I am assisting with the recovery of an inherited property. The existing
heating scheme was designed and installed by the (now deceased) owner in
the mid 70s or early 80s.

It consists of a floor standing Potterton Diplomat with 2 water outlets
one labelled DHW+Upstairs which is split to supply two separate pumps,
the other labelled downstairs, with its own pump.

Timers/thermostats for upstairs and downstairs but no timer on DHW (Just
a tank thermostat). And a relay box to ensure only two of the three
pumps can run simultaneously. (or maybe its just to ensure upstairs and
DWH don't run together)

No TRVs anywhere, obliviously.

Massive twin panel radiators (no fins) in every room, no obvious signs
of corrosion on any of them (I would assume it has been regularly
inhibited at least until the last 5 years or so)

The current water supply temperature from the boiler is 49C (this is
clearly as designed as each pipe has a clip on thermostat with an arrow
marked on the glass. The water temp is on the arrow.

The system certainly used to function as the house was always warm when
visited - but I have no idea what the gas bills were.

From discussions with the owners brother he believed that large
radiators at low temp was the most efficient way to run the heating.

That might well be true and it might well work if you are in the house
all day but we have recently discovered that it takes 9 hours to bring
the house up from 15C to 21C. (Outside temp 8-12C, the property has DG
and Cavity wall insulation)

All the radiators are barely warm at the top and cold at the bottom.

So something has to be done in the short term but the house may be
undergoing major upgrades in the intermediate future (Showers fitted ,
possibly en suite etc) but the exact detail/layout of all this is still TBD.

The new owners are considering a modern boiler, I think as much for
safety reasons as any other as they don't trust this huge great lump in
the kitchen not to be leaking noxious gasses, (a CO monitor has been
fitted as a temporary measure) and the chances of getting anyone to
service it are pretty close to zero.

So my questions are.
1) I am planning to remove all the radiators take them outside and give
them a good hosing through. Would this leave sludge in the pipes and if
so how can it be removed prior to fitting a new boiler. Would this be
adequate or with radiators of this age should they be replaced along
with the boiler?

2) Would the system described above be suitable for adding a modern
boiler pretty much one for one swap with the existing (having flushed
out all of the radiators and fitted TRVs) or would major changes be
necessary. I have looked at the DIY WIKI and it states that with modern
TRVs oversized radiators are not a problem.

3) If a modern boiler is fitted this winter are they all suitable for
using with a pressurised water cylinder if that is the route taken in a
year or so when other modernisation work is done? The Worcester Bosh
website seems to state that their regular Greenstar boilers are
compatible with gravity HW or their own Greenstore (pressurised) cylinder.

Any helpful advice appreciated.

--
Chris B (News)

On Wednesday, 8 November 2017 13:20:17 UTC, Chris B wrote:

I am assisting with the recovery of an inherited property. The existing
heating scheme was designed and installed by the (now deceased) owner in
the mid 70s or early 80s.

It consists of a floor standing Potterton Diplomat with 2 water outlets
one labelled DHW+Upstairs which is split to supply two separate pumps,
the other labelled downstairs, with its own pump.

Not listed in the efficiency table I looked at. If it's a cast iron exchanger, around 65% efficient.

Timers/thermostats for upstairs and downstairs but no timer on DHW (Just
a tank thermostat).

there's no need for one. It is required for current BR but not actually very useful.

And a relay box to ensure only two of the three
pumps can run simultaneously. (or maybe its just to ensure upstairs and
DWH don't run together)

No TRVs anywhere, obliviously.

adding those would be good

Massive twin panel radiators (no fins) in every room, no obvious signs
of corrosion on any of them (I would assume it has been regularly
inhibited at least until the last 5 years or so)

you're lucky there, keep them. Modern ones last a fraction of the time oldies do.

The current water supply temperature from the boiler is 49C (this is
clearly as designed as each pipe has a clip on thermostat with an arrow
marked on the glass. The water temp is on the arrow.

that's a problem in HW mode if there's a shower, HW should be 60C at least to remove legionnarire's risk

The system certainly used to function as the house was always warm when
visited - but I have no idea what the gas bills were.

