Banging/Knocking hot water baseboard heat
Comments
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Are there any zone valves on the system?
How about posting some pics of the boiler and its near piping from a few feet back?Bob Boan
You can choose to do what you want, but you cannot choose the consequences.0 -
Thanks for your response. I'm not sure. Aren't zone valves for if I don't have individual pumps per zone? I'll take some pics the best I can, not a lot of room in the utility room. Be right back.
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That is classic expansion noise. Really classic! The solution is to find the pipes which are rubbing on something as they expand, and either shift the hangers slightly so the don't rub or slip a piece of polyethylene -- a plastic milk jug is ideal -- between the pipe and whatever it is rubbing on. Should fix it right up. However, if you can't get at the pipe you may be out of luck.Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England-1 -
That's what I was afraid of. Thanks for confirming. Unfortunately it will require ripping out the entire living room filing to find it! Thanks again.0
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Can you get the full model number off of the circulator's data tag? It's on the electrical cover of the pump.Bob Boan
You can choose to do what you want, but you cannot choose the consequences.0 -
Like Jamie said, definitely sounds like expansion noise. You don't hear it on the first cycle in the a.m. because it's a cold start aquastat and the circ runs pushing cold water through the loop, then slowly heats, avoiding that rapid cold to hot expansion that you get on later cycles. The easy fix is... play some Metallica, loud.1
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You could try constant circulation with outdoor reset including a low loss header or another type of primary/ secondary near boiler piping. Outdoor reset would reduce the rapid expansion that occurs when ambient temperature water is replaced by high temp boiler water........-1
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Iron Man, the # is Taco 007-F5Ironman said:
Can you get the full model number off of the circulator's data tag? It's on the electrical cover of the pump.
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HVACNUT, that has been the other half of my band-aid solution!HVACNUT said:
Like Jamie said, definitely sounds like expansion noise. You don't hear it on the first cycle in the a.m. because it's a cold start aquastat and the circ runs pushing cold water through the loop, then slowly heats, avoiding that rapid cold to hot expansion that you get on later cycles. The easy fix is... play some Metallica, loud.
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have you checked the temp leaving the boiler? I had one that was making steam cause the controls failed and gauge was unreliable? Definate agree w/constant circ with or without O>D> reset. Things that go bump in the day, " Scarey" john-1
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Shut the boiler off and just run the circulators if you can. Is it quiet?? This will tell you if the noise is related to changes in water temperature or not.-1
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Have you checked the air charge, in the expansion tank? Had a system doing the same as yours, the tank had lost it's charge. Pumped it back to the proper pressure, and all was quite.-1
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Yeah, I've ran it at the lowest temp on the boiler and it still banged. Thanks.
> @HEATON said:
> have you checked the temp leaving the boiler? I had one that was making steam cause the controls failed and gauge was unreliable? Definate agree w/constant circ with or without O>D> reset. Things that go bump in the day, " Scarey" john0 -
I'm not sure if I can do that... I'll give it a shot. Thanks
> @EBEBRATT-Ed said:
> Shut the boiler off and just run the circulators if you can. Is it quiet?? This will tell you if the noise is related to changes in water temperature or not.0 -
I thought the pressure was fine, but I will check the expansion tank. Thanks.
> @Mike said:
> Have you checked the air charge, in the expansion tank? Had a system doing the same as yours, the tank had lost it's charge. Pumped it back to the proper pressure, and all was quite.0 -
This is a very technical response! I will have to forward it to someone that understand this better than I. Thanks for your response!!
> @MikeL said:
> You could try constant circulation with outdoor reset including a low loss header or another type of primary/ secondary near boiler piping. Outdoor reset would reduce the rapid expansion that occurs when ambient temperature water is replaced by high temp boiler water........0 -
I had loud banging myself. I've been testing a fix for two weeks at this point. So far it has helped so much I don't notice the banging anymore because it's so faint.
In both my new furnace and prior furnace, I had the same banging. I managed to improve the problem a little for the main floor by securing and padding pipe sections I could access from the basement. The second floor was hopeless. I couldn't get to any of the piping without cutting into walls. With the new furnace I could set the pump on low and that helped a little but not enough.
I read that with Honeywell zone controllers, that's me, you can alleviate the problem somewhat by removing one of the two internal springs that pull the valve closed when the thermostat stops calling. The explanation offered was that the springs close the valve too quickly thus the water is still flowing somewhat and runs up against the closed valve. This triggers something like a backwards shock wave similar to a wave reflecting off a hard surface. I'm not schooled in hydraulics and I'm not keen on modifying the internals of a zone controller. But it sounded plausible to me. So, I mimicked the idea in a simple and non-intrusive, non-destructive way that is easy to reverse. I attached a self-adhesive picture hanger to the cover of the zone controller. It's a pretty strong one, holds 22 pounds. I put it on the side that you move the manual open lever towards. I attached the hanger so that the bottom of the hook is roughly one inch up from the bottom of the cover. Then I attached a 11/32 by 1 and 7/16 spring to the hook and the manual open lever. The spring is the kind with a loop at each end. I slipped the loop up the lever above where there's a jag such that the spring catches the jag and will not slide off the lever. I made sure that the lever will still close all the way on its own and not hold the valve open any. Because the spring has to wrap around the corner from the side of the cover down to the lever on the bottom of the controller, I could actually shift how much of the spring is on each side of the corner. That allows for a bit of adjustment of the spring's tension. Adjusting wasn't necessary. My idea is to slow down the closing of the valve from the outside instead of taking out one of the internal springs.
This has been working great! Both zones are down to a faint jiggle that is hard to hear.
I'd love to get peoples' thoughts.
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Just one thing to watch out for. That valve has close of pressure of 20 psi. So when you remove 1 spring, or add a "helper" spring you reduce the close off pressure of the valve. Take one spring off as some suggest and you have a 10 psi close off. I've demonstrated this in my shop to see the result.
So when that valve is closed and others open, circulator running, you can sometimes push flow thru the valve, when you think it is closed.
Feel the pipe about 2 feet or so downstream of the zone valve when it is off, see if it is warm. If so some flow is pushing across the "closed" valve. Most likely when only one other zone is open.
It depends on the circulator and the ∆P it develops, and the circuit it is piped to.
A delta P circ is another good option, it changes flow as valves open and close, so you don't over-pump a zone or circuit.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0
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