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Re: Balancing a large one pipe system

From what can be seen in the pictures, the near boiler piping is incorrect and no where near enough main venting. That’s where I would start.

EzzyT

1

Re: Tankless Coil Intermittent Hot Water

He set the boiler at five cycles per hour to eliminate any cooling of the water in the boiler. It was always above…………175°………….give or take.

At 1 cycle per hour…………..now it cools down below………….140°…………and that's insufficient for a shower considering the heat transfer of the tankless coil.

The boiler needs an aquastat that will maintain the boiler at 180° consistently, independent of the heating demand. This is acceptable in the heating season but is highly inefficient for the remaining six months.

I'm not grasping the "then warms up again" statement. Be curious to know if the boiler started at this moment………….and, if so………….did the thermostat call? I tend to doubt it because you'd have consistent hot water for at least 15 minutes.

You could also try a low cost experiment and set the boiler at 3 cycles per hour. This might provide acceptable HW for most showers but you'll notice a drop in the temperature of the shower if you started the shower at the end of a boiler cycle. A lot of this speculation depends on how much water the boiler holds.

All of the above, other than a new aquastat depends on the boiler actually running 3 cycles per hour. If a thermostat is controlling it, it MAY run three cycles per hour………….or it may not run at all if there is no heating demand. If this is the situation, you must install the aquastat. If outdoor temperature climbs to………..say 45F…………the boiler might run once every two hours………….independent of the claimed 3 cycles per hour.

LRCCBJ

1

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

1

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

Screenshot 2025-01-05 at 8.04.41 AM.png

Screenshot 2022-12-13 at 8.50.10 PM.png

hot_rod

2

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

2

Re: Is our building's hydronic heating water pressure too high? What's causing this high pitch whine?

https://forum.heatinghelp.com/discussion/comment/1832024#Comment_1832024

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

1

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

2

Re: Vacuum from supply side of a 2 pipe steam radiator while boiler is operating

Are other radiators on that same main working properly say take offs before and after issue radiators . This 2 pipe system is it using any vacuume pump return ,contain f and t traps and condensate pumps and all the good stuff suppose that comes w it .Or is this a gravity return system , if so are the main vents working same goes for any on the dry returns , do you know if the system pulls a vacuume at the boiler or in the piping ,have you seen any vacuume breakers and is this all radiators w no zone valves or contain steam coils possibly in air handles ? Has the dry returns been checked for any pressurization ,after all that what kinda pressure is it set and running at ?
Peace and good luck clammy