From discussions with the owners brother he believed that large
radiators at low temp was the most efficient way to run the heating.

correct. It gets the most heat out of the flame.

That might well be true and it might well work if you are in the house
all day but we have recently discovered that it takes 9 hours to bring
the house up from 15C to 21C. (Outside temp 8-12C, the property has DG
and Cavity wall insulation)

probably largely down to a stat being set to 49C.

All the radiators are barely warm at the top and cold at the bottom.

they just get as warm as they need to, but are capped to 49C I gather, the latter not being ideal

So something has to be done in the short term

what's the problem with the system?

but the house may be
undergoing major upgrades in the intermediate future (Showers fitted ,
possibly en suite etc) but the exact detail/layout of all this is still TBD.

The new owners are considering a modern boiler, I think as much for
safety reasons as any other as they don't trust this huge great lump in
the kitchen not to be leaking noxious gasses, (a CO monitor has been
fitted as a temporary measure)

is it room sealed? I don't know the diplomat at all.

and the chances of getting anyone to
service it are pretty close to zero.

I don't believe that at all

So my questions are.
1) I am planning to remove all the radiators take them outside and give
them a good hosing through. Would this leave sludge in the pipes and if
so how can it be removed prior to fitting a new boiler. Would this be
adequate or with radiators of this age should they be replaced along
with the boiler?

the standard advice is to flush them all when fitting a new boiler. A decent magnetic filter & strainer should catch the crap though.

2) Would the system described above be suitable for adding a modern
boiler pretty much one for one swap with the existing (having flushed
out all of the radiators and fitted TRVs) or would major changes be
necessary. I have looked at the DIY WIKI and it states that with modern
TRVs oversized radiators are not a problem.

From what you've said I'm not seeing a problem with a new boiler

3) If a modern boiler is fitted this winter are they all suitable for
using with a pressurised water cylinder if that is the route taken in a
year or so when other modernisation work is done? The Worcester Bosh
website seems to state that their regular Greenstar boilers are
compatible with gravity HW or their own Greenstore (pressurised) cylinder.

Any helpful advice appreciated.

You've not really told us what the problem is with the system yet, other than it being slow to heat due to low stat setting.


NT

On 08/11/2017 11:09, Chris B wrote:


All the radiators are barely warm at the top and cold at the bottom.

Assuming "barely warm" means much less than 49 degrees C the water is
not circulating properly, which could be due to sludging or ineffective
pump(s) or a combination of both.

--
Biggles

On Wednesday, 8 November 2017 17:51:37 UTC, Biggles wrote:
On 08/11/2017 11:09, Chris B wrote:


All the radiators are barely warm at the top and cold at the bottom.

Assuming "barely warm" means much less than 49 degrees C the water is
not circulating properly, which could be due to sludging or ineffective
pump(s) or a combination of both.

Yes, unless the OP only checked the rads when the pump hadn't run for a while. The system needs a filter to catch the crud - it may take a fair few emptyings of it before it stops clogging.


NT

On 08/11/2017 17:27, wrote:
On Wednesday, 8 November 2017 13:20:17 UTC, Chris B wrote:


You've not really told us what the problem is with the system yet, other than it being slow to heat due to low stat setting.


NT


House unacceptably Slow to heat, kitchen space used by boiler could be
better used, device has never been serviced other than by previous owner
DIY. New owners worried that anyone brought in to service boiler will
condemn it, as standards have no doubt changed since it was installed.

Diplomat details

https://www.freeboilermanuals.com/as...mat-35-921.pdf




--
Chris B (News)

On 08/11/2017 17:51, Biggles wrote:
On 08/11/2017 11:09, Chris B wrote:


All the radiators are barely warm at the top and cold at the bottom.

Assuming "barely warm" means much less than 49 degrees C the water is
not circulating properly, which could be due to sludging or ineffective
pump(s) or a combination of both.

Yes, radiators even at the tops are not as warm as the circulating pump
outlet temperature.


--
Chris B (News)

On Wednesday, 8 November 2017 18:47:44 UTC, Chris B wrote:
On 08/11/2017 17:27, tabbypurr wrote:
On Wednesday, 8 November 2017 13:20:17 UTC, Chris B wrote:

You've not really told us what the problem is with the system yet, other than it being slow to heat due to low stat setting.

