Heatmaster 35 TC Installation, Operating And Servicing Instructions Download Page 4

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664Y2800.B

TOTALLY CONDENSING :

The HeatMaster

TC combines the

unique ACV Tank-in-Tank concept with

a dual primary circuit resulting in

exceptional performance from a totally

condensing combination boiler.

Tank-in-Tank technology

ACV’s advanced implementation of thermal storage technology is
tried and tested and is remarkably simple, efficient and reliable.
At the heart of the

HeatMaster

is a stainless steel tank

through which the flue tubes pass.
This is surrounded by a mild steel shell containing the primary
water, which extends down to the combustion chamber and even
around the flue tubes. The burner fires onto the primary water
which indirectly heats the stainless steel tank containing the hot
water. As with all Tank-in-Tanks, this is corrugated over its full
height and is suspended in the

HeatMaster

by its hot and

cold water connections.
The area of the heat transfer surface is therefore much greater
than that of standard direct fired water heaters. A much larger
heat transfer surface means that Tank-in-Tank units recover much
faster than any other kind of hot water storage device - and keeps
boiler cycling to a minimum. The high storage temperature within
the inner tank also results in exceptional hot water outputs.

Dual primary circuit technology

The

HeatMaster

primary circuit is split into two sections - a

high temperature upper circuit and a low temperature lower circuit,
divided by a separation plate. The hot water storage tank is located
in the upper circuit which always operates at a temperature of
between 60°C and 90°C. This is ideal for hot water production as
it maintains the stored water at constantly high temperatures,
eliminating bacterial formation such as Legionellae, as well as
resulting in high volume hot water production.
The down-firing flue tubes pass through the upper circuit, through
the separation plate and into the lower circuit. The primary water
here operates at a temperature typically between 30°C and 60°C
for heating (dependent on the heating return temperature), perfect
for condensing when working in heating mode.

Dual coil technology

During hot water mode, the bottom circuit operates at a much
lower temperature, typically 5°C to 20°C depending on the
cold water inlet temperature. The incoming cold water enters
the lower primary circuit via an indirect water preheater. As
this preheater is wrapped around the lower flue tubes of the
combustion chamber, it is able to absorb the remaining heat
from the flue gases. The result is that during hot water mode the

HeatMaster

totally condenses whether on full or part-load.

INTRODUCTION

Heating

The heating return
enters the lower circuit
of the boiler, which allows
the boiler to operate
in condensing mode.
The upper circuit of the

HeatMaster

is kept

at a consistently high
temperature due to the
internal shunt pump which
ensures that the primary
water circulates around
the heat exchanger flue
tubes.

Heating and
hot water

Once up to temperature,
the

HeatMaster

capable of producing
heating and hot water
simultaneously.

Hot water

With the upper circuit
maintained at high
temperature, the

HeatMaster

is always

ready to supply hot water
on demand.

The cold water enters
through the indirect water
preheater at the base of
the heat exchanger and is
preheated before entering
the hot water tank. The low
temperature of the bottom
circuit results in continuous
condensation of the flue
gases in hot water mode.

Operating modes

In both heating and hot water modes, the premix
gas burner fully modulates the power to match
the system demand.