Why do radiator valves only turn 180 deg.


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Old 10-21-04, 06:24 AM
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Question Why do radiator valves only turn 180 deg.

Just purchased an old home in Maine. I'm told the current hot water system was originally a gravity system. 3 storey house and it heats up great. Each radiator has an independent inlet and outlet pipe. Here's the problem:

My mother wants to turn the heat in her bedroom completely off. The radiator shutoffs only turn 1/2 turn. They have metal "stops" that prevent the valve from turning more than that. In either full CW, the mid-point, or full CCW positions, I get heat. A local radiator guy said in the past he recalled when houses had rented rooms, radiators sometimes were set up so you couldn't turn the heat off, to prevent freeze-ups. Does anybody recognize this set up? Any ideas as to how to turn this radiator off (short of major surgery?)

Thanks,

RoryTony
 
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Old 10-21-04, 10:17 AM
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I'll tell you what to look for. If the valve was made for hot water, it should turn only 90 degrees. It should have the stops like you mention BUT if someone took off the handle and got it on wrong, the stops will be on the wrong side of the tab on the valve. Now the valve will turn more than 180 degrees but you will never find the off position because it is somewhere in the middle of the valve travel. Take out the screw and see if you find what I am trying to describe. Put the handle back on so that the valve can only turn 90 degrees from stop to stop and you should be back in business. If it's not that, post back and maybe we can get a better idea of exactly what kind of valve you have.

Ken
 
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Old 10-22-04, 07:26 AM
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Well, I really appreciate your writing. I have a few more questions. Are you saying ALL hot water systems (which mine definitely is) had valves like this?? Funny that neither of the heating places I called here in Portland (Maine) seemed at all familiar with this set-up, since hot water systems are clearly common. Is it possible most had "crank-down" valves, and only a few old ones had these 90 deg. types??

Second, you're right about there being two ways to mount that thing. I took the knob off. The shaft is 1/2-round, and the protrusion thingy slips down over it. So that can only go on one way, but if you rotate the shaft before slipping the protrusion thing on, it would be different. In fact, putting it on one way gives 90 deg. rotation, and the other gives 180 deg (due to the fact that the protrusion has some width.) [But oddly, the stops are such that when set in the 180 deg. way, the protrusion hits the stop full on, but in the 90 deg. way it hits at a definite angle. If I were the designer, I would have built it this way only if the 180 deg. setting were correct. Hmmmm.]

OK, the third question is, if the 90 deg. way is correct, once I put it on that way, what position should OFF be -- CW or CCW?? I'm trying it now, but with the pipes already hot, it will be some time before I'm sure if it is OFF. My first guess was CCW is OFF, reasoning that an imaginary pointer on the knob would move from left to right, cold to hot. Then I'll try the other way. But please answer my first question if you can. Thanks again.

RoryTony
 
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Old 10-22-04, 10:20 AM
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The valve you have was made to be used on a forced hot water system. Many valves USED on hot water systems were made for either gravity flow hot water or steam. The correct position is to allow the valve to turn only 90 degrees. CW is closed CCW is open. There is a flat 'butterfly' inside the valve and when it is across the opening of the internal body, it stops flow. When it is parallel with the water flow, it is open. Thats why 180 degrees of rotation cannot work in a valve that does not 'unscrew'. If you had a valve that had a washer in it, like a globe valve, then opening the valve would raise the washer off the seat. You would notice the valve handle raising up as the stem did. On your valve the handle does not move up as you open the valve. That means it works more like a ball valve. All that nonsense aside, I think you have solved your problem and I hope you can regulate temperature like you want.

I re-read your last post and you can picture it this way. The flat sides on the valve stem are parallel to the butterfly in the valve. When the flat sides are perpendicular to the pipe, the flow is OFF.

Ken
 
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Old 10-29-04, 06:00 PM
Pabs
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Unhappy New to these old valves

[ I have these type of valves in my newly purchase , first house .
I let curiousity get the best of me the other day , not knowing how these valves worked . I turned the knob on the valve past the metal stop , thinking I was opening the valve more . If I forced the knob past the metal stop ,what will happen? What can I do now ? Did I break it ? The radiator is not heating up much .
 
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Old 10-29-04, 07:43 PM
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Re-read this thread and take the handle off and bend the stop back and you will be OK.

