Hi muzzytt,
The hose should not be popping off. The regulator should only be supplying somewhere around 20 psi. It sounds like it is leaking through from the high pressure side. In other words a bad regulator. That said, a couple of other thoughts...
If the regulator is "heated" it sounds like it is for CO2. CO2 in a pressurized tank is in fact a liquid. As it is drawn off the liquid must turn to a gas and this requires considerable heat input. A "normal" regulator may freeze up if used on CO2. If you are using a CO2/Argon mix as is common for MIG welding, you do not need a heated regulator.
Here is an example of a typical flow meter regulator
http://www.harrisproductsgroup.com/en/P ... lator.aspx Is this something like what you have?
There is a proper procedure for placing one of these in operation.
1 - Make sure the needle valve which controls the gas flow is SHUT. If the needle valve is open you may shoot the flow meter ball up with enough force to damage the flow meter tube when you open the valve on the tank.
2 - SLOWLY open the valve from the high pressure tank. Stand to the side of the gauge face just in case the gauge leaks (so you don't catch the gauge cover in the teeth).
3 - Once the gauge shows the full pressure of the tank, open the valve fully and tightly against its back seat. This prevents gas from leaking along the valve stem.
4 - SLOWLY open the needle valve to pressurize the hose to the welder. Just open it a little.
5 - Set the desired flow rate. I do this by placing the welder in PURGE mode and pulling the trigger on the gun. This allows gas to flow without feeding wire. If you do not have a purge mode on your welder you can just release the tension on the wire feeder and it will revolve but not feed any wire. 20 CFH is a good starting point. You will get to know when you need more flow or less.
To secure the system you should first shut the valve on the tank then bleed off the gas pressure. Shut the needle valve in case you are in a hurry next time.
Bottom line it sounds like you have a bad regulator and/or the wrong regulator. Try placing it in operation per the above steps. If it still pops the hose see it the seller can provide you with a replacement. If not, shop around for a new one. If you need assistance selecting a proper unit just ask in this forum.
Ken