Will circulator pump cause water hammer


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Old 05-23-07, 05:18 AM
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Will circulator pump cause water hammer

Will circulator pump on one zone of a 4 zone BB water system cause Water Hammer,in that zone.I'm going to have 4 zones with there own pumps.Should you put a zone valve after the circulator pump,to open slower so no WH
 
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Old 05-23-07, 06:18 AM
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Huh? Neither, when installed properly should cause water hammer. Combining them would be a bad move. It would actually increase the odds of water hammer, zone no-heat situations, installation expense, complexity of controls...
 
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Old 05-23-07, 05:17 PM
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zone valves

When using a circulator for each zone, you do not use zone valves. You use either circulators with internal flow checks or separate flow checks, but not zone valves.
 
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Old 05-24-07, 04:06 AM
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zone valves or what

What I'm trying to do is put a thermostat in each bedroom. The 3 BR's would come of the one zone that has one pump. What would be the best way to do this.I was thinking of zone valve that would be controlled by the thermostat for each room. The 3 BR's would probably need a second manifold ,I think.After this manifold I was thinking of using zone valves or something else,to regulate the separate rooms.The BR's would be 1/2 copper with 3/4 feed into second manifold. I've looked into TRV's but I don't see that I can change the temp easily if we use that room for only a few hours a day.Thanks for any help.
 
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Old 05-24-07, 06:15 AM
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Off the top of my head, it sounds like you will need to put some moderately heavy thought into this. Basically, you are micro-zoning. Nothing wrong with that, but there are some considerations. Some I can think of:

1) if you set this up with one circulator for 3 zones, make sure you get the overall pipe sizing correct so that when all 3 zones are calling, you have enough water (quantity and flow rate) to deliver the BTUs needed. There may be some issues with a 3/4" manifold serving three 1/2" zones.

2) if you have a lot of 1/2" piping in one or more of these zones, the head is going to be pretty high, so you may need a differential pressure bypass valve (and associated piping) so that you don't have problems when only the smallest zone is calling. Or maybe one of the newer circulators that auto-senses for changing pressure differential (zones opening and closing) and modulates speed accordingly.

3) if only one or two small zones are calling, you may start short-cycling the boiler because the load is so small. In which case, you might consider a buffer tank setup.
 
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Old 05-24-07, 09:26 AM
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Xiphias is correct. Another thing to consider is the cost to accomplish what you propose vs. the monetary return. If monetary return is of no concern and all you are looking for is increased comfort then go for it.

Micro-zoning in a single-family residence is rather costly and almost never has an economic return.
 
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Old 05-24-07, 03:46 PM
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Micro Zoning

Xiphias & Furd speak wisely. Another way to overcome the flow problem is to use three way zone valves & install a by-pass loop for each zone. If you have unused bedrooms, you can cover the fins of the baseboard with heavy duty aluminum foil. Once the covers are re-installed, the foil won't be visible & it does an amazingly good job.
 
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Old 05-24-07, 07:39 PM
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Yes it will cost

The 3 rooms will have total of about 25ft heat and about 240 feet of pipeing split to each room,to second maniflod.The total pipeing is split almost even between the 3 rooms.This is not going to be a series it will be home run from 2 maniflod.About the short cycle ,one or more of the room will be used when the main part of house is in use so I don't think that will be a problem.Economics isn't only factor, confort is what I'm looking for.As I and wife are get older I'v noticed were getting colder or need more heat.This is one way of doing it to these rooms.
Now for an important part,given the total lenght I gave, do you think I should go from 3/4 to 1 in for feed to second maniflod.
 
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Old 05-24-07, 08:48 PM
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3/4" can move 40,000 BTUs
 
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Old 05-25-07, 06:25 AM
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Any chance you can draw a diagram of what you want to do, and/or post pics of the existing near-boiler piping? Host at photobucket.
 
 

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