn the high limit down to 180f again.
You mentioned you raised the low to 145f. Is that low boiler water temp or minimum boiler water temp?
Forgetting all else the question would be, before any settings were changed did the boiler heat the home?
What type of radiation do you have?
How many zones are in the home?
If you are using a multi-zone relay the post purge will do nothing for you. The thermostat will stop the pump through the relay.
I don't have a problem with a wider differential.
BTW my house built in 1978 has a heat loss of about 40k and is 2800 sq ft. The heat loss is even less as I just added 9" to the attic.
 
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Old 12-07-11, 05:50 PM
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Almost forgot....,

The thermostat, what kind is it?

What is the cycle rate, or differential?

Most Honeywell and Lux programmable thermostats have a way to set the cycle rate. They almost all come out of the box set for electric heat or forced air.
I have mhy Honeywell set for the next to widest setting,. It is done on mine by screws on the bottom. The Lux i have is done in software, by degrees.





Peter
 
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Old 12-07-11, 06:19 PM
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The room that had the "cold" baseboard, was the air temp itself cold or did you just put your hand down at the baseboard and figure that it wasn't working because you didn't feel any heat coming out of it?
 
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Old 12-07-11, 06:51 PM
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An extensive heat loss was done. For the two floors of occupied living space, the bottom line was 86,239 BTU/Hr. It's a big balloon frame house that's been insulated with cellulose and otherwise improved (and that made a big difference) but still drafty like the devil and the floors and ceilings remain cold - I'm convinced that strong wind still blows through the second floor framing that's been sealed. Balloon framing is like a big letter "H" where the studs go from the sill plate to the roof and the second and third floor joists are supported by sleepers on the side walls. Makes it real easy for an electrician to snake a wire from the basement to the attic and for fire to spread.

The system was designed to accommodate expansion into the attic and there's also a big heat exchanger in the garage/workshop area. There are three stubs on the manifolds for future expansion. The garage/workshop has a valve that taps off the house main zone. Those were gray areas. Bottom line come winter, the demand will likely be there.

I set 145 as the LB minimum setting for the water that will circulate. I don't know what the LT (minimum boiler temperature) does and it's unchanged.

If you are using a multi-zone relay the post purge will do nothing for you. The thermostat will stop the pump through the relay.

We are using a multi-zone relay box and if the boiler provides post purge power after the thermostat is satisfied, it would seem that the yellow wire in the boiler that provides power to the circulator would continue to power it for the set number of minutes after the call for heat ends. Likewise, if that yellow wire powered the relays that control the circulators, it would seem that post purge would be active. Am I missing something? Thus my query about connecting the yellow wire to the zone control ZC as described earlier, something which might make the post purge functon.

The place has low end Slant Fin baseboard, like they sell at the big orange store. There are no bleeders, valves or ways I know of to control the output other than to close the cover. One zone covers three rooms that are mostly occupied, the rest of the house is on the other. We keep the three rooms warm and the rest of the place is chilly. An electric baseboard heater supplements the heat in the one room of the second zone that we use. It's likely a lot cheaper to spend 20 cents an hour for that than to heat the whole house. The second zone maintains about 55 degrees 24/7. We have yet to even turn that one on this season. There are circa 1997 Honeywell thermostats with 7 day controls set for the right type of system. I think there's about a 2 or 3 degree range.

Good point on the upper end setting. Not having a need for it, I shouldn't have changed it. However, the old boiler on really cold days had to be set to 200, so it's likely going to be requiring a change. But I'll give the 180 a try. At the setting of 130, the heat output at the end of the loop was negligible, even to the touch and the area was chilly.

I boosted the differential to 25 wanting to make change gradual. Curious what it was when I had the old Beckett Heat Saver (Manager?) connected. Sure liked what that did.

Should the heat loss calculation match the input MBH (which I see now is 140k),the DOE capacity (120) or the water ratings (104)?

Tried keeping this concise.... I've updated this with more information that was asked for.

Thanks again.
 
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Old 12-07-11, 08:04 PM
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The low boiler and high boiler temperature are used to set the slope for the ODR. This is drawn on a graph with water temp vs. outside air temp. These settings determine what the set point for the water temperature should be based on the current outside air temp. The min boiler temperature is a setting that doesn't allow the set point to be set below. For example, if the min boiler temp was set to 120 degrees and the ODR slope called for 110 degrees, the boiler would still heat the water to 120.
 
