Most Cost Efficient Modifications

cdrat

I have a 3-story, 3-unit apartment building in DC built in 1913. The original coal/gravity hot water system has been changed to a gas boiler with a zone on each floor. I am installing a larger compression tank and replacement relief valve and I thought this was a good time to make some changes (after reading "Classic Hydronics"; waiting to receive "Pumping Away"). The Peerless has a built in circulator on the return side, and I was hoping to improve the performance without moving it. Basically I was thinking of changing the location of the compression tank and adding an air separator. I was not sure of the importance of having the "fill" at the "point of no pressure change", and assumed (from studying this forum) that the air separator works best on the supply side. I welcome any advice. Thanks in advance.

clammy

Personally I always move the pump to the supply as prescribed in pumping away . Have your make up and expansion tank and spriovent on the suction side of your pump. I have been moving the factory location on the return to the supply for over 20 years and would never think of installing any other way . With the pump on the supply you will in effect be using the pump displacement to your advantage in which will improve your system distribution ,in every case which I moved the pump on boiler replacements and jobs w constant air issues there fuel consumption had decreased and all air and distribution issues where gone . If you are using an mod con boiler them a boiler pump is usually required due to the pressure drop across the boiler in which case it should be piped primary secondary . If it’s a standard cast iron boiler then move the pump to the supply be sure to add some isolation valves for your pump and make up water and expansion tank . Have you performed a heat lose to ensure your boiler is not oversized and if a high mass high water volume then possibly consider some return temperature low temp protection w possibly a system bypass or a simple danfoss thermic valve w a 135 degree element to protect your boiler from both thermal shock and prolonged low return water protection which will ruin your masonry chimney and increase the chances of condensation being formed on the cast iron heat exchanger . It s great that your educating yourself w some of dans books be sure to read them at least twice cover to cover to ensure both your understanding the reasoning behind pumping away . I still work w guys who refuse to change and leave the pump where it is and later deal w issues . While I prefer to do it once and have no issues . Peace and good luck clammy

cdrat

Thanks Much for your reply. I am going to have to look into how to mount the pump, it is one of those Bell and Gossett 100 series (which I failed to mention) , and pretty heavy. I am sure there is info on this site. I saw an article here https://industrialcontrolsonline.com/training/online/how-avoid-problems-your-hydronic-system-pumps that says that this is considered a "low energy" pump (head max 8ft) and would not affect the system pressure as much. I will keep digging into Dan's books and this site.

hot_rod

here is another option with the circulator on the return. Pumping into the return of a boiler is fine as long as the expansion tank connection is upstream as shown here.

On the return it works well if you add a return temperature mix valve, as you are pumping away from the mixed port also.

The air purger wants to be at the hottest point, supply out of the boiler, but exp tank does not need to be at the purger.

cdrat

Great, yes the mix valve was what "Clammy" was saying, excellent. So I put a mixing valve to take supply water and increase the temperature of the return water. Can I leave the "fill" and the pressure relief on the supply side as it is now piped?

jumper

If I was already installing an expansion tank in a new place; then I 'd think about a vacuum tank above the system. But don't use automatic make up. No air means less fuel burned.

cdrat

Thanks to all, I really feel like I have a plan. Great Forum!

clammy

You should up grade the pump to a ecm style pump ,I would use pd style being u have zone valves would consume nothing compared to the b &g series 100 and weights nothing in comparison . I replaced 2 of my grunfos 15/58 w 2 wilo ecm stratso and I was impressed w a lower winter electric bill . Only hitch is you should add a magnetic separator and add a good inhibitor like sentinel there are other companies that also make products . Due to the higher emf they tend to attract magenite hence the need for a magnetic separator . The other plus is there’s no motor coupling ,no oiling and extremely quite like most 1 piece pumps . It’s a upgrade worth considering , there not cheap but every pump manufacture manufactures them . I had got a good deal on a few wilo plus it greatly helped dial in the ft head that I need . Peace and good luck clammy

dopey27177

Go with pumping away. Because Peerless put the pump on the return side of the boiler does not make it a necessity.

Pumping away continually removes air from the system. You will never need to bleed radiators. The positive pressure on the supply side will always force the air around the system till it gets bled out of the master vent valve.

Jake

cdrat

Thanks guys! I will look into my pump options I am sure there is more info on the site. (OMG I just looked at the price of a wilo ecm stratso, over $2K, gulp, tough to justify that) The B&G is dead silent. I assume I should match the GPM. I have no problem adding a magnetic separator while I am shopping for the air separator and 3-way Thermic. I might as well do all the changes at once and the maintenance turns into an upgrade.

cdrat

My gut tell me that moving the old B&G is a doable thing, but upgrading the pump should probably wait until I need to replace this old workhorse. One other question, I bought an SX30 floorstanding tank but I am having trouble with floorspace. There is no reason that I could not hang that from the joists, right? And it could be horizontal?

hot_rod

cdrat said:

My gut tell me that moving the old B&G is a doable thing, but upgrading the pump should probably wait until I need to replace this old workhorse. One other question, I bought an SX30 floorstanding tank but I am having trouble with floorspace. There is no reason that I could not hang that from the joists, right? And it could be horizontal?

There is conflicting info about acceptable mounting positions for diaphragm style tanks.

The installation manual shows floor standing only.

Then Amtrol Engineering Handbooks seems to indicate horizontal is also acceptable? Maybe just for smaller models?

I have seen smaller #30 and 60 tanks on their sides that are 20 plus years old, so....?

cdrat

I just called Amtrol and they will not recommend the tank be anywhere but the floor because, if waterlogged, it could weigh 140 lbs; understandable. I asked if I could do it horizontal and he said "it is a vertical tank" but, when I asked if that was because of function, he said no. I think he needed to be evasive because of liability issues, I should be wise and try to get it on the floor.

cdrat

But then again, I have some 4" joists right above the boiler..... seems to me, this would work fine.

hot_rod

That might be a bit light for the tank, unless you find a heavy gauge. Go buy some 1/8" X 1 or 1-1/2" flat stock and curve some bands. Hardware store and box stores generally have 3 foot sections of various steel stock. That is how the old compression tanks were hung in the joist bays.

cdrat

That makes sense, this is 1/16" , but 1/8" is also available, looks like an easy fix.

I just received "Pumping Away" and am actually a little more confused. On page 37 the author says " when all we had were 1750-rpm low head pumps, it really didn't matter where you put the pump" then he mentions the new high speed pumps producing twice as much head pressure cause this problem! Now I am using a Bell and Gossett 100 which I think is exactly what he is referring to.

On the next page he makes it very clear that the only place to locate the feed valve is at the tank...that answers that question.

Then, on page 42, he says NOT to move the tank before the pump that is before the boiler because it will increase the pressure too much and pop the relief valve. Now I could also move the relief valve to the return side but I am not interested in overstressing my old system. The boiler in in the basement with 3 stories above.

Any thoughts? Thanks in advance.