This is rather overdue. My plan is to check the safety PRV, clean the
filter in the combination valve, check/adjust the air pressure in the
expansion vessel, and check the operation of the over-temp stat.
What didn't I think of?
Are there any gotchas when getting at the filter?

On 05/02/2023 20:55, nothanks@aolbin.com wrote:
> This is rather overdue. My plan is to check the safety PRV, clean the
> filter in the combination valve, check/adjust the air pressure in the
> expansion vessel, and check the operation of the over-temp stat.
> What didn't I think of?
> Are there any gotchas when getting at the filter?
Bah! Typo alert! "safety PRV" should, of course, be "over-pressure
release valve".

On 05/02/2023 20:55, nothanks@aolbin.com wrote:
> This is rather overdue. My plan is to check the safety PRV, clean the
> filter in the combination valve, check/adjust the air pressure in the
> expansion vessel, and check the operation of the over-temp stat.
> What didn't I think of?

I would say you have all the required bits covered in a general case:

http://wiki.diyfaq.org.uk/index.php/Unvented_DHW#Servicing_requirements

Worth looking at the installer manual for the particular unit in
question in case there are model specific servicing actions required.

> Are there any gotchas when getting at the filter?

IME many are fairly simple strainer type arrangements - designed to
catch large particulate stuff mostly. Normally a case of unscrewing a
cap on the enclosure, withdrawing a mesh basket and giving it a clean.

--
Cheers,

John.

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

On Sun, 5 Feb 2023 20:55:47 +0000, nothanks@aolbin.com wrote:

>What didn't I think of?

Don't do it on a day where you can't get a new PRV/"overpressure relief valve"?

They like to leak after being tested/disturbed, and this is exacerbated by doing
it on day where there are no spares available.

Thomas Prufer

<nothanks@aolbin.com> wrote:
> This is rather overdue. My plan is to check the safety PRV, clean the
> filter in the combination valve, check/adjust the air pressure in the
> expansion vessel, and check the operation of the over-temp stat.
> What didn't I think of?
> Are there any gotchas when getting at the filter?
>

How are you going to test the overheat stat?

Tim

--
Please don't feed the trolls

In article
<1251825034.697363783.986658.tim.downie-gmail.com@news.individual.net>,
Tim+ <tim.downie@gmail.com> wrote:
> <nothanks@aolbin.com> wrote:
> > This is rather overdue. My plan is to check the safety PRV, clean the
> > filter in the combination valve, check/adjust the air pressure in the
> > expansion vessel, and check the operation of the over-temp stat.
> > What didn't I think of?
> > Are there any gotchas when getting at the filter?
> >

> How are you going to test the overheat stat?

Just check if it's gone open circuit

--
from KT24 in Surrey, England - sent from my RISC OS 4té
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

On 06/02/2023 08:10, Tim+ wrote:
> <nothanks@aolbin.com> wrote:
>> This is rather overdue. My plan is to check the safety PRV, clean the
>> filter in the combination valve, check/adjust the air pressure in the
>> expansion vessel, and check the operation of the over-temp stat.
>> What didn't I think of?
>> Are there any gotchas when getting at the filter?
>>
>
> How are you going to test the overheat stat?
>
> Tim
>
Mine's adjustable so I'll just turn it down a little

On 06/02/2023 07:52, Thomas Prufer wrote:
> On Sun, 5 Feb 2023 20:55:47 +0000, nothanks@aolbin.com wrote:
>
>> What didn't I think of?
>
> Don't do it on a day where you can't get a new PRV/"overpressure relief valve"?
>
> They like to leak after being tested/disturbed, and this is exacerbated by doing
> it on day where there are no spares available.
>
>
> Thomas Prufer
:-)
I've had that problem once before, but got it to seal eventually

On 06/02/2023 07:52, Thomas Prufer wrote:
> On Sun, 5 Feb 2023 20:55:47 +0000, nothanks@aolbin.com wrote:
>
>> What didn't I think of?
>
> Don't do it on a day where you can't get a new PRV/"overpressure relief valve"?
>
> They like to leak after being tested/disturbed, and this is exacerbated by doing
> it on day where there are no spares available.

