Ecomac 824e cycling

[Backboiler]

Went to Ecomax 824e today which was peeing water out the blow off. The filling loop had been cracked open by customer to compensate for pressure loss so I switched the filling loop off. The boiler had been out of use and electrically isolated at the fused spur by the customer. I checked the pv which was full of water (fault 1). I switched on the boiler and operated it on CH. It fired up but only for approx 10 seconds then cooled down for 20 seconds. Then fired up for 10 and cooled down for 20, and so on. No error code. it just goes through it's status codes. I opened a tap and same thing happened but probably fired for 5 seconds and cooled for 20. The diverter was moving fine. I was thinking blocked plate heat ex at first but if that was the case the fault wouldn't show in CH mode. I checked the DHW thermistor which showed 18 kohms. Pump was spinning.

Anyone have any ideas what the fault will be?

thanks for any advice

 

[breakdown]

Inside boiler casing on the flow pipe there is a rubber sleeve clipped on to the copper pipe at each end. Feel in the middle for blockages it will be hard.I would try that first.

 

[Backboiler]

Inside boiler casing on the flow pipe there is a rubber sleeve clipped on to the copper pipe at each end. Feel in the middle for blockages it will be hard.I would try that first.

Thanks will try it

 

[breakdown]

Did you have any luck ?

 

[ambrosia]

could it be a blocked heat exchanger, also how strong is the pump can you slow it with a screw driver

also what is pv, is that the expanssion vessel, if so, although a fault im pretty sure that is unrelated to the problems you discribed