I currently have a 4 bed house with a Potterton Profile 50 powering a
Gledhill Boilermate which is about 15 year old. Having extended the
house a couple of times, when the heat is on full blast on a cold
morning, the first shower is fine but a consecutive shower runs cold.

Household is 2 adults and 2 kids, one being a pre-teenage daughter who
loves long showers :-( . We have 2 bathrooms - one bath and two high
flow showers.

I'm intending to replace the boiler with a condenser but the hot water
issue is the difficult bit. I have read the various ramblings on
unvented v heat stores and I'm still unsure as to which way to go.

The current thermal store has worked well so I'm not scared of the
heatbank option, but DPS quoted me =A3945 for a 180L Pandora which
wassignificantly more than the 210L Megaflo.

I like the Powermax for its compact design, but I'm concerned that I
can't find any solid recommendations for it. Also I'm told the
servicing is tricky. Does anyone have any experience of these?

Taking the separate boiler/cylinder route, I like the DIYability of the
Heatbank and the associated safety. Is there any way I can go down this
route for less money, or should I look at unvented?

nickd wrote:
I currently have a 4 bed house with a Potterton Profile 50 powering a
Gledhill Boilermate which is about 15 year old. Having extended the
house a couple of times, when the heat is on full blast on a cold
morning, the first shower is fine but a consecutive shower runs cold.

Household is 2 adults and 2 kids, one being a pre-teenage daughter who
loves long showers :-( . We have 2 bathrooms - one bath and two high
flow showers.

I'm intending to replace the boiler with a condenser but the hot water
issue is the difficult bit. I have read the various ramblings on
unvented v heat stores and I'm still unsure as to which way to go.

The current thermal store has worked well so I'm not scared of the
heatbank option, but DPS quoted me £945 for a 180L Pandora which

inc or ex VAT? 210L square Panny is about £800 (ex VAT) with standard
100kW heat exch, standard 22mm mixing valve, no CH pumps, controls etc.
Letting them add CH or sealed system components seems to push the price
way up. Even without that clobber it's still £1K inc VAT which is
probably a lot more than the buy price of a megaflo, but practically
zero cost/hassle in the long term, unlike the unvented.

Gledhill have changed the specification over the years of the BoilerMate. Yours will have an internal DHW take-off coil. The new models have plate heat exchangers. Is that so? It appears the thermal store is struggling to cope after house extensions. All is not lost.

Q1. Does the store gives adequate showers in summer when the heating is not extracting heat from the store?

Q2. How did it perform, in heating and DHW, before the hosue extensions?

Q3. What percentage has the house increased in size?

Q4. Does the boiler heat the store via an internal coile, or does it heat the store direct (the same water in thye store and boiler)?

Q5. Is the CH taken off the store. Most Boilermates this is the case.

Firstly:

a) I would replace the boiler with a larger boiler of approx 30kW (twice the size of the extisting) with 28mm flow and return to the thermal store. This will give a far higher recovery rate and be heating up the store as water is being drawn-off.

b) Fit a blending valve on the boilers flow and return to ensure only 75-80C water enters the store.

c) De-scale the DHW coil, as this may degrade performance if scaled up. Ring Gledhill in Blackpool, they will recommend a solution to de-scale.

d) Fit a flow switch in the cold DHW feed to switch off the CH pump when DHW is called to prevent heat being extracted from the store to the rads when DHW is being called. The flow switch can energise a relay to cut out the pump. Simple to do.

If still not up to scratch, then do:

e) Have the flow switch also override the thermal store cylinder stat and bring the boiler in immedately DHW is called. You could put this on a 20.30,40 second time delay to prevent nuisance boiler cycling. This will pump heat into the store imediately, whereas if you rely on the cylinder stat you would have lost 1/4 to 1/3 of you hot water before the boiler starts to pump heat into the store.

Installing the above two points is not difficult or expensive and saves a wedge on a new store. This should cure the problem.

Further:
If the store is being heated adequately and the problem is that the internal DHW coil is not man enough produce the hot water, which I doubt from what you say, You can always retrofit a plate heat exchanger and pump for DHW take-off and use the existing DHW as a pre-heat, in essence turning it into a hybrid heat bank/thermal store.

