optima 701 DHW problem

[corbyboy]

Hi my hot water stoped working yesterday il describe what happens

Nothing when you open the hot water tap not a sound comes from the boiler no clicks or anything.Central heating works fine.
so today i decided to join the forum to see if i can get any help but before i did i downloaded the Manual and noticed the fault finding LEDs were fine no faults were showing so i decided to press the reset button on the clock and run the heating for 30 mins and the hot water decided to work it seems fine now working as it should but am pretty sure this wasnt a one off so need some advice if it happens again

many thanks

[gas man]

could be a thermistor fault

[corbyboy]

ok great many thanks i shall order one just incase

thanks again

[Mbear]

IT sounds like a dhw flow switch fault but i can't for the life of me remember if the optimas have a flow switch. If no flow switch then I'd say sensor also

[corbyboy]

Hi there is a Flowmeter acording to the manual and i will paste a section here of the only mention of a flow switch

"

The pump circuit also has a 6 minute over-run
time. There is a Domestic Hot Water flow switch fitted and when there is a demand for Domestic Hot
Water the Central Heating pump is switched off making available the maximum output of the gas burner

for Domestic Hot Water"

[Mbear]

Hi there is a Flowmeter acording to the manual and i will paste a section here of the only mention of a flow switch

"

The pump circuit also has a 6 minute over-run
time. There is a Domestic Hot Water flow switch fitted and when there is a demand for Domestic Hot
Water the Central Heating pump is switched off making available the maximum output of the gas burner

for Domestic Hot Water"

there u go mate. It'll be this flow switch, it won't recognise that you are running a tap obviously if it's goosed, it's the same as not running hot water if it was working correctly as far as it's concerned at the min, therefore no fault code will show for this particular fault

if u are able to link out the flow switch and the boiler fires for hw then it's defo at fault. This is the easiest way to prove a faulty component

One last thing to add.

U could try removing it and clean it. U may find it's not faulty and simply choked up

[corbyboy]

hi any idea were it is? my problem is in the manual the only part listed sith the word switch is
Low water pressure switch
is this it?

many thanks

[Mbear]

hi any idea were it is? my problem is in the manual the only part listed sith the word switch is
Low water pressure switch
is this it?

many thanks

no that's the low system pressure switch ie pressure is at 0.25bar then this switch breaks for example.

The flow switch will be on the mains in pipe internally in the boiler

[corbyboy]

Hi sorry all i can see on the diagram is a flowmeter

[Mbear]

Hi sorry all i can see on the diagram is a flowmeter

That sounds like the culprit. I'm sure flowmeter is the term ferroli use. They definetely use a flowmeter on the ferroli Modena combi for the hw side

[corbyboy]

nice one i will strip it tomorrow failing that its only £38 to replace