commercial building low water pressure and temperature sometimes

[jpaul]

Hi. I will be working maintenance in a building with 70 efficiency bedroom units, a kitchen to feed the residents and a small laundry room. I worked there prior, left and now will be returning. This was a problem when I left 4 months ago and is still a problem now.

In the "boiler room" there are 4 large 185 degree water heaters. (one had been replaced) 3 mixing valves. 2 mixing valves service all of the residential units and no problem there except for maintaining a 120 degree temp. but this is not the problem this is about.The 3rd mixing valve controls the kitchen and laundry. This is the problem area. These mixing valves had been rebuilt or replaced while I was working there. the building is 3 years old. And I think there are 4 circulators as well. Several of these had been replaced. All the work was done by plumbers. A large water conditioning unit in there as well. The water pressure gauge always read about 58lbs I believe and didn't fluxuate very much if I remember correctly.

The kitchen had complained many times (daily or almost) about low water pressure (almost none) and low water temperature. No rhyme or reason when this would happen although it was always the day worker who complained. Intermittent problem for short periods of time. I experienced it once in the laundry but had seen it in the kitchen as well while it was happening.

Looking for any thoughts you may have. Thank you.

 

[Reach4]

Have you seen the water pressure gauge while you are having an event?

Can you add some taps, such as boiler drain valves, closer to the kitchen than the current pressure gauge, that you could mount pressure gauges to? Or maybe you have some branches in that path already, that could be used to measure pressure.

I am thinking the problem is likely a hot water pressure problem, rather than cold. You can temporarily mount a pressure gauge to the WH drain valve.

 

[Sponsor]

 

[jpaul]

Thanks for the reply. There are 4 water heaters, so we would need one on each, correct?

 

[Reach4]

How are these WHs plumbed? How many serve the kitchen?

If these are all in parallel, I would think that one gauge could be informative. But garden hose thread gauges are cheap. Under $20, and sometimes significantly under.

You can take a movie of a gauge to be able to look back at what the gauge said at a particular time when a symptom was observed.

 

[John Gayewski]

You'll need to observe this more. For instance low pressure can mean different things to different people. How many fixtures are experiencing this? Are you checking a sink while the dishwasher is running? Mixing valves have a minimum and maximum flow rate. If your flowing too much or too little water the valve won't perform correctly depending on the type of mixing valve that could effect the volume which people mistake for pressure.

 

[Jeff H Young]

58 psi isnt low is it only a hot water issue?

 

[Fitter30]

When running the wh at 185° it driving all the minerals out of the water. Wouldn't doubt mixing valves start having control problem from the mineral build up on the temperature bellows. All hot water valves need to be exercise at least every 3-4 months. Personally never trust a gage or a thermometers without checking them. Pull thermometers out of their well set them together check them 30 minutes later should be within 2° installed with contact compound. Gage might not zero out, seen needles stick or their ports mineral up. Pump failure motor bearing assembly or the impeller? Flow problems look at faucet aerators

 

[WorthFlorida]

The kitchen had complained many times (daily or almost) about low water pressure (almost none) and low water temperature. No rhyme or reason when this would happen although it was always the day worker who complained. Intermittent problem for short periods of time. I experienced it once in the laundry but had seen it in the kitchen as well while it was happening.

Looking for any thoughts you may have. Thank you.

Replacing the mixing valves was the right move. If possible can the kitchen have its own WH. I assume this is like a commercial kitchen, three tub sinks, T&S faucets without flow restrictions, dish machines, etc. It all takes a lot of water and since this is where the problem usually occurs. Low temp is one thing, low pressure is another but anti scalding affects both.

Is there any anti-scalding devices? You mention circulators, is this for immediate hot water delivery at the 90 units? Are these water heaters standard tank units?

What provides building heat?

 

[jpaul]

58 psi isnt low is it only a hot water issue?

I just started back working there yesterday. Talking to the kitchen director today he didn't say anything about low water pressure only water temperature. The mixing valve for the kitchen is also for the laundry. The hot water temp in the laundry was 169 degrees and I then checked one faucet in the kitchen and it was 90 degrees. I couldn't check elsewhere at the time as all sinks were full soaking stuff. Someone earlier asked about how the water heaters are piped. I have a couple of pictures but are too large to post. I'll try and reduce them and post them. The temp on the mixing valve guage was 155-160 degrees. Thanks

 

[jpaul]

58 psi isnt low is it only a hot water issue?

Right now it appears to be hot water issue only. I will find out more Monday.

 

[jpaul]

Replacing the mixing valves was the right move. If possible can the kitchen have its own WH. I assume this is like a commercial kitchen, three tub sinks, T&S faucets without flow restrictions, dish machines, etc. It all takes a lot of water and since this is where the problem usually occurs. Low temp is one thing, low pressure is another but anti scalding affects both.

Is there any anti-scalding devices? You mention circulators, is this for immediate hot water delivery at the 90 units? Are these water heaters standard tank units?

What provides building heat?

Electric HVAC in each unit for heating and cooling. Yes commercial kitchen like you describe. The utility kitchen guy who was telling about the problem before I left the facility 4 months ago is no longer working there to ask more about the problem and I just started working there again yesterday.

 

[jpaul]

This is how the heaters are piped.

 

[WorthFlorida]

I'm about to bet my home on your problem. It also happened at my church, lack of hot water in the kitchen. Do you have any of the overhead sprayers faucets. Every commercial kitchen has them. There was an auxiliary dish machine in another room with a sink and one of these faucet. Someone, I think it was a cleaning person, would open both hot and cold valve and leave them way. Only the sprayer was used to to turn off the water.

Big problem, cold water has more pressure than hot water. When another faucet was used, the cold water would push back the hot water at the sprayer and mix with the hot. As soon as I closed the valves at the sprayer, water was hot again. A fix is install check valves on the hot water side or users must not leave these faucets open. You might check the model number and see if internal checks valves were ever added, I doubt it.

I one of my summer jobs as a teenager was working at T&S Brass and Bronze in Westbury, NY. The original location and founded by two WWII Veterans. I assembled hundreds of these faucets.

 

[jpaul]

I'm about to bet my home on your problem. It also happened at my church, lack of hot water in the kitchen. Do you have any of the overhead sprayers faucets. Every commercial kitchen has them. There was an auxiliary dish machine in another room with a sink and one of these faucet. Someone, I think it was a cleaning person, would open both hot and cold valve and leave them way. Only the sprayer was used to to turn off the water.

Big problem, cold water has more pressure than hot water. When another faucet was used, the cold water would push back the hot water at the sprayer and mix with the hot. As soon as I closed the valves at the sprayer, water was hot again. A fix is install check valves on the hot water side or users must not leave these faucets open. You might check the model number and see if internal checks valves were ever added, I doubt it.

I one of my summer jobs as a teenager was working at T&S Brass and Bronze in Westbury, NY. The original location and founded by two WWII Veterans. I assembled hundreds of these faucets.

View attachment 93587

There is an overhead sprayer but I'm not sure if there is a faucet as well, I don't recall. That would be an easy fix. I'll check it out on Monday. Thank you