I had a problem with some corrosion / hard water scale on the metal
mating surface of the PRV that was causing it to let by very slightly.
And yes this was on a day where getting a spare (which was manufacturer
specific) would have been tricky!

I fixed it by resurfacing the metal part. I had a set of small dremmel
style tools - one was a ~15mm grinding wheel on a mandrel. I put that in
a pillar drill, and used light even pressure to grind the surface of the
valve using the side of the grinding stone.

--
Cheers,

John.

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

On 05/02/2023 23:37, John Rumm wrote:
> On 05/02/2023 20:55, nothanks@aolbin.com wrote:
>> This is rather overdue. My plan is to check the safety PRV, clean the
>> filter in the combination valve, check/adjust the air pressure in the
>> expansion vessel, and check the operation of the over-temp stat.
>> What didn't I think of?
>
> I would say you have all the required bits covered in a general case:
>
> http://wiki.diyfaq.org.uk/index.php/Unvented_DHW#Servicing_requirements
I didn't think about looking at the Wiki ...
>
> Worth looking at the installer manual for the particular unit in
> question in case there are model specific servicing actions required.
>
>> Are there any gotchas when getting at the filter?
>
> IME many are fairly simple strainer type arrangements - designed to
> catch large particulate stuff mostly. Normally a case of unscrewing a
> cap on the enclosure, withdrawing a mesh basket and giving it a clean.
>
Hmm, getting to the strainer in the Caleffi multibloc valve is defeating
me at the moment. The only info I can find says that the cartridge can
be pulled-out by pulling on the bolt head once the grey plastic cap has
been removed, but the cartridge won't budge.

I'd prefer not to remove the whole valve and work on it on the bench
because it's in an awkward place that would be hard to protect from
water loss, and the pipework around it is quite tight.

I presume the bolt sets the operating pressure, rather than retaining
the cartridge(?), so do I just pull harder?

<nothanks@aolbin.com> wrote:
> On 06/02/2023 08:10, Tim+ wrote:
>> <nothanks@aolbin.com> wrote:
>>> This is rather overdue. My plan is to check the safety PRV, clean the
>>> filter in the combination valve, check/adjust the air pressure in the
>>> expansion vessel, and check the operation of the over-temp stat.
>>> What didn't I think of?
>>> Are there any gotchas when getting at the filter?
>>>
>>
>> How are you going to test the overheat stat?
>>
>> Tim
>>
> Mine's adjustable so I'll just turn it down a little
>

Are you sure? Isn’t that just a regular immersion stat? The overheat stat
is a secondary stat that needs manual resetting.

Tim

--
Please don't feed the trolls

On 06/02/2023 11:35, Tim+ wrote:
> <nothanks@aolbin.com> wrote:
>> On 06/02/2023 08:10, Tim+ wrote:
>>> <nothanks@aolbin.com> wrote:
>>>> This is rather overdue. My plan is to check the safety PRV, clean the
>>>> filter in the combination valve, check/adjust the air pressure in the
>>>> expansion vessel, and check the operation of the over-temp stat.
>>>> What didn't I think of?
>>>> Are there any gotchas when getting at the filter?
>>>>
>>>
>>> How are you going to test the overheat stat?
>>>
>>> Tim
>>>
>> Mine's adjustable so I'll just turn it down a little
>>
>
> Are you sure? Isn’t that just a regular immersion stat? The overheat stat
> is a secondary stat that needs manual resetting.
>
> Tim
>
I'm sure.

