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Re: How to re pressurisecentral heating system
I'm Harvey the Master Plumber.
Your problem is: The Alpha SY24 boiler has stopped working. The pressure gauge has dropped, you need to know how to re pressurise the system once the radiators have been bled
Every hydronic heating system is required to have a presure regulator. Most guys call it a feeder valve. Every one I've installed or worked on had one. It's job is to keep the water pressure constant by adding water when you release some air without over filling the system. Sounds like it's not working. Some types can be serviced, others cannont so you may have to replace it. If you're not sure what to do it might be prudent to check the Repair Directory for a repairman.
Feel free contact me again! Please give me a rating here at fixya.com before you sign off Thank you, Harvey your Master Plumber
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I assume losing pressure through the PR means Pressure Relief Valve (PRV) or temperature pressure (TPR). Open in TPR may mean boiler is overheating/overpressurized. Open in PRV means the Pressure Reducer/Fill Valve in the fill line of the boiler is broken.
House Water Pressure in a home is 30/40 PSI min to 60-80+PSI max.
Boiler PRV/TPR are set at 30 PSI open (SYSTEM PRESSURE) so too high a house water pressure will open the PRV/TPR. Replace the reduction regulator on/in the fill valve assembly
The squealing sound generally comes from a circulator pump, if it has a drive coupling between motor and impeller housing there is an oil cup/or oil hole, add oil until it is full! If it is a cartridge style circulator you may have to replace it.
Sometimes air in a system will cause this squeal noise as well. Purging the air out of system may be required. If you need to know how to purge a system there is a good pdf file at this link for $8.95 The Basics of Purging Air From your Forced Hot Water System & Troubleshooting A Leaking Boiler Relief Valve Miller Furnace Books Repair
The Expansion tank is factory set to 12 psi and the only way to tell if it remains with 12 psi is to drop the system pressure to zero and check the tank with a pressure gauge. If water comes out the air valvestem when you apply the pressure gauge, the tank is bad, replace it! If there is less then 12 psi on the tank add air to 12 psi and open water valves back up to normal operating pressure. Usually the feed valve will automatically stop at the preset setting.If the boiler is leaking water out any relieve valve drains, the feed valve, relief valve and or expansion tank may need to be replaced.
Hi, your boilers pressure should be holding 1.5 bar with the relief set about 3. If the pressure is below this the flow switch will cause the boiler to stop as theirs not enough pressure to operate. Another thing, does your boiler have an auto fill system or do you need to plug a hose in to fill it? If its an auto fill system and you lose pressure you could have a leak.
Pressure relief valve - replace The internal seal gets bunged up with dirt & scale and then leaks water [pressure] to that outside pipe To avoid draining the whole system, turn off the two central heating taps on the 3/4 pipes and then operate the valve manually and / or disconnect - only a small amount of water will escape / drip to below the boiler Replace valve and fill as before. If you think your system needs flushing out - now is a good time Turn off mains electricity to boiler before starting work
Sounds like the expansion vessel in the boiler has lost pressure or is faulty. If you have a tyre pressure gauge, locate the expansion vessl and check the pressure via the schraeder valve. It should be around 1.5 bar. If there is no pressure you can re pressurise it with a bicycle pump. Should it not pressurise then you will need a new one. The pressure relief pipework outside is damp because the system is over pressurising at relieving pressure at 3 bar. This obviously causes a system pressure drop. You can install a pressure vesel into the heating return pipework should accessing the boiler be difficult.
there should be a pressure rellief valve fitted.
it also sounds like the heat exchanger is blocked if the hot water is not as good as it used to be and the boiler reaches temperature too quickly then there is scale in the heat exchanger and needs to be cleaned or replaced
The first thing you need to do is to put some more water into your heating system. This is usually done by allowing water from your (pressurised) domestic cold water supply to flow into the system: On older boilers, this is done with a connection (often made with a removable hose) on the pipework just outside the boiler. Newer boilers may have a built-in connection with some sort of removable link (sometimes looks like a plastic key).
Once you've got the boiler up to working pressure (typically about 1 bar - 15 psi), you should be able to bleed your upstairs radiator properly.
This may be all it takes, though the pressure excursions you're getting when you run the hot tap suggest there may be another problem. See what happens to the pressure as the boiler heats up and cools down. There really ought to be very little pressure difference between the two conditions. If you see significant changes, this usually means that the "pressure vessel" (or in hydraulic terms, system accumulaor) has lost its air charge.
The pressure vessel is a metal container inside the boiler, usually painted in red enamel. Somewhere near the top, you will find a schrader valve (like the one on a car tyre), and you can use this along with a tyre pump to replenish the air in the top of the vessel. This will reduce your pressure transients for a while, but you need to keep an eye on it. If the problem returns, you probably need to replace the pressure vessel (or clag another one into the plumbing alongside the boiler).
a couple of things , is your filling loop disconected ? , and are all your radiators blead from air, have you got a high point where the air can get stuck in system say pipes going into roof etc you may need to fit a air release valve in line at highest point to remove the air from system , your boiler should be around 1.5 bar running preasure average setting . if you are constanly filling with water you could be exceeding the pressure valve limet which releases pressure from system this could be faulty ?