Boiler dhw problem

[Agile]

You remove the pipes from the hydraulic unit on the left.

First remove the two wire clips, ideally with forceps.

Then loosen the two clamping screws about four turns.

The pull the unit towards the left until it exits the clamping part,

The gently rotate it a few degrees in either direction untill hopefully the seal is loosened and the two pipes can be withdrawn.

On reassembly silicone grease in the sockets and on the "O" rings will aid reassembly.

Tony

 

[charleszhuang]

Thank you very much. I'll give it a go!

 

[charleszhuang]

Hi Tony,

Thanks for your support. I did get to replace the diaphragm but it still takes at least 2.5 minutes of tap on to get the dhw going. sometimes it takes about 4 - 5 minutes of taps on to get it firing up. Can it be something else that need changing?

Many thanks.

Charles

 

[Agile]

Can you view the DHW flow switch which is behind the gas valve, perhaps from underneath after removing the bottom cover.

Does the pin come out promptly?

Is the switch all wet and with rust around itr from a leaking gland?

Tony

 

[charleszhuang]

Yes, I can see the flow switch.

the flow switch is not rusty and not damp but it takes that few minutes and after taps on and off for the pin to come out to knock the switch on. Once it is warm then it will come on immediately the tap is on.

 

[charleszhuang]

it's strange, when I switch the ch on the pin comes out immediately and the dhw works fine. when I switch the ch off the pin refuses to work till a few minutes of taps on.

 

[Agile]

You are not looking at the DHW switch!

You are looking at the system flow switch.

However you have identified that the sys flow pin is slow to come out on DHW.

Thats usually the result of dirt in the eye of the pump or a blocked plate HE or both. Can be several other things too!

Tony

 

[charleszhuang]

Yes! I can see the switch now but cannot see the pin because the other parts are so near blocking the view. Yes, the safety clip holding the switch is rusty.

Charles.

 

[Agile]

You really need to see if the DHW pin is coming out promptly when there is a demand for hot water.

If so then there is a flow restriction.

If not then the diverter valve is sticky or the diaphragm is failing.

Tony

 

[charleszhuang]

I cannot see exactly the pin but I can see that the switch is pushed on whenever tap is turmed on. So the pin must be working.
Can it be that flow pin that is slow to come out creating the problem?
Sorry, what is the eye of the pump and how can I clean it please?
Also what is HE?

Many thanks.

Charles

 

[charleszhuang]

Why is it that when the ch is on the dhw
works?

 

[charleszhuang]

Also once it fires then it will continue to work till it is stoped for some time and cools down