check valve question - PHOTO

[mele63]

I believe this assembly includes a check valve. While cleaning with the hose I put some water in the pipe and it ran out (quite slowly) through the bottom. Does this mean the valve is bad? For what it's worth, somebody put a second check valve on the system. I don't know if the second one was installed because of a problem, or incidentally when they put a radon system in the basement and sealed the pit.





Anyway, even if it's bad, is there any harm in leaving it in-line? As you can see in the second photo, it appears the bottom connection is cross-threaded and I'd prefer to leave everything together (it all worked OK before pulling the pump out).

Also, my newly-purchased Liberty pump has a 1 and 1/4" outlet; the old pump is clearly rigged with 1 and 1/2" pipe. I assume it would be easy enough to use an adapter on the new pump (1 and 1/4" to 1 and 1/2")?

The new one's going to be a back-up.

[LazyPup]

The backwater valves used in sump pump applications are notorious for allowing a small percentage of seepage backflow but this is generally not seen as a problem because any water backflowing past the valve would ultimately end up back in the sump. The only real concern here is that in a worst case scenario the amount of water backflowing into the sump could be sufficient to raise the sump level above the cut in point for the pump motor and would result in a short cycling condition. For this reason it is often recommended that we install a manual gate valve above the backflow valve to allow a positive shutoff for instances when we need to pull the pump or backwater valve for maintenance or replacement.

The device shown in this picture is connected to the pipe by means of compression fittings therefore it would be a very easy task to loosen the compression couplings, remove the device and re-connect the pipe by gluing in a coupling.

The threaded connection at the pump does appear to be cross threaded but as you stated, it does not appear to be leaking. Here again, even if it were leaking any water leaking out of the fitting would return to the sump so it would cause no problems other than a slight loss of pump efficiency.

Cross threading the thread adapters at the pump is a very common problem which usually results from a slight incorrect installation procedure. Many people glue the thread adapter on the pipe then thread it into the pump port. When done in that manner the weight of the pipe will often make initial alignment difficult and result in a cross thread such as you have. The preferred method is to screw the thread adapter into the pump first, then glue the pipe into the adapter.

In residential plumbing the only drain in the house that is permitted an 1-1/4" drain line is the bathroom lavatory bowl waste arm which is limited to 5' or less. In commercial plumbing 1-1/4" may be used for a drinking water fountain or office type water cooler, but here again, it is usually very limited in lenght. By code the size of the trap and drain line should be the same size as the drain tailpiece however the code will permit an increase of one nominal trade size. Due to the extremely limited amount of 1-1/4" pipe permitted in a structure it is common to opt for the code exception and use 1-1/2" pipe simply because we no longer need to maintain an inventory of 1-1/4" pipe and fittings. As a result, it is becoming increasingly more difficult to even find 1-1/4" pipe or fittings outside of the commercial plumbing supply house.

In creasing the size of the pipe from your sump pump will not present any problems, in fact, if you will consult the instructions that came with your new pump you will find a performance chart. In another post you stated that your pump is rated at 30gph. Technically that should be gpm but we all make slight typo's here and there so that is not a problem. At 30gal/min that would then be 30gal/min x 60 min = 1800gal/hr which is a typical rating for a 1/3hp sump pump. You should note that the performance chart also lists a vertical rise such as 1800gph @ 10' vertical head. The chart or graph will also indicate how much the pump performance falls off as the vertical static head increases. The rate that performance drops off is quite dramatic, in fact most sump pumps will drop off to zero at approximate 2 times their max performance lift, which in this case would be 2 x 10' = 20' vertical head.

When computing vertical head we must not only consider the actual distance that we intend to lift the water, we must also consider pipe friction which is expressed in vertical head as well, thus the total vertical static head is a combination of the actual vertical lift plus the line friction. In sump pump instruction manuals rather than get involved with detailed line friction charts they typically suggest a maximum lift and if your total length of horizontal run exceeds 25 or 30' you should increase the pipe size by one nominal trade size to compensate for pipe friction. The horizontal pipe must also be supported with a 1/4" per foot pitch downward toward the discharge end. This is to insure that any water in the pipe will continue to drain out when the pump stops.

To make the conversion from the 1-1/4" port on your pump to 1-1/2" pvc pipe you will need an 1-1/2 pvc slip x 1-1/4MIP adapter which you can find in any hardware or home supply center.