Oil Boiler ROI

@LRCCBJ, thank you, we appreciate you compliment about being extraordinary! Regarding your comment about limited thermal purge to an indirect tank, I would agree with you if System 2000 was a high mass boiler with an indirect tank with an internal coil. But it's a low mass boiler with a hot water tank heated by an external plate heat exchanger which is a game changer.

System 2000 is designed as a system, with optimized heat and hot water efficiency. The plate heat exchanger allows the tank to be heated from the top down, leaving a reservoir of cold water at the bottom when the tank thermostat is satisfied. By design, the "cold" tank reservoir almost perfectly balances with the amount of heat left in the boiler, and counterflow allows thermal purge to recover that heat so the boiler finishes cold and the tank finishes hot. You can see this description and illustration on the third page of this brochure.

@JayMcCay posted a link to the Department of Energy Lab study so the details you questioned are available. That study used ASHRAE Standard 118 for rating residential water heaters. From the study: "Termed the Energy Factor, the test method involves a direct input/output measure with the use of a standard domestic hot water draw pattern of 64.3 gallons in 6 draws over 6 hours, followed by 18 hours of idle period."

We like to be quite careful with comparisons.

Best,

Roger

Thank you for your feedback and warm comments, @WMno57 and @Steamhead . I appreciate the vote of confidence, although a steam boiler is not in our R&D portfolio right now - I don't want to start any rumors, especially in such a remarkable community of steam experts!

Best,

Roger

That is a well designed system. My compliments. Presumably you stop the purge at a specific boiler temperature as you cannot exchange anything more. What temperature would that be?

Also, is there any adjustment available by the user that allows a larger differential on the tank? The typical 7 degree differential is beyond wasteful, IMHO, and the boiler starts way too frequently. Even the Carlin 90000B2S on the Bock does not permit any adjustment to the differential. It's frustrating.

Thank you, @LRCCBJ System 2000 was a great design to start with and we’ve had 45 years to improve it even further. The boiler cools off down toward room temperature; 85F for condensing systems and a few degrees higher on non-condensing systems. Counterflow in the plate heat exchanger allows this to happen.

The tank is charged with 140F water based on the domestic flow rate through the plate heat exchanger, and that fills the tank from the top down. That makes it almost like an instantaneous water heater because the hot water is at the top of the tank, right near where it flows out to the fixtures (the rest of the tank can be cold). It only needs to heat for a few minutes before you have continuous hot water flow. The aquastat itself is more like an on/off switch set for 120F that triggers when enough cold makeup water fills the bottom of the tank, so that 7F differential does not influence cycling.

Without a hot water draw, the super insulated tank can sit idle for days without the need to be replenished. The boiler is also super well insulated, and the combination of thermal purge, low mass, and heavy insulation almost eliminates idle loss. This operating design in both hot water and heating cycles significantly contributed to System 2000 outperforming all condensing boilers in the Department of Energy study.

Roger

All true.

I "inherited" this setup and am quite pleased with it. I did have some upgrades to do for it, including the installation of the Carlin control and the timer. The tank, installed in 2004, certainly is getting to the end of its useful life. I'll find a replacement 8-10 year Bock that someone is dumping because they converted to gas.

I believe I mentioned to you that this oil setup is 1 1/2 pipe. A bit strange but works effectively. Can manage SOME air…………more than one pipe………….but still has its limits. I found its limit when I had the system open and then closed it to start the burner. A quick bleed and it was fine.

Yes, the cost of a new install by a contractor would absolutely make no sense. Just get the System 2000 and be done with it. It is identical (or possibly superior) to the system efficiency of the Bock considering the greatly increased combustion efficiency of the System 2000.

If I read this correctly, with a 7F differential, presumably the boiler will start at 113F. The difference between the top of the tank and the bottom of the tank would not be considered the "differential" under conventional terminology for a control. I agree that it is the differential between the top of the tank and the bottom of the tank.

I was under the assumption that the aquastat is at the top of the tank (to limit the output to 140F). If the aquastat is at the bottom of that tank, the top of the tank would be considerably hotter than 140F.

If the differential is 27F, the aquastat would close when the bottom of the tank reaches 113F.

This would work extremely well.

What brand would I put in my house?

To me, it would depend upon the installer I choose. I want to be comfortable with him, his choices and his training. There are many different manufacturers and none of them suck. However we all hear "don't use XX, nothing but problems. Use YY, the help me out of a lot of problems XX didn't"

Are these manufacturer issues or application issues?

Stand by your installer and the brands he uses. He or she will also use a brand that has parts available locally and can get the system up and running again if needed quickly.