House unacceptably Slow to heat,

desludge radiator system, install magnetic/filter cleaner. Pump vanes might also be blocked with crud, clean em out. CH thermostat may need turning up..

kitchen space used by boiler could be
better used, device has never been serviced other than by previous owner
DIY.

from what you've said it sounds like the original installer was very knowledgable, I'd very much expect it has been serviced. And a service isn't costly.

New owners worried that anyone brought in to service boiler will
condemn it, as standards have no doubt changed since it was installed.

It's not room sealed, so no it's not ideal, but that doesn't make it illegal. I'd certainly have a CO alarm with it. A service involves clearing the heat exchanger as necessary, the other risk factor. Also ensure cold air ventilation is never blocked, that's necessary to avoid CO poisoning.

Diplomat details

https://www.freeboilermanuals.com/as...mat-35-921.pdf

If the heat exchanger is cast iron, a new boiler would take the system from 65% to 90%+ efficient, lowering gas bills. But you'd gain buy/fit/repair/replace repeatedly costs.

2 things must not be neglected with this old fashioned type of boiler: ventilation, and the heat exchanger being cleaned out on occasion.


NT

Chris B Wrote in message:
I am assisting with the recovery of an inherited property. The existing
heating scheme was designed and installed by the (now deceased) owner in
the mid 70s or early 80s.

It consists of a floor standing Potterton Diplomat with 2 water outlets
one labelled DHW+Upstairs which is split to supply two separate pumps,
the other labelled downstairs, with its own pump.

Timers/thermostats for upstairs and downstairs but no timer on DHW (Just
a tank thermostat). And a relay box to ensure only two of the three
pumps can run simultaneously. (or maybe its just to ensure upstairs and
DWH don't run together)

No TRVs anywhere, obliviously.

Massive twin panel radiators (no fins) in every room, no obvious signs
of corrosion on any of them (I would assume it has been regularly
inhibited at least until the last 5 years or so)

The current water supply temperature from the boiler is 49C (this is
clearly as designed as each pipe has a clip on thermostat with an arrow
marked on the glass. The water temp is on the arrow.

The system certainly used to function as the house was always warm when
visited - but I have no idea what the gas bills were.

From discussions with the owners brother he believed that large
radiators at low temp was the most efficient way to run the heating.

That might well be true and it might well work if you are in the house
all day but we have recently discovered that it takes 9 hours to bring
the house up from 15C to 21C. (Outside temp 8-12C, the property has DG
and Cavity wall insulation)

All the radiators are barely warm at the top and cold at the bottom.

So something has to be done in the short term but the house may be
undergoing major upgrades in the intermediate future (Showers fitted ,
possibly en suite etc) but the exact detail/layout of all this is still TBD.

The new owners are considering a modern boiler, I think as much for
safety reasons as any other as they don't trust this huge great lump in
the kitchen not to be leaking noxious gasses, (a CO monitor has been
fitted as a temporary measure) and the chances of getting anyone to
service it are pretty close to zero.

So my questions are.
1) I am planning to remove all the radiators take them outside and give
them a good hosing through. Would this leave sludge in the pipes and if
so how can it be removed prior to fitting a new boiler. Would this be
adequate or with radiators of this age should they be replaced along
with the boiler?

2) Would the system described above be suitable for adding a modern
boiler pretty much one for one swap with the existing (having flushed
out all of the radiators and fitted TRVs) or would major changes be
necessary. I have looked at the DIY WIKI and it states that with modern
TRVs oversized radiators are not a problem.

3) If a modern boiler is fitted this winter are they all suitable for
using with a pressurised water cylinder if that is the route taken in a
year or so when other modernisation work is done? The Worcester Bosh
website seems to state that their regular Greenstar boilers are
compatible with gravity HW or their own Greenstore (pressurised) cylinder.

Any helpful advice appreciated.

--
Chris B (News)


From experience....
Take off rads and fire mains pressure water through them. Shake
them, turn them upside down and rotate to every angle with water
flowing through to get rid of all crud.
When old boiler has been removed, run mains pressure water through
every segment of pipe work. Put fine gauze on the open-to-drain
end of pipe so you can see the nature and volume of crud removed.
Do this thoroughly and it will clear the system much better than
power flushing.

