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Hot water heating system problems
Thomas
Member Posts: 3
1. Water has been spitting out of the pressure relief valve for a long time now. (I have lost all my glycol.) Does this automatically mean that the pressure relief valve needs to be replaced? Or could it be something else?
2. Lately, the system has been losing pressure, as well. I pump it up to 18 PSI, using a bicycle pump connected to the air valve on the expansion tank, but it is back down to close to 0 PSI within a day (where of course, the pressure relief value will spit less water). I removed the expansion tank and checked the air valve (under water) for a leak. The valve does have an extremely slow leak, a single bubble every minute or two. Is this enough to lose 18 PSI in a day?
3. I also have a pressure-reducing valve. Could this be the problem?
The good news is that I have plenty of heat. But when the pressure falls, the system starts to make little banging noises, prompting me to pump it up to 18 PSI (and start the cycle all over again).
2. Lately, the system has been losing pressure, as well. I pump it up to 18 PSI, using a bicycle pump connected to the air valve on the expansion tank, but it is back down to close to 0 PSI within a day (where of course, the pressure relief value will spit less water). I removed the expansion tank and checked the air valve (under water) for a leak. The valve does have an extremely slow leak, a single bubble every minute or two. Is this enough to lose 18 PSI in a day?
3. I also have a pressure-reducing valve. Could this be the problem?
The good news is that I have plenty of heat. But when the pressure falls, the system starts to make little banging noises, prompting me to pump it up to 18 PSI (and start the cycle all over again).
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Comments
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The x tank does need to be replaced as well as the relief. I would also at the same time put on new air vents and check to make sure the pressue valve is not seeping past the set point.0 -
Losing glycol
Are you having the glycol tested every year to see if it's not turning to acid? Since your having a problem now make sure the correct glycol is back into the system and keep it tested.0 -
Glycol
Thanks, but I've lost so much of the glycol, there's nothing left to test. The water I'm losing now is almost clear. I put a container of it outside, and it froze. There's no point in replacing the glycol until I fix what's allowing it to escape.
I didn't know glycol turned to acid, so thanks for that advice. I'll keep my eye on it , once everything else is fixed.0 -
Losing Water
The expansion tank should be pumped up when the system is empty to what ever pressure required say 15 psi. or what ever. Then the system should be filled to the same pressure as you have in the expansion tank. Then as the water expands this pressure will force back against the bladder and take up the expansion.
If you have leaks in the system then you will need to isolate it section by section and test each section for pressure drop.
The system pressure is only needed to be able to lift the water in the system to the higest point. If you are single storey then 8-11 psi is more than ample, 2 storey 12-15. It depends on how far above the boiler is the higest point in the system.
2.3 ft height = 1psi. ie 23 ft vertical height above the boiler = 10psi + a small margin say 2-3 psi. = 13 psi.
There is little point in running too high a pressure.
To test the tank for leackage take the valve core out, tip the tank valve down and see if there is any water in the tank if it is leaking replace tank.
If the valve leaks just replace the core with a new auto valve core.0 -
Bang when zone valves close.
Last year I bought this 16 year old house. It has a new furnace, 2 years old. I have read some info on zone valves. Some suggest putting them on the return end of the loops, some suggest a hammer arrester, or seperate circulator on each line and some suggest putting in a differential pressure buypass. I tried removing one of the springs on each Honeywell v8043 but that didn't help much. Any thoughts out there to what is the best to do????0 -
This is scary!
Frank was the only one who started to see the real problem. If you are "pumping up the system pressure with a bicycle pump", through the expansion tank, you need to call a professional.
The expansion tank is comprised of an air chamber with the bicycle style Schraeder valve (air tapping), a bladder, and a chamber open to the heating system. The expansion tank bladder has ruptured and the expansion tank needs to be replaced. THAT is why you are losing water through your pressure relief valve. If you have a boiler makeup water feed line attached to your system, it fills with water through your boiler makeup line, then the boiler fires, heating up the water and with no room for expansion (shot expansion tank) the pressure increases and blows the pop-off. If you don't have that, you could still have some water leakage through the pop-off due to you charging the system pressure with your bicycle pump, then when the water heats up the pop-off releases, and all your pressure goes down to zero.
Change the expansion tank first then try the pop-off if it is leaking. And add glycol again (not RV antifreeze) so your system doesn't freeze.0 -
Furnace?
Furnaces are for scorched (forced) air systems with ducting. They don't have zone valves. Hot water boilers have zone valves that control the flow of water to each zone.
The most common source of banging in heat pipes is air. Thoroughly purge your system of all air and there is a good chance the banging will go away.
Otherwise, the second most common reason is due to a zone valve being put in backwards. Look for the arrow on the zone valve and trace the piping. The supply for a hot water boiler comes out of the top of the boiler, the return goes in at the bottom on the front or back.
Zone valves normally go on the supply piping, with a boiler drain attached to the return piping allowing for purging of the system. Individual circulating pumps are the fairy tale of circ pump manufacturers (read $$$$$). They do not allow for positive stoppage of water flow which creates a ghost flow situation many times. Plus it is much more expensive to put the system in like that, AND to run it like that. Zone valves may use $2 in electricity a year as opposed to circ pumps which may average about $80 per year.
