Posts Tagged ‘Operating’
March 25th, 2012 | 
Author: Some tankless units are sized to heat a cup of tea, while others provide enough hot liquid for two or more bathrooms. Also, the region of the country you live in has a lot to do with how much hot water a tankless heater can produce.
There are a lot of factors to consider with these appliances so you need to know about the heater so you can make an informed decision before you buy. The tankless radiator works by directly heating on demand, as it is required.
Unlike traditional hot water heaters using a storage tank, the units have no storage tank and thereby have no standby heat loss. Standby heat loss is the heat lost and energy wasted by heating only to store in a tank and is characteristic of traditional heaters.
Avoiding standby heat loss is primarily how tankless radiators make their claim of being energy efficient. Whether a radiator is point-of-use or a whole-house unit, they work the same basic way.
Cold liquid enters the appliance and is heated by a heating element which is turned on by a flow activated switch. The heat exchanger can be electric resistance heating coils or a gas fired burner using natural gas or propane.
There are two basic types of tankless radiators; they include Point of Use and Whole House. The type you select is based upon your intended use and your intended use will have even more to do with the cost of these units.
The point of use radiator is relatively small and will usually fit inside a sink cabinet or in a closet. They are typically dedicated-use radiators, meaning that the unit serves one sink, one faucet, or one shower, etc.
Point of use tankless water radiators are less expensive than whole house appliances and cost around a few hundred dollars for the unit. Whole house units mean that they have higher GPM flow rate capacity and can handle demand for more than one fixture at a time.
For example, an appliance may handle two shower fixtures at one time or a dishwasher, kitchen sink and lavatory hot water faucet at one time. The size and number of whole house radiators you need will be largely driven by flow rate and that is determined by the number and types of fixtures you may have running at one time.
The worst culprits of excessive usage are shower heads. That is why you may need more than one whole house tankless radiator hooked up in parallel to meet your hot liquid demands, especially for simultaneous shower usage.
Whole house units are much more expensive than point of use appliances and range in cost from several hundred to several thousand dollars without installation. The difference between the temperature of the hot water exiting the radiator and the cold water entering the unit is called the temperature rise.
If you want a shower up to 110 degrees F and you live in south Florida with groundwater at 72 degrees F, then you need a 38 degrees F temperature rise (110-72=38). A radiator is sized by rating its temperature rise at a given GPM.
So a unit could be rated at a 33 degrees F Temperature Rise at 2.0 GPM. Based on manufacturer’s data, this same appliance could also provide a 65 degrees F Temperature Rise at 1.0 GPM.
To determine your required GPM, add up how many fixtures of what type you will have served by the tankless water radiator. Often you can get below 2.2 GPM with low flow aerators but before 1992, older fixtures used much more than 2.2 GPM.
You should go through and check your bathroom faucet, shower head and kitchen sink faucets, even relatively new ones. You need to know the usage of each before you size and install your tankless water heater.
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Industrial dishwashers are just like any normal, family-sized dishwasher, right?
Wrong!
The worst thing about the industrial dishwasher is the way it looks. It looks big and scary and very complicated, but in actual fact it is as easy as pie, once you’ve been given a few starting points to set off from. Therefore, if you suddenly find yourself in a situation (whether it be work related or something social) where you have to wash the dishes for a huge number of people in one of these powerful industrial machines, make sure that you use the following step by step instructions to ensure that everything goes smoothly from the very first wash.
Before you begin, make sure that your have everything you need and that all equipment is ready to go.
If you are planning to wash the dishes of a very large number of people in a short space of time, you will always need the following tools to complete the job:
- An industrial-sized dishwasher
- Soap specifically made for industrial dishwashers
- A sink, with a hose connected to a high-pressure spray nozzle
- Dish racks
- DIRTY DISHES and LOTS OF THEM!
Step by Step Instructions
1. The industrial dishwasher should always be loaded with dishwasher soap beforehand. Ensure that you have filled the soap dispenser to the correct amount, turn the power on and wait for the machine to fill with hot water.
2. Once the dishwasher is full of water and ready to start cleaning, use the hose and spray nozzle to give the dishes a bit of a spray cleaning to begin with.
