Radiant question

JK_3

The system is zoned with zone valves. as I suspected the pump is located in the wrong place and there is no bypass in place. Do You have a sugestion on sizing and con figuring the by pass. The supply and returns are 1" with 9 zone valves supplying 20 loops of 1/2" pex.Thanks again for your help.

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JK_3

Pumping in a radiant system

I got a call today to replace a circ pump on a radiant system. I have very little knowledge on the install but the cust. informs me that the are burning out a pump every two years. My question " is it okay to pump into the system return side of a Tekmar 4 way mixing valve?" I have always set them up pumping out of the system supply but i am not sure if it makes a difference to the pump. If any one has any other suggestions on what else may be the cause of pumps burning out I appreciate th input . Thanks and I hope everybody has a great day.

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Steven Gronski_3

How is the system zoned

The poper way for the pump to be set up is to pull thru the mixing valve "mix side" and pump away into the system. Is the system set up on zone valves? Does this pump run on constant circulation? If so, it sounds like the pump could be deadheading againts itself which would cause it to burn out. Check to see if there is a pressure differential bypass on the system somewhere.It should be tied in at the end of the supply and the begining of the return after the last zone, or you can tie one in at the pump if there is room. If there is pressure differential bypass on the system, check to see if it is working.

Steven Gronski

Gronski Plumbing and Heating

Cranston RI

hot_rod

another, even better option

would be a delta P pump. That pump would adjust to the various zone valves opening and closing. And they are not damaged by dead heading, although you should be able to fire the pump only when a zone valve opens. And they use a bunch less electrical energy in the process.

Right now Wilo and Laing have small delta P circs available. Rumor has it the Grundfoa Alpha will be available in the US second quarter of 2009.

I've had 4 Alphas running for over a year now, they are amazing. I even have one on a drainback solar installation in my shop.

hr

JK_3

hot rod

Thank you for your input but the cust. had already purchased a Taco 0010 and asked me to install. I have no responsability as far as the work that has been done or for the pump itself , but I was asked to look at what I could and make any determinations or reccomendations as far as the system piping. I will look into the pumps you mentioned and possibly reccomend but I think my first recomendation would be to correct the piping or at least allow me to do further testing. Thank you again for your input as your opinions are always respected.

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hot_rod

Is it the correct pump?

20 loops of pex flowing 1/2 gpm or less per loop is 10 gpm (or less) Wouldn't a Taco 007 be plenty?

I use the 4 zone valve or more rule of thumb for using a PAB pressure activated bypass. It can be plumbed in just after the circ or at the end of the zone valve manifild. Be sure to add a ball valve to isolate it and ease purging.

Honeywell, Danfoss, Caleffi and others offer PAB valves, angle and straight versions.

Pumping into the 4 way should not be causing the circ failure. Is it piped primary secondary? If so you need a primary loop pump, and the zone pump to operate properly.

hr

JK_3

It is not pumped primary/secondary. only one pump pumping the mixed return into the 4way mixing valve. one tee on boiler supply before the mixing valve goes to the indirect and the pump for that is on the return from the tank into a tee with the return from the mixing valve.

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Joe Mattiello

The fact is you have 0010 pumps burning out after a few weeks of service. What is the failure mode? Taco pumps are very robust, and of a high quality. Typical applications will allow the pumps to run for several years. Taco even offers a generous three year warranty on the replacement cartridge.
There has to be a system related issue detrimental to the pump. Did anyone consider osmosis?

nm_2

pump

what is the orientation of the pump?
Is the motor horizontal or is the motor vertical position?
A pump mounted with motor in the vertical position requires much more system pressure

gary disney

taco oo10

Buy A Grunfoss, the pump probally runs all year and dos most of its dead heading in the summer, check what shuts the pump of in warm weather shutdown, most jobs the controls are set wrong. if the pump shuts off in the summer you will get 4 years out of it. Buy A Grunfoss

Anonymous_5

Dude...........

First of all, I would learn to spell the name of the product I promote, secondly, No manufacturer of ANY PUMP recommends dead heading. Third, Ive seen pumps , no matters who brand it is that are 40 years old and still pumping, because the were installed properly, and met the flow requirements of the system. So I guess the only thing you can be right about if the pump shuts down you will get 4 years out of it........yopu probably could get 20 out of it......no matter what type brand it is.

JK_3

Thank you for the input

The original pump was A bell and Gossett. At the moment I do not remember which model. The customer chose the Taco based upon input from a friend that owns a plumbing supply company. There are several problems with the system that will take quite a bit of investigation and probably will not be correctable, such as I have no way of telling length of the loops or spacing. I am however attempting to offer the customer what ever worthwhile solutions that I can. I have an appointment with the customer again on Tuesday at which time I will take some photographs and post them.

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