Isolation valves and pump removal Q

doug_10

Thanks for the post! Brought back a long-ago memory that I can laugh about now. No, you do not want to hear the vacuum start to break loose when you're not ready & inexperienced. And then having that vacuum break loose, and then hoping the subsequent rush of air will pull itself into a vacuum that will hold. It won't. It quickly becomes a lesson you'll never forget, especially when it's a big old system with lots of rads. & lots of big pipes. Aaaaah, the good old days!

Alan_2

Isolation valve and pump removal

At a rental house we own is an old American Standard oil burner (mid 1950s vintage) with two B&G circulators mounted on the return side of the boiler.
Works great and burns clean with a recently replaced Beckett burner.
Flow control valves are shortly after the circulation leaves the boiler.
I have drained and refilled the pumping away system at our house successfully in the past but this is the first time at the rental and I have a question....

The two circulators each have a isolation valve - isolation valve, circulator and then onto the return to the boiler.
If I want to replace a circulator, I could shut off the isolation valve above the pump. However, water will still empty out from the boiler side because I don't have a second isolation valve after the circulator.
Are there any tricks to minimizing the water discharge during pump removal ?
There is a floor drain right next to the boiler but my concern is minimizing the need to top off the system and getting the air out as well as properly charging the steel pressure tank and setting the cold system pressure at around 12 lb.
The current setup is running nicely except for one of the circulators may be due for a replacement, which I asked about in a different thread...

(Next spring the system will be reconfigured/updated around the boiler, and then the following year the boiler will be replaced.)

I appreciate any wisdom.

bob young

shut the supply valve , the flow control valve,the circul. isol. valve . blow down pop safety to zero pressure. then close. & open the draw off cock. some water will drain but a vaccum will probably occur and you can replace the pump and restore system to normal fairly quickly. the floor drain is a big plus.

Alan_2

bob -

thanks so much for the tips.
everything you mention makes sense.

there are several drawoff cocks which includes the one nearest to the boiler.

ScottMP

Alan my reply

Bobs advice can work. If you've done it before, and If you can change a circulator in one minute. I think you would be better served ( if you really want to do this yourselve ) by shutting the water off to the boiler, turning off the electricity, draining the zones and replacing the pumps. After your done fill and purge the air from the zones before you fire it up.

Also remember that the smaller pumps sometimes are so smaller than the old B+G's that the wires don't allway reach. Nothings easy.

I leave pulling a vacum for changing a T+P or a quick valve change.

You do Not want to here a vacuum start gurglin while the new pump is sitting on the ground at your feet.

Just my two cents

Scott

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

Alan_2

re - If you can change a circulator in one minute.
-----

No, I don't think I am at that level...

Draining may be the route I take because the house will be empty for a week next week.

Thanks for your suggestion.