This will help with removing large bits of food, etc. and keep your machine running better for longer.
3. You should then load the dishes onto the dishwasher’s plastic dish racks. It is really important to arrange the dishes neatly and to spread them out. Otherwise the water cannot get to all the places it needs to get during the clean and you’ll be left with lots of unclean dishes at the end of the run and a lot of wasted time. Also, industrial dishwasher jet the water from below the dishes, therefore always put the dirtiest sides of the dishes facing downwards. This way they’ll benefit greatly from the power of the jet clean.
4. Slide the racks into the dishwasher once they are full and then pull the lever downwards to shut the door fully. Once the door is shut, the washing cycle will begin automatically. Check that everything is running smoothly before going away to do something else incase there’s a problem and the cycle doesn’t even begin.
5. When the cycle has finishes you need to open the dishwasher and pull out the dish racks from the other side of the machine. They should all be sparkling clean and ready to use. What is most important here is that you do not put your face close to the machine when you open the door because the heat of the steam could really burn your face and potentially cause scarring, so take care.
6. If you want to hand-dry the dishes you can do so with a hand towel, but if you leave them on the dish racks they will dry naturally on their own too. Less work for you!
7. Repeat steps 2 to 6 if you have more dishes to clean until everything has been completed and cleaned.
8. When you no longer need to use the industrial dishwasher you should drain the water from it by removing the “trap” which is a tray inside the machine that strains all of the rubbish out of the dishwasher. Take the tray out and spray it clean. Replace it and turn the dishwasher off until the next time.
You can’t get any simpler than that now, can you!
Cold water is supplied to the tank and injected at the bottom of the tank through a dip tube. The denser cold stays there and is heated by the gas burner.
As the liquid heats up, it naturally rises and is drawn off by the hot discharge pipe. You’ll notice that the hot pipe is much shorter than the cold pipe.
This ensures that only the hottest liquid is being used from the container. The hot heater has simple parts and some safety features.
Cold water is provided to the tank by a cold supply line and controlled by a shutoff valve. It is important to know where the supply shut off valve is located so maintenance can be performed on the container.
This is the business end of the heater and the hot liquid line is what supplies all your sinks, tubs, showers and appliance needing hot water. The container jacket itself is made of steel and encloses a pressure tested storage tank.
Between the storage tank and the container jacket is insulation to reduce heat loss of the heated water. It is a good idea to supplement the insulation by adding a fiberglass insulation container jacket to the outside of the heater.
These are inexpensive and easy to install. Inside the tank you will see a dip tube, which is where the cold liquid supply enters the container to be heated by the gas burner.
Since cold air and cold water are denser than hot, the cold water sets at the bottom of the tank until it is warmed by the burner and heated enough to rise to the top of the container where the hot hangs out. In glass-lined containers there will also be a metal rod in the container called a sacrificial anode.
The anode rod is bolted and fastened to the top of the container and extends deep into the container. Its purpose is to draw corrosion to itself instead of the metal tank.
Some models do not have a separate anode but combine the function of the anode with the hot outlet. Plastic lines containers do not have an anode
The natural gas or propane is supplied by a pipe having its own gas shutoff valve. Just like you need to know where the supply shutoff valve is located, you need to know where the gas line shutoff is located too.
The gas line fees into a gas burner control module that serves as a kind of thermostat for the heater. It also controls the ignition of the pilot light.
From the control module we now proceed to the gas burner assembly. This includes the pilot light and gas burner itself.
The pilot light and burner adjustment are key to proper and energy efficient operation of the heater. The gas flame should about 1/2 inch in height and should have blue tips.
The exhaust flue exhausts combustion gasses from the burner and it serves as a type of heat exchanger helping to heat the liquid in the storage tank. The flue must be properly exhausted to the outside and there are specific code requirements for the type of flue construction and acceptable details.
A safety feature of the hot water heater includes the pressure relief valve and discharge pipe. The purpose of this valve is to relieve excessive temperature or pressure builds up inside the container if it approaches the limits of the container’s safe design range.
This valve is located on top of the tank and often is threaded directly into the container top itself. To test the valve, lift up on the handle slightly and hot liquid should discharge out of the overflow pipe.