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Old 12-07-11, 08:47 PM
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If you want to take a short cut in setting the outdoor reset heating curve ,turn all the thermostats all the way up and set the design temperature to that recommended for your area.After the building is above the comfort range adjust the heat curve up or down until the supply water temperature will keep the building a few degrees above comfort level. then use the thermostats to fine tune the room temperature.The control will then adjust supply temperature as the outside temperature changes.No need to due a complicated heat loss calculation unless you are putting in a new heating system.
 
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Old 12-07-11, 09:32 PM
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That's a 'short cut' ? Sounds to me like it would take hours and hours waiting for the building to come to temp, then to trial and error with the heating curve, then hours and hours of waiting for the temp to 'stabilize' a few degrees above the 'comfort level'.

And all this while, wasting fuel overheating the home...

Yeah, I can understand how it would work... but don't agree that it's any kind of 'shortcut'...

and the 'complicated heat loss' has already been done anyway.
 
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Old 12-08-11, 02:17 PM
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I suppose it may not be a short cut, the method that results in delivering the lowest possible temperature water to the building will be the most comfortable and save the most fuel, just physic.
 
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Old 12-09-11, 01:47 PM
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So, back to the initial query for a moment....

What's an ideal typical cycle run time for this boiler? Should it run for 30 seconds, be off (of with the circulator going) for 20 seconds and then come back on for 30 seconds and off for 20? Or run for a few minutes and rest several like the old monster did, or what?

Also, I've noticed the circulating water thermometer at the supply connection reads about 10-15 degrees cooler than the boiler water temperature LED display (not the set point temperature). Is that typical, or could the water be running through the boiler too fast to pick up the heat it's generating?
 
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Old 12-09-11, 03:20 PM
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It should read fairly close. The temperature from the LED display is taken from the top of the heat exchanger. This is where the aquastat gets its data from.

If your boiler is cycling on and off every 30 seconds, that is too much. It sounds like your boiler is grossly over sized. It should run for a several minutes and be off for several. Can you take pictures of your boiler and the piping around it and post it for us to see online?
 
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Old 12-09-11, 04:42 PM
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This time of year a 5 minute run time would be good but when it gets colder 10 minutes and cold weather around 20 minutes.
Back to the yellow wire. The thermostat pulls in the relay to run the pump. When you wire the yellow wire to ZC you are supplying voltage to the relay for the pump. Once the thermostat satisfies the relay opens and no matter where the voltage comes from for the pumps the pumps will shut down. The post-purge will not work with a multi-zone relay wiring yellow wire to ZC.
If the pump was moving the water too fast it would run longer cycles.
 
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Old 12-09-11, 05:22 PM
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Should it run for 30 seconds, be off (of with the circulator going) for 20 seconds and then come back on for 30 seconds and off for 20?
Good gosh, NO!

If it's doing that, something is terribly wrong!

Is that what it's doing or are you just using an 'example'?
 
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Old 12-14-11, 06:51 AM
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On Cycles

The boiler LED now display reads 71 hours and 986 cycles.

Or, a quick calculation shows in 4260 minutes that's a cycle every 4.32 minutes. Sometimes it cycles very quickly, other times it might actually run a few minutes. Is that frequency typical? It seems like a lot.

I have noticed that if the boiler reaches a set point of say, 150, that the thermometer at the supply side is consistently about 10 degrees cooler and would read 140. Which means that by the time that 140 water returns about 15 degrees cooler at 125, with a differential of 15 or 20 (was 15, now 20) it's going to start the boiler right up. Would doing something to slow the flow so the water in the boiler has a longer time to absorb the heat be beneficial?

I tend to keep just one zone on, it's about 75' of baseboard on the first floor, and is powered by a Taco 007.

Given up on the post purge, rbeck made it perfectly clear thank you, although it does sound like a good thing to have.
 
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Old 12-14-11, 04:31 PM
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Or, a quick calculation shows in 4260 minutes that's a cycle every 4.32 minutes. Sometimes it cycles very quickly, other times it might actually run a few minutes. Is that frequency typical? It seems like a lot.
I repeat,

Good gosh, NO!

If it's doing that, something is terribly wrong!
You need to call the installers back and get that fixed...
 
