Thought I would pass on a piece of information that is relevant to the use
of Thermal stores and modulating condensing boilers, which may be of use to
others.

In 'normal' systems without a thermal store, modulating boilers would be
ideal, although they would be required to fire up regularly due to the fact
that there is no energy buffer present

With modulating system boilers which modulate the flow rate to maintain an
ideal "Delta T", when used with thermal stores a problem arises with the
production of domestic ho****er, in that the modulating reduces the heat
coming into the store when you need it under heavy loads.

The stored boiler water should really flow at a constant flow through the
heat exchanger in order that domestic hot water production be maintained
under heavy load situations.

With thermal stores it's better to go for a condensing, non modulating
boiler.

I have a Baxi Barcelona, and this by default is a 70,000 btu/h boiler, to
convert to maximum output of 80,000 btu/h you need to remove bridge No.2 on
the control pcb.

To turn off the modulation and have maximum output remove all 3 bridges on
the pcb.

The same applies to the 100HE

Rick

"Rick Hughes" wrote in message
...

Thought I would pass on a piece of information that is relevant to the use
of Thermal stores and modulating condensing boilers, which may be of use
to
others.

In 'normal' systems without a thermal store, modulating boilers would be
ideal, although they would be required to fire up regularly due to the
fact
that there is no energy buffer present

With modulating system boilers which modulate the flow rate to maintain an
ideal "Delta T", when used with thermal stores a problem arises with the
production of domestic ho****er, in that the modulating reduces the heat
coming into the store when you need it under heavy loads.

Have you tried the Barcelona connected up as standard with modulation? If
so how did it perform?

The stored boiler water should really flow at a constant flow through the
heat exchanger in order that domestic hot water production be maintained
under heavy load situations.

With thermal stores it's better to go for a condensing, non modulating
boiler.

It is best to have a DHW only thermal store and a boiler that switches in
and out the modulation. Some Ravenheat condensing boilers do this. When
DHW is called the boiler ramps up to maximum power until the store of water
is satisfied. When switching back to CH it then modulates giving maximum
efficiency when on CH.

I have a Baxi Barcelona, and this by default is a 70,000 btu/h boiler, to
convert to maximum output of 80,000 btu/h you need to remove bridge No.2
on
the control pcb.

To turn off the modulation and have maximum output remove all 3 bridges on
the pcb.

The same applies to the 100HE

Is it possible to have a plug that just plugs into the bridge pins and then
wire this out to the control system instructing the boiler to modulate or
not? Maplin may have such plugs complete with wire. Any electronic board
people care to comment? geoff?




---
--

Checked by AVG anti-virus system (http://www.grisoft.com).
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In message , IMM
writes
It is best to have a DHW only thermal store and a boiler that switches in
and out the modulation. Some Ravenheat condensing boilers do this. When
DHW is called the boiler ramps up to maximum power until the store of water
is satisfied. When switching back to CH it then modulates giving maximum
efficiency when on CH.

I have a Baxi Barcelona, and this by default is a 70,000 btu/h boiler, to
convert to maximum output of 80,000 btu/h you need to remove bridge No.2
on
the control pcb.

To turn off the modulation and have maximum output remove all 3 bridges on
the pcb.

The same applies to the 100HE

Is it possible to have a plug that just plugs into the bridge pins and then
wire this out to the control system instructing the boiler to modulate or
not? Maplin may have such plugs complete with wire. Any electronic board
people care to comment? geoff?


I don't see why not. I'll look at a Barcelona next week and see. The
potential problem is one of modification and insurance liability.
--
geoff

"geoff" wrote in message
...
In message , IMM
writes
It is best to have a DHW only thermal store and a boiler that switches in
and out the modulation. Some Ravenheat condensing boilers do this. When
DHW is called the boiler ramps up to maximum power until the store of
water
is satisfied. When switching back to CH it then modulates giving maximum
efficiency when on CH.

I have a Baxi Barcelona, and this by default is a 70,000 btu/h boiler,
to
convert to maximum output of 80,000 btu/h you need to remove bridge
No.2
on
the control pcb.

To turn off the modulation and have maximum output remove all 3 bridges
on
the pcb.

The same applies to the 100HE

Is it possible to have a plug that just plugs into the bridge pins and
then
wire this out to the control system instructing the boiler to modulate or
not? Maplin may have such plugs complete with wire. Any electronic
board
people care to comment? geoff?


I don't see why not. I'll look at a Barcelona next week and see. The
potential problem is one of modification and insurance liability.

My boiler powers up the board when call for heat, otherwise it is
de-energised. If a board is powered up 100% of the time and you power on
and then off, will this affect the board?

This switching in and out modulation is such a simple and, and totally
necessary, especially when a boiler is coupled to a thermal store or a quick
recovery cylinder. Situation where you may require full output. Very few
boilers have this simple function. All it needs is a couple of terminals
with a jumper wire.



---
--

Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.548 / Virus Database: 341 - Release Date: 05/12/2003

In message , IMM
writes

The same applies to the 100HE

Is it possible to have a plug that just plugs into the bridge pins and
then
wire this out to the control system instructing the boiler to modulate or
not? Maplin may have such plugs complete with wire. Any electronic
board
people care to comment? geoff?


I don't see why not. I'll look at a Barcelona next week and see. The
potential problem is one of modification and insurance liability.

My boiler powers up the board when call for heat, otherwise it is
de-energised. If a board is powered up 100% of the time and you power on
and then off, will this affect the board?

There's no reason why it should


This switching in and out modulation is such a simple and, and totally
necessary, especially when a boiler is coupled to a thermal store or a quick
recovery cylinder. Situation where you may require full output. Very few
boilers have this simple function. All it needs is a couple of terminals
with a jumper wire.



---
--

Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.548 / Virus Database: 341 - Release Date: 05/12/2003



--
geoff

"geoff" wrote in message
...
In message , IMM
writes

The same applies to the 100HE

Is it possible to have a plug that just plugs into the bridge pins and
then
wire this out to the control system instructing the boiler to modulate
or
not? Maplin may have such plugs complete with wire. Any electronic
board
people care to comment? geoff?


I don't see why not. I'll look at a Barcelona next week and see. The
potential problem is one of modification and insurance liability.

My boiler powers up the board when call for heat, otherwise it is
de-energised. If a board is powered up 100% of the time and you power on
and then off, will this affect the board?

There's no reason why it should

I believe some electronic components don't like being switched off and on.

This switching in and out modulation is such a simple and, and totally
necessary, especially when a boiler is coupled to a thermal store or a
quick
recovery cylinder. Situation where you may require full output. Very
few
boilers have this simple function. All it needs is a couple of terminals
with a jumper wire.



---
--

Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.548 / Virus Database: 341 - Release Date: 05/12/2003