March Pump Prime

Any one have difficulty getting thier March pump to work correctly? On my Cart is 2 10 gal Igloo bevergage coolers (liquor tank and Mash Tun) and a 7.5 gallon stainless kettle on top of a turkey burner ( which is on the floor). The pump is well below the bottom of both coolers and kettle.

I have setup two 1/2 ID ball valves on both sides of a March 250 deg rated pump with 12'. Infront of the intake is a line to my kettle and one to my liquor tank. I can open either the tank or the kettle valve wide open and wont be able to push back up to the top of the Mash tun. I had to put in a drain off valve at ground level, run it until no bubble in line, then shut that valve and open the valve to the top of the mash tun for it to work. It works for a couple minutes then slows to a trickle.

I guess tonight I will try and remove the pump intake ball valve, but wanted to know if anyone else had some suggestions. All my hose is 3/8 ID poly.

ps. Man its frustrating to put together a cart, and end up lugging around hot liquid anyway!!

I've never had trouble with mine. It's only 2-3 inches below the kettle and starts moving wort as soon as I turn it on. I have 1/2 ID on the inlet and it's 2 feet long. No valves either.

It's possible the pump is cavitating (turning wort into steam inside the impeller). A throttle valve on the outlet might help.

Maybe a clog in your source pot? I use my pump to recirculate to vorlauf. I've got a tee after the pump so that when I'm happy with the clarity I close one valve and open the other to send it to my boil pot (drain line). This is also what I use to prime with. Open the drain line until liquid come out the pump and then close the valve. I also use the pump to recirculate the cooled wort back to the boil pot to cool the whole wort at once. Here I sometimes have problems with slow flow and this is always attributable to hops and break material clogging my boil pot outlet filter.

Another possibility is a leak in your connections BEFORE the pump. You might not notice a drip and once the pump starts it can suck air INTO the lines and after some time, enough air could get in to loose your prime.

Well, I took the whole rig apart last night, removed the valve on the input side of the pump, changed the position of the pump so that the outlet is facing up, and added a "prime valve" off a T, post pump.

It definately seems to work better, I have to let gravity fill the pump and then turn it on. However I am still losing pressure after a time. I suspect that the inside diameter of the kettle valve is too small and the pump is drawing air from the HLT input. I plan to put a vavle there, but eventually get larger kettle. I would like to get to 10 gallon batches eventually anyway...

thanks,
Adam