System 2000, nearly double the cost of Weil McLain, is it worth it?

techforlife

o.k., I'm done. I did not think the issue here was marketing. I just wanted the public to benefit from my practical experiences.

Hot_water_fan

@techforlife can you show some before and after gallons per heating degree day for these installs?

techforlife

No, sorry, I retired last May. I don't recall anyone that saved less than 20%. The jobs that ran for H.W. tended to save the most. Between only heating 2.5 gals. water coupled with the post purge feature it stands to reason. We did a lot of high mass gravity pipe/ stand-up cast-iron jobs that had older boilers such as American standards and Ideals that saved 50% and more. Important there is the proper use of primary/secondary piping. EK supplies the hydraulic separator or high-mass kit. Sorry but I do not have access to any detailed individual customer info.

riny

@techforlife can you kindly explain primary/secondary piping for someone who has an engineering degree but no background in home heating? (although I'm learning as I go...)

I thought radiant heat was simple. Each zone is a straight loop, no branching, and the circulator is either on or off. That's how it works in my house anyway. Is there more to it than that?

jesmed1

https://forum.heatinghelp.com/discussion/comment/1845858#Comment_1845858

Here's a brief tutorial on primary/secondary from heating expert @Ron Beck :

https://www.comfort-calc.com/PS_Piping_Tutorial.cfm

Whichever boiler you ultimately choose will come with piping instructions. Some give you options like primary/secondary, or piping the usual way but adding a bypass that gives the hot supply water a "shortcut" to return straight to the boiler, thereby boosting the return temperature.

I will mention that we have two Weil McLain cast iron boilers that were NOT piped according to the instructions (the bypass was omitted) and have been running for 30 years with low return water temps (below 130 F) with no apparent ill effects. So while I am not advocating ignoring the installation instructions, I am saying that, in some cases, low return water temperatures are not necessarily fatal.

Just make sure your installer pipes the boiler according to one of the approved methods in the instructions, and you'll be fine.

Greening

We put a System 2000 in an older house with mediocre insulation. It is also our hot water supply.

The summer savings were jaw-dropping. Also, the basement was cooler, so reduced AC cost. This is not applicable to you as you are running electric hot water.

Our winter savings is high too, maybe closer to 50%. But we replaced a WW2 boiler that was failing. And added a fresh air intake. And added 2 zones so can keep the upstairs cooler.

I would highly recommend the fresh air intake. More efficient. And makes the house less drafty. And runs quieter.

»»That 2-year pay-back period quoted is not possible, especially if you are replacing a newish boiler and running electric water.

EBEBRATT-Ed

On hot water I like to use primary secondary all the time if I can.

Its just my opinion.

Todays boiler in my opinion are not as robust as the older stuff.

Todays boiler hold less water

I like the idea of keeping the heat exchanger happy so the boiler will last as long as possible.

Having a dedicated circ to just do the boiler and near boiler piping makes sense to me. You will always have the correct flow through the hx no matter what is going on elsewhere in the system. Although Pri/sec is not a substitute for low return temp protection in most cases it will provide that as well

LRCCBJ

Having a dedicated circ to just do the boiler and near boiler piping makes sense to me. You will always have the correct flow through the hx no matter what is going on elsewhere in the system. Although Pri/sec is not a substitute for low return temp protection in most cases it will provide that as well

I am going to take a contrarian view of this. The reasons are as follows:

Firstly, if the boiler is a conventional CI, there really is no possibility of providing flow that is insufficient on direct piping, so the entire discussion is related to mod-cons.

All the manufacturers for mod-cons strongly suggest P/S for one simple reason: They are deathly afraid that the installer will end up with low flow to the HX on direct piping when the boiler is at or near maximum output.

So, we install a p/s system with a Taco 007 primary pump that will flow a constant 8 GPM through the HX.

The system also has a Taco 007 that feeds four zones. With a single zone open, the flow rate is……….say 3 GPM………

Since the single zone can only dissipate 15K, the DT on that zone is only 10. If you piped it direct, the mod-con would see 3 GPM with a DT of 10. Most of them would be perfectly fine with this.

However, it is not so good with P/S:

With P/S, the secondary is flowing 3 GPM and the primary is flowing 8 GPM. 5 GPM from the primary supply must make a U turn and head back to the mod-con. So, you have a mix of primary and secondary flows returning to the mod-con that results in a DT at the mod-con of only 3.75. With such a narrow DT, most mod-cons will shutdown on limit because of their inability to modulate quickly enough to manage a DT that small.

It is my contention that 90% of the mod-cons would benefit by DIRECT piping. They do not have a magical flow rate and their "correct flow" is variable. They simply need to meet a minimum flow rate and will BENEFIT by the largest DT you can provide for them. This gives them plenty of margin to successfully modulate without a shutdown. In theory, if you must pipe them P/S, they need a variable speed pump on the primary………….then they would have the "correct flow" at all times.

The P/S demands by the manufacturers are only for their protection to prevent a warranty claim caused by low flow that is created by the installer when he selects a secondary pump. But, most mod-cons can manage with a flow rate of 3 GPM or less (some can work with 1 GPM) and it is a rare situation where a 3/4" loop will not provide that.

I never pipe them P/S…………. If I am the least bit concerned about flow rate, I'll just use a slightly larger pump. It rarely happens.