Hammering zones

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Old 12-29-08, 08:15 PM
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Hammering zones

I have a Buderus hot water system with Taco valves on each zone that the hammering and circulating of each zone is enough to keep the entire family up every night! This system has a number of quirks that I would love to discuss with someone who understands hydronic heating! Thanks in advance. Bob
 
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Old 12-29-08, 10:45 PM
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Bob, that's why were here! Talk to us.

Can you describe the sounds? Do they occur when the valves are closing? If not, when?

What are the quirks?
 
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Old 12-30-08, 07:35 PM
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Dear NJ Trooper,
Thanks for the first REAL assurance that my life with my wife(and this heating system) will not be glossed over as "it is what it is." First of all the new boiler is in the basement of the original house that was seriously added on to 6 years ago. The system has 6 zones(basement in-law unit) 1st floor, and 3 zones on the second floor with a third floor zone left unused. A header system was installed on the second floor in a utility room as the distribution center. This room is about 18' above the boiler and circulator pump. The 3 zones on the second floor have some partial circulation plumbing up to the attic and then drop down to the rooms that they looped to because of several design plan changes and code issues with drilling holes. Now I hear the slow "tink-tink-tinking" of the Taco valves opeing when a thermostat calls and the pipes heat up as well as the dripping of water attempting to get pumped up to the next floor in it's circulation route and then suddenly succeeding and syphoning the poorly pressurized water behind it! I am at the point of cutting open the sheetrock walls and either redirecting the hard piping so it does not go to the third floor or I am am told that a "spiral valve" will alleviate this issue. Thoughts? And thank you in advance. Bob
 
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Old 12-30-08, 08:07 PM
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Sounds like a fun one. Let's see some pics of the boiler, near-boiler piping, and the 2nd floor distribution system. Host them at photobucket.com or similar free service, provide links here.

I'm assuming this is fin-tube baseboard. If so, can you guestimate how many feet of piping for each zone?
 
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Old 12-30-08, 08:20 PM
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Ski,
It doesn't sound like water hammer. It sounds like air. Water hammer would be loud banging that could happen when the zone valves open and close. Now because of the number of zones I'd guess you have a good size circ pump which could cause hammer if only one zone was calling at a time. Other wise circ pumps are usually not strong enough to cause hammer.

It sounds like you have a lot of up and down pipe runs in the system. Any bleed valves? If not, getting air out may be a long process. Being able the hear the flow in the pipe is characteristic of air in the system.
 
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Old 12-30-08, 08:24 PM
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Bob, my first questions are going to deal with the system pressure.

What is the total height of the system from the lowest point (boiler in basement, correct?) to the very tippy-top? ... I guess that would be where the piping loops up and over in the attic.

The water sloshing noises could be due to not enough pressure in the system...

The tinky-tinking... that's undoubtedly from the expansion of the piping... you have fin-tube baseboards, correct? SOME (maybe all) of that sound may subside after the system has been in operation for a while... mine did... but (and I'm sure you've done this already) you might wanna pop the covers off the baseboards and make sure that the plastic 'cradles' are all in place properly. If you have loud intermittent 'BANG!'s going on, it's a sign that a pipe is binding somewhere... usually on a piece of flooring or framing... where the holes weren't made large enough... those can sometimes be fixed by sliding plastic shims in the offending holes. Finding the offenders is the hard part.

So, tell me about the height, and the system pressure when the boiler is cold, and again when it's hot.

And, speaking of HOT... what controls are on your boiler? and what is the HIGH LIMIT set to in the aquastat?

You also mentioned 'hard piping'. Can I take that to infer that you also have some 'soft piping' ... i.e. PEX ? If so, hopefully they used an O2 barrier PEX product...
 
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Old 01-03-09, 06:55 PM
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Dear NJ Trooper,
Sorry I have not been back to you sooner, I have been rather busy between snowstorms and the holidays. But I will try to give you as much input and feedback to help me resolve this(these) issues...by the way "Happy New Year." The boiler(and the circulator pump)are located in the basement. To avoid a lot of zone loops from the boiler to the second floor we(the installer and Buderus rep and myself) designed a utility room with a header system using a 1" supply and return to the boiler, pressure and temp guages, an expansion tank and relief valve, and an automatic feed for make up. The header has three thermostatically controlled Taco valves. Two of the three zones were plumbed up and over (through the attic) because of design and code issues. They are the ones giving me problems and they happen to be the zones in the kids and master bedrooms. I am certain you are on to something when you question the height that the circulator pump has to achieve around 27' and that these loops are trying to push air. The water pressure is 15-20 lbs and the temp is 140-160F. The "knocking" is really the draining and expansion(some holes were too tight!)Do you think that venting these loops in the attic will help or not? What do you think about the Taco valves? I have had 2 fail in 6 years and actually had a freeze-up because of a defective one! The system recently had a Honeywell ambient monitor added and it has
reduced consumption but the circulator pumps constantly at lower temps and takes longer to raise room temp. Regards, Bob R.
 
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Old 01-03-09, 08:30 PM
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Hi Bob, HNY to you too!

Yeah, busy time of year for all of us...

With a 27 foot height from the boiler to the tippy-top, you should have a COLD system pressure of 16 PSI. This should insure that you always have a minimum of 4 PSI at the top of the system.

a utility room with a header system using a 1" supply and return to the boiler, pressure and temp guages, an expansion tank and relief valve, and an automatic feed for make up.
If I understand correctly, this room is on the 2nd floor? What does _that_ pressure gauge read when the system is cold? It should read lower than the one at the boiler. (0.433 PSI per FOOT)

Is there another expansion tank at the boiler?
If so, where is this tank in relation to the circ pump?

The circulator pump is at the boiler, correct?
Is it pumping the supply, or the return?

Honeywell ambient monitor
Do you mean an 'OutDoor Reset' (ODR) ?

I'm sure it would not hurt and may help tremendously if you were able to vent the 'up and over' loops. I would not use automatic type vents up there though, instead go for the ones that open with a coin or 'clock key' ... if it leaks, and they do, an auto vent is not something you want hiding in an attic ...

Those vents would probably work best at an elbow where the flow goes back down, and bleed them with the circ running because that's where the air will collect.

Taco valves? all the same as far as I'm concerned... zone valves all seem to be the weakest link... none seem to be uber-reliable.

I wouldn't mind seeing some pictures if you would... free account / Image hosting, free photo sharing & video sharing at Photobucket / upload there / post link to album here. Most of the questions I asked can be answered with pics... and I do have more, so if you can't post pics let me know and I'll ask 'em.

Did I 'hit' all your questions?
 
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