Condensing boiler not staying at max temp

[scalextrix]

I have a Vaillant ecotec condensing boiler and we seem to be getting variable heating results on both central heating and hot water tank recently. The boiler will switch on start heating the water, get up to 65deg target temperature, then immediately backs off and the water temp drops to about 45deg, the boiler then is content to keep heating the water at this lower value. To a layman, I would expect the boiler to run continuously at 65deg until a control like the hall thermostat tells it to turn off cos the house is warm enough.

 

[picasso]

Press the i button when the boiler is running at 45c and post back what the display says .

 

[ScottishGasMan]

Can smell an s.54/53 code coming on

 

[wannocks]

Or it's a 4 series and hitting target temperature during the ignition phase. Which model ecotec is it?

 

[ScottishGasMan]

A 4 series hitting s.53/4 .......

 

[scalextrix]

it says 5.53 ecotec plus 418

 

[Dan Robinson]

What's the pump?

 

[picasso]

Mystic meg will be back in a mo to sort you out.

 

[ScottishGasMan]

How many radiators is it running?

 

[Dan Robinson]

Its gonna be a 15-50 - or UPS2 on speed 1 or 2.

Shall we start a sweepstake?

 

[scalextrix]

grundfoss UPS 15-60
8 rads

 

[ScottishGasMan]

Could be an old wilo gold, still get plenty of new installes running one of they old bad boys, just not very well

 

[ScottishGasMan]

Whats the pump set to I II or III?

 

[scalextrix]

II

 

[ScottishGasMan]

First thing to try is set the pump to III.