Banging Zone valves

BillW@honeywell

I was at the 2002 NAOHSM trade show, so you must not have spoken to me about the zone valves banging, or you would have had your answer already! The boiler guy was right, and so are the other wallies who suggested removing one spring, and changing the pump. For future reference, add the following things to what's been posted here. #1 cause of banging...valve installed backwards. The water should flow in the direction of the arrow on the body. #2 cause...long, unsupported or poorly supported piping runs (common in new construction). Sorry it took so long, but at least you got an answer.

Jim_47

Banging Zone valves

As a reference, prior to commenting on this topic, please read Dan's Hot tech topic with the same Subject line as this post.
Awhile back I had a very similar experience with banging zone valves, except I was responsible for causing it.
A customer of mine had an old cast iron "brand name" boiler that had developed a leak in the casting. Money was tight for this young couple and I was able to select a steel boiler that was within their price range. I had only planned on doing a boiler swap since the zone valves and plumbing looked pretty dame good for the age. After the installation the customer called to complain about the zone valve banging, just as Dan describes in his hot tech topic. It was very timely, the week before the 2002 NAOHSM trade show and convention. Just as Dan had I chatted with the zone valve company. (The valves with the 2 springs) and they also said they would get back to me. (I too am still waiting.) I also stopped by the steel boiler MFG's booth. THese guys got me through this.
THe steel boiler had a lot less resistance than the older cast boiler. I had basically two choices.
A) I could put a balancing valve in the system to "slow down" the boiler water.
He also suggested I could change the circulator from the green thing to a 3speed unit and allow the system to run in the middle speed, thus slowing the water down.
Since I wanted to be in and out asap, I elected to try the circulator swap. Much to my delight, the 3 speed circulator works great in top speed. THe pump curve from the green circulator to the 3 speed is just diffrent enough to solve the problem.
Not to bore anyone with the flow and zones etc the 3speed could have worked fine in either 2nd or 3rd. The neat thing is that the steel boiler guy had the answer and the zone valve guy did not. Just an addition to the wall.

king947

zone valves

I had a problem with zone valves. Honeywell zone valves.
If these are the zone valves you have than you did not have to change the circulator. Honeywell zone valve have two springs. What I did to stop the problem was take on of the springs off. That should stop the banging.

Jerry Boulanger

A note about the proposed balance valve solution

This will not solve the problem. As zone valves close and flow is reduced, the pressure drop through the balance valve drops off sharply. As the pump moves up its curve, it will develop nearly the same head as it would without the balance valve.

Terry_4

How about

a pressure activated by-pass valve? When I read Dan's article a couple of weeks ago I wanted to write and ask him why he didn't install one before changing to circulators. We pretty much use zone valves exclusively in our area and by-pass valves are common. Works great to keep the pump in the curve.

hot_rod

The bypass valve

I agree with Jerry, it needs to be more than a manual bypass valve. Pressure activated valves, properly sized, are a better solution. This link will answer some questions for you.

hot rod


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