Fresh water pump sucks air at half tank

[bottieri]

My fresh water pump sucks air at half tank, then I have to refill the tank. This is an actual half tank - not by gauge.

Anyone have this experience they would share with me?

[larrybell]

This is going to sound funny, but have you checked your vent to make sure it is clear. If the vent is clogged, dropping level will reduce pump suction pressure, and it may not have sufficient suction pressure.

[bottieri]

Upon closer inspection, I found that the pickup pipe is mounted at about the 1/3 level - way to high to get full use of the supply.

I'm going to move the pickup to the drain line and cap off the other.

[john&scotty]

We had a similar problem with our - Our repair guy saw that the vent was no straight and this caused water to get in and not let the air out - also, our fill hose was about 2/3rds up the tank.

Check where the pump gets it's water - it is probably about 2 inches of the bottom, so you will never get all of the water out with the pump.

Anyyway, our guy put a pressure fitting in place of the gravity fill port and put the input to the tank directly on top of the tank - He then added a vent line from the top so I do not over pressurize the tank.

Hope this helps

[ghamblen]

Upon closer inspection, I found that the pickup pipe is mounted at about the 1/3 level - way to high to get full use of the supply.

I'm going to move the pickup to the drain line and cap off the other.

When you move the pickup make sure to connect it so you can still drain the tank when necessary.

[bottieri]

This problem is now resolved. Here's what I did to correct it:

The pump pickup pipe being almost half way up the tank was the cause. I cut that pipe and plugged it with a half inch OD brass nipple and capped the end. It is necessary to heat the blue plastic factory installed water pipe a little to soften it, to get the standard fittings to go into it. That was necessary at every connection. I of course, used clamps too.

I cut and spliced a tee in the drain line (which is at the bottom of the tank). It was necessary to install a ball valve between the tee and the drain cock as for some reason the cheap plastic drain cock allows air to be sucked in even when turned off. Regular clear plastic flexible pipe (hose) was used from the tee to the pump fitting. It is possible that this type of pipe could collapse under the pump suction if warm enough, but probably will be o.k. for such a short distance.

The pump intake is now teed off the drain pipe at the bottom of the tank and works perfectly.