Question in regards to pool plumbing

[DennisP]

I am getting to the point of plumbing the equipment pad and I was wondering how much of a loss would there be using those combination 1.5"/2" (socket/spigot) valves on my setup?

As it stands I have 2" PVC run to the pool and to the equipment pad. I am running a Pentair Dynamo 1.5hp 2-speed above ground pool pump, which has a 1.5" NPT inlet. From the piping I will have a ball valve, then a union which will have a 2" to 1.5" NPT male adapter in it which will go directly into the pump. From the pump I have a 1.5" buttress union going to a 1.5" to 2" adapter street elbow. That goes via 2" PVC to the Sta-Rite System3 cartridge filter. From the filter it is all 2" to a check valve, then 3 way valve (one way will bypass the heater to the return, the other will go to the heater), then to the heater, from the heater to a check valve and ball valve (to totally isolate the heater positively if it is in bypass for service), then to the return piping (which will also have a ball valve).

Now the big question is how much flow is lost through the 1.5"/2" combo valves that are out there?

I know there is a flo-tech ball valve that is half union with that combo, a clear check valve that is configured that way, and the Jandy 4715 3 way valve also has this combo. Going with these items is almost a 1/2 cost savings going with these combo valves, but I don't want to kill the advantage of going with 2" piping and filter if going with these valves will compromise it that much.

I also have plumbed in extra 2" piping to the pool to give me options for water features or extra skimmers/returns, so it is not out of the question that I may upgrade to a higher-flowing pump in the future.

Last question is it acceptable to use "all purpose" PVC adhesive to connect CPVC piping to PVC piping? The heater (Jandy Lite2 250k) calls for CPVC connections at the heater with at least a 6" nipple, so I was going to use a close nipple with 90 degree CPVC elbows to allow for closer connections since my equipment pad space is at a premium with the heater on it.

[CarlD]

I'm not sure about the 1.5 to 2" connections, but I do wonder why you don't go 1.5" all the way.

There are special glues formulated to handle CPVC heat, and I believe they can be used for PVC as well. But I'd be leery of using PVC on CPVC where there's heat.

[DennisP]

I'm not sure about the 1.5 to 2" connections, but I do wonder why you don't go 1.5" all the way.

There are special glues formulated to handle CPVC heat, and I believe they can be used for PVC as well. But I'd be leery of using PVC on CPVC where there's heat.

Well, considering the pool is 70 feet away from the equipment pad I am trying to limit head loss. Since I am doing the installation, I figure 2" is the way to go, since the price is negligible compared to 1.5".

Also, since the filter is 2" connections, the heater is 2" connections, it just kinda makes sense to keep things 2" all around as much as possible.

I have hard that a single 1.5" fitting isn't as big of a deal as all 1.5" pipe, thus my query. I figure if folks have been doing this a while, someone would probably know if there are any issues one way or another.

In regards to the CPVC to PVC connection, I will probably just use the CPVC cement to connect the nipples to the elbow and use a threaded connection to connect the opposite side of the elbow to the regular PVC piping then. I know the instructions for the heater state to use the CPVC nipples to connect to regular PVC piping, in which case they expect a glued connection. No big deal and I would rather be safe about it and I know the "preferred" method of CPVC to PVC transition is via male/female connections, so I will just go that route.

[nefretrameses]

My pool had three 1-1/2 inch lines on the suction side of the pump all teed together to the 1-1/2 inch pump fitting. Then 1-1/2 to the filter and back to the pool. At the pool there's an in-floor cleaner valve to four circuits. I had the opportunity to change to 2 inch from the pump discharge to the in-floor valve - about 60 feet total. My discharge pressure dropped by about 1/3. Your fittings will cause some loss, but the 2 inch pipe is really gonna be the biggest factor. You can use two 45 degree fittings instead of 90's and save a bit more.

Not sure about your combo valves or adhesive. There should be a way to adapt PVC to CPVC, but its not in my bag of tricks to know how. If your heater wants a 6 inch nipple, its probably for "straightening out" the water stream before it gets inside. Not sure how much you want to compromise that, but again, its not really in my bag of tricks. Sorry.

[DennisP]

My pool had three 1-1/2 inch lines on the suction side of the pump all teed together to the 1-1/2 inch pump fitting. Then 1-1/2 to the filter and back to the pool. At the pool there's an in-floor cleaner valve to four circuits. I had the opportunity to change to 2 inch from the pump discharge to the in-floor valve - about 60 feet total. My discharge pressure dropped by about 1/3. Your fittings will cause some loss, but the 2 inch pipe is really gonna be the biggest factor. You can use two 45 degree fittings instead of 90's and save a bit more.

Not sure about your combo valves or adhesive. There should be a way to adapt PVC to CPVC, but its not in my bag of tricks to know how. If your heater wants a 6 inch nipple, its probably for "straightening out" the water stream before it gets inside. Not sure how much you want to compromise that, but again, its not really in my bag of tricks. Sorry.

Yeah, I am more worried about the 1.5"/2" combo fittings/valves being a restriction point more than anything else...

In regards to the 6 inch nipple, the only reason they have that is so that if there is a thermal control problem with the heater you don't melt connected PVC pipe (since CPVC has a much higher rated temperature). The issue has more to do with the potential heat of the manifold compared to the water, ie, if there is a thermal problem the water can be cooler but the manifold can get much hotter. By the time the thermal overload switches disable the heater the manifold can be much to hot for PVC to handle, so with CPVC and a length of 6" they are just anticipating that it would hopefully save the PVC up/downstream from the heater. The big concern outside of a thermal issue is if you don't put a firemans switch in and just shut down the pump/heater and water boils inside the heater. A much more common occurrence and 6" of CPVC is hopefully enough to protect any PVC downstream/upstream from the heater.

I figure a short nipple with an immediate 90 and another nipple being threaded into a PVC female should afford for at least 6-8" of total CPVC distance. That coupled with my installing a firemans switch will make sure I don't run into that situation. The only time it *might* happen is if we lose power while the heater is running. At that point there isn't much I can do, so the CPVC should hopefully do it's job.

[nefretrameses]

Makes sense. Didn't think about heat.