05-02-2013, 08:53 AM
(This post was last modified: 05-02-2013, 08:54 AM by Radio Fixer.)
I imagine they changed the controller on top of the diverter valve Colin. Not much used to go wrong with the 3 port valve: 1 in and 2 out with a paddle that closes one of the outs at a time. One feeds boiler water to the rads and normally has priority, the other when the room stat goes 'off', allows hot water to flow to the cylinder coil.
After many years, the ones I used, developed leaks around the spindle to the paddle, where it exited the valve body to mechanically engage with the shaft from the controller sitting on top. When this happens it’s a pain as I used to drain most of the system and then have to get the air out after refill. Unlike pumps they never used to be fitted with isolating valves although this may be a modern requirement.
The controller was a synchronous motor, with mechanical means of always ensuring it started in the right direction. From the motor was a gear box that dropped the speed to a crawl but upped the torque to do the job. Inside there was a cam that opened micro switches, and cut the power to the motor, when it had got the valve paddle in the right position to open the particular port.
So the valve would be left with one micro switch open and the other closed, this would be the one to get power applied to it next, via the programmer (a big name for a largely simple box) and the room and cylinder stats.
The common fault is the micro switches, which in the models I fixed, were tiny things. I got some and used to change them and put the controller back for several more years of use (well hopefully
)
Gary
After many years, the ones I used, developed leaks around the spindle to the paddle, where it exited the valve body to mechanically engage with the shaft from the controller sitting on top. When this happens it’s a pain as I used to drain most of the system and then have to get the air out after refill. Unlike pumps they never used to be fitted with isolating valves although this may be a modern requirement.
The controller was a synchronous motor, with mechanical means of always ensuring it started in the right direction. From the motor was a gear box that dropped the speed to a crawl but upped the torque to do the job. Inside there was a cam that opened micro switches, and cut the power to the motor, when it had got the valve paddle in the right position to open the particular port.
So the valve would be left with one micro switch open and the other closed, this would be the one to get power applied to it next, via the programmer (a big name for a largely simple box) and the room and cylinder stats.
The common fault is the micro switches, which in the models I fixed, were tiny things. I got some and used to change them and put the controller back for several more years of use (well hopefully
)Gary
