Turbomax 828e (non condensing)
DHW is doing the thing where it is hot then cools *slightly* then runs
hot again, I understand that this usually indicates a scaled/blocked DHW HE.

This has hapened overnight though, so while I don't discount it, I do
wonder if anything else might be responsible?

Reported flow temp is staying constant, but the gas valve is modulating,
(the diag screen is showing the current changing) I assume this is
normal behaviour if insufficent heat is being taken away by the cold water.

Pump sounds like it's running at the normal speed, I think the diverter
valve is moving as it should, (the CH pipe dosen't heat up in DHW mode).
For some reason the software dosen't display return temp in DHW mode,
though it obviously does measure it internally.

Yeah I know, I'm just trying to talk myself out of having to have the
DHW HE replaced

On 03/09/2020 20:23, Lee wrote:
Turbomax 828e (non condensing)
DHW is doing the thing where it is hot then cools *slightly* then runs
hot again, I understand that this usually indicates a scaled/blocked DHW
HE.

This has hapened overnight though, so while I don't discount it, I do
wonder if anything else might be responsible?

Reported flow temp is staying constant, but the gas valve is modulating,
(the diag screen is showing the current changing) I assume this is
normal behaviour if insufficent heat is being taken away by the cold water.

Pump sounds like it's running at the normal speed, I think the diverter
valve is moving as it should, (the CH pipe dosen't heat up in DHW mode).
For some reason the software dosen't display return temp in DHW mode,
though it obviously does measure it internally.

Yeah I know, I'm just trying to talk myself out of having to have the
DHW HE replaced

It is possible to descale the plate HX - although that normally requires
taking it out of the boiler, and then circulating some descaler through
the mains water side of it.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 04/09/2020 10:40, John Rumm wrote:
On 03/09/2020 20:23, Lee wrote:
Turbomax 828e (non condensing)
DHW is doing the thing where it is hot then cools *slightly* then runs
hot again, I understand that this usually indicates a scaled/blocked
DHW HE.

This has hapened overnight though, so while I don't discount it, I do
wonder if anything else might be responsible?

Reported flow temp is staying constant, but the gas valve is
modulating, (the diag screen is showing the current changing) I assume
this is normal behaviour if insufficent heat is being taken away by
the cold water.

Pump sounds like it's running at the normal speed, I think the
diverter valve is moving as it should, (the CH pipe dosen't heat up in
DHW mode).
For some reason the software dosen't display return temp in DHW mode,
though it obviously does measure it internally.

Yeah I know, I'm just trying to talk myself out of having to have the
DHW HE replaced

It is possible to descale the plate HX - although that normally requires
taking it out of the boiler, and then circulating some descaler through
the mains water side of it.


Thanks. I've ordered a new one, I believe it's a "pattern" part but it's
a reputable company and it's got a warranty. But I will probably attempt
to descale the old one as a spare.

At least it *looks* straightforward to change and don't have to go near
any gas carrying parts either.

On 04/09/2020 12:56, Lee wrote:
On 04/09/2020 10:40, John Rumm wrote:
On 03/09/2020 20:23, Lee wrote:
Turbomax 828e (non condensing)
DHW is doing the thing where it is hot then cools *slightly* then
runs hot again, I understand that this usually indicates a
scaled/blocked DHW HE.

This has hapened overnight though, so while I don't discount it, I do
wonder if anything else might be responsible?

Reported flow temp is staying constant, but the gas valve is
modulating, (the diag screen is showing the current changing) I
assume this is normal behaviour if insufficent heat is being taken
away by the cold water.

Pump sounds like it's running at the normal speed, I think the
diverter valve is moving as it should, (the CH pipe dosen't heat up
in DHW mode).
For some reason the software dosen't display return temp in DHW mode,
though it obviously does measure it internally.

Yeah I know, I'm just trying to talk myself out of having to have the
DHW HE replaced

It is possible to descale the plate HX - although that normally
requires taking it out of the boiler, and then circulating some
descaler through the mains water side of it.


Thanks. I've ordered a new one, I believe it's a "pattern" part but it's
a reputable company and it's got a warranty. But I will probably attempt
to descale the old one as a spare.

At least it *looks* straightforward to change and don't have to go near
any gas carrying parts either.


Make sure you have 4 new O rings.... do not attempt to re-use the old O
rings or you will heave leaks galore!

On 04/09/2020 15:06, No Name wrote:

(snip)

Make sure you have 4 new O rings.... do not attempt to re-use the old O
rings or you will heave leaks galore!

Duly noted