Pump, 3 port valve or boiler problem?

[ahjun]

Y-plan system, Baxi solo 2 boiler. Until several days ago, it has been running smoothly even it is a 20+ years system.

Problem: after the first 5 minutes firing up, boiler starts mild whistling then turns on and off every 2-3 minutes. rads are warm. but looks like the hot water also flows to the cylinder even hw is not called on (ch is on).
3-port valve: i assume it is not the classic sticky valve problem, tried to move the lever to man with power off, the lever moves with resistance and bounces back slowing to 2/3 position. The valve moves freely with ch power on.

Could it be the pump and valve failure? or is it the age of the boiler?

Thank you for your time and thoughts. Rgds.

 

[ianmcd]

3-port valves:

you wont have 3 port valves, you will have 2 x 2 port valves (S plan) or 1 x 3 port valve (Y Plan) what is it that you have

 

[ahjun]

Thank you for your response ianmcd. appreciate it. It is 1 x 3 port valve (Y Plan). got two pics, please see below.

 

[ianmcd]

yes you do indeed have a Y plan system, the noise you describe normally means that the boiler is having trouble getting the heat out to the system, you have a very tried and tested wee boiler which is usually very reliable, would be worth getting someone in , lock your 3 port into mid position and if the noise persists tou have a boiler or pump problem

 

[ahjun]

yes you do indeed have a Y plan system, the noise you describe normally means that the boiler is having trouble getting the heat out to the system, you have a very tried and tested wee boiler which is usually very reliable, would be worth getting someone in , lock your 3 port into mid position and if the noise persists tou have a boiler or pump problem

Ian, thanks a lot for the prompt reply again. really appreciate it. Will call an engineer.