Water hammer arrestors have no business in a hydronic system and I don't believe any of them are rated for those high temperatures.
All copper water piping up through 1 1/2" is required to be supported every 6', pex is required every 32". If your piping is supported like this and is still banging, check your circ pump sizing.1 -
Expansion tank
Thanks for getting me on the right track. I was using the bicycle pump because I know the Schraeder valve is leaking air (at least a little). Pumping it up with some air brought it up to the correct pressure again.
The expansion tank had become water logged a year ago. I removed the tank and removed the Schrader valve. I refilled the tank with water from the pipe end. No water leaked out from the valve end. (Of course, it wasn't under pressure.) When I replaced the Schrader value, some very slow bubbles did leak out when held under water. All of which led me to believe that the bladder was OK and air loss was the problem. I thought that until I replaced the Schrader valve, that I could keep the the pressure up on occasion with my bicycle pump. Of course the bladder could have rupturerd since then, or have been ruptured all along, and my original testing just wasn't sufficient.
Could the tank have now filled with water again (without the bladder rupturing), simply because the air leaked out on the other side of it?
I will pull the tank again. Can you recommend any specific test (other than the obvious one I did before) to deterimine if the bladder has ruptured?
Thanks.0 -
Expansion tank
Hi,
Even a small bubble over a period of time will drop your pressure in the expansion tank. So you need to make sure this is not leaking pays to keep the cap on as well but the valve should still hold without the cap.
IF the tank is not piped right it will become waterlogged but of course if you lose pressure in the tank then water may come up into the tank. The pipe between the system and the tank should be as long as possible and should have a heat loop in it. ie the connection into the return SHOULD BE FROM THE BOTTOM of the pipe. underneath in other words. Or a U shaped heat loop to prevent Hot water getting into the tank as if allowed this will shorten it's life.
In over 30 yrs I've only ever had to replace about 2-3 tanks in that time. (Because of wrong installation), Mind you we also use the better quality European tanks here.
As I said before the air pressure in the tank should be the same as the system pressure COLD with the system EMPTY, I suggest you pump the tank to say 15 PSI while it is disconnected from the system then connect it up and pressurise the system to the same 15 PSI,Then as the water heats and the water expands it will push against the baldder. It is better to pump the tank with nitrogen as the 21% oxygen in the air you pump in will seap out over time though the bladder.0 -
oh my!
expansion tank with bladder = waterlogged? =replace leaks air =replace !antifreeze turning to acid ? wow! nitrogen? wow! if your system is on city water could be thermal expansion but most likely by reading what you wrote you have a bad expansion tank . check #1 turn off supply water after you get air set in expansion tank to proper level and water press between 12 and `15 lbs. on boiler rplace pop off valve as it has been used and seat is most likely dirty and may never stop spewing run boiler up to temp . does pressure hold and popoff not leak? if so open water supply . does press hold ? does popoff leak if so bad feeder! tank has water on wrong side of bladder (water from air valve)if so tank is bad ! does any of this make sense i hope so theese parts are cheap and a hell of a lot easier to change than hooking up the old bike pump every night .as for the zone valve vs pumps debate if the installer pays attention to some small details when piping his system you wont have ghost flow that is why they make checks and flo controls im a user of pumps not a maker and i dont tell fairy tales 16 years with pumps 3 failures in that time and 2 were factory defects bet ya your zone valves dont have as good a record . sorry for bluntness but i like to see things done right good luck with your problem hope the tests help0 -
Even if the boiler was fed by city water, thermal expansion wouldn't occur becasue of the backflow preventer. Your glycol should really be checked yearly, even with it all drained out now, the damage that may have been caused fromt he untreated glycol may still be there. We went to a middle school once that hadn't treated their glycol in ten years.. it wrecked 10 failry new burnham boilers from all of the acidity. Not to mention all the shmegma caked in the piping. We had to **** out hte sytem with a caustic liquid that smelled freakin horrible before we piped in the new boilers....0 -
expansion tank problem
if the shraider valve is leaking air you expansion rate is zero, and causing the relief valve to release. You need to correct the problem of the expansion tank first.
The second thing to correct would be you pressure reducing fill valve. If you system stays at zero pressure after the relief valve has spilled this valve is not working to bring your pressure back to 12 or 15 PSI.
With a system spilling continuously will give you the next problem of you water having new oxygen in the system and attacking the ferrous metals causing more corrosion. A simple solution to this can be with adding a product calle d the AXIOM system feedef. This is being installed in a lot of new systems to avoid having a direct water tie in to the system. You have a capacity of 5 us gallons of a premixed glycol/water mix (no more than 30% solution of glycol) a corrosion inhibitor can be added to this to give the fullest protection to your heating system. This tank also allows you to have a visual to see if the fluid level drops. If you have a drop in level you have some form of a leak in your system.
Good Luck
RF0 -
venting hydronic series loop
I have a series loop system. Two zones, one upstairs and the other downstairs. My installer split each of these systems but did not up size the common returns on either. I have been living in the house for 10 years with few problems. This winter, however, I have been experiencing the sound of water flowing through the upstairs loop. I have no purge valves but I do have key vents on each section of baseboard. I try bleeding from these points but the water sound continues. I have auto water makeup to replenish as I bleed. Should I continue bleeding?0
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