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Is a Hot Water Expansion Tank required

12K views 9 replies 4 participants last post by  Bob999 
#1 ·
Here is the situation, I am on a "OPEN" (no Check Valves) well system. I had replaced the water heater, well pressure gauge, well pressure release valve and well pressure switch in January 2009. Well pump is set to 40/60 bladder tank set to 32psi .I have noticed a small drip which comes and goes from well pressure release valve, and hot water tank release. My shower (first tap in water line ) has also started to drip in the middle of night only. I called the plumber back and he stated I need a hot water pressure expansion tank installed... Is this the case, I would think the thermal expansion would be picked up by the bladder tank. And from pressure stand point would still be the weak link in the line as the expansion tank would be set to max water pressure 60 psi. Am I missing the ark or am I being sold one?
 
#2 ·
Go for the expansion tank--in my area the are required by code in most towns --so most new tanks get one.

The symptoms you describe sounds like a pressure problem.--Your plumber is in the drivers seat on this one.--Mike--
 
#3 ·
Go for the expansion tank--in my area the are required by code in most towns --so most new tanks get one.

The symptoms you describe sounds like a pressure problem.--Your plumber is in the drivers seat on this one.--Mike--
I would normally agree with the pro being in the drivers seat, however it was last year when he was driving and missed the exit? I did not seem to need one last year when all was replaced or is it lets see if a pressure issue developes before installing one? Again would the Well bladder not do this as well same type of tank just a lot bigger
 
#4 ·
Sorry you have reached the end of my knowledge --without putting a pressure gauge on the system.

There is a fellow here named Beenthere--He is the one that will give you the best advice---Seem like he's seen just about every odd situation.

The pressure tank is the most likely solution--let's see what the old pros have to add.--Mike--
 
#5 ·
If the water heater is directly connected to the well pressure tank with no check valve then the well pressure tank should be adequate to accept the expansion and no additional expansion tank should be necessary..

If your well pressure switch is set 40/60 the well bladder pressure tank should have 38 lbs pressure in the bladder when there is no water in the tank--not 32.

The fact that you are experiencing multiple problems that seem to be symptons of high pressure and have a well tank suggest that there is a problem with the pressure switch--perhaps the line that connects to the switch is plugged and the switch is not properly sensing pressure.

You need to get a known good pressure gage and check the pressure in your system to find out what is going on.
 
#8 ·
The results you post suggest the pressure switch is working correctly but is not adjusted correctly for 40/60. The results also clearly indicate that the pressure precharge on the bladder tank is low.

How large is your bladder tank?

What is the temperature setting of your water heater and is there any indication that the thermostat on the water heater is not working correctly? I ask these questions to try to rule out that you have a very small bladder tank--that can be overfilled by expansion from the water heater--or that your water heater is overheating and causing a pressure rise.

Also, it is possible that your bladder tank has failed and is sufficiently waterlogged that the capacity is very small. Do you get moisture at the schrader valve on the bladder tank when you check the pressure?
 
#9 ·
The results you post suggest the pressure switch is working correctly but is not adjusted correctly for 40/60. The results also clearly indicate that the pressure precharge on the bladder tank is low.

How large is your bladder tank?

What is the temperature setting of your water heater and is there any indication that the thermostat on the water heater is not working correctly? I ask these questions to try to rule out that you have a very small bladder tank--that can be overfilled by expansion from the water heater--or that your water heater is overheating and causing a pressure rise.

Also, it is possible that your bladder tank has failed and is sufficiently waterlogged that the capacity is very small. Do you get moisture at the schrader valve on the bladder tank when you check the pressure?
Well pressure tank is a WX-202 Well-X-Trol 20 gallon, I emptied the tank and flushed it and with pump off, house off water valve open water pressure went to zero and I checked air pressure and it read 32 psi. No water or moisture around water pressure tank. Hot water heater is 50 gallon set to factory default of 125 f. I checked water temp in sink and it reads 125 f as well. The water heater was installed January 2009.
 
#10 · (Edited)
Are you confident that the air pressure gage you are using is accurate?

Given all you have reported its seems there are only a couple of possibilities at this point:
1. You have a relatively small bladder tank (pump cycle of only 30 seconds while shower is running is suggests you should consider a larger tank or install a cycle stop valve) and that combined with low precharge pressure is causing a problem;
2. There is an intermittent problem with the pressure switch that occasionally results in late cut-off;
3. There is an intermittent problem with the water heater thermostat;
4. Three valves are failing at the same time.

I suggest you adjust the pressure switch to 40/60 and adjust the bladder tank precharge to 38 (with a known good gage) and see if the problem persists.

One easy check on your air pressure gage is to compare the air pressure in the tank with the water pressure reading--they should be the same when the tank is filled with water.
 
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