New Alpha CB28 micro switch

[ianmcd]

Ian, you are missing the point!

When the switch is removed it initiates a DHW demand condition.

Where the heat goes, depends on the position of the diverter valve.

At rest, the heat goes to the rads.

If a tap is turned on, the diverter valve moves and the heat goes to the DHW.

I appreciate that Dan is the one with an English degree but surely others can understand simple English?

OK Tony I will type this really slowly so you can understand, the diverter valve if stuck in the DHW position, which I have never heard of then the heat would not go to the radiators and the boiler would be constantly short firing untill a hot water outlet was opened and removing the switch would make absolutely no difference what so ever as the switch was already in demand before removed. you have absolutely no Idea how this boiler operates

 

[Agile]

I have been trying to buy an English tin helmet to go with my army trousers and shirt.

There was a German one in the market last Saturday but at £85.

Few English ones still have the webbing left.

 

[Agile]

I fully understand how the boiler works thank you.

But many of you are unable or unwilling to describe the boiler operation variables.

Remove the DHW demand switch and the diverter can still be in any position as dictated by the hydraulic actuator.

 

[ianmcd]

I fully understand how the boiler works thank you.

But many of you are unable or unwilling to describe the boiler operation variables.

Remove the DHW demand switch and the diverter can still be in any position as dictated by the hydraulic actuator.

NO TONY IT CAN NOT!!!!!!!

 

[Agile]

What would you think if I posted something like that?

So tell us why you think removing the DHW demand switch stops the diverter valve moving under the control of the hydraulic unit?

 

[Steelmasons]

What would you think if I posted something like that?

Something like what?

 

[DP]

Ian your credentials and experience is out of the window against someone who refuses to believe he is wrong and cannot understand how the valve functions. In theory anything is possible, but we are talking about working boilers or shall I say non working boiler.......

 

[bernardgreen]

Remove the DHW demand switch and the diverter can still be in any position as dictated by the hydraulic actuator.

NO TONY IT CAN NOT!!!!!!!

Assume the DHW demand switch is correctly fitted to the divertor assembly.

What makes the divertor move from CH position to DHW position ?

Is it an electrical signal ? No

Is it a hydraulic pressure differential on the diaphragm that pushes the actuator into the CH position. ? Yes

Is the hydraulic pressure differential created by water flowing in the DHW pipewprk when a tap is open ? Yes

So therefore if there is water flowing in the DHW then the position of the actuator is DHW.. That is the case both when the switch is fitted and when it it not fitted

 

[DP]

Bernard, you are correct on all counts, BUT What I have said........withdraw the switch, boiler fires and water to rads. No where have I said hot tap is run at this stage, so the diverter cannot be in any other position except open to rad circuit.

When one is working day in day out fixing boilers, one does get to know certain boilers better than others. If a person who has more knowledge about an appliance like Ian does, am I going to dispute what he says? Certainly am not!
Tony has a habit of belittling others, check out his posts if you want. Then there are gems like flattening gas pipes to pass behind soil stacks and carrying out boiler repairs with London buses being mode of transport. You are a problem solver.....think about it. Does that phrase 'are you serious' comes to mind?

 

[bernardgreen]

so the diverter cannot be in any other position except open to rad circuit.

It would be in CH if (a) a hot tap was open or (b) the divertor had not returned to CH after all hot taps had been turned off.

Does that phrase 'are you serious' comes to mind?

Very often. When analysing the design of equipment that is prone to problems due to a mixure of cost cutting in design by designer(s) who were not given the full picture of how and where the appliance / equipment would be used and the extent of mis operation / abuse that it would get at the hands of the users / operators / service engineers.

Four inputs. each can be either on or off. So 16 possible combinations of input states. Designer knows that some of those 16 states cannot happen. So (s)he does not take those impossible states into account. But in reality when when the equipment is faulty ( or being repaired ) some of those "impossible" states may occur and therefor have to be considered if only to ensure the equipment remains safe.

 

[DP]

Be it as it may Bernard, but this diverter in said boiler will not be in any other state other than open for delivery of primary water to radiators with no water running at the hot tap. This basic concept is used for fault diagnoses.

The phrase used was not directed at you but inability to understand some of tony agiles comments and advice he imparts

 

[bernardgreen]

but this diverter in said boiler will not be in any other state other than open for delivery of primary water to radiators with

so the mechanical design of the diverter is such that it can never stick in the CH position when there is no reason for it to be there.

For example in the CH position the actuator of the switch goes into a recess in the actuator rod of the divertor. When the divertor rod returns to DHW it has to push the switch actuator up and out of the recess. If the switch actuator has jammed then the divertor may not ge able to return to the DHW position.

A better design might be a raised cam on the diverter rod that pushes the switch actuator to be ON when the divertor rod was in CH position

 

[DP]

CH port open is the at rest position. For hot water, valve closes CH port and opens HW port. At the end of demand CH port opens and HW port closes, therefore it cannot be in any other position when at rest

 

[Agile]

Of course not.

But Ian has stated that the diverter CANNOT be in any other position when the switch is removed.

The reality is that the diverter can still be in either position according to whether a demand has been made for hot water.

 

[bernardgreen]

The reality is the diverter could be stuck in any position between the CH and DHW position. WD40 not advisable, could ruin the diaphragm.