Fixing Apartment Building flow issues

[Johnplumb]

This is my first post although I have been searching and reading the forum for quite some time. I haven't been able to find any guidance on my situation.

I recently purchased a 4 unit apartment building. It is an older building and I am sorting out some long time existing issues.

I have a 3/4'' supply that transitions immediately into 1/2'' copper which then goes to the meter and then immediately back into a concrete floor only to re appear in an equipment room. The equipment room is a mess of junctions valves and "T's", all in 1/2'' copper.

I have 125psi in the equipment room and there is only one 60 gallon hot water tank.

Tenants are complaining about not having enough hot water (no surprise there) and having big spikes in water pressure when they are taking a shower, basically good temp/pressure that goes to very hot or very cold (I am assuming when someone flushes a toilet or runs water somewhere else in the building)

While the pressure seems high, the volume seems low.

I would like to add 3-38 gallon hot water tanks and stabilize the pressure spikes.

I was thinking that I would add a 3/4'' manifold off of the 1/2'' line in the equipment room with 4- 3/4'' feeds and add 4 pressure regulators to each supply line set at 45 psi each. Is this overkill or should I just add a pressure regulator before the manifold? I would also add a 40gallon pressure tank (the type commonly used in well water systems) before the 3/4'' manifold to add some additional volume and hopefully control pressure spikes.

Or should I add a pressure regulator then a "T" into the 40 gallon pressure tank and then a manifold?

Ideally, I would get the 3/4'' supply to the manifold but I can't see any way to get it there short of destroying the floors in multiple commercial units.

The high pressure and low volume problem is a head scratcher for me and I could use some guidance from someone who has been in a similar situation.

Thanks for any reply's and thanks for a great forum.

John

 

[hj]

IF you are really trying to feed the system with a 1/2" line, forget it, regardless of HOW BIG you make the manifold it feeds. Once water gets into a long small line, its dynamic pressure and volume are FIXED and nothing, sometimes not even a pump, will increase it.

 

[Sponsor]

 

[Johnplumb]

IF you are really trying to feed the system with a 1/2" line, forget it, regardless of HOW BIG you make the manifold it feeds. Once water gets into a long small line, its dynamic pressure and volume are FIXED and nothing, sometimes not even a pump, will increase it.

Thanks for the reply.

I found a way to get the 3/4 inch line to the equipment room. But the main valve coming off the 3/4 inch line goes to 1/2" immediately then into the meter and out 3/4 from the meter.

1. Will a 3/4" line be big enough to feed 4 single bedroom apartment (no laundry) or do I need to look at getting something bigger into the building?

2. Would you typically size up in pex off the 3/4 copper main? Ie: should I use 1" pex?

2. If the 3/4 main line is big enough: should i stub (1" or 3/4) off the valve even though it reduces to 1/2" or should I replace that valve as well?

Thanks for any advice.

I tried attaching a picture