Worcester 24CDI HW only works if Heating is on.

[armyash]

Hi, My bro has the above boiler (not the newer model). The HW does not work unless he presses button 2 on the boiler where it says learn mode. Even then the HW doesn't always work. I was assuming it was the diaphragm but now i'm leaning towards the actual diverter valve. Looks like it will be a pig of a job to change either so I want to get it right first time. Could possibly be Microswitch/pcb fault I have been told though. How can I check to know for sure? Thanks.

 

[kris]

You should be able to see the pin rise up and press against the microswitch if it doesn't rise then you know it's the diaphragm and you can also wile running the tap press the switch with a screwdriver again if works then diaphragm. The microswitch has the 2 connections make or break.

 

[armyash]

Thanks for the reply. I will have a look tomorrow night. Never changed one of these before on this boiler, usually this is easy to see but the microswitch/div valve is sat behind the hw hex from what i can tell looking at the MI's wasn't sure if i would be able to see the pin moving.

 

[bigads28]

It's not the PCB! When you turn on the tap does the HW light come on? If it doesn't go underneath the boiler and take off the bottom panel so that you can see the diverter. Turn the tap on and off to see if the spindle hits the switch, make sure you try it at slower speeds. If it won't hit the switch then diaphram is your problem.

If the diaphram hits the switch and the HW light comes on but the hot water is still rubbish put your hand on the heating flow pipe and see if that gets roasting hot. If it does then its the diverter.

If you live in a hard water area scale is another issue. Going by your description its one of the two above.

 

[armyash]

Thanks guys, just thought i'd update. I have just got back from having a look at the boiler. Actually neither hw or ch are working, although they said ch was working ok last night. The pump did not seem to be running (but did have power). The boiler will fire up for 15 secs on ch mode only then there is a loud 'clunking' noise then boiler shuts down. Pump is red hot. Thinking pump has had it, unable to free it up to get it moving. Would this cause the HW to not work too. I'm thinking changing the pump will sort it. The boiler has been playing up for a while and it's my bro so not like I have to keep a customer happy but also want to get it sorted by the weekend without trying too many parts. Fault finding is not something I do a lot of (as you can guess).

 

[armyash]

Sorry also after firing up a few times the boiler will **** down. hw and ch lights flashing - MI'S say reset. Boiler then continues to repeat this cycle.

 

[bigads28]

When the boiler is cold take the silver vent pug off the pump and put a flat blade screw driver in to see that it spins. If its seized free it off to get them going, if it won't spin once you put then the heating on the its windings or capacitor are knackered! Either way I'd just put on a new head only not the complete pump.

The clunking is it boiling it's brains out btw..... :thinking:

 

[Simon F]

the hot water relies on the pump quickly turning the water round inside the boiler,
maybe there was some flow, enough for ch to not cut out but water to suffer.
now nothing, as you say sounds like pump has died.

 

[kris]

Yeh defo sounds like a fooked pump, the waters getting hot instantly as no pump to push , do as bigads says , good luck

 

[armyash]

Thanks guys, I did try to free up the pump using a screwdriver but no joy. It's getting red hot then going in to reset mode. I will change the head on the pump this week and see how it goes.

 

[bigads28]

Thanks guys, I did try to free up the pump using a screwdriver but no joy. It's getting red hot then going in to reset mode. I will change the head on the pump this week and see how it goes.

The boiler is over heating, thats the fault lights you are getting. Change out the head but make sure its the standard head you buy and not the UPS2.

https://www.heatingspares247.com/pumps/worcester-1560-pump-head-87161135940-p-6914.html

Thats the one you need

 

[armyash]

The boiler is over heating, thats the fault lights you are getting. Change out the head but make sure its the standard head you buy and not the UPS2.

https://www.heatingspares247.com/pumps/worcester-1560-pump-head-87161135940-p-6914.html

Thats the one you need

Brilliant, yep that's what is in there now. I'll order it tomorrow.

 

[armyash]

Hi guys just thought I would update. Pump changed easy enough, getting div valve out was difficult due to me not checking MI's properly. Decided to double check the diaphragm was operating before changing the pump and lucky I did because that was broken also. all put back together easy enough and next time it will be much easier and quicker. Have had a text off my bro saying there is the slightest weep from the dhw hex but all working ok. Said I will pop round at the weekend with new o rings. All working fine though and that's a job I was glad to do and learn in my own time and not stressing trying to get it done during work.

 

[bigads28]

The secret with those jobs is to replace all o rings and grease them, clean all the faces for the fibre washers too. If you ever think the plastics are goosed too they are pretty cheap.

 

[armyash]

The secret with those jobs is to replace all o rings and grease them, clean all the faces for the fibre washers too. If you ever think the plastics are goosed too they are pretty cheap.

O Rings replaced - No leaks!

 

[Billy Bob Bob]

O Rings replaced - No leaks!

sorted,did you use silicone grease?even furniture polish will work if you have none

 

[armyash]

sorted,did you use silicone grease?even furniture polish will work if you have none

Yes, used silicone grease and all sorted. It was a nice job to do for a family member and learn it with no pressure. The fact they had to put up with a small leak for 48 hours was nothing, they were just happy to have a boiler that works and I didn't have to stress that I was upsetting a customer.