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Old 12-14-11, 07:07 PM
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That is better than many. If the heat loss was 86,239 btu's the boiler is one size too big. The ES4 would have been a better choice. The ES5 at 120k DOE output vs the ES4 at 90k DOE output.
This changes the flow considerably. One zone of heat on the first floor with about 75 ft of baseboard. i hope that is cover and not element. The maximum btu's for 3/4" pipe is 40k. If the element is 75 ft that puts the btu's requirement at about 45,000 btu's. This is not terrible but still a load on 3/4" pipe.
A 3/4" pipe will usually flow about 4 gpm. The ES5 needs to flow about 12 gpm. If it were the ES4 it still would need 9 gpm for 20f delta-T. The minimum flow in these boilers are 6 and 4.5 respectively. At minimum flow this is a 40f delta-T. That means what ever the return temperature is the boiler will raise it by 40f. This will pick up the system temp quicker, thus short cycling. You would not want to slow flow but increase flow to extend run time.
I would try to increase the differential even more.
You could decrease the boost time or use less setback. ODR and setback don't play well together. I would not set back more that 3 degrees if at all. If I was to choose one over the other I would choose ODR hands down. It will save much more than night set-back.
 
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Old 12-20-11, 07:30 AM
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Follow up

Had a nice chat with the installer yesterday, and he firmly stood his ground against my concerns.

On the pressure, when cool it's around 21psi and when operating around 26psi. The pressure regulator is fed into the return pipe, the expansion tank is on the supply side and mounted on a dead end stub before the Spirovent. The expansion tank is also cool to the touch, only being hot at the very top for about 2" out from the connecting stub. I think it's hot there only because of convection from the heating pipe. It's been adjusted to 12 three times, and quickly goes back to the 20's. He tells me the high pressure is a good thing as the system will run quieter. Why is it important to have the pressure at 12? I see looking online that it might need to be higher for some places, but this is providing only heat to the first floor level.

On the short cycles, he states it's good that it's doing a cycle every 4.5 minutes, and that of course since the return is about 20 degrees cooler than the supply that it will start a new cycle right away. He had no concern that the thermometer at the beginning of the supply run was 10 degrees cooler than the boilers reported temperature as (1) the gauges are in different places and (2) the gauges are known to be inaccurate. I've verified the lower reading with an IR thermometer; it reads a few degrees lower than the dial thermometer and I need to account some for the surface it's reading from. As posted earlier, with the supply water being 10 degrees cooler than the reported boiler temperature, and the return being 20 degrees cooler than the supply, the boiler is running almost all the time the thermostat is calling for heat.

The suggestion of changing the night setback to a few degrees has worked well; I set it back 5 degrees at night and will see if the thermostats ability to learn when to start from a recovery will fill the void.

On the post purge that doesn't work with the controls installed, I can buy some time delay off relays for about $20 each and they'd be easy to install. Would that be worthwhile to install now for a system that will be in place many years, or should I forget about it? The post purge continues to run the circulator for a set number of minutes after the thermostat setting is met so as not to lose the benefit of whatever hot water remains in the boiler.

Should we be concerned with the high pressure and frequent cycling?

And rbeck was right... the proposal, specs and invoice I have are for a 5 and that's what I posted was here, but a 4 was installed. He commented that would have been a better choice.

This is all part of a learning curve with the new technology and I appreciate your help understanding it.
 

Last edited by TBurr; 12-20-11 at 07:50 AM.
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Old 12-25-11, 06:55 AM
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I know this thread has gotten long, and appreciate the help understanding how the new system functions.

Would really appreciate some help with the last bit, as I really don't understand the integrated fluid dynamics and functions. I'll summarize two unanswered questions:

1) The pressure remains high at 22 cold and 26 when operating, and the installer has been unable to reduce the pressure via the regulator. He now tells is it's a good thing that it's high.

Contrary to the installation manual the cold water supply is fed into the return, and the expansion tank is mounted on a 16" dead end stub before the Spriovent on the supply side. I'm thinking the expansion tank is air locked. Would that design maintain the pressure at a high level? If not, what else could be causing it and is it really good that the pressure is higher than called for?

