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[shane73]

I have a Central Boiler stove that I bought it was used for one year and was installed here last year.  I have one run to my house and the other to my shop about 125 ft away. When the boiler was installed the installer had a hard time getting the water up the lines in the shop (12 ft sidewalls).  He managed to get the line bled and it has been fine until last week we had a power outage and I cannot seem to get the water up the line again.  Both pumps are Taco 007-F5 pumps.  Both pumps are running and the one to the house is working fine.  I am looking for suggestions.

[yoderheating]

With a 007 you are going to have trouble if you get an air pocket in the lines. They are good pumps but don't have a lot of get up and go. I would probably just change it out for a bigger pump so this isn't a continual problem. Normally I will use a 007 on runs up to 150ft but only if its flat, adding the height is a huge problem. 007 pumps are only designed to have 10ft of head, with a loop you can run more because the water flowing downhill on the return will add some suction. However to get there you have to fill the lines completely to get it started. You could us a 008 which has 15ft of head although that still may be undersized. I would recommend using a  009 which has 35ft of head and you should never have any problem again.

[RSI]

I would go with a Grundfos 15-58 pump. If you want to stay with Taco, go with a 00R pump.
These both have a max head of around 20'.

[victor6deep]

Sir, sounds like you need a broeder 3 speed pump.

[bajonesy77]

LOL at victor 

I found out the Broeder 3 speeds max ambient temp is 104 degrees. Wonder if this is why these pumps fail a lot?

Broeder pumps fail alot but he still recommends them!  Listen to yoder and rsi they know their stuff!

[yoderheating]

RSI I had never used a 00R but after looking at the ratings it seems to be a very good pump for much of my jobs. My local dealer only carries the basic models but I believe I will order some of these and try them out. Thanks!

[slimjim]

The right way to solve your problem is by installing a plate exchanger below your boiler water level and the problem is gone. These circs are not designed to push water uphill and again not designed for use in a non pressurized system, regardless of the circulator sizing you will always have the issue of air being trapped at the high point and that air will make the water pretty nasty for your circ.

[Scott7m]

How do you recommend always installing a plate exchanger below the level of the boiler?  It would be an extremely rare case in my area for that to be feasible. 

I don't like using pumps that small...  But have.  Never had an issue with it in the systems, if I do have one air lock at the time of install I simply hook up a water hose to my flange which has a hose bib and force it through with the domestic water pressure

[yoderheating]

You can air lock a loop off a plate heat exchanger as well unless you use oxygen barrier pipe and a pressure tank.  In this situation the only reason I would recommend a flat plate was if you had any concerns about a water leak in your shop. Adding a flat plate reduces the risk of the furnace draining into the shop if you were to have a leak. Sometimes shops will freeze easier than homes because often they are not well insulated.

[WoodMOJoe]

These circs are not designed to push water uphill and again not designed for use in a non pressurized system...

Would you mind clarifying that?

I know nothing of these pumps but I thought that pumping water uphill was the main purpose of a pump, hence the head rating?  And not sure what you mean by not being designed for use in a non-pressurized system either, thanks.   

[RSI]

These circs are not designed to push water uphill and again not designed for use in a non pressurized system...

Would you mind clarifying that?

I know nothing of these pumps but I thought that pumping water uphill was the main purpose of a pump, hence the head rating?  And not sure what you mean by not being designed for use in a non-pressurized system either, thanks.   

The head rating on the pumps is not meant for to be used for the height of your system. It is a pressure drop rating. You pex lines, heat exchangers, fittings, etc will all cause some head pressure loss.
The pump are called circulators because that is their main purpose. Most have water lubricated rotors which are designed for pressurized systems. If no pressure, the rotor will not float properly. This is why it is a bad idea to put the pump at the top of the boiler. At the bottom usually supplies enough inlet pressure to keep the pump happy. Putting the pump in the house on a long run could be bad for the pump also but it really depends on what else is in the system. If the natural flow from the boiler can't keep up to what the pump needs then it will kill it much sooner too.

I would try to get a pump that has a head rating at least as high as the maximum height of the system above the pump. Otherwise it will not be able to move any water if it gets air in the lines. Depending on the length of the lines, it might also be a good idea to slightly restrict the return line at the boiler. If you have an air bleeder at the highest point (and you should on both lines) if you open it with the pump running, water should come out. If not, restrict the return till it at least trickles out.  If you have automatic bleeders you must do this otherwise they will work in reverse and let air in instead of out. Doing this will make sure it won't be trying to pull air in that could eventually airlock the system.

[WoodMOJoe]

Great explanation there RSI, thank you.