HOTEL DOMESTIC HW

Louie O.

Gentlemen,
I have three 350 gallon storage tanks for domestic hot water at a hotel."What is the normal temprature setting for the holding tanks before the water is mixed to the anti-scald valves?"
I get a call once in a while that they run out of hot water. It never gets cold, its just not always hot.They tell me its warm, when I arrive at job the water is hot?This always happens when the hotel is at full capacity, we are thinking the damand is at maximum and boilers cant keep up?
Water temp in holding tanks is about 130F, is this normal holding temp before mixing with the cold water??

Firedragon_4

If you're using good

high quality anti-scald valves I'd go to 140-150F and measure it with a thermometer at all points.

Hotels/motels are a stinker, peak demands and then woof, gone! Also, a lot of transmision losses. Do they recirculate?

BTW, the hotter temps will also help protect from water-borne bacterias.

Louie O.

There is a circulator which pumps water thru tanks and into boiler heat exchanger. The pump is controlled by two aqua stats wired in parellel imersed in both of the 350 gal tanks. These two tanks feed rooms and there is another 350 tank that feeds kitchen with its own pump and stat. All tanks piped in parellel to the hydro therm exchanger.

If tanks ares set for 150f as you recommend, what should my temp be after ITT mixing valves to rooms??

Louie O.

there is a loop pump from furthest room

Firedragon_4

If it were me, no more than 110F!

Mark Eatherton1

Professor Yates...

and WATTS regulator company has some recommendations on ths provided that there are proper ASSE antiscald vales at the points of use, and the point of generation. I beleive they recommend 180 degrees.

I had a control logic that would raise the tank temperature to 140 during peak loading (6 to 8 am) and then lower it to 120 degrees during the rest of the time. It showed an average of 30% reduction in energy consumption, which resulted in a complete cash on cash ROI in less than 5 years. But with todays concerns over legionella pneumophilla, not so sure I'd recommend its use.

Make DARNED sure you have anti-scald mixing devices on the supply before you raise the water temperatures above 140 degrees F. Tis a litiguous society in which we live...

ME

Larry Weingarten

silly questions..

Do all the rooms have low flow showerheads? Is laundry being done AFTER guests have checked out? Those are two sources of grief I've seen.

Yours, Larry

Louie O.

Larry,
Your questions are not silly, we have taken these into account. Most of the laundry is out service, there is a couple of washers for the maids to use in case the need arises. However they do fill the hotel with gest on weekens since their 3 ballrooms are used for weddings and parties. The rooms are the problem here from 6 am to 12 noon, since this is check out time.
I spoke to some one this evenong and they keep the storage tanks at 160f. There are 2 ITT mixing valves after the tanks to temper the water to 125F.
These two valves are being bypassed right now for the past 5 years!!! The tank aqua stats are at 125f. I beleive they were lowered since the hotel didnt want to pay to replace the ITT valves. I am giving them a proposal for replacement. Therefore setting the tanks higher and set valves at 125F.

Firedragon_4

Just so you know, the

American Medical Association has determined that any temperature in contact with skin in excess of 111F is 'scalding'.