2) The boiler can reach it's goal of, say 150 and stop firing. The thermometer mounted on the supply side where the water exits the boiler will read 140; it's always read 10 degrees lower than boiler temperature. The return water is 20 degrees less at 120. Since the differential is set to 25, the boiler fires up again with almost no pause. It's been doing a cycle once every 4 1/2 minutes. Is that an efficient way of running the boiler, or are the short cycles detrimental?

Thanks again for help understanding what's going on.
 
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Old 12-25-11, 07:46 AM
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1) The pressure remains high at 22 cold and 26 when operating, and the installer has been unable to reduce the pressure via the regulator. He now tells is it's a good thing that it's high.
The 'pressure reducing valve' is a simple device. There should be no reason that a skilled technician can not get that adjusted properly. If this was a new installation, there should have been a new valve. That valve was PRESET from the factory to 12 PSI and those things don't really need adjustment. They are pretty rugged little devices...

Telling you 'it's a good thing' is his Martha Stewart impersonation and his way of getting out of there without correcting any problems that may exist.

It's been doing a cycle once every 4 1/2 minutes.
I've said it before, and will again... if the boiler is behaving in this manner continuously, 24/7, then there is SOMETHING WRONG!

Don't worry about the length of the thread... it's not a problem... we want to help you get this fixed.

Have we asked for pictures? If you can, take a whole bunch of in focus, well lighted, and large enough for old dudes to see pics... upload them to a FREE account at Image hosting, free photo sharing & video sharing at Photobucket and come back here and place a link to your PUBLIC album. It may help if we can see the installation.

P.S. it's not at all likely that the expansion tank is air locked, and it's only hot on the top because when the water is heated and expands, it pushes into the tank, exactly as it should.
 
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Old 12-25-11, 07:55 AM
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The boiler can reach it's goal of, say 150 and stop firing. The thermometer mounted on the supply side where the water exits the boiler will read 140; it's always read 10 degrees lower than boiler temperature.
This is 'probably' OK. It's not at all uncommon for a boiler mounted gauge to disagree with a supply pipe mounted gauge. There are temperature differences inside the boiler from place to place.

Since the differential is set to 25, the boiler fires up again with almost no pause.
With a 25 diff, the boiler should not fire again with 'almost no pause'.

The water should cool by 25 before the boiler fires again. This should take some time!
 
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Old 12-26-11, 07:46 AM
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The pictures would be good. As far as the pressure problem you stated it feeds into the return side of the boiler. While this is not the best place to feed the boiler is this make-up water before or after the pump. If the line-up starting from the make-up on the return is Make-up, circulator, boiler, expansion tank this could add to your pressure problem. The make-up on the inlet side of the pump the PDV will feed water every time the pump starts until it equalizes and this stops happening. Thus always having a higher system pressure. Is it piped per the I&O manual?
 
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Old 12-26-11, 02:21 PM
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No, it is not piped according to the manual. I think these pictures will save a thousand words:

Pictures by TBurrPictures - Photobucket

It's missing the purge valve on the supply, some unions and both isolation and ball valves. The circulators were supposed to have a valve on both sides. No bypass.

I think this is right:
Supply outlet > pressure/temp gauge and pressure relief valve > T with expansion tank dead ending on one side and Sprirovent on the other > circulator > flow check > ball valve > heaters > and on the return side a hose bib > ball valve > return inlet with supply water feeding into boiler after a fill valve.

I posted a general number before and have since measured. Zone 1 goes to 61 feet of baseboard Slant Fin aluminum fin elements and zone 2 goes to 44 feet of element with a total of 105 feet of element. The exposed pipes in the basement are insulated with 1/2" foam.

I checked the setting on the Watts B1156F and it's appears set to the lowest possible pressure - the adjustment is about 2 threads in from falling off. Can also figure out a way to fill the zones, but it's a far call from what's described in the manual.

Will be happy to add photos of anything you'd like and look forward to your comments.

Thank you.
 

Last edited by TBurr; 12-26-11 at 03:02 PM.
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Old 12-26-11, 02:59 PM
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Originally Posted by TBurr View Post
Zone 1 goes to 61 feet of baseboard Slant Fin aluminum fin elements and zone 2 goes to 44 feet of element with a total of 105 feet of element.
An extensive heat loss was done. For the two floors of occupied living space, the bottom line was 86,239 BTU/Hr

Read more: http://www.doityourself.com/forum/bo...#ixzz1hgDH8D66
Most baseboard is 5-600 btu per foot.
If the house has a heat loss of 86,000 yet it only has 55-60,000 btu's worth of baseboard, something doesn't add up.

