Cracked multiport valve output

[jdevers]

I think this is the correct forum for this, if not let me know and I’ll fix it.

Last summer I installed a SWG on my return line after my sand filter. The filter and multiport valve are both pretty old (2008) but in perfect working order except apparently the plastic on the output had gotten a little brittle and when I replaced the NPT fitting to the output it cracked slightly. I was able to “fix” it pretty easily so that all I had was a very slight drip and water here is exceedingly cheap and comes almost perfectly balanced right from the tap.

Fast forward to this summer. We had a cold winter and are having an exceedingly hot summer and the thermal expansion on the PVC did it no favors. The leak is quite extreme now and even though the water is cheap, it is a pain to add as much water as I am, salt isn’t as free, and all the leaking salt is starting to bother my yard a bit. I know replacing the multiport is probably the best option, but the way the crack is looks like if I could use the OUTSIDE of the fittings instead of the inside it wouldn’t leak at all due to compression inward instead of outward. The multiport is a 1.5” Jacuzzi brand (dv assy 7-pos 1-1/2NPT TR) and while the inside fittings seem standard the outside fitting doesn’t seem as standard. Any advice on why part I should be looking for to utilize the outside of this fitting or if I should just abandon the idea and replace the MPV?

 

[1poolman1]

Its time to replace that valve, unfortunately. If your valve has thread on the outside of the ports, they are for a "bulkhead" fitting. Since the port is cracked, even one of those won't seal. When threading a fitting into the valve, do not thread al the way in. There should be about 3 pipe threads visible when the fitting is properly tightened. Any further and you can crack the new valve as threaded pipe fittings are tapered like a wedge and "expand" the further into the fitting they go.

Be sure to use a good thread seal designed for plastic. Look at the instructions for the new valve. Some will tell you to NOT use a paste-like sealant, but to use Teflon tape. I like to use about 5 or 6 tight wraps and then a little silicone sealant over that.

 

[jdevers]

Thank you! I was worried that would be the only option.

Yea, I’ve taken it off and removed it many times over the years (pump replacements, annual deep cleaning etc) and never had issues. Because of the alignment I tightened it to exactly the same point I always have (any tighter would require and entire additional revolution around) which is barely hand tight with about 5 complete pipe threads exposed. I’ll go ahead and replace it.

It LOOKS like a pretty standardized part, I wouldn’t have to order the EXACT same MPV to replace it, would I? I can’t imagine 14 years later it is still available and I have no idea where the original home owner bought it or the filter which doesn’t even have a label (from looking around it seems that they were sold together as the Lazer series from Jacuzzi).

 

[1poolman1]

Yes, you have to order a valve to fit that filter. Each manufacturer makes then a little different (understandably, so you have to use theirs on their filters). There are aftermarket makers, CMP, Praher, that make replacement parts that have proven to be good and may have one for your filter.
Using this in a search bar, "dv assy 7-pos 1-1/2NPT TR", shows some options that may fit your filter.