On 06/02/2023 11:35, Tim+ wrote:
> <nothanks@aolbin.com> wrote:
>> On 06/02/2023 08:10, Tim+ wrote:
>>> <nothanks@aolbin.com> wrote:
>>>> This is rather overdue. My plan is to check the safety PRV, clean the
>>>> filter in the combination valve, check/adjust the air pressure in the
>>>> expansion vessel, and check the operation of the over-temp stat.
>>>> What didn't I think of?
>>>> Are there any gotchas when getting at the filter?
>>>>
>>>
>>> How are you going to test the overheat stat?
>>>
>>> Tim
>>>
>> Mine's adjustable so I'll just turn it down a little
>>
>
> Are you sure? Isn’t that just a regular immersion stat? The overheat stat
> is a secondary stat that needs manual resetting.
>
> Tim
>
I'm sure.
The emergency stat has both a tweakable and a fixed stat in series. The
immersion heater has its own stat, so has the DHW controller (and, FWIW,
the DHW circulation pump) ...

On 06/02/2023 11:00, nothanks@aolbin.com wrote:
> On 05/02/2023 23:37, John Rumm wrote:
>> On 05/02/2023 20:55, nothanks@aolbin.com wrote:
>>> This is rather overdue. My plan is to check the safety PRV, clean the
>>> filter in the combination valve, check/adjust the air pressure in the
>>> expansion vessel, and check the operation of the over-temp stat.
>>> What didn't I think of?
>>
>> I would say you have all the required bits covered in a general case:
>>
>> http://wiki.diyfaq.org.uk/index.php/Unvented_DHW#Servicing_requirements
> I didn't think about looking at the Wiki ...
>>
>> Worth looking at the installer manual for the particular unit in
>> question in case there are model specific servicing actions required.
>>
>>> Are there any gotchas when getting at the filter?
>>
>> IME many are fairly simple strainer type arrangements - designed to
>> catch large particulate stuff mostly. Normally a case of unscrewing a
>> cap on the enclosure, withdrawing a mesh basket and giving it a clean.
>>
> Hmm, getting to the strainer in the Caleffi multibloc valve is defeating
> me at the moment. The only info I can find says that the cartridge can
> be pulled-out by pulling on the bolt head once the grey plastic cap has
> been removed, but the cartridge won't budge.
>
> I'd prefer not to remove the whole valve and work on it on the bench
> because it's in an awkward place that would be hard to protect from
> water loss, and the pipework around it is quite tight.
>
> I presume the bolt sets the operating pressure, rather than retaining
> the cartridge(?), so do I just pull harder?
I've found a cross-section drawing now which confirms that the answer
*is* to pull harder ... but the damn thing still won't budge. I'm
beginning to think that I'm going to have to remove the whole valve -
unless someone has a bright idea ... ?

<nothanks@aolbin.com> wrote:
> On 06/02/2023 11:00, nothanks@aolbin.com wrote:
>> On 05/02/2023 23:37, John Rumm wrote:
>>> On 05/02/2023 20:55, nothanks@aolbin.com wrote:
>>>> This is rather overdue. My plan is to check the safety PRV, clean the
>>>> filter in the combination valve, check/adjust the air pressure in the
>>>> expansion vessel, and check the operation of the over-temp stat.
>>>> What didn't I think of?
>>>
>>> I would say you have all the required bits covered in a general case:
>>>
>>> http://wiki.diyfaq.org.uk/index.php/Unvented_DHW#Servicing_requirements
>> I didn't think about looking at the Wiki ...
>>>
>>> Worth looking at the installer manual for the particular unit in
>>> question in case there are model specific servicing actions required.
>>>
>>>> Are there any gotchas when getting at the filter?
>>>
>>> IME many are fairly simple strainer type arrangements - designed to
>>> catch large particulate stuff mostly. Normally a case of unscrewing a
>>> cap on the enclosure, withdrawing a mesh basket and giving it a clean.
>>>
>> Hmm, getting to the strainer in the Caleffi multibloc valve is defeating
>> me at the moment. The only info I can find says that the cartridge can
>> be pulled-out by pulling on the bolt head once the grey plastic cap has
>> been removed, but the cartridge won't budge.
>>
>> I'd prefer not to remove the whole valve and work on it on the bench
>> because it's in an awkward place that would be hard to protect from
>> water loss, and the pipework around it is quite tight.
>>
>> I presume the bolt sets the operating pressure, rather than retaining
>> the cartridge(?), so do I just pull harder?
> I've found a cross-section drawing now which confirms that the answer
> *is* to pull harder ... but the damn thing still won't budge. I'm
> beginning to think that I'm going to have to remove the whole valve -
> unless someone has a bright idea ... ?
>

Is the valve working? If so, I’d just leave well alone.

