psi

aperson

I recently had my heating pipes purged and from there disaster. All floor pipes begain making loud noises they never made before. The guy also increased the psi from around 10 to 25. I have now lowered the psi to around 14. Am I to understand the psi of the line pressure needs to match the psi in the bladder tank? If so why? Also I closed a valve on the celling which should prevent new water from coming into the system, but when I bleed water from the radiators to try to get out air and tl lower the psi, I get the psi down to around 14 but it creeps up slowly by about 4 lbs in 2 days. Could the valve that shuts off water supply have failed? It is a small gate valve. It seems shut good. Help.

Alan (California Radiant) Forbes

Am I to understand the psi of the line pressure needs to match the psi in the bladder tank?

Just the reverse: You pressurize the expansion tank to the fill pressure of your system.

If yours is a 1-2 story house, 15 psi is all you need to fill all the pipes and radiators with water and keep air out. Twenty-five psi is not terrible, but it's getting close to 30 psi where your relief valve will open and dump water out of the system.

Without knowing what that valve does, I can't tell you to open or close it. If it goes to your expansion tank, it should be open. If it is the fresh water supply, is there a pressure reducing valve on that line?

aperson

So my house has a basement where the boiler is and a 1st floor and an attic type 2nd floor. 2.5-3 floors. When I had the expansion tank replaced 2 years ago it was not adjusted, I don't think, from the factory set 12 psi. At that time I think the line pressure was about 12 psi. I have been told my psi guage is high 4 lbs and all my numbers are adjusted for this 4lb difference. Now recently when the pipes were puged and the psi raised to 25, since adjusted down, the expansion tank was still not adjusted or checked. I assume the expansion tank has a psi close to 12 lbs. Why does the expansion tank psi need to correspond to the psi of the line pressure. I am trying to trouble shoot. Also and thank you, there is a pressure reducing valve or maybe it is an auto refill valve but I tried to circumvent it by cutting off new water because it seemed to insist on raising the line psi to around 25lbs even though it should have been reset at 12.

EdTheHeaterMan

Something comes to mind. Does your boiler make both your heat and domestic hot water? If so you may have a problem unrelated to the valve or the expansion tank.

The reason for matching the pressure in the expansion tank with the cold fill pressure of the boiler is to maximize the amount of expansion your expansion tank can accommodate. It is not rocket science where you must have a precise agreement of all the mathematics or you will end up on Pluto. But if your system has 100 gallons of water in it (it probably doesn't) and it is filled with 60°F water, after you turn on the burner and all the water gets to 240°F (which you probably never have that much heat), you will have 105 gallons of water.

If the 5-gallon expansion tank has low pressure, there may already be 1 gallon of water in it. So there is not enough room for all the expansion of the water. This is a very simple explanation, and there are other factors involved but I just wanted to make the point of starting out at the same air pressure in the tank in order to keep it void of water on initial commissioning.

Getting back to the pressure-increasing problem (that I assume is a recent phenomenon) something has changed and that could be a pinhole in your system somewhere. That could be in the expansion tank bladder but I'm thinking maybe a tankless coil for DHW or in an indirect DHW tank.

So... Where is your hot water coming from?

Respectfully submitted,
Mr.Ed

aperson

The boiler only heats the house. There is a separate hot water heater.

aperson

My goal is to balance the line pressure with the expansion tank and get the bubbles out of my pipes. And I want a nice alkaline system. Thank you for your help.

aperson

It is an Amtrol Extrol and it sounds goods, only a few years old.I want it to have at least 12psi. If I let out air will that increase or decrease it's psi.

Alan (California Radiant) Forbes

If you let out air, it will decrease the pressure.

The only way to properly check the expansion tank is to drop the pressure on the boiler side to zero. For some that have isolation and drain valves on the line to the expansion tank, it's easy. For others, they have to drain the entire system.

EdTheHeaterMan

If the pressure is slowly rising over an extended time and there is no tankless coil involved, then the feed valve is passing. that is the only other source of higher pressure. Add a new ball valve to the feed line so you can be sure the valve is really closed. An old gate valve or stop and waste valve is most likely the culprit.

