central heating controls, pump actuator

[stevethebiker]

hello folks, i am trying to sort out a system with hot rads upstairs, cold or very slightly warm down and have the following questions for you

1 what does an actuator do.. there is the pump above and a T junction below with an actuator on each branch, pipes are hot both sides of all three, but what do you think this set-up does ?

2 what is the three way valve, what does it do

it's an old system and i have already gotten a lot of sludge and small particles out, so replacing the pump as the next step, but what advice do you have

cheers guys

 

[compheat]

A 3 way valve diverts the water from the boiler via the pump to either the cylinder or the radiators or both. an actuater can be another name for a motorised valve but you don't normally have a 3 way valve and a zone valve on the same system.

 

[MANDATE]

If you have cold or warm radiators, first try bleeding them. It might just be air trapped in the radiator. Also try adjusting the lockshield valve, it may be restricting the flow of water.
Failing that, try closing the hot ones down and see if the cold ones now get hot water. If they get hot it suggests they are starved of hot water and you need to balance the system by adjusting the lockshield valves. closing the lockshield a little on the hot ones will restrict the flow so the cold ones will get more of the flow.