Tim

--
Please don't feed the trolls

On 06/02/2023 14:57, Tim+ wrote:
> <nothanks@aolbin.com> wrote:
>> On 06/02/2023 11:00, nothanks@aolbin.com wrote:
>>> On 05/02/2023 23:37, John Rumm wrote:
>>>> On 05/02/2023 20:55, nothanks@aolbin.com wrote:
>>>>> This is rather overdue. My plan is to check the safety PRV, clean the
>>>>> filter in the combination valve, check/adjust the air pressure in the
>>>>> expansion vessel, and check the operation of the over-temp stat.
>>>>> What didn't I think of?
>>>>
>>>> I would say you have all the required bits covered in a general case:
>>>>
>>>> http://wiki.diyfaq.org.uk/index.php/Unvented_DHW#Servicing_requirements
>>> I didn't think about looking at the Wiki ...
>>>>
>>>> Worth looking at the installer manual for the particular unit in
>>>> question in case there are model specific servicing actions required.
>>>>
>>>>> Are there any gotchas when getting at the filter?
>>>>
>>>> IME many are fairly simple strainer type arrangements - designed to
>>>> catch large particulate stuff mostly. Normally a case of unscrewing a
>>>> cap on the enclosure, withdrawing a mesh basket and giving it a clean.
>>>>
>>> Hmm, getting to the strainer in the Caleffi multibloc valve is defeating
>>> me at the moment. The only info I can find says that the cartridge can
>>> be pulled-out by pulling on the bolt head once the grey plastic cap has
>>> been removed, but the cartridge won't budge.
>>>
>>> I'd prefer not to remove the whole valve and work on it on the bench
>>> because it's in an awkward place that would be hard to protect from
>>> water loss, and the pipework around it is quite tight.
>>>
>>> I presume the bolt sets the operating pressure, rather than retaining
>>> the cartridge(?), so do I just pull harder?
>> I've found a cross-section drawing now which confirms that the answer
>> *is* to pull harder ... but the damn thing still won't budge. I'm
>> beginning to think that I'm going to have to remove the whole valve -
>> unless someone has a bright idea ... ?
>>
>
> Is the valve working? If so, I’d just leave well alone.
>
> Tim
>
The hot flow has decreased so the filter screen needs cleaning, and to
do that the cartridge needs to come out :-(
Slightly annoyingly, the cylinder PRV is functionally redundant because
I fitted a PRV that limits the pressure in the whole house ...