EdTheHeaterMan

Youngplumber said:

You need to check the expansion tank to see if the bladder is good. Depending on how it is oriented you should be able to let some air out to see if it's got water in it. If there's water in it (assuming it's a bladder type) trash it and get a new one. 

This is a test that some guys use regularly if the tank is oriented properly. I have. The proper orientation is with the lettering on the tank label in the upright position. This will usually place the Schrader valve at the bottom of the tank. If that quick burst of air has water in it, the tank is bad and needs to be replaced. The better test is to have a pressure gauge and an air pump or compressed gas to recharge a tank that is low on pressure. As long as there is no water on the airside of the tank, then charge it up to the proper pressure for your system.

A bicycle pump is all you need. And don't "overpressure" charge the tank. It needs to be at the cold system fill pressure in order to get the full expansion capacity of the tank.

Respectfully submitted,
Mr.Ed

aperson

Thank you all. The boiler does heat the hot water heater, it has it's own zone. I believe the expansion tank to be in good shape. If water is sneaking in the system it is most likely the gate valve that is the feed valve I think. Now might be the perfect time to drain the system and check the expansion tank and replace the feed valve. Of coarse the expansion tank might just be happy and at 12 psi and the feed valve might be fine, I will check the cold psi tomorrow morning, it was where I left it this morning but then again it did not run last night. The big issue is the bubbles in the line. I have never had trouble with bubbles. Then I had a guy come to fix a pounding in the pipes in the basement zone. He purged all the pipes and turned the psi from12 to 25. When he left the backflow preventer was leaking from seal and dripping from pipe. This went on all night dripping 2 quarts of water. The backflow preventer was replaced the next day and the pipes were not purged again. Ever since my pipes have sounded like they have rice crispies in them. I bled some radiators and at first just water came out but I became persistant as one radiator was making a non stop gulping noise at the elbow where the bleeder screw is so I opened the screw and let the water flow, it then begain to sputter and hiss and blast a frothy bubbly stream of water with anti freeze I could smell, because I did have some anti freeze left in my pipes. So why is this air no being rid of by my American Air Purger and auto vent. Is just too much air, could the american purger have got clogged with old anti freeze or goop. My auto vent did spit out some yellow slimy goop before it was replaced. Heeeellllllpppp!

aperson

When the guy first hooked up his power pump it sounded like he was injecting air into the system he said he pushed the bubbles "right back out" but I don't know. So ok, I can have it purged using my well water. Should I ask for a power purge with my well water? How long should it take. Why should I unhook my expansion tank? These bubbles are making me nuts!

JUGHNE

Why no well water?
Where does "city" water come from?

aperson

Yeh, why no well? Cause I'm thinking Perrier is a definate no. And that company, when I called back the next day told me to wait 2 weeks. They are done.

aperson

I can do this myself. I need to isolate the boiler so not to explode, cool down, turn off power, open some valves, close some valves, have a hose going into a bucket and the auto fill valve on full blast. Right! I'll have to send you guys some pictures.

JUGHNE

Are there any rocks in the river?

JUGHNE

It's in there, you just can't see it. But you are drinking it.

Zman

It is a good idea to look at the fill water no matter the source. Well water tends to be higher in TDS and alkalinity.

hot_rod

Youngplumber said:

There aren't any in the pipe after it's processed. Lol

85% of the US has hard water, above 5 gpg. If water comes from planet earth it has some minerals. A hardness and TDS test eliminates any guessing as to the water being suitable for boilers. Most public/ private water in the US is above the hardness that boiler manufacturers suggest.

Several way to reduce hardness remove it with ion exchange, or add hydronic conditioners that can lock up the hardness and help eliminate scaling.

I don't know of any water company that softens water, collected rain water perhaps? and in fact Denver is adding chemicals, taking the ph to 11 in some cases, to coat out old lead piping in the streets. Can't think of any good that will come from that, regarding hydronics


I'm of the opinion you "fix" the water before you put it in. Assuming it is above 5-7 gpg.

