Halstead Finest Platinum...again!!

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Hi all
I am still having problems with the Halstead Finest Platinum combi boiler.
I found the problems related to the DHW flow switch operation and was advised to replace the diaphragm. I got a new one and have replaced it but I am still having problems with the pin pushing out too far and not returning back when the dhw switches off. I can only assume the spring is getting weak or the mains pressure is high. The spring does seem to be ok though and is quite springy.
There is also a small screw to the side of the diaphragm which would seem to allow a balance of pressure across the diaphragm. However this doesn't seem to do anything when it's screwed in. If you screw it down and push the diaphragm some water comes up the middle of it.
Any suggestions on what to do apart from replacement of the boiler as I can't afford it at the moment.
Thanks for you help
 
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Is the spindle dirty or bent?
When you turn the tap off does it sound as though water is still running for a while?
 
Hi twgas
The pin which switches the micro switch is clean and moving freely. When the tap is turned off the water stops and the boiler 'clicks' right away.
I decided to strip down the diverter valve to clean it out. I managed to get the left hand nut off the end and get the spring and spindle out to clean them. But the right hand nut was stuck fast. I even had the 18" pipe grips on it but it wouldn't move. As the actuator mounts on this end I didn't want to damage it. I did however manage to work the spindle on this end back and forth with my fingers. It did seem a little sticky.
I assume if the diverter isn't opening or closing correctly it will affect the micro switch activation.
I am going to refill the system now and see what happens.
Thanks for the help





 
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Hi paulthegas
It is listed in the manual as the CH micro switch.

What I don't get though is why the top of the diaphragm is wet. There are no holes in it as it's new and when I remove the housing there is a lot of water on top.
However in the picture below on the right hand side of the diaphragm there is a small screw which is hollow down the middle and I'm guessing the pressure is passing to the top?

Any ideas?
Thanks

 
Is this an ongoing fault? If so, what are the faults you are having?
Sorry I read it and thought you were having hot water issues and saw the picture of the ch flow switch.
 
Your boiler does not have a dhw diaphragm, it uses a hall effect sensor and a switch, if you look to the left of the central heating switch your working on at the moment you will see the dhw switch, it simply unclips and the new one clips on.
 
Thanks guys

@paulthegas. It is an on going fault. The hot water is intermittent. It works correctly occasionally. Sometimes it locks out the boiler and it needs resetting by switching off and then switching on using the control knob on the front of the panel. Note it wont reset by pushing the reset button above the knob.

@picasso. The hall effect sensor is working fine. It lights up when the hot tap is turned on. However it would seem the boiler needs the micro switch to be in the correct position as well as the sensor recording before it will fire.

The heating is working ok.

Cheers
 
Disponded the part your playing around with constitutes a safety device so please understand how the boiler operates before you pull anything else apart.

The diaphragm assembly on top of the diverter block is the device used to sense primary water flow around the boiler. The pin should rise EVERY time the pump runs. When the pump stops the pin should drop. The "screw" you are playing with is a port to take water to the topmost side of the diaphragm via the brass top cover. Yes the diaphragm is completely immersed in water. There is no adjustment of the screw...leave it alone. When primary water flows around the boiler a pressure difference is placed across the diaphragm due to the drillings in the diverter block. Negative on the topside and positive on the underside. When you turn a tap off it's likely the pump will continue to run for some time in which case the pin will remain extended.

So are you saying that with a hot water demand (hall sensor LED on) the primary flow assembly pin does not always rise sufficient to operate the microswitch?
 
So are you saying that with a hot water demand (hall sensor LED on) the primary flow assembly pin does not always rise sufficient to operate the microswitch?

Yes. From what I can gather the pin is up for DHW and down for CH.
Thanks
 
And yet your central heating is working ok :rolleyes: the diaphragm your messing about with does exactly the same thing when either dhw or central heating is called for, it proves the pump is running, your problem is with either the hall effect sensor or the dhw switch,

just a thought if the plate heat exchanger is blocked you will have problems with the flow switch.
 
One last chance...

The pin MUST rise and operate the microswitch for the DHW or the CH to work correctly. The pin rises proving there is sufficient water circulating around the primary circuit...that's the system water NOT the domestic hot water.

So before you said the pin rises in CH mode and the heating works but the pin didn't rise for DHW mode....then you come back saying completely the opposite...then you come back saying the pin no longer rises for CH mode.

The problem appears to be poor flow around the boiler or the drillings inside the diverter that trasmit the water pressure to the diapgragm are blocked.

The chances are it's poor flowrate and the pump is sticking or running slow or the impellers clogged or there is a partial blockage in the boilers internal pipework.

The manual refers to the primary flow switch as the CH switch. That is INCORRECT but stupid thick boiler manufacturers often misname boiler parts. The switch operates in both modes.


I have no idea why picasso is going on about a "hall effect sensor or the dhw switch". Inside the left hand side brass manifold is a magnet assembly. On turning on a hot tap the mag assembly moves position. The hall effect sensor inside the clip on assembly detects the magnet and the LED comes on and the DHW mode initiates. There is no other switch.
 
Thanks Gasguru.
The CH which wasn't working, is now working. The fault is intermittent.
Sometimes the pin rises and sometimes it doesn't. Sometimes the pin recedes and sometimes it doesn't.
I think that poor flow is the answer but whether it's the pump or the heat exchanger is tomorrows task. I was going to remove the pump but I don't have any spare washers for it, so I better leave it for now.
I will strip it down again tomorrow and check everything.
Thanks for your help.
 
I missed the post where he said the led was coming on and would not have posted any more about the hall sensor or the switch, dying pump or blocked plate would be my guess.
 

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