Hard to say if it is just a high head loss in the exchanger or is there is something wrong causing the problem.
Need help with new spa installaion
- Thread starter cvaparo
- Start date
Even with the low flow I got almost 30 degrees of rise in about 8 hours of 1500 rpm. So maybe I should repipe, putting a 3 way valve after the filter and let the small flow of the heater do its thing alone. then at least I can clean the water properly
That would be a little more typical of a heater bypass setup. Although I worry about how much flow that little filter can handle when you want to run on higher speeds for the spa jets
Yes but can I keep the three way that is there now and just cut in after the filter and before the heater?
OK, Here's what I've found out.
If I picked the right exchanger you have the MPN5X12-8 and it has 1" npt ports on both sides. The minimum flow rate for this exchanger is 4 gpm and at that flow rate it has a 4.1 psi pressure drop. Thats a very high pressure drop, but typical for plate exchangers.
Since you're heating the spa if you fake out the flow switch there is enough flow going thru the exchanger to heat the water.
Do you know what the setpoint of the flow switch is?
It should be set for 4 gpm. If it's a lot higher than that, there's your problem.
If I picked the right exchanger you have the MPN5X12-8 and it has 1" npt ports on both sides. The minimum flow rate for this exchanger is 4 gpm and at that flow rate it has a 4.1 psi pressure drop. Thats a very high pressure drop, but typical for plate exchangers.
Since you're heating the spa if you fake out the flow switch there is enough flow going thru the exchanger to heat the water.
Do you know what the setpoint of the flow switch is?
It should be set for 4 gpm. If it's a lot higher than that, there's your problem.
good morning,
It is a mpn5x12-6 which has a slightly lower min flow rate than the one you chose, but regardless of that, I decided to use it because it said 20gpm max flow rate and I thought the Pentair would do all of that even at a lower rpm. I also thought 20gpm would be enough to filter the spa, that's why I put the filter and heat together in the same loop. I guess I don't understand all the losses in flow and pressure. Do you think the low flow rate will filter the spa enough?
As far as the switch, it is set as low as it can go and the plumber gave me that one. I am not sure where to buy a weaker switch
It is a mpn5x12-6 which has a slightly lower min flow rate than the one you chose, but regardless of that, I decided to use it because it said 20gpm max flow rate and I thought the Pentair would do all of that even at a lower rpm. I also thought 20gpm would be enough to filter the spa, that's why I put the filter and heat together in the same loop. I guess I don't understand all the losses in flow and pressure. Do you think the low flow rate will filter the spa enough?
As far as the switch, it is set as low as it can go and the plumber gave me that one. I am not sure where to buy a weaker switch
The pump will do 20 gpm at a fairly low rpm IF the head loss is low. When you insert the plate exchanger into the system the head goes up steeply and the flow goes down. The filter also adds head loss to the system as does the piping itself and the fittings in the spa itself. So of you take everything into account you'd have to run the Intelliflo at nearly full throttle to get much flow at all through the system and then you're probably not going to get 20 gpm through the exchanger loop.
Can you give me the models of the filter and the flow switch?
I'm assuming the flow switch is to control the heat to the plate exchanger?
Can you give me the models of the filter and the flow switch?
I'm assuming the flow switch is to control the heat to the plate exchanger?
The filter is a Pentair CC50 and the flow switch is a 0510, but has no name on it. 1" mpt with a large ss plate. I see Johnson Controls has a 1 lb switch available for $123.00
If these exchangers are made for pools, how are they normally piped? With the low pressure of pools/spas, how do they get any flow through the exchanger? I saw the diagram in the Flat Plate PDF and it is pretty much the way I have it, except they show the filter in the primary loop.
Yes the switch is in series with the Goldline temp controller.
If these exchangers are made for pools, how are they normally piped? With the low pressure of pools/spas, how do they get any flow through the exchanger? I saw the diagram in the Flat Plate PDF and it is pretty much the way I have it, except they show the filter in the primary loop.
Yes the switch is in series with the Goldline temp controller.
Without more info on the flow switch I can't tell more about it, but it sounds like it's set at too high a level for this service. I think the exchanger is getting enough flow to operate correctly so if you had the correct flow switch it should work as it's set up now.
The way it's plumbed isn't ideal and it would be better if the 3-way valve was after the filter so you'd be filtering all the water no matter which way the flow was directed, but that's not saying that the way it's plumbed now won't work.
The way it's plumbed isn't ideal and it would be better if the 3-way valve was after the filter so you'd be filtering all the water no matter which way the flow was directed, but that's not saying that the way it's plumbed now won't work.
Ok, I will start by replacing the flow switch and try everything for a while. Right now the filter is getting only what the exchanger will let through. I ran it for 8 hrs yesterday and about 3 today. Its almost up to 90 degrees while starting at 52 letting it sit overnight. The water was from my well which is filtered but still has some Manganese that is precipitating making a ugly waterline. hopefully I can keep wiping it clean until its gone.