Question about purging single zone

ererer

Hi all,

I need to replace a corroded and leaky globe valve that's part of a hydronic baseboard system for my girlfriend's grandparents. I've replaced a section of leaky pipe on our home system before, and done other plumbing work, so I think I have a pretty good handle on what I need to do.

It's an old single zone system, and doesn't have a purge valve, so I'm planning on installing that as well.

When I purged the zones on my house after replacing the leaky fitting, I put the zone valves for each zone in bypass. For this system, there's just a taco cartridge circulator. Am I right in thinking there's no need to do anything like the bypass on the zone valve so that water will still flow through this with the system powered off, so that I can purge the system? Water just will flow through from the pressure from the incoming water so I can purge it?

ererer

Valve that needs replacing

HVACNUT

There's no bleeders on the convectors or radiators?

Also, the circulator is pumping  into the expansion tank. Not good. The circulator should be downstream of the PONPC.

It also looks like the piping splits into 2 loops. If you pipe in a purge station, you'll need to be able to isolate the loops so you can alter flow through one or the other. 

EdTheHeaterMan

The pictures indicate that your girl friends parents, have a different design from the one at your house. You should Just Dump that girlfriend. Problem solved!

But seriously, If you are going to attempt that repair, you should understand the difference. Can you post some pictures of the radiators/baseboards/convectors, or whatever heaters are in the rooms.

ererer

HVACNUT said:

There's no bleeders on the convectors or radiators?

Also, the circulator is pumping  into the expansion tank. Not good. The circulator should be downstream of the PONPC.

It also looks like the piping splits into 2 loops. If you pipe in a purge station, you'll need to be able to isolate the loops so you can alter flow through one or the other. 

Yes, I do see that now. What issues could happen with the circulator pumping toward the expansion tank?

There are bleeders, I'll post pictures of the baseboards below.

ererer

EdTheHeaterMan said:

The pictures indicate that your girl friends parents, have a different design from the one at your house. You should Just Dump that girlfriend. Problem solved! But seriously, If you are going to attempt that repair, you should understand the difference. Can you post some pictures of the radiators/baseboards/convectors, or whatever heaters are in the rooms.

Ha, she's a pretty excellent girlfriend, no complaints here. Her grandparents are in Florida for the winter and we help by keeping an eye on their place while they are gone. I figured I could help out by replacing the leaky valve, which I figured was within my capabilities, but can definitely call a professional if I should! I like fixing and learning how things work, though, so appreciate any advice and learning opportunities. I did construction for a while and learned quite a bit of electrical working with a neighbor on a remodel who was a retired electrician.

ererer

Here are some pictures of the baseboards, and the bleeder valves. Not sure when the last time any of these things were turned, but perhaps I should just do it that way. Was just worried with the age of the system that something would break or leak and I'd have a bigger issue on my hands.

Intplm.

@ererer
The picture shows the globe valve needing replacement. Why is there always something in the way? Figures!?
Anyway. No zone valve so no bypass in the circ. You are correct.
Install the purge on the return with the ball valve below the boiler drain close to the boiler.
From your described experience, it sounds like you know the rest of what to do.
I would install the purge even with the coin vents on the rads. The system will be down anyway to change the bad valve so why not?
Go for it.

ererer

Intplm. said:

@ererer The picture shows the globe valve needing replacement. Why is there always something in the way? Figures!? 

That drain line was recently installed, someone installed a new washer/dryer upstairs since the grandparents are getting too old to go down the narrow stairs to the basement. Actually I see that the PVC is pushing that section of pipe up and forcing the valve up. I wonder if that contributed to causing the valve to leak.

You can see how much the pipe was pushed up from where it originally was.