As others have said, fit a magnetic filter such as MagnaClean or
Fernox to catch metallic crud in future.
If it's a decent size house, consider splitting upstairs and down
to separate zones.

Phil
--


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

In article ,
Chris B wrote:
House unacceptably Slow to heat, kitchen space used by boiler could be
better used, device has never been serviced other than by previous owner
DIY. New owners worried that anyone brought in to service boiler will
condemn it, as standards have no doubt changed since it was installed.

The only service this sort of boiler needs is a good clean.

I've never heard of running a system at 49C unless the boiler temperature
is the only way of controlling the temperature in the house. My system,
fitted in the 70s, ran the boiler at max and controlled the house temp and
hot water via valves.

Changing to a modern boiler will save the cost within a few years. I
worked it out as 3-4 here. But installed the new boiler myself, so no
labour costs. My old one was an RS Kingfisher, so slightly more efficient
than an open flue one.

--
*I'm not a paranoid, deranged millionaire. Dammit, I'm a billionaire.

Dave Plowman London SW
To e-mail, change noise into sound.

On Wed, 8 Nov 2017 21:33:10 +0000 (GMT+00:00), TheChief
wrote:

When old boiler has been removed, run mains pressure water through
every segment of pipe work. Put fine gauze on the open-to-drain
end of pipe so you can see the nature and volume of crud removed.
Do this thoroughly and it will clear the system much better than
power flushing.

If you are doing as much flushing as you are, maybe rent something like:

http://www.rothenberger.com/en/produkte/-/55-ropuls-flushing-compressor-for-scouring-and-cleaning-of-heating-systems-andflushing-of-drinking-water-pipes-according-to-din-19882/

Water-air mix pulsed through the pipes...


Thomas Prufer

On Thursday, 9 November 2017 10:56:16 UTC, Thomas Prufer wrote:
On Wed, 8 Nov 2017 21:33:10 +0000 (GMT+00:00), TheChief
wrote:

When old boiler has been removed, run mains pressure water through
every segment of pipe work. Put fine gauze on the open-to-drain
end of pipe so you can see the nature and volume of crud removed.
Do this thoroughly and it will clear the system much better than
power flushing.

If you are doing as much flushing as you are, maybe rent something like:

http://www.rothenberger.com/en/produkte/-/55-ropuls-flushing-compressor-for-scouring-and-cleaning-of-heating-systems-andflushing-of-drinking-water-pipes-according-to-din-19882/

Water-air mix pulsed through the pipes...


Thomas Prufer

You can take it all apart, hire a pulsing job etc, but probably none of it's necessary. Just fit a filter and add some cleaner, and be prepared to every the filter several times.

I'd recommend a filter with a filter mesh, not just magnet, much more effective. About £45 new on ebay, I forget the brand.


NT

On 09/11/2017 20:16, wrote:
On Thursday, 9 November 2017 10:56:16 UTC, Thomas Prufer wrote:
On Wed, 8 Nov 2017 21:33:10 +0000 (GMT+00:00), TheChief
wrote:

When old boiler has been removed, run mains pressure water through
every segment of pipe work. Put fine gauze on the open-to-drain
end of pipe so you can see the nature and volume of crud removed.
Do this thoroughly and it will clear the system much better than
power flushing.

If you are doing as much flushing as you are, maybe rent something like:

http://www.rothenberger.com/en/produkte/-/55-ropuls-flushing-compressor-for-scouring-and-cleaning-of-heating-systems-andflushing-of-drinking-water-pipes-according-to-din-19882/

Water-air mix pulsed through the pipes...


Thomas Prufer

You can take it all apart, hire a pulsing job etc, but probably none of it's necessary. Just fit a filter and add some cleaner, and be prepared to every the filter several times.

I'd recommend a filter with a filter mesh, not just magnet, much more effective. About £45 new on ebay, I forget the brand.


NT

Thanks to all who replied on this (and the other duplicate - Thank ES)
thread. Lots of cleaning/flushing/pump investigation to do but perhaps
the whole situation is not as bad as currently envisaged.

--
Chris B (News)