What are Differences between 2 pipe and 4 pipe fan coil?

There are many questions when setting up fan coil thermostats. While before choosing a suitable one, one of first question is you need to confirm your fan coil system is 2 pipe or 4 pipe system.

Do you know what is 2 pipe fan coil and 4 pipe fan coil? What are differences between these two systems?

Maybe you will said whether 2 pipe is only for cooling and 4 pipe will use for both cooling and heating? But I have to say “No”. In order to clarify the differences, following I will expose these two concepts for you.

2 Pipe Fan Coil

The 2 pipe system consists of a single water coil connected to two pipes and one valve that can support either cold water coil or hot water coil, which is depends on the mode of the system. But this 2 pipe fan coil cannot cool and heat at the same time.

4 Pipe Fan Coil

The 4 pipe system consists of two parts, cooling and heating water coils. Each coil has its own valve, that means this system need 2 valve to control, then can control cool and heat at the same time.

The 4 pipe fan coil can also use a chill water coil and an electric or gas heater. As long as the cooling and heating are independent of each other, the system will be a 4 pipe configuration.

Differences

1. 2 pipe fan coil usually need to install a changeover sensor to determine the mode of the system but 4 pipe fan coil do not need. That means for the 2 pipe fan coil, if cooling is available and no electric reheat coil is present, then the fan coil can only cool. If heating is available, no cooling is possible.

2. The 4 pipe system include heating and cooling available sources, which makes the fan coil independent of the system mode. Unlike to the 2 pipe system, it can cool and heat at the same time.

But if there is required, the 2 pipe and 4 pipe fan coil both can be equipped with an auxiliary electric heater to boost the heating capacity.

Hotowell, as a professional manufacturer of thermostats, valves and related HVAC products with more than 10 years. Most of our fan coil thermostats include 2 pipe and 4 pipe options. And we also accept special customize requirements accordingly. The following are some of our fan coil system products, include thermostats, valves and water flow switches.

Welcome to contact me as following methods if there is any interest of our products or any questions.

Email: delta@hotowell.com

Tel.: +86 153 5987 4486

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