On 06/02/2023 14:41, nothanks@aolbin.com wrote:
> On 06/02/2023 11:00, nothanks@aolbin.com wrote:
>> On 05/02/2023 23:37, John Rumm wrote:
>>> On 05/02/2023 20:55, nothanks@aolbin.com wrote:
>>>> This is rather overdue. My plan is to check the safety PRV, clean
>>>> the filter in the combination valve, check/adjust the air pressure
>>>> in the expansion vessel, and check the operation of the over-temp stat.
>>>> What didn't I think of?
>>>
>>> I would say you have all the required bits covered in a general case:
>>>
>>> http://wiki.diyfaq.org.uk/index.php/Unvented_DHW#Servicing_requirements
>> I didn't think about looking at the Wiki ...
>>>
>>> Worth looking at the installer manual for the particular unit in
>>> question in case there are model specific servicing actions required.
>>>
>>>> Are there any gotchas when getting at the filter?
>>>
>>> IME many are fairly simple strainer type arrangements - designed to
>>> catch large particulate stuff mostly. Normally a case of unscrewing a
>>> cap on the enclosure, withdrawing a mesh basket and giving it a clean.
>>>
>> Hmm, getting to the strainer in the Caleffi multibloc valve is
>> defeating me at the moment. The only info I can find says that the
>> cartridge can be pulled-out by pulling on the bolt head once the grey
>> plastic cap has been removed, but the cartridge won't budge.
>>
>> I'd prefer not to remove the whole valve and work on it on the bench
>> because it's in an awkward place that would be hard to protect from
>> water loss, and the pipework around it is quite tight.
>>
>> I presume the bolt sets the operating pressure, rather than retaining
>> the cartridge(?), so do I just pull harder?
> I've found a cross-section drawing now which confirms that the answer
> *is* to pull harder ... but the damn thing still won't budge. I'm
> beginning to think that I'm going to have to remove the whole valve -
> unless someone has a bright idea ... ?
I gave-up trying to pull the cartridge out so decided to replace the
whole combination valve - the job was much simpler than I'd anticipated
and the valve only cost £41. I needed to release some pipe clips to get
enough movement but the job was done without draining the tank and
without *any* water loss - hydraulic locks can be useful.
With the old valve on the bench I still couldn't pull the cartridge out
of the housing but a quick tap with a punch through it's rear end (a
secondary regulated pressure outlet) and it came out easily. The filter
had a fair amount of crud in it but the moving part had scale around the
shaft and I suspect that was upsetting its operation. It's all
cleaned-up now and in a box in case it's needed in the future.
It was good to tackle a job and find it much easier than I'd expected.

On 13/02/2023 19:09, nothanks@aolbin.com wrote:
> On 06/02/2023 14:41, nothanks@aolbin.com wrote:
>> On 06/02/2023 11:00, nothanks@aolbin.com wrote:
>>> On 05/02/2023 23:37, John Rumm wrote:
>>>> On 05/02/2023 20:55, nothanks@aolbin.com wrote:
>>>>> This is rather overdue. My plan is to check the safety PRV, clean
>>>>> the filter in the combination valve, check/adjust the air pressure
>>>>> in the expansion vessel, and check the operation of the over-temp
>>>>> stat.
>>>>> What didn't I think of?
>>>>
>>>> I would say you have all the required bits covered in a general case:
>>>>
>>>> http://wiki.diyfaq.org.uk/index.php/Unvented_DHW#Servicing_requirements
>>> I didn't think about looking at the Wiki ...
>>>>
>>>> Worth looking at the installer manual for the particular unit in
>>>> question in case there are model specific servicing actions required.
>>>>
>>>>> Are there any gotchas when getting at the filter?
>>>>
>>>> IME many are fairly simple strainer type arrangements - designed to
>>>> catch large particulate stuff mostly. Normally a case of unscrewing
>>>> a cap on the enclosure, withdrawing a mesh basket and giving it a
>>>> clean.
>>>>
>>> Hmm, getting to the strainer in the Caleffi multibloc valve is
>>> defeating me at the moment. The only info I can find says that the
>>> cartridge can be pulled-out by pulling on the bolt head once the grey
>>> plastic cap has been removed, but the cartridge won't budge.
>>>
>>> I'd prefer not to remove the whole valve and work on it on the bench
>>> because it's in an awkward place that would be hard to protect from
>>> water loss, and the pipework around it is quite tight.
>>>
>>> I presume the bolt sets the operating pressure, rather than retaining
>>> the cartridge(?), so do I just pull harder?
>> I've found a cross-section drawing now which confirms that the answer
>> *is* to pull harder ... but the damn thing still won't budge. I'm
>> beginning to think that I'm going to have to remove the whole valve -
>> unless someone has a bright idea ... ?
> I gave-up trying to pull the cartridge out so decided to replace the
> whole combination valve - the job was much simpler than I'd anticipated
> and the valve only cost £41. I needed to release some pipe clips to get
> enough movement but the job was done without draining the tank and
> without *any* water loss - hydraulic locks can be useful.
> With the old valve on the bench I still couldn't pull the cartridge out
> of the housing but a quick tap with a punch through it's rear end (a
> secondary regulated pressure outlet) and it came out easily. The filter
> had a fair amount of crud in it but the moving part had scale around the
> shaft and I suspect that was upsetting its operation. It's all
> cleaned-up now and in a box in case it's needed in the future.
> It was good to tackle a job and find it much easier than I'd expected.