I don't know how puttng 120,000 btu's of output into 60,000 btu's of radiation is not going to cause short cycling, especially given average weather, the house is probably only needing
25-30,000 btu's and all this is only if both zones are calling at the same time.

Again i'f try and widen the differential to 30 or even 40 degrees.




Peter
 
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Old 12-26-11, 03:11 PM
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Yes, that is correct.

The Taco zone controller has four zone capacity. At this time two zones are connected for the first floor. There will another zone added for a heat exchanger in the attic which will supply the second floor and also a "microzone" will be added to an unheated part of the house as a fourth zone.
 
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Old 12-26-11, 03:11 PM
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It's missing the purge valve on the supply, some unions and both isolation and ball valves. The circulators were supposed to have a valve on both sides. No bypass.
None of these things are really show stoppers though I don't think... mostly things to make maintenance and service easier... at least they certainly don't account for the pressure problem. Not at all familiar with this boiler, that's rbeck's territory, but with fin-tube baseboard, the bypass is probably not needed either.

But the pressure problem is secondary to the fact that the thing is just sitting there cycling 24/7...

You've got two zones... the thermostat wires are the white ones leading into the Taco panel, correct? and both pumps are wired to this panel, also correct?

Inside that panel box, there are 'X X' endswitch terminals.

On the boiler control panel are a pair of ' T T ' terminals.

Are the X X in the Taco wired to the T T in the boiler?
 
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Old 12-26-11, 03:16 PM
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Yes, wired exactly as you described. Can add photo if you'd like.
 
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Old 12-26-11, 03:16 PM
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Did you mention whether or not your system has any of the optional modules installed?
 
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Old 12-26-11, 03:20 PM
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If you disconnect one of the X X wires in the Taco box, does the boiler continue to cycle incessantly?

Sure, pics are always good...
 
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Old 12-26-11, 03:21 PM
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The ESC 4N has an ODR installed.

Just posted a picture of the Taco box for you. With an X wire disconnected, the boiler shuts off while the circulator continues.

Pictures by TBurrPictures - Photobucket
 

Last edited by TBurr; 12-26-11 at 03:47 PM.
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Old 12-26-11, 03:59 PM
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I just scanned through the entire thread... I'm still not very clear on the nature of the 'cycling'.

Since disconnecting the X to the boiler shut it down, then we must presume that it's not a problem with the boiler controls themselves keeping the thing running... the circulators should continue to run in this case though... the Taco is running those.

I need to recap a little bit.

1. Is the boiler cycling in this fashion whether or not there is a thermostat calling for heat?

2. You mentioned at one point, "on for 30 seconds, off for 20" . At what point in the heating cycle do you see this behavior?

3. There's a 'glare' on the 'master/slave' switch in the Taco panel, that is pushed to MASTER, yes?

4. Peter said:

If the house has a heat loss of 86,000 yet it only has 55-60,000 btu's worth of baseboard, something doesn't add up.
And this would certainly explain why even with the old system you had to push the temp up when it got really cold. It's not inconceivable to me that a balloon framed building could have a higher heat loss even if inuslated... and will also explain the reason for slow recovery from deep setbacks with the new boiler.

If you do in fact have 86K heat loss, and only 60K of installed emitters, not even a nuke plant in the backyard will keep the home warm on a 'design day'.

5. You have said that you adjusted the diff to 25 yet the boiler still re-fires almost immediately. Have you observed the temperature gauge on the boiler when this happens? Does the temperature in fact drop 25 degrees before it re-fires?
 
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Old 12-26-11, 04:05 PM
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Originally Posted by PeterNH View Post
Most baseboard is 5-600 btu per foot.
If the house has a heat loss of 86,000 yet it only has 55-60,000 btu's worth of baseboard, something doesn't add up.

I don't know how puttng 120,000 btu's of output into 60,000 btu's of radiation is not going to cause short cycling, especially given average weather, the house is probably only needing
25-30,000 btu's and all this is only if both zones are calling at the same time.

Again i'f try and widen the differential to 30 or even 40 degrees.


