Undersized boiler

HomerJSmith

Neal, I looked at your photo. It's neat the way you click on it and it expands. However, what a mess. I realize that the boiler is added to a older system. Never the less, all the leaking fittings should have been repaired at the time of the boiler install. This was obviously put together by a plumber and not a hydronic specialist and mistakes should have been corrected. You really don't have a primary-secondary system.

The fact that your inlet and outlet temperature are so closely matched tells me that something is amiss in the heat transfer.
Neal, get a IR thermometer and shoot the incoming and out- going pipes on the BB on each circuit and see if you are really getting the heat you are suppose to be getting. You can also shoot the system set up and look for temperature anomalies.

If your system design is incorrect, the output to the BB will be incorrect.

Download Caleffi's Idronics #19 and look at proven hydronic distribution system designs. Idronics is a college course in plumbing engineering. Thank you, Caleffi and 'Hot Rod' for your great contribution.

A badly designed system is only going to work marginally. You got the horsepower, you just can't get it into gear.

HomerJSmith

Neal, I don't know how cold it get in Maine. I reside west of the Rockies. Glycol freeze protection down to -30 degrees, pumpable to -40 degrees probably has a concentration of glycol to water ratio of 40-45 percent. That greatly impacts system design. I just pulled out my Taco book and looked at the design curve for a 007 IFC circulator. At 4 gal/min you have 9.35 ft/hd. You can reduce that by 15 to 20 percent with glycol. You can add piping losses to that. Is a 007 adequate?

By the way, I never use a Taco pump in an old system only Grundfos because I can take a Grundfos pump apart and clean it if I have to. Taco pumps have cartridge that has to be replaced. More often than not, this cartridge will fill with debris and cease rotating. Your pumps maybe compromised and not delivering the full head energy to your system so the flow is compromised.

Flow is the conveyor belt that carries BTU's.

bob eck

Could the 4 Taco pumps be over pumping the system? Would it work better with 1 pump and 4 zone valves?

NealFoley

> @HomerJSmith said:
> Neal, I looked at your photo. It's neat the way you click on it and it expands. However, what a mess. I realize that the boiler is added to a older system. Never the less, all the leaking fittings should have been repaired at the time of the boiler install. This was obviously put together by a plumber and not a hydronic specialist and mistakes should have been corrected. You really don't have a primary-secondary system.
>
> The fact that your inlet and outlet temperature are so closely matched tells me that something is amiss in the heat transfer.
> Neal, get a IR thermometer and shoot the incoming and out- going pipes on the BB on each circuit and see if you are really getting the heat you are suppose to be getting. You can also shoot the system set up and look for temperature anomalies.
>
> If your system design is incorrect, the output to the BB will be incorrect.
>
> Download Caleffi's Idronics #19 and look at proven hydronic distribution system designs. Idronics is a college course in plumbing engineering. Thank you, Caleffi and 'Hot Rod' for your great contribution.
>
> A badly designed system is only going to work marginally. You got the horsepower, you just can't get it into gear.

Thanks for the input. I wish I had recourse to get the company that installed this system to make it right. But they installed it for the previous owner who used the house part time.

As far as I know this whole system was installed at the same time. I'd have to check back at the records tho.

Everything about this system screams cobbled together by apprentices.... (Despite the work being by one of the leading local heating companies....) Especially the un insulated Pex in the crawl space. In fact, when the owner complained that those zones didn't get the house warm the company sold her two propane wall heaters.....

The system I built myself at my last farm was simple, elegant and effective--- gasification boiler heating 1000 gallon water "battery" in the cellar and three panel radiator zones and dhw running off of exchange coils.

I think for now I'll make due with what's here and plan for improvements in the spring, starting with panel radiators and possible new home runs.
I think I'd go with 4" insulated Pex pipe in the crawl space and no glycol.....

HomerJSmith

Neal, this is what pisses me off. So many installers never document their installs. I know it takes work to do so and I was laxs in this regard in my younger years, but having gone on so many repairs and cursing the installer for lack of information while I analyze the system, trying to figure out what's wrong.

You can maybe use test strips to give you an idea of the concentration of glyco. Hercules makes test strips or buy a cheap refractometer ($15) on Ebay or Amazon or send a sample to Rhomar for testing.

I have a feeling that your's is a simple fix. You don't come off a circulator with a 90 ell and then make another rapid change in direction. If it were me, I would fix the delivery system first and then see where I am in the heat output area. After all, you can put lipstick on a pig, but deep down it's still a pig.

HomerJSmith

Correction! "I have a feeling that your's is (NOT) a simple fix."

HomerJSmith

Neal, I looked at your photo again. It appears that it is a primary secondary system with hydrolic separation with closely spaced tees. A Caleffi Hydrolink would have worked a lot better and uncomplicated the piping. Are there any ghost flows in this system? Are you sure all the air is evacuated out of the BB?

The Spirovent should have been checked and cleaned or replaced on the boiler install. Is it evacuating air out of the system? It looks corroded. I have had situations where the mesh was coming apart and the vent was plugged.

HomerJSmith

If I were to make a guess, I would say it is an old system with a new boiler.

Gordy

@HomerJSmith what leads you to the assumption each zone needs 40k btus? 4gpmx500x20dt=40k

There is only enough radiation for 64k all zones together unless I missed a post.

If over pumping I doubt you’ll see the 20 delta even at design.

I say the system is over pumped, and that’s why the supply/return delta is so narrow.

