Boiler firing up but water only warm...

[MikeMikeMike]

So we are currently living in a static while we do our house up and it's got a Saunier Duval sd 14 tc boiler in it.
It was working fine but it's now only making the water a bit warm not hot.
It fires up fine when the water is on and looks like the gas is coming through as it should but it's just not getting the water to any kind of temperature.
I was thinking it was something to do with the heat exchanger but I've no experience with boilers so who knows.
Can anyone diagnose what's wrong?
I'm hoping it's not serious, it's a really old boiler I'm betting it's hard to get spares for it.

Thanks for any advice!

Mike

 

[AGAS]

never worked on sd model could be sensors which are still available ( expect others will know )
is your incoming cold supply the same flow as before ?

 

[Agile]

You need to measure the flow and return pipes at the boiler with a contact thermometer.

Tony

 

[AGAS]

i thought it was a water heater ????

 

[45yearsagasman]

It is a multipoint water heater. A stretched or ruptured diaphragm would give your symptoms, but it may not be the only cause. Really needs a pro to check it out. Not many spares available......

 

[MikeMikeMike]

never worked on sd model could be sensors which are still available ( expect others will know )
is your incoming cold supply the same flow as before ?

Yes, or at least we've not changed it so unless the supply pressure's changed then it's the same.

 

[MikeMikeMike]

It is a multipoint water heater. A stretched or ruptured diaphragm would give your symptoms, but it may not be the only cause. Really needs a pro to check it out. Not many spares available......

I could probably manage to change the diaphragm myself if I can get one!
I don't have any expertise for diagnosis but we are reluctant to get an expert in only to charge us more than it's worth only to tell us they can't get spares for it. We don't really want to get something else fitted as we're only using the static for a few months until we move into the house.

 

[MikeMikeMike]

You need to measure the flow and return pipes at the boiler with a contact thermometer.

Tony

Okay I don't have a contact thermometer but if the water temperature is any indication then I can probably tell there is a significant difference using my hand!

To add more variables into the mix... The supply is LPG and it's working intermittently. Wasn't heating water this morning no matter what i tried, heats the water fine this evening.

 

[AGAS]

you need to sort the lpg supply out first , are you sure your getting right lpg supply while your water is changing temp . i don't work on lpg you'll need someone qualified to see whats happening . plus all rgi are not rip off merchants , why play with a boiler in a caravan now think about it , is it worth it for a little amount of money .

 

[holty]

you need to get this checked by someone qualified with lpg. as the pressures need to be checked first. i do alot of statics and can tell you its not all about the appliance. lpg seems to block a few things that can only be checked by an rgi.