Pex shrinks

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VAJerry

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Pulled the pump off my OWB and that sucker was rusted to crap. What cheap so and so put a cast iron pump on a circuit that uses water and is vented to atmosphere? Some body advised me that if was a Taco pump to get a Bell & Gossett. (Thanks rx7145) And that was the case. The first look at the B&G I knew that was the way to go. Plus I went with a brass pump. They had stainless but I was afraid to ask. Pulled the pump yesterday, got the new one and went to install it and the Pex is about 6" too short (pumps are the same size, although the B&G draws about3 more amps, and that's a good thing.) I got longer bolts and am slowly drawing the pipe together, but I don't want to break the ears on the pump flange.I may look at getting a pipe nipple to extend the pipe on the stove, but when the Pex heats up and expands I'm afraid it will kink.:censored:
 
Must like using more power? :confused:
I've had 3 cast pumps on my CB for 4 years that's vented to the atmoshpere, and they are'nt rusted, I just had one off to re-route a line in the fall.....The rust inhibitor additive is alot cheap than a brass pump, and a rotted out water jacket!

Put the nipple in to make up the difference, it was originally assembled cold in the first place... I highly doubt it'll kink.
 
Blazin said:
Must like using more power? :confused:
I've had 3 cast pumps on my CB for 4 years that's vented to the atmoshpere, and they are'nt rusted, I just had one off to re-route a line in the fall.....The rust inhibitor additive is alot cheap than a brass pump, and a rotted out water jacket!

Put the nipple in to make up the difference, it was originally assembled cold in the first place... I highly doubt it'll kink.
Click to expand...

I don't know that inhibitor was in the system. Looking at the pump I would say not. I did not hook up the system but I will take the blame and pay the price. The more I think about it I wonder if the ground settling may have had more to do with moving the Pex. When unhooking the pump it released tension on the tubing and it settled down.
 
I know when my line temps are way up the incoming line will grow about six inches in a 50 foot run.
 
VAJerry said:
B&G draws about3 more amps, and that's a good thing.).:censored:
Click to expand...

Are you sure?
I just did some rough and ready electro math

120 volts x 3 amp = 360 watts
360/ 1000 = .36 killowatts

if you are on 9 months a year= 6500 hours

6500 x .036 = 2340 killowat hours

2340 times 10 cents a kw hour = $234 bucks MORE each year to run that 3 amps.

New TACO iron = about $90
New TACO bronze = about $250

Dont think I want 3 more amps going 24-7 at my place. My bronze TACOs are both in year 4.
 
Damn...this is gettin way over my head with the math and all... rust inhibitor, cast pump, and a nipple calls it a done deal. :clap:
 
No problems with cast Taco

I am going on year 11 with my 70 watt (.7amp) CAST taco pump without a hitch.The filter in your system before your pump should have picked up any slag from building of your furnace.My "O" ring in the filter started to weep water and called the dealer for a new one.He said your filter has done its work and is not needed anymore.When I took the filter apart there was some welding slag bits and such in the mesh but no wheres near plugged.I have used the inhibitor faithfully every fall before startup.Same tiny Taco pump still too.I do have a brand new pump sitting on the shelf in case mine does crap out though.
 
Doesn't anyone want to challenge the initial assumption? Does Pex shrink? I ask because if it shrinks that means it expands too, and where are provisions made for pipe that gets longer? Are there none?
 
No need to challenge the intial "assumption" Yeah the pex shrunk cause it was cool, pex grows and shrinks with hot and cold on a regular basis I recon. Obviously it had a place to "shrink" too. Hopefully it has a place to grow too....Damn I hate it when my draws get to tight :hmm3grin2orange:
 
Butch(OH) said:
Are you sure?
I just did some rough and ready electro math

120 volts x 3 amp = 360 watts
360/ 1000 = .36 killowatts

if you are on 9 months a year= 6500 hours

6500 x .036 = 2340 killowat hours

2340 times 10 cents a kw hour = $234 bucks MORE each year to run that 3 amps.

New TACO iron = about $90
New TACO bronze = about $250

Dont think I want 3 more amps going 24-7 at my place. My bronze TACOs are both in year 4.
Click to expand...

There is a major flaw in your math or assumptions. The increase in amperage is 3 total is 13, or 4 times. That would mean it costs $936.00 a year to run the pump to circulate the water. My total electric bill for the year does not come to that.
 
The failure in the math should be obvious to anyone. The initial formula assumes the motor runs 24 hours a day. Look at the 9 month = 6500 hours. Well, there might be 6500 hours in 9 months, but the electric motor doesn't run 6500 hours during that 9 months, just that lesser number of hours that it is actually turned on during the 6500 hours. Fix that and you should get a more sensible answer.
 
I just went and looked up the coefficient of expansion for PEX. The stuff sure does grow.

Put a loop in the line about a foot or two in diameter and all of your problems should be solved.

So now it looks like this: Existing line -> valve. Modify it to make it look like this: Existing line -> Loop -> valve.

So as the line expands and shrinks the loop will grow slightly larger or smaller to take up the expansion but allow everything else to remain as is.
 

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