njcampbell8
04-07-2009, 08:17 PM
Last weekend, I replaced 4 anti siphon valves (3/4") because they were leaking from multiple points. The bad valves were plastic and the new valves are brass. The main water line feed at this point in the system is PVC. To connect the main water line to the inlet part of the new brass valves, I used a 3/4" male adapter which I screwed into the valve and then glued the PVC main line into the slip part of the adapter. For 2 of the 4 valves, I'm now seeing a constant leak at the point where the adapter is screwed into the valve on the inlet side (the outlet side is set up the same way, but any leaks would only occur when the valve is open and that zone is being watered, I'm only concerned with the pressurized side of the valve that is connected to the main water line). When I connected the adapters to the valves, I used 3-5 wraps of teflon tape and some pipe dope for good measure, thinking that it would prevent any leaks.
Questions:
1. I got some advice that I could use a brass version of the 3/4" adapter to attach the PVC main water line to the valve. The justification for this thinking is that the brass threads will line up better than the PVC threads and will result in a better seal. Is this acceptable and how should I connect the slip part of the brass adapter to the PVC? Is it OK to glue the PVC to the brass adapter?
2. If I have to use a PVC adapter, what am I doing wrong that is preventing me from getting a watertight seal? Also, how can I test the seal before I install the whole valve back into the system? (I've now cut out and reinstalled these two valves multiple times only to find the same leaks.)
I'm looking for solutions that work, not necessarily up to code. Thanks for your help. I'm in a bind.
Questions:
1. I got some advice that I could use a brass version of the 3/4" adapter to attach the PVC main water line to the valve. The justification for this thinking is that the brass threads will line up better than the PVC threads and will result in a better seal. Is this acceptable and how should I connect the slip part of the brass adapter to the PVC? Is it OK to glue the PVC to the brass adapter?
2. If I have to use a PVC adapter, what am I doing wrong that is preventing me from getting a watertight seal? Also, how can I test the seal before I install the whole valve back into the system? (I've now cut out and reinstalled these two valves multiple times only to find the same leaks.)
I'm looking for solutions that work, not necessarily up to code. Thanks for your help. I'm in a bind.