worcester greenstar 24i junior

[gasmarc]

I have a customer who has told me the hot water flow rate has dropped off by 60% this week. I arrived this morning and tested the boiler which works fine and fires up everytime. The flow is fine for about 15 seconds and then the flow just reduces to a slow flow but the water is nice and hot. I have checked the mesh filter which was clean I removed the flow turbine and checked the filters behind the turbine , I removed the pipe completely and checked it was clear , I have removed the heat exchanger and put the mains through it which was giving a good flow rate on both sides, The isolation valve to the boiler has been checked and that is clear also. The flow on the cold main is good , I have put the cold mains through the shower mixer to prove that there is blockage to all the taps. My last thought is there could be a partial blockage where the rising main branches off to supply the boiler , Any thoughts would be great :thinking2:

 

[SimonJohns]

doesnt the boiler have a flow restrictor? perhaps thats on the blink

is it only from one outlet or all?

 

[gasmarc]

Cheers Simon have I missed that I thought the flow restrictor was after the flow turbine which I checked , Yes all 4 hot outlets have the same flow problem

 

[SimonJohns]

i would say the flow regualtor is on the blink, i dont know if you can omit this from the boiler, but their never a good idea imo

 

[gasmarc]

Cheers Simon I will have a look at the manual as maybe I missed that , I didnt think there was anything after the turbine and filters , What a doughnut

 

[SimonJohns]

depends on which model of gstar junior you have, i think they are on v4 now

 

[gasmarc]

I have cleaned the flow regulator which sits into the the back of the flow turbine this is just a piece of plastic that regulates the flow and does nothing else that I am aware of. it is the model with the stepper motor below the flow turbine if that helps ,

 

[newgas]

It seems your problem is the cold inlet into the boiler so all the taps are affected, In this case it sounds like you have something like a stone or similar that swims up when hot demanded and the swims back down when off , thats why you ca'nt find anything.
Thats where I'd start.

 

[gasmarc]

Yes thats the way I am thinking ,I had a vw diesel van before and the thing kept breaking down after trying everything they eventually flushed the fuel line and problem sorted, Guy said bit of dirt can act like butterfly in pipe if that makes sense, I have told the customer who is a plumber to check the isolation valve which he did as i had no acces to the stopcock today. He checked it and said it was clear. I have told him to connect a pipe to the cold inlet going to the boiler and hopefully that may clear the obstruction in the pipe , fingers crossed

 

[kon]

It seems your problem is the cold inlet into the boiler so all the taps are affected, In this case it sounds like you have something like a stone or similar that swims up when hot demanded and the swims back down when off , thats why you ca'nt find anything.
Thats where I'd start.

That brings back bad memories,i once spent days trying to cure an air lock to the dhw when i installed a new ind cylinder,and eventually dis-con hot water draw off from cylinder to find a perfect sized peice of foam.