The current thermal store has worked well so I'm not scared of
the heatbank option, but DPS quoted me £945 for a 180L Pandora
which assignificantly more than the 210L Megaflo.

Hmmm. I think I paid 750 inclusive for my 180L Pandora.

Christian.

Just to add. If the store is merely not large enough, a cheap conventional cylinder can be installed (space permitting, could stacked over the existing store) to increase the thermal store size. If the BoilerMate has in internal DHW take-off coil then a pump is used to pump hot water from the extension cylinder to the main store.

On Mon, 14 Feb 2005 11:19:00 -0000, "Christian McArdle"
wrote:

The current thermal store has worked well so I'm not scared of
the heatbank option, but DPS quoted me £945 for a 180L Pandora
which assignificantly more than the 210L Megaflo.

Hmmm. I think I paid 750 inclusive for my 180L Pandora.

Christian.




Maybe they've seen sales improve........




--

..andy

To email, substitute .nospam with .gl

In article ,
Christian McArdle wrote:
The current thermal store has worked well so I'm not scared of
the heatbank option, but DPS quoted me £945 for a 180L Pandora
which assignificantly more than the 210L Megaflo.

Hmmm. I think I paid 750 inclusive for my 180L Pandora.

Double Hmm and a chin-scratch... They quoted me quoted nearly 1500 for
what I wanted which is why I've embarked down the home-build route..

Gordon

On Mon, 14 Feb 2005 17:39:32 +0000 (UTC),
(Gordon Henderson) wrote:

In article ,
Christian McArdle wrote:
The current thermal store has worked well so I'm not scared of
the heatbank option, but DPS quoted me £945 for a 180L Pandora
which assignificantly more than the 210L Megaflo.

Hmmm. I think I paid 750 inclusive for my 180L Pandora.

Double Hmm and a chin-scratch... They quoted me quoted nearly 1500 for
what I wanted which is why I've embarked down the home-build route..

Gordon


Perhaps the price depends on how grand the project sounds as a measure
of your ability to pay....



--

..andy

To email, substitute .nospam with .gl

John Stumbles wrote:

inc or ex VAT? 210L square Panny is about =A3800 (ex VAT) with
standard
100kW heat exch, standard 22mm mixing valve, no CH pumps, controls
etc.
Letting them add CH or sealed system components seems to push the
price
way up. Even without that clobber it's still =A31K inc VAT which is
probably a lot more than the buy price of a megaflo, but practically

zero cost/hassle in the long term, unlike the unvented.

This price was ex-vat for the cylindrical version. I did specify a 3
way diverter with it, but still seems high.

Doctor Evil wrote:

Gledhill have changed the specification over the years of the
BoilerMate. Yours will have an internal DHW take-off coil. The new
models have plate heat exchangers. Is that so? It appears the
thermal store is struggling to cope after house extensions. All is
not
lost.

Indeed it does have the internal coil. Also has header tank as part of
the unit.

Q1. Does the store gives adequate showers in summer when the heating
is not extracting heat from the store?

Absolutely. Not had any problems in the summer at all.


Q2. How did it perform, in heating and DHW, before the hosue
extensions?

Thats a tricky one as the first extension was shortly after moving in.
Heating has never been a problem, just that DHW runs out during cold
weather. Noticed it mostly after second extension.


Q3. What percentage has the house increased in size?


Approx 15%

Q4. Does the boiler heat the store via an internal coile, or does it
heat the store direct (the same water in thye store and boiler)?


Its the direct type.

Q5. Is the CH taken off the store. Most Boilermates this is the
case.

Yes. Works well too.



Firstly:

a) I would replace the boiler with a larger boiler of approx 30kW
(twice the size of the extisting) with 28mm flow and return to the
thermal store. This will give a far higher recovery rate and be
heating up the store as water is being drawn-off.

b) Fit a blending valve on the boilers flow and return to ensure
only
75-80C water enters the store.

c) De-scale the DHW coil, as this may degrade performance if scaled
up. Ring Gledhill in Blackpool, they will recommend a solution to
de-scale.

d) Fit a flow switch in the cold DHW feed to switch off the CH pump
when DHW is called to prevent heat being extracted from the store to
the rads when DHW is being called. The flow switch can energise a
relay to cut out the pump. Simple to do.

