Hot water heating system Low Pressure Problem


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Old 10-28-07, 08:01 AM
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Hot water heating system Low Pressure Problem

Hello:

I just moved into a house and have a how water heating system. I have a pressure guage that reads consistently below 10 PSI. When I bleed the radiators on the top floor, air comes out for a bit and after a while nothing -- no water. I figure, from these symptoms, the obvious thing to try from reading these forums is to add water to the system.

There is a Watts pressure reducing vavlue installed, but it is unlike any I have seen online. There is no screw on the top. Instead there is a nut and a threaded sleeve. The threaded sleeve can be turned and will move in and out of the valve. I have tried turning the sleeve, but it appears to do nothing. Inside the sleeve there is a metal slug that is about 0.5cm (.25") in diameter. I can lift the slug right out of the sleeve and remove it from the valve, but cannot push down on it.

Has anyone seen such a system before?
Am I adjusting the valve incorrectly or could I have a different problem in the system?

On another note, I did drain the expansion tank recently (it does not have a diaphram). The pressure was low before draining it and it did not change after draining it. In hindsight, it was probably it probably would have been better to fix the pressure probelm first, but what's done is done. The expansion tank seems to be remaining empty now.

I can post pictures if it will help diagnose the problem. Thanks in advance.
 
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Old 10-28-07, 09:06 AM
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First off, that regulator seems to be missing a piece. There is a little 'handle' mechanism that is supposed to screw down on top of the threaded sleeve. The handle on that missing part is supposed to push down on that removeable metal rod when you lift the handle. That would be for your 'fast fill'. It forces the regulator open and let's you get water in faster. You probably won't be able to push that rod down with your finger.

Loosening the nut, and turning the sleeve clockwise should increase the pressure in the system. Don't make major changes all at once, it takes a few minutes to 'equalize' the pressures. If you screw it in, and nothing is happening, you obviously have a problem. Is there a valve in the water feedline running to the regulator ? (there should be) Is it open ? The regulator could also be plugged up. I don't think it is though, because when you bled the system, and the pressure stayed at 10 PSI, it would indicate that some water is probably making it through, it may just be backed out to the lower limit of the regulator.

I think the lower limit on those valves is like 10 PSI, so it could be that it's just not screwed down far enough. Try turning it clockwise SLOWLY! until you feel some resistance to turning. You should be able to turn that screw down using a dime in the notches on top of it. If you need to use force to continue turning, STOP! and have the valve replaced. If it will turn with minimal force, then continue slowly from there a teeny bit (like 1/4 turn or so) at a time and LISTEN for water flow through the valve (slight 'hissing' noise). If you hear water flow, stop and wait a few minutes and watch the gauge. You want to get to like 12-15 PSI with the boiler cold. A few PSI higher if it's hot. If you don't hear water flow, and the gauge pressure doesn't increase, it may be time to have the valve replaced.

Draining the tank was fine, no problem with that, you probably needed to do that anyhow.

Pictures never hurt. photobucket.com and a link here would be great.

There are ways to get water in the system if you are in a bind and need heat in the house, but post the pics first so we can properly instruct.
 
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Old 10-28-07, 09:33 AM
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I think it stinks that I can't edit my own messages after 20 minutes... how does one get any response from the folks who run this system ?

I want to also mention that if and after you are able to adjust the regulator, that you should snug (not muscle!) that nut on the threaded shaft to prevent it from turning in the future. It should only need proper adjustment once.
 
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Old 10-28-07, 10:39 AM
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Thanks for the response NJ Trooper. I tried turning the sleeve clockwise as you suggested slowly. I eventually kept turning for perhaps 5 full turns or so, all the while listening for flowing water and keeping my eye on the pressure gauge. There was no flowing water and the pressure did not change. I should clarify that the 9-10 psi is the pressure when the system is on its best behavior (i.e. running full blast). When it's not on, the pressure is more like 3 psi or less.

Another thing I have noticed is that when the system turns on, the pressure reducing valve gets hot, along with the copper piping on the other side that is going to the external water supply. I don't know if this is due to conduction or that the pressure reducing valve is allowing backflow (doesn't make any sense since we have water pressure in the house). I have verified that the valve to the external supply is open BTW.

Here are some pictures of the setup. Let me know if pictures of anything else will help. Thanks again.




 
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Old 10-28-07, 01:36 PM
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got yer PM, thanks!

If you've got that thing screwed down that far and no change, it's shot. Are you sure there are no other valves in that feedline though ? followed it all the way back to where it comes from the main house water, and no others ?

If you _do_ find another valve, don't open it until you've backed out the screw in the regulator...

When that valve is changed, whether you do it, or a plumber does, have a "backflow preventer" installed also, that's standard issue on new systems, and it will prevent boiler feedwater from creeping back into the house system in the event you lose pressure on the house supply for whatever reason. Also, if the new one is installed with 'unions' on either side, and a valve on both sides, it will be much easier to service in the future.

See your PMs ...
 
 

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