Hot water playing up

[fubar1000]

Afternoon all

Installed a new glow worm flexicom 18kw, pump & 3 port in October for a family member, everything was working fine until Xmas time.

Heating is pukka

But hot water is only getting luke warm (approx 47c at the nearest hot tap)

She only told me this last Friday

So popped round there today armed with a cylinder stat, after I'd changed it the boiler would only light for approx 60sec then stop's for a bit then lights back up for 60sec or so (this is with the programmer only set in hot water).

In heating mode with the room stat turned up to max the boiler stays on for as long as needed.

Can't see what else it could be????

Am I missing something????

 

[JCplumb]

First guess would be a restriction in the pipework going to and from the cylinder. Try the magnet trick.

 

[fubar1000]

First guess would be a restriction in the pipework going to and from the cylinder. Try the magnet trick.

I was thinking that, but what put me off was the whole system was power flushed (including the cylinder) about 18months/24months ago

 

[lame plumber]

power flushing can loosen lumps that fly into your system later!

 

[Terry_the_piper]

Whats the divertor doing while boilers cycling?

 

[diamondgas]

's' or 'y'plan?

Sealed or open system?

Does sound like a restricted flow around the domestic circuit. Any balancing valve or the like on the cylinder circuit?

 

[fubar1000]

Just had a text saying all is 100% ok. Looks like it was just the cylinder stat, just needed a bit of time to heat up a whole take I think

Thanks all for the advise guys