Can the check valve at the outlet of the circulation pump in the heating system be removed?
Thread Content
In a closed-loop system, the operating circulation pump stops suddenly due to a power outage or malfunction. Will the pump and impeller be subjected to the force resulting from the sudden impact of the medium from the high-pressure outlet side to the low-pressure inlet side? Is this water hammer? So, a check valve needs to be installed at the outlet of the circulation pump, so that the impact force acts on the check valve, thereby protecting the pump and the impeller? Can the slow-closing check valves at the outlet of some circulation pumps also serve this purpose? Can a check valve with a valve disc that closes within 10 seconds still eliminate water hammer? Some people say that check valves are used to prevent the backflow of fluid; then how can backflow occur in a closed-loop system? If that’s the case, then there’s no need to install a check valve at the outlet of the circulation pump at all. I’m a bit confused; I hope someone with more knowledge can help me out.
This post was last edited by zdl1966 on 2018-4-18 at 19:27. A check valve with a slow-closing function can reduce the impact of water hammer on the pump. Check valves can prevent backflow and completely avoid water hammer.
Check valves are used to prevent the backflow of fluid from causing damage to the pump’s flow-related components as well as other electrical equipment; they cannot be removed
A check valve is an essential device in a pump’s pressure pipeline; its function is to prevent fluid from flowing back, eliminate water hammer, and protect the equipment and pipelines
It cannot be taken; under normal circumstances, on all design drawings related to cooling (or heating), there are check valves and shut-off valves (gate valves or butterfly valves) at the water pump outlets
What everyone has said makes a lot of sense; I’d like to add one more thing. When the equipment is operating normally, the circulation pump usually operates with one unit in use and another as a backup. When the backup unit is activated due to a fault in the operating pump or a drop in system water pressure, it is necessary to keep the inlet and outlet valves open so that the backup unit can start quickly. Without check valves, it is not possible to ensure that the outlet valve remains open, which could lead to an escalation of the accident. 2. When a pump in operation experiences an outage due to some fault (such as an electrical issue), the stopped pump can cause backflow in the system, reducing the pressure difference between the supply and return water. The circulating pump that is still running will see a sharp decrease in the pressure difference between its inlet and outlet, which leads to an increase in flow rate. This results in overloading of the electric equipment, causing damage to it and affecting the proper functioning of the system.
Code for Boiler Room Design 13.1.9: When each hot water boiler is connected to the main hot water supply and return pipes, shut-off valves shall be installed on the boiler’s inlet and outlet pipes; a check valve is advisable to be installed in front of the shut-off valve on the inlet pipe. These are all similar, right? You can take a look at the explanatory text