I have a customer that wants a closed loop stand alone ice melt system (small 40x12 driveway). Can the expansion tank be sized to provide volume and proper system head pressure?
@jk685
Жыл бұрын
@@MechanicalPros can you suggest whom could assist in sizing, say a mfr rep??
@rogerg4916
Жыл бұрын
I have a closed loop hydronic system heating only a floor slab. My 2 gallon expansion tank loses air pressure but water does not leak into the tank and the Schrader valve does not leak when soap tested. Have you ever seen a situation where air is leaking through the diaphragm but water does not leak into the tank?
@rogerg4916
Жыл бұрын
@@MechanicalPros Actually, I did replace the valve core but it made no difference. My system is low pressure (7-15 PSI recommended) and low temperature (~100 F) so I'm thinking that the only reason that water does not leak back is because of the low pressure. I have ordered another tank but not yet installed it. I have a question regarding initial air filling pressure. I have always been more concerned about the pressure going too low than too high. (It has a 30 PSI relief valve.) But if for some reason the gas burner goes out the pressure would drop (maybe even go negative if the weather is very cold) and the pump could be damaged if it is still running without pressure. So if I connect the tank while the system is cold I'm thinking I should then add water to bring the system pressure actually a little above the initial tank pressure so that there is a reserve of water in the tank to allow for the contraction of water volume due to temperature drop. So maybe 8 PSI intial tank pressure, then add water to bring cold system pressure up to 12 PSI, then when the burner comes up to cut off temperature the pressure would still be well below 30 PSI. Am I right about this?
@rogerg4916
Жыл бұрын
@@MechanicalPros I don't know what the water pressure will be until it heats up and cuts off. How much air pressure do I put in the tank before it heats up?
@rogerg4916
Жыл бұрын
@@MechanicalPros Just to give you a follow-up: I did replace the expansion tank and connected it the way I described. 8 PSI intial tank pressure, then brought cold system pressure up to 12 PSI. Turned on the propane water heater and when it came up to cut off temp around 100ºF the system pressure was 16 PSI. Since then it has been functioning just fine with system pressure holding between 14 - 16 PSI. So definitely the bladder was leaking air into the system without any water returning into the tank. I would think that probably the leak was acting as a one way valve due to the low system pressure.
Пікірлер: 6