Good to hear!

Which reminds me I ought to service mine!

--
Cheers,

John.

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

On 16/02/2023 20:07, John Rumm wrote:
> On 13/02/2023 19:09, nothanks@aolbin.com wrote:
>> On 06/02/2023 14:41, nothanks@aolbin.com wrote:
>>> On 06/02/2023 11:00, nothanks@aolbin.com wrote:
>>>> On 05/02/2023 23:37, John Rumm wrote:
>>>>> On 05/02/2023 20:55, nothanks@aolbin.com wrote:
>>>>>> This is rather overdue. My plan is to check the safety PRV, clean
>>>>>> the filter in the combination valve, check/adjust the air pressure
>>>>>> in the expansion vessel, and check the operation of the over-temp
>>>>>> stat.
>>>>>> What didn't I think of?
>>>>>
>>>>> I would say you have all the required bits covered in a general case:
>>>>>
>>>>> http://wiki.diyfaq.org.uk/index.php/Unvented_DHW#Servicing_requirements
>>>> I didn't think about looking at the Wiki ...
>>>>>
>>>>> Worth looking at the installer manual for the particular unit in
>>>>> question in case there are model specific servicing actions required.
>>>>>
>>>>>> Are there any gotchas when getting at the filter?
>>>>>
>>>>> IME many are fairly simple strainer type arrangements - designed to
>>>>> catch large particulate stuff mostly. Normally a case of unscrewing
>>>>> a cap on the enclosure, withdrawing a mesh basket and giving it a
>>>>> clean.
>>>>>
>>>> Hmm, getting to the strainer in the Caleffi multibloc valve is
>>>> defeating me at the moment. The only info I can find says that the
>>>> cartridge can be pulled-out by pulling on the bolt head once the
>>>> grey plastic cap has been removed, but the cartridge won't budge.
>>>>
>>>> I'd prefer not to remove the whole valve and work on it on the bench
>>>> because it's in an awkward place that would be hard to protect from
>>>> water loss, and the pipework around it is quite tight.
>>>>
>>>> I presume the bolt sets the operating pressure, rather than
>>>> retaining the cartridge(?), so do I just pull harder?
>>> I've found a cross-section drawing now which confirms that the answer
>>> *is* to pull harder ... but the damn thing still won't budge. I'm
>>> beginning to think that I'm going to have to remove the whole valve -
>>> unless someone has a bright idea ... ?
>> I gave-up trying to pull the cartridge out so decided to replace the
>> whole combination valve - the job was much simpler than I'd
>> anticipated and the valve only cost £41. I needed to release some pipe
>> clips to get enough movement but the job was done without draining the
>> tank and without *any* water loss - hydraulic locks can be useful.
>> With the old valve on the bench I still couldn't pull the cartridge
>> out of the housing but a quick tap with a punch through it's rear end
>> (a secondary regulated pressure outlet) and it came out easily. The
>> filter had a fair amount of crud in it but the moving part had scale
>> around the shaft and I suspect that was upsetting its operation. It's
>> all cleaned-up now and in a box in case it's needed in the future.
>> It was good to tackle a job and find it much easier than I'd expected.
>
> Good to hear!
>
> Which reminds me I ought to service mine!
>
What has surprised me is how great the showers are now - when things
degrade slowly over a long period it isn't easy to spot the degradation
.... until it's rectified. The improvement can't be explained by the
amount of crud on the filter so it must have been the scale affecting
the piston "thing"'s movement. Note to self: it is worth cleaning and
descaling the magic PRV gubbins annually.

