Akagis_white_comet
New Member
Hello All,
I'm Travis and this is my first post here. Coming from the world of Rotary Engines (3-rotor RX-7 owner here... ), I'm pretty well-versed in electrical, mechanical and plumbing when it comes to oil/coolant/fuel/etc. Since our cars use NPT connections here and there, I know how to teflon tape metal pipe connections correctly. But what is troubling are the nonmetallic NPT connections.
My fiancee and I bought a mobile home built in the early 70s on the cheap. No surprise, the plumbing was in abysmal condition due to prior owners' "repairs", a combination of copper, galvanized, brass and anything else found at the big box stores' clearance aisle. between this and a scary number of fittings applied to every junction, the writing was on the wall.
After having three different lines fail in two weeks, plus the hot water heater (from 2006) due to incorrect practices, I determined that ALL of the supply plumbing was suspect and we decided to start completely fresh on it. The plan was to run fresh CPVC pipe inside the house, eliminating all of the old stuff from the house as a whole.
I know how to correctly handle CPVC and opted to go this route to keep the project cost as manageable as reasonably possible. I extracted the old Umbilical line, disassembled it and found that it was cobbled together and in rather poor condition. Removed the copper from it, then cleaned it up and reassembled it. Re-routed it to the Kitchen in place of the bathroom to eliminate as much plumbing exposed to cold as possible. Put a Main Shutoff Valve (sillcock with flange mount, Lowes# 21508) inside where it enters the house. This works fine and has no issues.
With all of the external plumbing resolved, I started on the inside. As our hot water tank was on its last legs, we opted to go with two smaller tankless water heaters. One for Kitchen and one for Bathroom, in order to cut the plumbing effort in half. Did the whole kitchen in CPVC, adding a branch line for the refrigerator (planning for a newer one with ice maker later) and dishwasher. The way I did this was with a 1/2" CPVC Male Adapter at each device's connection, and a 1/2" PVC quarter turn Ball Valve to shut off the supply for servicing. These were cheaper than regular shutoff valves and far easier to mount solidly on 1x4s
Did a test on it, no leaks where the valves meet the CPVC male adapters. So I continued onward to the bathroom, using the same logic as the kitchen. All is good so far. The only exception to this are the washer's lines. CPVC male adapter meets 1/2" braided stainless steel sink hose (IPS/NPS thread, with the gaskets in both ends). Then a 1/2" brass hex nipple, 1/2" PVC street elbow and finally a flange mount sillcock (Lowes# 21508 again).
All of the aforementioned washer plumbing is housed inside a removable panel, with the sillcocks protruding through.
So here's the problem:
#1: Female Brass threads (Sillcock) + PVC Male Thread (on street elbow)
#2: PVC female thread (street elbow) + brass male thread (nipple)
#3: Brass Male thread (nipple) + Female Stainless thread (sink hose)
#4: Female Stainless thread (sink hose) + CPVC male adapter (supply line)
#2 leaks despite having 2 turns of regular white Teflon tape and being tightened to the point that 3-4 threads are still visible.
There are similar connections I've had to make which also leak. For example, the Kitchen sink's cold supply line has a 1/2" PVC valve, brass nipple and then the braided stainless hose running up to the faucet. It leaks where the nipple meets the valve.
Did I do something wrong or miss an important step?
I'm Travis and this is my first post here. Coming from the world of Rotary Engines (3-rotor RX-7 owner here... ), I'm pretty well-versed in electrical, mechanical and plumbing when it comes to oil/coolant/fuel/etc. Since our cars use NPT connections here and there, I know how to teflon tape metal pipe connections correctly. But what is troubling are the nonmetallic NPT connections.
My fiancee and I bought a mobile home built in the early 70s on the cheap. No surprise, the plumbing was in abysmal condition due to prior owners' "repairs", a combination of copper, galvanized, brass and anything else found at the big box stores' clearance aisle. between this and a scary number of fittings applied to every junction, the writing was on the wall.
After having three different lines fail in two weeks, plus the hot water heater (from 2006) due to incorrect practices, I determined that ALL of the supply plumbing was suspect and we decided to start completely fresh on it. The plan was to run fresh CPVC pipe inside the house, eliminating all of the old stuff from the house as a whole.
I know how to correctly handle CPVC and opted to go this route to keep the project cost as manageable as reasonably possible. I extracted the old Umbilical line, disassembled it and found that it was cobbled together and in rather poor condition. Removed the copper from it, then cleaned it up and reassembled it. Re-routed it to the Kitchen in place of the bathroom to eliminate as much plumbing exposed to cold as possible. Put a Main Shutoff Valve (sillcock with flange mount, Lowes# 21508) inside where it enters the house. This works fine and has no issues.
With all of the external plumbing resolved, I started on the inside. As our hot water tank was on its last legs, we opted to go with two smaller tankless water heaters. One for Kitchen and one for Bathroom, in order to cut the plumbing effort in half. Did the whole kitchen in CPVC, adding a branch line for the refrigerator (planning for a newer one with ice maker later) and dishwasher. The way I did this was with a 1/2" CPVC Male Adapter at each device's connection, and a 1/2" PVC quarter turn Ball Valve to shut off the supply for servicing. These were cheaper than regular shutoff valves and far easier to mount solidly on 1x4s
Did a test on it, no leaks where the valves meet the CPVC male adapters. So I continued onward to the bathroom, using the same logic as the kitchen. All is good so far. The only exception to this are the washer's lines. CPVC male adapter meets 1/2" braided stainless steel sink hose (IPS/NPS thread, with the gaskets in both ends). Then a 1/2" brass hex nipple, 1/2" PVC street elbow and finally a flange mount sillcock (Lowes# 21508 again).
All of the aforementioned washer plumbing is housed inside a removable panel, with the sillcocks protruding through.
So here's the problem:
#1: Female Brass threads (Sillcock) + PVC Male Thread (on street elbow)
#2: PVC female thread (street elbow) + brass male thread (nipple)
#3: Brass Male thread (nipple) + Female Stainless thread (sink hose)
#4: Female Stainless thread (sink hose) + CPVC male adapter (supply line)
#2 leaks despite having 2 turns of regular white Teflon tape and being tightened to the point that 3-4 threads are still visible.
There are similar connections I've had to make which also leak. For example, the Kitchen sink's cold supply line has a 1/2" PVC valve, brass nipple and then the braided stainless hose running up to the faucet. It leaks where the nipple meets the valve.
Did I do something wrong or miss an important step?