Galvanized pipes tend to corrode from the insides, but guess what? That corrosion IS the pipe, and eventually, it can do one or both of two bad things: decrease the flow significantly (you're seeing that now I think) but the next stage is it just starts to leak since there's nothing left. It is rusting...eventually it will rust out enough to leak. It is kind of foolish to wait once symptoms start to show. Think of the complaints when the walls and floors need to be replaced from the leaks - much more problematic than fixing it now.
I also live in a condo, and while the owners don't like it, sometimes, you just have to bite the bullet. We've been fairly lucky, but have had to do assessments a couple of times over the last 20-years to fix things we didn't have enough in the reserves to cover. Nobody likes it, but it must be done.
Trying to flush the lines may hasten them leaking, and probably loosen up enough crud to plug up everyones' shower heads and valves.
If there's a bad check valve on one branch, or someone has a failed shower mixer or faucet valve - some valves can generate a cross-over situation which could prevent the recirculation system from doing its job...the water will take the path of least resistance. One way to check on sink faucets is to feel both supply lines...only the hot one should be hot. If both are, then the valve has failed and the hot water is crossing over, short-circuiting the recirculation.
Good luck, but I do see a re-pipe in your future. Having hot water is a requirement, and the condo association is required to provide it. It's more common to have individual WH, but you have what you have, a shared resource...now, you have to get everyone reasonable access, or you may end up getting sued.
Hey Jim. Thanks for your comments. You've helped me a time or two at John Bridge forum too. My second bathroom project is 98% done. I have a few pieces of trim, a little more grouting, and some paint then I'm finished. Whew! I put the toilet back in on Sunday. Woohoo! Three working bathrooms now.
Anyway, the hot water issue has been on going for a long time off and on. We've had quite a few leaks since I've lived here (most recently in April) and had to pay for the repairs and cleanup. I've seen inside of the pipes that were clogged and some had the diameter of a soda straw from the corrosion though the pipe is 1-1/2 or 2". And it's usually the hot water that has leaked, IIRC.
Bottom line the HOA just doesn't have the money to re-pipe the building for various reasons including that the money is allocated for other repairs and or maintenance some of which is more pressing such as the foundation settling.
The homeowners pay >$300 per month already so we cannot raise dues which would price some out of their units.
We have some who are struggling to make ends meet as it is.
If it were an option we'd probably look into it further. Also, we'd need permission to get access to the units.
Since they're individually owned and we don't have keys we're at the mercy of the resident/owner to let us in to do the work.
We have a right of entry in our documents, but it's reserved for emergencies. We had enough trouble to get people to be home
for a foundation inspection and this would be about the same.
For now we're stuck with flushing the pipes and checking for leaks.The plumber we use is scheduled for the 28th.
We've done this a few times usually after a plumbing repair on then hot water lines. There is a valve on the building that can be opened to let water out and check if it's OK. It is a gate valve though a bugger to close fully once opened, so the plumber is going to change it to a ball
valve so it can be opened at times to check for sediment.
I've actually asked this guy about changing the pipes and he said it would be monumental and expensive.
He's usually eager to do most anything but he said he wouldn't even want to bid on such a job. His specialty is old plumbing.
Works on galvanized pipe and other old stuff but does a good job of working new in where needed.
I will ask him to check on the check valve on the HW heater. It might even be fairly new though since he did some new piping around the heater to accommodate it to pass inspection. He also told me the heater that was there had copper connections without dielectric unions which hastened it's demise though it was only 8 years old. I wonder how much that also has hastened the demise of the pipes in the building. I guess we'll find out...
Henry Ramsey