clogged hot water loop in hotel circa 1980s

[MPdesign]

Gentlemen,

I have a hotel circa 1980s with domestic hot water loop piping that is not leaking (because although the sidewall is likely fairly still thick enough), but they have not treated the water and it is clogged everywhere - no hot water. They have been trying to fix it for a long time.

I am recommending piping replacement, but as a first step, I would recommend the following:

System should be flushed, filters added, filters checked & cleaned weekly for 3 weeks, then flushed again.

Is this proper?

They do not have leaks - just clogs

This sounds proper and it is what I would do if it were at my home, but what is really proper - This is not my specialty!

Thank you for your insight!

[Jim Baird]

I like the common sense approach. Have you asked a plumber?

[Jim Katen]

If there's no water flow, how are they going to flush it?

[MPdesign]

It would have to be flushed in sections.

Flushing will probably not solve the problem though...

[Jim Katen]

What is the pipe material?

If they replace the pipe, how will they stop it from happening again?

[MPdesign]

Separately I have recommended to add water treatment to the domestic hot water loop.

Copper.

They have a slew of issues that I did not want to muddy the water here with such as:

2,200 gallon steam to hot water heater storage tank with 1,000 gallon storage tank with a pump between that has not worked for over 4 yrs; never any hot water loop treatment, a city water main charcoal filter broke about 8 years ago and that was distributed throughout causing all of the toilet flapper valves to be replaced - but they did not do a thurough job - only replaced what stopped working, many shower mixing valve issues...

[Jim Katen]

Perhaps I've been blissfully ignorant, but I haven't heard of copper pipes scaling up to the point where water flow is stopped. It seems much more likely that they've got debris built up in the fixtures.

Are you sure that the pipes are the problem?

Has anyone removed a section of pipe to look at it?

[MPdesign]

That is a good point.

I do still worry about clogs at fittings, elbows, and valves. The clogs seem to move periodically as well.

They are completely remodeling most of the remaining areas - so the piping - and fixture - replacements would not be as costly as in other finished areas.

They are already planning fixture replacements in most areas.

[plummen]

Is there a check valve someplace in the system?