On 16/02/2023 21:02, nothanks@aolbin.com wrote:
> On 16/02/2023 20:07, John Rumm wrote:
>> On 13/02/2023 19:09, nothanks@aolbin.com wrote:
>>> On 06/02/2023 14:41, nothanks@aolbin.com wrote:
>>>> On 06/02/2023 11:00, nothanks@aolbin.com wrote:
>>>>> On 05/02/2023 23:37, John Rumm wrote:
>>>>>> On 05/02/2023 20:55, nothanks@aolbin.com wrote:
>>>>>>> This is rather overdue. My plan is to check the safety PRV, clean
>>>>>>> the filter in the combination valve, check/adjust the air
>>>>>>> pressure in the expansion vessel, and check the operation of the
>>>>>>> over-temp stat.
>>>>>>> What didn't I think of?
>>>>>>
>>>>>> I would say you have all the required bits covered in a general case:
>>>>>>
>>>>>> http://wiki.diyfaq.org.uk/index.php/Unvented_DHW#Servicing_requirements
>>>>> I didn't think about looking at the Wiki ...
>>>>>>
>>>>>> Worth looking at the installer manual for the particular unit in
>>>>>> question in case there are model specific servicing actions required.
>>>>>>
>>>>>>> Are there any gotchas when getting at the filter?
>>>>>>
>>>>>> IME many are fairly simple strainer type arrangements - designed
>>>>>> to catch large particulate stuff mostly. Normally a case of
>>>>>> unscrewing a cap on the enclosure, withdrawing a mesh basket and
>>>>>> giving it a clean.
>>>>>>
>>>>> Hmm, getting to the strainer in the Caleffi multibloc valve is
>>>>> defeating me at the moment. The only info I can find says that the
>>>>> cartridge can be pulled-out by pulling on the bolt head once the
>>>>> grey plastic cap has been removed, but the cartridge won't budge.
>>>>>
>>>>> I'd prefer not to remove the whole valve and work on it on the
>>>>> bench because it's in an awkward place that would be hard to
>>>>> protect from water loss, and the pipework around it is quite tight.
>>>>>
>>>>> I presume the bolt sets the operating pressure, rather than
>>>>> retaining the cartridge(?), so do I just pull harder?
>>>> I've found a cross-section drawing now which confirms that the
>>>> answer *is* to pull harder ... but the damn thing still won't budge.
>>>> I'm beginning to think that I'm going to have to remove the whole
>>>> valve - unless someone has a bright idea ... ?
>>> I gave-up trying to pull the cartridge out so decided to replace the
>>> whole combination valve - the job was much simpler than I'd
>>> anticipated and the valve only cost £41. I needed to release some
>>> pipe clips to get enough movement but the job was done without
>>> draining the tank and without *any* water loss - hydraulic locks can
>>> be useful.
>>> With the old valve on the bench I still couldn't pull the cartridge
>>> out of the housing but a quick tap with a punch through it's rear end
>>> (a secondary regulated pressure outlet) and it came out easily. The
>>> filter had a fair amount of crud in it but the moving part had scale
>>> around the shaft and I suspect that was upsetting its operation. It's
>>> all cleaned-up now and in a box in case it's needed in the future.
>>> It was good to tackle a job and find it much easier than I'd expected.
>>
>> Good to hear!
>>
>> Which reminds me I ought to service mine!
>>
> What has surprised me is how great the showers are now - when things
> degrade slowly over a long period it isn't easy to spot the degradation
> ... until it's rectified. The improvement can't be explained by the
> amount of crud on the filter so it must have been the scale affecting
> the piston "thing"'s movement. Note to self: it is worth cleaning and
> descaling the magic PRV gubbins annually.

Yup. I was noticing that I could not get my shower as hot as I would
like. The cylinder was still heating to the correct temp. I was about to
look at the thermostatic shower valve, but then SWMBO mentioned that she
did not think the water from the hot taps was as hot as it once was. So
I looked at the thermostatic blending valve I had installed on the
outlet of the cylinder. I had left it set at its maximum output (low 50s
IIRC - just enough limit to protect against scalds but leave enough
"headroom" in the hot water to allow mixing down at point of use.

So I cranked that all the way down to minimum and then all the way back
up to max, and the hot water was back to normal. So it seems that was
getting stuck somewhere as well.

--
Cheers,

John.

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