Ken
 
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Old 11-05-04, 12:52 PM
LI Neil
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Same Situation Here

KField:

Your input is highly appreciated, I moved in this summer to a 1955 Split Level Ranch home with force hot water gas system (new system I had installed). I have convectors and all except 2 of them knobs are dry rotted and broken off. I was following your explanation of the butterfly valve system. I have the same valves. After this heating season is over, I will drain and my questions are:
Can I unscrew that valve (seems I can) and change that assembly out?
As its is now, I think I have the "sweet spot" for all of the convectors except one, and like you said, the butterfly valve is parallel to the sides, I see the sides but with 4 sides on the outside (knob is gone) I guess I have a 50/50 chance as to which two sides are for on/off position? And if I do find the side that is ON, being perpendicular to the pipe would place me in the full open position?

Thanks again,
Neil
 
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Old 11-05-04, 01:01 PM
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You would be correct about the placement of the flats in relation to the pipe. I would not recommend removal of the packing nut, it will probably leave you with a can of worms in one hand and a time bomb in the other. If you can try to turn the nut as you turn the valve stem, you may break it loose and be able to change the valve position without causing a leak. If you want to change the valves you should drain and unsolder them and put new ones in. That is a bigger job but one that will yield the benefit of long term control.

Good luck and I'm glad my explanation made sense to you.

Ken
 
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Old 11-05-04, 01:13 PM
LI Neil
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Ken:

I can turn the valve (a metal 4sided pc) freely, So I will experiment with finding the full open position. My attack of the valves next spring is because 3 units are leaking slightly, a cap full in approx 4 days or so, therefore I have to place a small container by said valves. I was able to use metal plumber epoxy to seal off 2 of the 3 leaky units (I made sure they were in the open position first ).

However, because of the small leaks and no control, I would like to replace the valve or remove them completely. The valves appear that it can be unscrewed and I can put a blank cap inplace, however if that goes "bad" I will have to unsolder the entire valve assembly and replace.

I have no need for the valve, as I installed an outdoor reset to control my boiler temp and have a comfortable heating enviroment. This is all new to me as a first time how owner, but being an engineer and a bit hands on, I am trying to clean up the system. However my approach is to be educated about the system, then attack.

Thanks again,
Neil
 
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Old 11-05-04, 01:21 PM
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If the leaks are at the packing nuts, you may be able to remove the nuts and add some new packing and snug them up. You can buy small rope packing at a plumbing store or possibly a home center. Make sure the valve stem isn't all rough at the top and with most of the system pressure removed (not the water, just the pressure) take out the nut and add one wrap of packing and then put the nut back in. Don't make it bleed, just snug it up and you may not have to replace the valve after all.

Ken
 
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Old 11-08-04, 08:57 AM
LI Neil
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Pressure Drop

Ken:

The leaks are comming from between the stem and the nut, not from the nut and the threads. How do I drop the pressure without draining the system? By bleeding? and of course I have to turn off the valve to the automatic fill valve correct?

Currently my system is at 12-15 PSI cold and 20 when warm, how do I get the pressure down to 0 without losing the water in the system?

Thanks,
Neil
 
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Old 11-08-04, 09:08 AM
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First close the water feed valve to the system. If you have the old expansion tank in the basement ceiling joists, turn off the valve between the tank and the boiler. If you have a small pre-pressurized expansion tank you don't have to close anything else.Turn off the power to the boiler. Close any automatic air vents that may be on your system. Put a bucket under the pipe from the relief valve and let out the pressure. You won't get out much water. Maybe a gallon. As long as air can not enter the system, water won't come gushing out. The nut you are talking about is the packing nut. It's job is to crush down a soft packing material and make it seal up where the valve stem comes up through the valve body. When the packing was new, a little snugging up on the nut would stop a leak. After many years, you may not be able to stop a leak because someone used up all the 'snugging' room in the packing. If you can remove the nut and add some more packing and gently re-tighten the nut. you will be good as new. There is no need to remove the old packing as that may cause a different problem. Just add a wrap of the teflon rope packing available at any home center.

Ken
 
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Old 11-08-04, 09:28 AM
LI Neil
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Ken:

This is great information and I thank you kind sir. I was able to stop my leak on the last unit by turning the valve stem a few times

However I will go around to each unit after the heating season is over and improve each valve so no future leaks come about.

Neil
 
 

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