Published on Sep 14, 2017. Boilers have a flow and return pipe connected to the heating system. This is called the primary circuit with the flow pumping the heated water to the radiators and hot water cylinder(s). The cooled water then exits the radiators and returns to the boiler via the return pipe..
Then, which is flow and return on a radiator?
The flow pipes are connected to one end of the manifold in a number of radiators, and then return to the other end. But both the feed and return microbore pipes are connected to the same end of the radiator.
Similarly, how does heating flow and return work? As your boiler heats up water, it's pumped out and circulated around your central heating system; this hot water comes out of the flow pipe. The water then travels around your heating system and returns to the boiler via the return pipe.
In this way, does flow and return matter on a radiator?
Its a process known as convection and the heat will still pass through from the flow and return pipes on the circuit. most modern TRVs have no orientation, you can fit them on the flow or return and they will work.
Should a central heating pump be on the flow or return?
The location of the pump would all depend on ehat kind of a heating system you have. If you have multiple zones and the zone valves are on the supply, then the pump can go either on the return or the supply. If you have multiple zones but with circulating pumps the i would put them on the supply.
Related Question Answers
What direction does water flow in a radiator?
Water comes into the radiator from the upper hose at the left of the car, flows through the radiator from left to right, and is picked up at the lower radiator hose on the right side of the vehicle.Which side of a radiator should a thermostatic valve be fitted?
Many modern homes will have TRVs – Thermostatic Radiator Valves – attached to most of the radiators on the opposite side from the lockshield valves. A TRV should always be fitted to the inlet on the radiator and the LSV to the outlet.Which side of the radiator turns it on?
Turn valves clockwise to turn your radiator off and anticlockwise to turn it back on.How much should lockshield valve be open?
As you progress further away from the boiler, the Lockshield valve will need to open slightly more. It's not uncommon for the Lockshield Valve in the first radiator to be open around one-quarter of a turn, while on the last radiator, it may need to be fully open.Can I add a radiator without draining system?
1 Answer from a MyBuilder Heating EngineerEnsure both the flow and return pipes are empty and you can get away without draining. Before you go cutting into the system though undo the existing rad on the same level to make sure its ok. Then fill the system back up, bleed the system and refill.How long does it take to bleed a radiator?
20 to 30 seconds
How do you balance radiators?
How to Balance Radiators — Step by Step - Bleed all radiators.
- Remove the lockshield (2).
- Open up the valves on all the radiators in the house by turning them anti-clockwise (5).
- Turn the central heating back on and note down the order the radiators heat up (6).
How do I know if my radiator has water flow?
Start your car's engine and allow it to idle. Look through the radiator filler neck to see if the coolant flows. At this time, it should not be flowing as your car has not reached the operating temperature to cause the thermostat to open. If you find the coolant is flowing, it means the thermostat valve is open.Can you add a radiator to an existing system?
If you want to add in a radiator to your central heating system, it's easy enough to do. You can add a radiator at any point in the flow and return circuit, but you must make sure you don't take heat away from the current radiators.What is the difference between a lockshield and radiator valve?
Lockshield valveLockshield valves are used to balance the radiators. With the cap removed, a small spanner is used to open and close the valve. Progressively closing the valve restricts the water flow through the radiator.What side of the radiator turns it on?
Look on the right side of your radiator near the floor to find the valve. Use a screwdriver and turn the screw counter-clockwise until it's loose.Which valve is the lockshield?
which is the lockshield valve ? It is normal practice to have the lockshield valve on the return pipe and the control valve on the flow. When the heating comes on from cold check each rad for which pipe heats up first and identify this as being the flow. The system can now be balanced if required via the lockshields.How do central heating controls work?
When the air around the thermostat reaches the set temperature, it sends a signal to the central heating pump and boiler to stop sending hot water around the system. Your radiators will then cool down.Can you put 2 pumps on a central heating system?
It will as long as both pumps are on the flow or both on the return - you don't want them pumping against each other. If your existing pumps is old - upgrading the pump may work.Are radiators connected in series or parallel?
The primary benefit of series radiators is that you can guarantee that the flow through each radiator is equal. This is necessary for optimum efficiency. In a parallel system, you can make all hose lengths identical and have all the same fittings (minor losses) for each path, but it is not a guarantee.What are flow and return pipes?
The flow pipes are connected to one end of the manifold in a number of radiators, and then return to the other end. But both the feed and return microbore pipes are connected to the same end of the radiator.Does it matter which side of radiator flow and return?
Yes, but it doesn't really matter if the TRV is on the return end of the radiator but it must be hooked up the right way round. Some valves are designed for one way flow and there is an arrow on the valve head. If your valve is on the return side the arrow should be pointing away from the radiator.Does central heating pump go on flow or return?
If you have multiple zones and the zone valves are on the supply, then the pump can go either on the return or the supply. Pumps "pump" because they create a lower pressure on their suction side, and a higher pressure on their discharge side, and flow is created. The higher pressure will always seek the lower pressure. 
James Holden 
