Best Of
Re: Looking to move a circulator and fill valve, system is now pumping toward tank
i'm with @LRCCBJ on that. if its working fine and your not having air problems don't worry about it. This is the the difference between commercial and residential. Smaller circulator pressure differentials wont really come into play where as in a commercial setting it can really be a problem.
But…. if you need an option you can do the Weil-Mclain way. Put the expansion tank and fill on the return side right before it enters the boiler or on a tapping in the boiler. Both put the expansion tank on the suction side of the circulator creating a pumping away system.
pedmec
Re: Looking to move a circulator and fill valve, system is now pumping toward tank
I don't think you system will see much gain from the repipe. In some systems pumping toward the tank can pull a negative pressure in the piping. Air could get into the system from an auto vent located at that negative pressure area.
Another option would be to add a tee where the red purge valve is and move the tank connection to that point. Now you are piping away with a simple piping change.
A B&G drawing that started the Pumping Away movement
hot_rod
Re: Looking to move a circulator and fill valve, system is now pumping toward tank
You are correct in the preference to pump away from the tank rather than toward it. But, before you take out the wrenches and the soldering tools………….consider the fact, in not too distant past, that all the boiler manufacturers would provide packaged units with the circulator on the return. 98% of the time, the systems worked fine. And, if they failed to work fine, raising the pressure on the boiler usually cured the problem.
So, is your current installation ideal? No. Will it affect the operation of the boiler? Likely not.
The location of the fill is typically irrelevant. You use it once and forget it.
LRCCBJ
Re: Is our building's hydronic heating water pressure too high? What's causing this high pitch whine?
Yeah I've been measuring the 473Hz peak and comparing with the pressure (the boiler room is just one flight of stairs away), and it's been consistently louder when the pressure is higher. When the furnace was recently shutdown because a flame rollout issue, the water ran cold for a couple days, and the noise was completely gone. I'm not saying it's not the bearing, but if I can mitigate it by lowering the pressure, than that's a good enough short term solution. Long term I'm still trying to get the HVAC company to admit their fault and replace the part, or maybe we'll finally replace the old inefficient system this year…
Any suggestion how I could mitigate at the source? I already oiled the bearing according to instructions, no difference.
DDoS
Re: Space Heat Limiting, Draft and NG Pressure Drop Mod/Con Lochinvar NKC 150N Combi
The pressure drop is due to either the regulator or the gas line, unless there is something boogering up the gas valve. Are you measuring the drop on the designated gas valve port or elsewhere? And yes, low fire all heating season will cause undue stress on the burner/HX but if it's being meticulously maintained as you say, it's of little consequence.
@LRCCBJ though it wasn't specifically stated, Lochinvar only makes one 150k NG combi boiler so it's an NKC-150N
GroundUp
Re: Vacuum from supply side of a 2 pipe steam radiator while boiler is operating
Peace and good luck clammy
clammy
Re: Is our building's hydronic heating water pressure too high? What's causing this high pitch whine?
As an example, assuming the radiators are on the floor of the upper level, calling each level 10'
So 35' X .433= 15 psi. Add a 5 psi safety factor, 20 psi fill is adequate.
The tank, assuming it is sized properly, would have a 20 psi air charge before being connected to the system.
5, 10 even 15 psi increase as the water heats from room temperature to 180°F is not unreasonable. On a system with a properly sized 50 psi relief 35 psi is not an issue.
hot_rod
Re: Does underwater near-boiler piping act as a sacrificial anode for a steam boiler?
I been in this business for forty years both as an installer, repair tech and consultant. I have seen buildings with underground wet returns last for more than 20 years, buildings with above ground wet returns in them for as long as 50 years and of course dry returns in some buildings for 75 years.
If you look at the real old buildings you find that the fittings were cast iron and no corrosion occurred where brass or copper was installed into the cast iron fittings.
Today many jobs are done with steel fittings, even there it is rare that for the brass or copper fittings will corrode to point that a leak will occur in 20 years.
Every thing depends on how much air is in solution with condensate return.
to lessen galvanic action dielectric grease can be used in lieu of pipe compound.
Jake
