Check valve, it is designed for users who want to use zero cold water gas water heater and do not bury the return water pipe in advance, replace the return water pipe with a check valve, installed at the farthest water point to achieve zero cold water.
First of all, let's talk about the principle of zero cold water: conventional water heaters have a built-in hot water circulation pump. After the circulating pump starts, the cold water in the circulating waterway is returned to the water heater for heating, so that the tap is hot water.
There are two ways to achieve zero cold water:
1 The return pipe is embedded. Many new home decoration will take this situation into account, pre-buried the return water pipe, then as long as the purchase of zero cold water gas water heater, direct installation can be.
2 No return pipe is embedded. Some new homes do not bury the water pipe in advance, and many old community users also want to use zero cold water gas water heaters, then you can install a check valve. At present, many zero-cold water gas hot water products have their own check valves, which do not need to be purchased separately.
It can be said that the check valve solves the problem of wanting to enjoy zero cold water but not burying the water pipe back, but the check valve has a disadvantage, that is, after installation, zero cold water is indeed achieved, but the water in the front of the toilet becomes hot water.
Therefore, before the purchase of zero cold water gas water heater, if there is no pre-buried water pipe, you must first consider whether you can accept, if you do not care about this, then you can buy zero cold water gas water heater.
Built-in or external a return water system, through the circulation of preheating, to achieve the effect of immediate opening and heat; Simply put, it is to pump the cold water inside the gas water heater back to cycle heating, to ensure that the water is hot when you use water, and if there is no return pipe reserved, you can consider installing a check valve at the farthest water end.
If there is a pre-buried water pipe at home, you can consider a zero cold water heater, if not, it is recommended to use a better ordinary water heater.
There is a circulating water pump inside the water heater, this circulating water pump is an important device to achieve the principle of zero cold water, as long as you start to use the gas water heater, this time the gas water heater starts to ignite.
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At the same time, the circulating pump inside it has begun to operate, will pump the cold water inside the hot water pipe to the place where the tap water of the gas water heater is fed, and then wait until the hot water comes out, at this time it will go inside the hot water pipe, that is, in the process of returning water, the gas water heater will produce hot water, and there is no vacuum and air in the hot water pipe. In fact, the pump and the circulation pump are similar, so that the gas water heater can achieve zero cold water.