Jamie Hall

Actually, @hot_rod , a number of the more rural water companies in "fly over" country which depend on deep wells do soften their water -- but not by ion exchange. There are much better, more controllable methods.

But...

They require trained operators to keep an eye on things and do the necessary testing. Not a homeowner thing!

All that said -- municipal water, without any exceptions that I know of, has at least some chemicals added (one of the least treated is New York City, which has some of the best raw water in the nation! Hartford, Connecticut, too, and Boston. All three of which control all or most of their watershed lands and are surface water). The treatment processes, however, are not inexpensive -- and attempts to cut corners to keep water rates down are usually a mistake (see Flint, Michigan...).

aperson

I live in Michigan. I have not had problems adding my well water to my system in the past. I live close to lake Michigan and there is a lot of clay. The HVAC guy just got a lot of air in my system with his drippy backflow preventer and then replacing it and not purging after. The second guy I had come out is a former co-worker of the first guy. All the second guy did was hook up his circulatir pump and recycle the water through all the zones, too bad he started with the main floor then did the top floor then the basement, because they are numbered on the zone valves 1,2,3. But... the numbers mean first floor, second floor, basement. It pays to double check what you are doing. I have a man coming today from a new company. I just don't trust myself to do it or maybe I don't want to learn. But I am also worried about this person causing more problems like the last 2. And no the last 2 were not payed so their shoddy work wasts my time and theirs. Should be good business for the dept collectors, although they will never see a dime. My psi seems stable.

Jamie Hall

Ah yes. Mississippi River water. I helped out with some analyses for the City of St. Louis once. Interesting stuff, you've got there. Nitrates are, indeed, your biggest problem -- once it's been properly filtered -- and nitrates are one thing, oddly, which is exceedingly difficult to get rid of. I forget -- at this distance of time (getting on for 50 years now) just what treatment they were using, and I dare say it's changed in the succeeding years. I do not recall, however, that softening was one of the steps; surface water is very rarely hard enough to require that. I do recall alum, of course, and filtration, and chlorination...

JUGHNE

I guess we have one of the rare exceptions of municipal water supply.
It is pumped out of the ground, thru the mains, up the stand pipe/tower tank and piped to all houses. No treatment at all.
We did have to chlorinate the system perhaps 3 times in the last 30 years. The taste lasted for maybe 3 days each time.

As we added another well to avoid nitrates...down to 400'+, the water got harder, we now average about 4.6 grains of hardness for all 3 wells. 1.25 nitrates.
(as we drill deeper we get into those "rocks" that provide those minerals)
Water heaters here are expected to last 20-30 years.
Mine is 27 years old.

We are on the edge of the Nebraska sandhills and tapped into the Ogallala Aquifer.
25' to water, a lot of single stage jet pumps in a pit or basement were the normal.
1/2 mile south and maybe 6' to water.
100' to better water, wells might be drilled 100-150' deep.
Most towns here and farther west have no treatment plants.

Just some history trivia for those interested, Jamie, perhaps.
In the 1880's the railroad was built from Omaha to the northwest across NE.
They followed the small Elkhorn river. The RR was placed just on the edge of where you could pump water with a windmill and still have fairly solid soil. South of the RR is the 6' to water, occasionally wetlands, along the railroad is the 25-30' to water. North of the RR may be 50' or much more to water and hilly terrain. A watering station was needed every 10 miles for the steamer. So we have a small town/village every 10 miles from here to Omaha (20 towns) and the same way to the west. I have to admire the surveyors of the 1880's as they rode horses and walked the 400 miles of this route, dragging rods and chains.....Huh? Google that if you want.

Most of the RR has been abandoned and turned into a "Cowboy Trail" walking and biking route, though you are not to ride horses on it??
One good thing of this buyout by a conservatory organization is that the ROW is still intact and available to be rebuilt back to a RR.
A few miles of track was rebuilt to transport the "Evil Ethanol" product from a tank station to get it on it's way east of us. You are burning it in your car now.