Alpha 280e low hot water flow

[dk64]

Dear Forum,
I have a 280e that has decided to deliver only 5 l/min of hot water (half of what it should). At first it gushes out of the hot tap and then it backs off to a dribble. The water input pressure is a decent 6 bar the cold main flow rate in is a reasonable 18 l/min.
I'm assuming there must be a filter somewhere that is blocked or some flow regulator that has been missed.
It has been serviced twice by professionals to no avail. -any suggestions would be greatfuly received.

 

[ChrisR]

There's pprobably a flow restrictor which has a rubber O ring. They swell and block the flow.
Not something a service would go near.

There is also a filter which could block, but I haven't seen it happen yet.

 

[gas4you]

Is this just on one hot tap, or all of them?

If just one then check that tap washer and/or tap body, same reason as Chris says about 'o' rings.

 

[dk64]

There's pprobably a flow restrictor which has a rubber O ring. They swell and block the flow.
Not something a service would go near.

There is also a filter which could block, but I haven't seen it happen yet.

Thanks Chris, I will look at the tech-specs for the flow restrictor. Only thought is there is a rush of water to begin with then when the boiler gets up to heat the flow dwindles. I thought there might be a heat regulated flow restriction in there somewhere?

 

[dk64]

Is this just on one hot tap, or all of them?

If just one then check that tap washer and/or tap body, same reason as Chris says about 'o' rings.

Thanks Gas4You, the flow is pretty rubbish on all the taps, as I said to Chris it starts well them falls away.

 

[gas4you]

Is Devon hard or soft water? If hard an outside chance could be the plate heat exchanger scaled up, but check the other simple things first.

 

[dk64]

Hi Dave,
sorry soft as they come down here, our kettle shines for years! I'm going to disconnect the direct 15mm inflow and test that for pressure and flow and then hitch up a pipe directly on to the hot water outlet just to satisfy myself i'm looking in the right place and its not something in the plumbing!