# Elite HTP Pressure problem



## Wyoplumber (Dec 25, 2011)

I have a Elite HTP 150,000 btu lp boiler with indirect water heater installed. It has a primary grundfos 15-58 on supply side of system and same pump on return side of system for secondary return, running honey well zone valves. The make up water is set at 12-15lbs as normal when system kicks on pressure will het up to 22-28 lbs and sometimes trip t&p valve. The book calls for a 2 gallon expantion tank installed on it so that is what i have. Can not figure out why t&p valve keeps tripping. Not sure if primary pump is to small and can't pump water fast enough but i have both pumps turned on high so it should be moving enough water,maybe its building up steam and pressure so it trips? Or maybe the book is wrong and i need a bigger expantion tank. Ive installed alot of systems in the past but these high efficency computerized boilers are a pain the in a%&!! Let me know if you can help thanks.


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## easttexasplumb (Oct 13, 2010)

Is there a full moon tonight.


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## Dangle72 (Dec 17, 2011)

The expansion tank might be water logged


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## easttexasplumb (Oct 13, 2010)

Yep full moon.


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## gtmechanic (Feb 15, 2009)

*tripping valve*



Wyoplumber said:


> I have a Elite HTP 150,000 btu lp boiler with indirect water heater installed. It has a primary grundfos 15-58 on supply side of system and same pump on return side of system for secondary return, running honey well zone valves. The make up water is set at 12-15lbs as normal when system kicks on pressure will het up to 22-28 lbs and sometimes trip t&p valve. The book calls for a 2 gallon expantion tank installed on it so that is what i have. Can not figure out why t&p valve keeps tripping. Not sure if primary pump is to small and can't pump water fast enough but i have both pumps turned on high so it should be moving enough water,maybe its building up steam and pressure so it trips? Or maybe the book is wrong and i need a bigger expantion tank. Ive installed alot of systems in the past but these high efficency computerized boilers are a pain the in a%&!! Let me know if you can help thanks.



expantion tank size is calculated by volume of the water in the system. 2 gallons is too small by any means. even for average one family house you need at least 4.7 gallons, same as watts et 30. or bigger. Bigger is better. as per circulator, on primary loop you must install grundfos 26 booster, the 15 one is not moving water fast enough trough heat exchanger and boiler gets stack on low fire to prevent boiling. Those high efficiency boilers is the best thing happened to our industry. You just have to learn new tricks. They work exactly in reverse to conventional boilers.


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## Redwood (Sep 8, 2008)

Wyoplumber Try making an Introduction Post and the Full Moon will set....:yes:


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## Wyoplumber (Dec 25, 2011)

Well the expantion tank seemed small to me as well and I double checked with tech support and they said it was fine. The book sizes pressure tank but not pumps, tech support won't recommend pump sizes, why I don't know.ill try bigger tank and maybe a taco 0013 hope it works when I put a three hundred dollar pump on the system.


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## ZL700 (Dec 8, 2009)

By your primary/secondary description I'm bettin it's piped wrong, a pic would be interesting


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## Wyoplumber (Dec 25, 2011)

What do you by the piping is wrong? Clearly shows in the book primary is on the supply side and secondary is on return side.


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## ZL700 (Dec 8, 2009)

Wyoplumber said:


> What do you by the piping is wrong? Clearly shows in the book primary is on the supply side and secondary is on return side.


What?
Primary and secondary are two seperate loops, each circulator decoupled from the other, that's why. Primary is boiler flow loop. Secondary is zone loops teed into the primary loop 

Your second explanation is as scary as the first.


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## Airgap (Dec 18, 2008)

*Hello! Introduction Requested* 

An intro is requested from all new members. In case you missed it, here is the link. http://www.plumbingzone.com/f3/.

The PZ is for Plumbing Professionals ( those engaged in the plumbing profession)

Post an intro and tell our members where you are from, yrs in the trade, and your area(s) of expertise in the plumbing field.

This info helps members who are waiting to welcome you to the best plumbing site there is.

We look forward to your valuable input.

:thumbsup:


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## gtmechanic (Feb 15, 2009)

*pump*



Wyoplumber said:


> Well the expantion tank seemed small to me as well and I double checked with tech support and they said it was fine. The book sizes pressure tank but not pumps, tech support won't recommend pump sizes, why I don't know.ill try bigger tank and maybe a taco 0013 hope it works when I put a three hundred dollar pump on the system.


in the manual for boiler you will find , that @ 15 gpm(150,000btu), you need 27' of head For heat exchanger. if you look at chart for Grundfos 15, you will see, there is no way this pump can deliver. switch to grundfos 26, and install bigger expansion tank. if you did piping right, your problems are over. I do it day in and day out. i know. just do it.


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## Wyoplumber (Dec 25, 2011)

I know the piping is correct I will install grundfos 26 and bigger tank thanks. Gt mechanic


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## plbgbiz (Aug 27, 2010)

Just follow the piping in this photo and I'm sure it will all work out.


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## HTPtech (Dec 27, 2011)

hello 
a grundfos 15-58 on high speed will pump roughly 9gpm through the Elite 150 which will give roughly a 33* rise through the boiler if you are giving up 20* through the system the boiler is going to run hot and short cycle which equalls more expansion.
In the installation manual when it says a 2 gal expansion tank we are saying we want the tank to accept 2 gallons of fluid.For instance a Extrol 15 exp tank will accept .9 gal of fluid but tank size is 2 gal,An extrol 30 tank is 4.4 gal but accepts 2.5gal 
So the expansion tank you want will accept 2 gal of fluid and tank air charge should be tested before installing matching your system pressure on a cold boiler 
As for sizing the circulators all the info is in the manual for you to pick a pump for your system design, and the design delta t through boiler hope this helps


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