If still not up to scratch, then do:

e) Have the flow switch also override the thermal store cylinder
stat
and bring the boiler in immedately DHW is called. You could put this
on a 20.30,40 second time delay to prevent nuisance boiler cycling.
This will pump heat into the store imediately, whereas if you rely on
the cylinder stat you would have lost 1/4 to 1/3 of you hot water
before the boiler starts to pump heat into the store.

Installing the above two points is not difficult or expensive and
saves
a wedge on a new store. This should cure the problem.

Further:
If the store is being heated adequately and the problem is that the
internal DHW coil is not man enough produce the hot water, which I
doubt from what you say, You can always retrofit a plate heat
exchanger
and pump for DHW take-off and use the existing DHW as a pre-heat, in
essence turning it into a hybrid heat bank/thermal store.


--
Doctor Evil

Thanks for the advice.
The other problem I have is that I want to relocate the store
downstairs. As it has a header tank attached, this is not possible
without ripping the header tank off and running a pipe up to the loft,
which i'm trying to avoid.

You can have the store downstairs. Have it as high as possible so the header is near the ceiling and above the boiler. I hope that sorts that.

Now the heating system. Make the CH circuit a pressurised circuit isolated from the store. Take the CH flow and return off the store (I assume the pump is on the store) and run the two pipes into a plate heat exchanger (the size of a book). Take the rads flow and return into the other two ports of the plate. Install a new pump for the rads. This isolates the CH from the store. Install a pressurisation kit on the rads side of the plate, so you can have all the rads anywhere, with: vessel, blow-off, guage, filling loop. You will have two pumps running the CH. Just have the two pumps off the same wire, so both are either off or on. The whole lot should cost you about £150, inc pump.

- Install a large boiler with 28mm flow and return
- Clean out the scale in DHW coil
- install a flow switch on the cold DHW mains to cut out the CH pumps when the DHW is being called, making it a priority system. A small relay from maplin in a plastic housing will do to switch the pumps in and out.

The larger boiler will reheat very fast.

That will solve all probs.

That's certainly a solution I hadn't considered. What size heat
exchanger would you recommend for this?

Overall though, I still have a problem in that I don't think I have the
room to get the boiler sufficiently lower than the cylinder in the area
where I need to install it. If I could find a way to raise the header
tank I'd be in business. How much above the boiler could I get away
with?

A normal 14 plate job will do the heating side. Do a Google on this group for GEA, Ecobraze. You need a heating boiler. Try the Glow Worm condenser. They do one around 27-30kW. A basic open vented boiler. Worcester Bosch Greenstar do a similar. You will have to check the makers specs for the head, which is usually a matter of inches. You can detach the header tank from the Boilermate, so this can easily go up near the ceiling.

If you need a new thermal store try the Gledhill Systemate, using a modulating heating boiler; it comes with the pressure vessel. This will do the job with the heating being run directly. Gledhill thermal stores, and many cylidners, are all now in nice square neat cases that don't have exposed pipes and look like a boiler house, and are heavily insulated. They have the optional electric backup which will also provide heating as well as DHW if the boiler is down. Not cheap but a class quality act. I have one.

makers specs for the head, which is usually a matter of inches. You
can detach the header tank from the Boilermate, so this can easily go
up near the ceiling.


Hard to see how I can do this. As the store is in service I can'tsee
clearly how the tank is attached to the cylinder. Seems to have welded
ties, but the main connection between the two is not obvious. Any
experience of this?

If you need a new thermal store try the Gledhill Systemate, using a

I looked at the Systemate and was impressed, but can't seem to find a
price guide anywhere on here.

Incidentally, in my original post I asked if the Powermax was an
option. I have since received a tip from Baxi Potterton employee who
advised me against it. Apparently after the warranty has run out,
nobody wants to insure them, not even Baxi Potterton. Also the parts
are expensive and hard to get hold of.

"nickd" wrote in message
ups.com...
makers specs for the head, which is usually a matter of inches. You
can detach the header tank from the Boilermate, so this can easily go
up near the ceiling.


Hard to see how I can do this. As the store is in service I can'tsee
clearly how the tank is attached to the cylinder. Seems to have welded
ties, but the main connection between the two is not obvious. Any
experience of this?