Ironman

NealFoley said:

> @Ironman said:

> Neal,

> Can you post another pic from a little farther back?



It's in a tight cellar access. That's as far back as I can get without the door being in the way...

>

> It looks like the boiler pump is pumping into the house manifold instead of away from it. That's a big mistake, though it may not be obvious to many. You're probably not getting sufficient flow through the boiler when multiple circs are running.



I wondered about that. Is it right that the pump leg is tied to both the outgoing manifold and the return?. Not how I would have done it....



If I can, will switching the pump around help?

The pump should be in the line below it pumping into the boiler.

HomerJSmith

Gordy, a delta T of 20 is good for boilers, 30 even better. I've seen a delta T of 40 and it worked fine. One does want to prevent short cycling. My reasoning is this.

Neal has plenty of BTU's. It is only a matter of getting it into the house envelope. He has a fixed amount of BB. How do you increase the emission in to the house? Only three ways. Time, flow, temperature. The longer the time heated water flows thru a zone, the more BTU's are transferred. The faster the flow, the less variation in the temperature of the water between the first heat emitter and the last heat emitter. As I remember, my old tables for Fineline 10 E-75 had flow rates for 1 gal/min and 4 gal/min. There were significant increases as the flow increased. There is a limit to flow, where an increase in flow will reach a point where the is less of a transfer of BTU's from the water to the pipe. 4 gal/min is a safe bet. 3/4" copper at 4 gal/min has a velocity of 2.94 ft/sec. Well less than can create erosion. Although, the Head Loss is 6.16 fthd per 100ft is much higher than 1/2 fthd at 1 gal/min. Neal's circulators 007 at 4 gal/min can only deliver 9.35 fthd. Other pressure losses in the system may be such that he doesn't have enough head energy to even get to 4 gal/min. As the Temperature is increased the amount of BTU's released over time increases. Sure, the boiler may not be operating in the condensing mode as well as if the return water was 120 deg., but I thought we were looking for comfort this winter season.

Neal, I understand that you have one zone that is a bifurcated zone and controlled by a Honeywell zone valve with one 007 pump. What happens in this situation without balancing valves is that when both branches are calling for heat, the shortest branch get the greatest flow, in effect starving the longer zone of BTU's. Could this be Happening? Is one of the bifurcated branches cold?

HomerJSmith

Neal, regarding on whether it is better to pump into or away from the boiler. The old cast iron reservoir boilers had about 1/2 fthd thru the heat exchanger. It really didn't matter which end you pumped. Slantfin, Crown, etc mounted their pumps on the input to the boiler. The mod/con boilers all seem to pump in to the input to the boiler and my rule of thumb is to pump into the highest pressure loss. That would be your boiler. I don't know if you changed it, if it would make a difference as I have only done it one way, but I suspect it may. It would certainly improve your piping arrangement. If you change, remember to keep 12 diameters of straight pipe on the input to the pump and 5 diameters of straight pipe out of the pump before making any direction changes. If it were me I would certainly do it. Keep the closely connected tees on the secondary piping for hydrolic separation.

NealFoley

> @HomerJSmith

., but I thought we were looking for comfort this winter season.

Need to balance comfort and economy. We're paying 2.89/gal propane right now.....


> Neal, I understand that you have one zone that is a bifurcated zone and controlled by a Honeywell zone valve with one 007 pump. What happens in this situation without balancing valves is that when both branches are calling for heat, the shortest branch get the greatest flow, in effect starving the longer zone of BTU's. Could this be Happening? Is one of the bifurcated branches cold?

Yes... One of the longer zones is the bifurcated zone and it is the coldest area of the house.

NealFoley

A couple better views of the system

Gordy

That's a feeble attempt at P/S piping.

Most mid/con manufactures want to pump into the boiler so the pressure differential of the primary pump is added to the hx.

HomerJSmith

Oh! Boy! Neal, you can have comfort or economy, but with this system set up you can't have both.

My wife's so frugal, you would think she was born in Scotland. My system that I installed will reach any set point, but she want to keep it at 60 degrees. I keep sneaking it up to 63. I'm married to an Eskimo and there's sno on the ground outside.

The reason to have a mod/con boiler is because of its economy, but you have to have a system designed to take advantage of that economy. Your system is a mess and I sorry that contractor did the former owner wrong.

The top 007 is labeled IFC and is the new green that Taco is using. The 3 lower 007's are the old color green and may not have an IFC. I think the top pump has been replaced. If there are IFC's, you don't need a Taco 219 flo-chek two feet away. It's a redundancy you can't afford. A Taco 219 has the pressure loss of 143' of straight copper pipe and a CV of 2.5. That's terrible. Also, the Honeywell zone valves have a CV of 3.5 and directing it into the side of a tee adds 5' of equivalent pipe. Taco ESP zone valves would have been a better choice. Your radiation is all below your heat source except for the studio on the second flr. You don't need the 219's on them because you have a natural thermal trap and they're restricting flow and if you have a 219 on the IFC you don't need it there either.

Please tell me that the installers put BB vents (coin vents) on the BB. The studio, because it is above radiation, may have air trapped in the BB. A circulator will not pump thru an air bubble.
If you have the vents, open them and release any entrapped air. This will restore flow.

Neal, I would forget the panel radiators if money is tight and concentrate of making the necessary changes in the mechanical room.

Personally, I don't think you have the flow, low flow-low heat delivery. A cheap IR thermometer would verify that.

HomerJSmith

I see turbulence all over your system. The only time turbulence is good is in the heat emitters.