Two times now the hot water heater has started making a pounding sound and starts losing water volumn. This happens at all faucets. The cold water works fine with normal pressure and volumn. The water pump acts like it is trying to pump water into the heater but something is stopping the water from going in normally. I have checked the lines from the pump to the heater (have not disconnected) and all look goodl. This weekend was the second time this problem started. The first time it happened I was taking a shower and the water pressure dropped. After a couple of hours it worked normal again. Thanks for any ideas to check.
Water Heater Pressure
- Thread starter Snellcloud9
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Heating electrically? or from engine heat? Steam coming out or just limited water flow?
Sounds like the tempering valve on the heater may be causing some "water hammer" .. It may be that the electrical thermostat has failed and the water is so hot that the cold shots from a tempering valve are making it hammer..
another thought.. many heaters don't have a thermostat and will get really hot on electric power from dockside.. if the heater is left powered on for a day or so it may be getting hot enough to almost boil the water and causing the temperature/pressure valve (T/P Valve) to release, causing a hammer. These usually blow off to the bilge space, so it would be hard to find.. could also be a bad T/P valve.
So check from model/type heater if it has a thermostat.. if so, is that working.. check the P/T valve next .. then check to see if the heater has a tempering valve and if it is working correctly. Good Luck in the hunt !
Sounds like the tempering valve on the heater may be causing some "water hammer" .. It may be that the electrical thermostat has failed and the water is so hot that the cold shots from a tempering valve are making it hammer..
another thought.. many heaters don't have a thermostat and will get really hot on electric power from dockside.. if the heater is left powered on for a day or so it may be getting hot enough to almost boil the water and causing the temperature/pressure valve (T/P Valve) to release, causing a hammer. These usually blow off to the bilge space, so it would be hard to find.. could also be a bad T/P valve.
So check from model/type heater if it has a thermostat.. if so, is that working.. check the P/T valve next .. then check to see if the heater has a tempering valve and if it is working correctly. Good Luck in the hunt !
Hot Water Bang
The only time it bangs is when we turn the facet on and it seems the pump is trying to fill the water heater. I checked the relief valve and it seems to work. The water is really really hot when it comes out so I will follow that lead. It had been on a couple of days on electric when it does this. Next time I will turn off the electric for a while and see if that takes care of the problem. I don't know if it has a thermostat but will check. It is a Seaward. One thing about boats - you have to learn something new all the time. Thanks.
The only time it bangs is when we turn the facet on and it seems the pump is trying to fill the water heater. I checked the relief valve and it seems to work. The water is really really hot when it comes out so I will follow that lead. It had been on a couple of days on electric when it does this. Next time I will turn off the electric for a while and see if that takes care of the problem. I don't know if it has a thermostat but will check. It is a Seaward. One thing about boats - you have to learn something new all the time. Thanks.
Kloudie has a very good idea of the problem. It sounds like a classic example of a "water hammer" where air gets trapped within the system. When you turn on the pump and repressure the system an air lock (trapped air in the system) causes the water to be slammed backward into a closed valve or other closed body of water and makes a hammer sound. Opening and quickly closing a water faucet can also cause it to hammer. The only way to remove or stop the problem is to bleed the system of all air. This means finding all the areas that air can be trapped in or high points and making a exit point there where water and air can excape to remove the trapped air. This can cause damage to your water pressuring equipment if left uncorrected.
Ray
Ray
household domestic water heaters now require a vacuum break on the inlet side of the tank to eliminate the hot water from going out in the tank and not be replenished due to sometimes vacuum issues on the cold water resupply...regardless if you do not have one and it may or may not be an issue it definately does no harm to install and is very easy..and as well convert to pex at some point in copper if you have copper as modifications and repairs are very easy and faster then copper
Water hammer or steam
Water hammer only occures when you turn the valve off, never when you turn it on. the water is moving and suddenly comes to a stop and the inertia has to go somewhere. When you turn the valve on the water is at rest and just gets smoothly accelerated by the pumps pressure with no hammer. Steam can be produced when you turn the valve on however. EX: The temp of the water heater is 212.00001 F but the pressure of the pump causes the the boiling pooint to be 212.0002 F. When you open the valve you lower the pressure and get a steam explosion (bang) that is rapidly quenched by the increase in pressure due to the steam itself. course the actual flow of water is going to be reduced because the steam acts like an accumulator and the pump has to fill it before it sends water to the faucet.
I'd turn down my thermostate a bit. You don't need 210+ F water for any application anyway and you are just causing more heat loss (from the higher tem differential) and cost.
Water hammer only occures when you turn the valve off, never when you turn it on. the water is moving and suddenly comes to a stop and the inertia has to go somewhere. When you turn the valve on the water is at rest and just gets smoothly accelerated by the pumps pressure with no hammer. Steam can be produced when you turn the valve on however. EX: The temp of the water heater is 212.00001 F but the pressure of the pump causes the the boiling pooint to be 212.0002 F. When you open the valve you lower the pressure and get a steam explosion (bang) that is rapidly quenched by the increase in pressure due to the steam itself. course the actual flow of water is going to be reduced because the steam acts like an accumulator and the pump has to fill it before it sends water to the faucet.
I'd turn down my thermostate a bit. You don't need 210+ F water for any application anyway and you are just causing more heat loss (from the higher tem differential) and cost.
A water heater can hammer from the momentary drop in pressure when a tap is opened.. The hot water can flash locally and then the steam will collapse causing a hammer as it sees more pressure (pimp on) or cooler water in a downstream line. Should not happen if the thermostat is holding the water temp below boiling..
That can generate some pretty impressive forces! Had a 24" pipe about 300 yards long jump roughly 6 feet high and rip concrete foundations from this effect.. Something to be avoided!
That can generate some pretty impressive forces! Had a 24" pipe about 300 yards long jump roughly 6 feet high and rip concrete foundations from this effect.. Something to be avoided!
on occasion a fawcet or shower cartridge malfunction can cause pounding/hammer type issues while flowing water without having leakage problems..sometime caused by soldering and heat may deform cartridge and it bounces/vibrates
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