Here it is. Aqual cal recommended this as they said anything flow above 70gpm will damage the heater. I don't plan on going to 70gpm but with priming and also if someone else ever works on it or owns it, it's protected. What do you think?
3/4" vs. 1" return eyes make a difference?
- Thread starter mihzyd777
- Start date
M,
I removed the MPV on two rent house pools and it lowered my filter pressure about 3 or 4 lbs.. To be honest, I know it is lower, but I did not run a before and after test, My goal was not to lower the pressure, but both valves were bad and since I clean the filters twice a year instead of backwashing, it did not make sense to spend the money on new valves. As soon as the filters themselves bit the dust, I'm replacing them with large cartridge filters.
Thanks,
Jim R.
I removed the MPV on two rent house pools and it lowered my filter pressure about 3 or 4 lbs.. To be honest, I know it is lower, but I did not run a before and after test, My goal was not to lower the pressure, but both valves were bad and since I clean the filters twice a year instead of backwashing, it did not make sense to spend the money on new valves. As soon as the filters themselves bit the dust, I'm replacing them with large cartridge filters.
Thanks,
Jim R.
M,
Thanks for the pic of the by-pass.. I have not seen that one and was just curious..
Jim R.
Thanks for the pic of the by-pass.. I have not seen that one and was just curious..
Jim R.
- May 3, 2007
- 17,115
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
Heat pumps in general have a lot of head loss (3x NG w/ internal bypass) so that could be a source as well. Given the heater bypass only opens over 70 GPM, below that would force it through the heater. Just curious, can you run at full speed and post the readings.
Quick question. Does the Backwash valve I have cause a lot of back pressure...is it better to just remove? I had a similar setup just with a Gulfstream heater at my old house and I could run 35gpm a little over 180 watts. Nowhere close here.
When you say full speed what should I set the GPM to or do I just put RPM to 3450?
Thanks!
- May 3, 2007
- 17,115
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
RPM to 3450. The idea is to make sure the bypass is open and identify the operating point (i.e. plumbing curve) when it is open vs closed.
Backwash valves do have quite a bit of head loss. But also different HP will have different head loss.
Backwash valves do have quite a bit of head loss. But also different HP will have different head loss.
- May 3, 2007
- 17,115
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
The plumbing curves for these two speeds (3450 vs 1808) is very interesting.
Plumbing curve @ 1808 = 0.03
Plumbing curve @ 3450 = 0.016
Normally, plumbing curves do not change much with speed. However, when there are spring loaded devices such as check valves and bypasses, this can happen. But the 1808 RPM curve is almost double that of the 3450 curve which is very significant. So this may explain the higher than normal RPM for 30 GPM. But even at 3450, the plumbing curve is double what I would expect from 2" & 2.5" plumbing so still excessive but certainly not as bad as the lower speed curve. So given these results, my conclusion is the HP is causing a significant amount of head loss at lower RPM and the bypass could be causing excessive head loss at higher speeds. Given that there are unions on the bypass and heater, how hard would it be to make a separate bypass (pipe only) for some testing just to confirm that it is those items that are causing the higher head loss? It might be worth the effort to just confirm.
Plumbing curve @ 1808 = 0.03
Plumbing curve @ 3450 = 0.016
Normally, plumbing curves do not change much with speed. However, when there are spring loaded devices such as check valves and bypasses, this can happen. But the 1808 RPM curve is almost double that of the 3450 curve which is very significant. So this may explain the higher than normal RPM for 30 GPM. But even at 3450, the plumbing curve is double what I would expect from 2" & 2.5" plumbing so still excessive but certainly not as bad as the lower speed curve. So given these results, my conclusion is the HP is causing a significant amount of head loss at lower RPM and the bypass could be causing excessive head loss at higher speeds. Given that there are unions on the bypass and heater, how hard would it be to make a separate bypass (pipe only) for some testing just to confirm that it is those items that are causing the higher head loss? It might be worth the effort to just confirm.
I like having a huge cartridge filter. Only down side is my pressure may jump 1 psi when it’s dirty
I can make a whole new pipe run from my pump to filter and then from Filter to heater. Or are you asking me to make a pipe that completely skips the heater? Only problem is where do I get the correct sized unions?
- May 3, 2007
- 17,115
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
Yes, I was suggesting a temporary bypass with unions that mate with the existing unions of the HP bypass currently used so both the heater and the existing bypass are excluded. The temporary bypass would be with just straight pipe and wouldn't require any permanent plumbing changes. However, as you pointed out, it might be a problem getting compatible unions. You would need to match the existing threads.
Some of these might work?
Rubber couplers could work as well
Ok give me some time to get this fixed up and I'll let ya know. And just to be sure I understand ya you want me to remive the bypass valve on filter and also remove the pressure check valve connect led to heater and bypass the heater all together so that the water doesn't flow through the heater at all right? Don't forget me
thank you for all the help I really appreciate it.
- May 3, 2007
- 17,115
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
Yes, completely bypass the heater but don't cut any pipe. I don't think that is necessary. If you can do it with some spare parts, great. Otherwise, it is probably not worth. My belief is that the heater has a lot of head loss and even the bypass valve has substantial head loss albeit better than the heater. I just thought if there was an easy way to confirm that, then you would know for sure what is causing the issue. Although there may not be a lot you can do about it. It is up to you if you think this is worthwhile.
I follow you and think your right on the heater and bypass cause to much back pressure. I can do that it shouldn't be a issue, so if that is the issue, would it be worthwhile to have my PB install a heater bypass valve and kind of reconfigure the pipes in that area so that when the heater is off the intellivalve is turned 1 way and when heater turns on it diverts the water to heater? Thanks!
- May 3, 2007
- 17,115
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
Yes, if you had an 3-way valve you could completely bypass the heater when not using it and not rely on the bypass to do that. Also, with an actuator, the valve could be automated.
Ya that's what I was thinking. Also, just to make sure we are on the same page. That "H" shaped bypass at the heater is only there so when waterfowl is over 70gpm it diverts it so that it doesn't damage the heater as per AquaCal.
- May 3, 2007
- 17,115
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
Correct. That is why at lower flow rates there is so much head loss. It forces the water to go through the heater. But even in bypass mode there is still a lot of head loss because of the spring in the valve and size of the valve.