The header tanks were detachable. Depending on model and year then. Get your
model number and rung Gledhill, they will put you right. If it cannot be
detached theb install a small F&E tank on brackets at high levels on the
wall and cut into the existing pipes serving the extising header tank.
Check pipes sizes

If you need a new thermal store try the Gledhill Systemate, using a

I looked at the Systemate and was impressed,
but can't seem to find a
price guide anywhere on here.

The new Boilermate is as impressive. Travis Perkins can supply one, so give
them a ring. They use thick grade copper sheet for all their products. The
thermal store alone, which runs on atmospheric pressure, can take up to 1
bar.

Incidentally, in my original post I asked if the Powermax was an
option. I have since received a tip from Baxi Potterton employee who
advised me against it. Apparently after the warranty has run out,
nobody wants to insure them, not even Baxi Potterton. Also the parts
are expensive and hard to get hold of.

The Powermax was originally made by IMI using a thermal store. Potterton
bought them out and make it into an unvented cylidner. Feedback has been
sketchy.

Try the Gledhill Gulfstream 2000. A combined boiler thermal store all in one
package. Once again, not cheap, but a class act.

Or look at the Ideal Istor:
http://www.idealboilers.com/high_sysstorage.htm

No experinece of the Istor as few are around.



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Doctor Evil wrote:

The header tanks were detachable. Depending on model and year then.
Get your
model number and rung Gledhill, they will put you right. If it
cannot be
detached theb install a small F&E tank on brackets at high levels on
the
wall and cut into the existing pipes serving the extising header
tank.
Check pipes sizes


Excellent. I've found the feed pipe round the back of the store now so
I think I'll be able to re-use it. Would it be worth using the store
just for hot water and having the CH straight off the boiler?

"nickd" wrote in message
oups.com...

Doctor Evil wrote:

The header tanks were detachable.
Depending on model and year then.
Get your model number and ring
Gledhill, they will put you right. If it
cannot be detached then install a
small F&E tank on brackets at high
levels on the wall and cut into the
existing pipes serving the extising header
tank. Check pipes sizes

Excellent. I've found the feed pipe
round the back of the store now so
I think I'll be able to re-use it. Would
it be worth using the store
just for hot water and having the CH
straight off the boiler?

If the header tank is on the ground floor then no, as the F&E tank has to be
higher than the rads. If the header tank can be higher than the boiler, get
an open vented "heating boiler", and use a plate heat exchanger off the
BoilerMate for the CH, which will get the rads over the header tank. Only
the CH circuit on one side of the plate will be pressurised.





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If the header tank is on the ground floor then no, as the F&E tank
has to be
higher than the rads. If the header tank can be higher than the
boiler, get
an open vented "heating boiler", and use a plate heat exchanger off
the
BoilerMate for the CH, which will get the rads over the header tank.
Only
the CH circuit on one side of the plate will be pressurised.


Sorry, I didn't make it very clear. I think I can get the F&E tank
higher than all the rads now, so I could easily have the whole system
OV.

In this case, I don't need the heat exchanger and can connect it
exactly as it is at the moment (with a larger boiler) or I could take
the CH off the Boilermate and feed it seperately (which would give me
the whole store for DHW).

Which do you think would be best?

"nickd" wrote in message
oups.com...

Sorry, I didn't make it very clear. I think
I can get the F&E tank higher than all
the rads now, so I could easily have the
whole system OV.

In this case, I don't need the heat exchanger
and can connect it exactly as it is at the moment
(with a larger boiler) or I could take
the CH off the Boilermate and feed it seperately
(which would give me the whole store for DHW).

Which do you think would be best?

The larger boiler should be adequate to re-heat fast enough and solve any
problems. Take the CH off the Boilermate as that is how it is currently and
this eliminates inefficient boiler cycling. If there are problems even with
a larger boiler, you can make the system a DHW priority system by inserting
a flow switch on the cold main just before it enters the store, and have
this, via a cheap relay from Maplins (about £5) cut out the CH pump. So when
DHW is called the CH is not extracting heat. Of course, get the DHW take
off coil cleaned out. This will entail pouring chemicals into the coile.
Best done when you have the thermal store out.




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