Preheater problems-Any advice??

[larrboy]

We have a 2x8 D&G, I had a plumber make a copper tubing preheater that sits on top of the flue plan (no hood). We have it slanted so the water from the steam runs off it so we have warm water to use. We ran water thru it today to get the "bugs" out of it. If the holding tank is half full or more the water ran thru the preheater fine. As soon as the tank got lower than half it is not running in the evaporator fast enough. The evaporator is on blocks about 5 inches off the ground. If we have it going full bore the sap will not run in fast enough :(

Do we need to lower the evaporator to ground level? The vat sits higher than the evaporator. Any ideas?

Thanks

[Haynes Forest Products]

What size pipe did you use 3/4 I hope. Is the float to big so the head pressure cant over come the float. Add weight to the to the float it might help. But it could over fill when the tank is full. Raise the vat/tank.

[Maplebrook]

Somewhere I read that your tank should be at least 18" above the pan.

[NH Maplemaker]

Yes it sound like the head tank is not high enough!! After my alarm goes off telling me I only have 6"left in my head tank,I have got to really pay attention to the flu pan level ! So you may have to raise your head tank!! JimL.

[MFarmall]

I think Jim has it right. I made a pre-heater last year from 3/4" copper and have the bottom of the head tank 30" above the float box. Even with the head tank 1/3 full it has plenty of pressure at the float box to still flood the pans good if need to. I'd say if you can raise the head tank to get a little more pressure. With 3/4" from the tank to the float box has plenty of flow for me.
Also if you can get a hood over the pre-heater it will make a real big difference in the temps you get from the pre-heater. Mine has been averaging 195 degrees coming out of the pre-heater, with a damper in the stack out of the hood.
Mel