Check valve woes

[RepairNovice]

OK this is ridiculous.

I have what I thought was 'standard' ABS black piping from my sump pump up about 8 feet and then leaving the house through a basement wall.

On recommendation from a sump pump tech guy, I just bought a second check valve. At the store I asked which of the 4 or 5 models I should buy, the clerk said they're all basically the same.

I picked the one that looked most like the one I already had.

The package states: Burke Model 350362

1 1/4" x 1 1/2" "Union" type check valve. Universal fit

I take it home and get ready to do my plumbing job. Wouldn't you know it? The damn valve won't fit over the ABS pipe!

I measured the pipe: ID: 1 4/8" - 1 5/8", OD: 1 7/8"

There is no way the ABS pipe is going to fit into this check valve!

Please let this dummy know what type of check valve I need to buy. :( TIA

[Eric in North TX]

Wouldn't the proper thing be to buy an internally threaded one and 2 hose type fittings the size of your tubing.

[RepairNovice]

Not sure. I just know that the existing one is similar in design to the one I bought, and has rubber fittings at each end that slip on top of the ABS pipe. Then they are fastened with metal clamps (clips).

[Harry K]

You do have standard size pipe. All pipe sizes are based on the _internal_ dimension. What you have is a check valve sized for an 1

1/4" (internal) pipe on one and and an 1 1/2" pipe on the other.

You might do some googling to find what size pipe (internal) is for a given outside diameter - must be a chart somewhere.

Harry K

[Anonymous]

You do have standard size pipe. All pipe sizes are based on the _internal_ dimension. What you have is a check valve sized for an 1

1/4" (internal) pipe on one and and an 1 1/2" pipe on the other.

You might do some googling to find what size pipe (internal) is for a given outside diameter - must be a chart somewhere.

Harry K

You do have standard size pipe. All pipe sizes are based on the _internal_ dimension. What you have is a check valve sized for an 1

1/4" (internal) pipe on one and and an 1 1/2" pipe on the other.

The external size of all pipe stays the same and it is the inside diameter that changes.

[RepairNovice]

OK thanks for your responses.

After running around today to no less than four different local hardware stores, none of which had the proper check valve, I was referred to a Stan the Plummer's shop.

Only at Stan's was I able to find the correct 1 1/2" check valve that would fit my standard 1 1/2" ABS pipe.

Quite a learning experience.

It's funny because as I was pulling into Stan's back driveway I remembered being there about ten years ago to buy an obscure fitting for my sump pump that no one else had.

[Harry K]

So was it a standard pipe size? I got to wondering about it after I posted.

Harry K

[Harry K]

Say what? You are joking, right?

Harry K

[Don Young]

Say what? You are joking, right?

Harry K No, he isn't but it can cause confusion and argument because of the way iron pipe is sized. The nominal sizes of iron pipe are based on the nominal inside dimensions and schedule 80 pipe is pretty close to the nominal size. However each size (1/2, 3/4, 1, etc.) has its standard dimension for the outside since that is the dimension that is threaded for the fittings. If you get a schedule 40 3/4" pipe it has the same outside dimension as a schedule 80 or schedule 160 3/4" pipe. The schedule 40 pipe, which is what is commonly used for plumbing, is thinner wall and larger inside while the schedule 160 is thicker wall and has a smaller inside dimension.

Don Young

[Harry K]

Okay, I think I knew that :) but I misread his post as a, for example,

1/2' pipe would have the same outside diameter as a 3/4", 1", etc.

Harry K