Peter
I thought this was established very early on in the thread. What exactly are we discussing at this point?

After rereading post #11, where you say that the old boiler had to be boosted to 200 degrees on really cold days makes me think that you may be short on radiation. So PeterNH's latest comment about you only having 60,000 BTU's of radiation and with your stated heat loss of 86,000 says there is a problem here. Even so, 120,000 BTU output on your boiler is way too much for 86,000 heat loss. It's also double what your radiation is capable of putting out. And if only one zone is running, forget it. This is why your boiler is cycling too much. It's way too big.
 
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Old 12-26-11, 04:11 PM
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Originally Posted by TBurr View Post
The ESC 4N has an ODR installed.
l]
Ahh If we can get all the specifics on the
ODR cntrol settings...
I have one other question:
Earlier you mentioned:

there's also a big heat exchanger in the garage/workshop area. There are three stubs on the manifolds for future expansion. The garage/workshop has a valve that taps off the house main zone.
Which zone is the connected to?
What are th epipes sizes for the zone and the heat exchanger?
Is this connected at this time?
Does it run automatically?

IMO if this is part of one of the zones, then it is going to raise heck with the ODR control.


Off to read about the Burnhom ODR,
Peter
 
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Old 12-26-11, 04:33 PM
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Some things are getting confuzzled... here's a quick summary that will save a lot of look back.

Pictures by TBurrPictures - Photobucket

It's a model 4 boiler with a 90k output. The proposal and invoice were for a 5, but a 4 was installed. It was my error to post that it was a 5; I simply took the information off the paperwork.

It will have four zones, two are in use now for the first floor and others will be added for the second floor. The first floor heat loss is 63k. The second floor heat loss is 23k, and it has it's own heating system. We'll eventually be scrapping the second floor system and running it off the new boiler - but there's a bunch of things that need to be done before that happens. There are other things that can be run off the boiler, but since they are not turned on, and aren't really in use, they're not part of the picture. That's all part of the joys of an old house that's been hacked and merged over the years.

Currently two things:
1) High pressure
2) Short cycling

I can't explain anything about the high pressure other than it's just there, and don't understand it's implications.

On the short cycling, it appears the boiler is reaching it's set point of, say 150. It shuts off, the circulator continues as expected. The thermometer at the supply fitting typically reads about 10 degrees less than the set point. The return temperature is about 20 degrees less at 120. The temperature within the boiler rapidly drops as the cooler water enters, and it quickly starts up again. It's doing this as long as the thermostat is calling for heat. Other than to change the velocity, I wouldn't know how to alter that. There have been times it has rapidly cycled (less than a minute on/off) and it's display indicates it's doing a cycle every 4.2 minutes.

The ODR differential has been increased to 25 and the low water temp for the boiler has been increased to 145. Everything else is at default settings.

We've taken advice from this board and changed the night setback to 5 degrees, a bit more than suggested but am hoping the smart thermostat makes up the recovery difference. And that works much better.

I asked about the burner's post purge and have learned it is incompatible with a two zone system. But it still sounds like a good thing to have and maybe someday will try "Trooper's Circulator Post Purge "Mod"" posted on this site.

So, is the high pressure of concern and what would you recommend? After repeated attempts to reduce it the installer reports it's fine as is. Could it be high from the way the system is set up - it's very different from the install manual - and maybe just not an issue he'd like to face?

And is the cycling to be expected, or detrimental and is there anything I can do that would be beneficial?

Finally, as long as pictures are posted, is there anything that would improve the system?

Thanks again.
 

Last edited by TBurr; 12-26-11 at 05:06 PM.
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Old 12-26-11, 05:01 PM
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I am not convinced at this point that you have ODR. This is an optional plug in module with a wire going to an OD sensor. The ODR module is not where the differential is located. the differential is located in the IQ control. If you it the "I" button once you will see "bt". This stands for boiler temperature. Hit the "I" button one more time and you will see "SP". This stands for Setpoint Temperature. If it is lower than 180 I would be sure you had ODR module.
The higher pressure is not a problem except that higher pressure holds more oxygen.
the adjustment is about 2 threads in from falling off.
If the PRV is screwed in almost all the way the pressure is increased. The longer the screw is out the lower the pressure. Loosen the nut and back it out. Take some water out of the system and see where the pressure stops at.
 
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