Ti Series Installation and Operation Instructions
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Trinity
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Cleaning –
Brazed plate heat exchangers operate with high turbulence flow, even at low flow rates. This high turbulence keeps
small particles in suspension minimizing fouling and scaling. However, in some applications the fouling tendency can be very
high, e.g. when using extremely hard water at high temperatures. In such cases it is always possible to clean the exchanger by
circulating a cleaning liquid. Use a tank with weak acid, 5% phosphoric acid or, if the exchanger is frequently cleaned, 5% oxalic
acid. Pump the cleaning liquid through the exchanger. For optimum cleaning, the cleaning solution flow rate should be a
minimum of 1.5 times the normal flow rate, preferably in a back-flush mode. After use, do not forget to rinse the heat exchanger
carefully with clean water. A solution of 1-2% sodium hydroxide (NaOH) or sodium bicarbonate (NaHCO3) before the last rinse
ensures that all acid is neutralized. Clean at regular intervals.
Instantaneous DHW (w/o Storage Tank)
The Combi will provide domestic hot water continuously when flow is sensed by the flow switch. This method is the most
efficient means of heating water by allowing the boiler to operate at a lower return water temperature, thus increasing combustion
efficiency, and by minimizing standby losses. See Figure 10-1 for installation details.
DHW Limitations –
As the Combi produces domestic hot water instantaneously; there are inherent limitations of the system:
NO STORAGE - As there is no water storage, the boiler can only provide water at the temperature specified at the
corresponding flow rates. Flow through the fixtures must be regulated so not to exceed the ability of the boiler to heat the
water. MORE FLOW = LESS TEMPERATURE. See “Procedure for Setting up Domestic Hot Water” and Tables 10-1
and 10-2.
DOESN’T MAINTAIN TEMPERATURE – When there is no call for domestic the unit is off. From a dead stop the unit
will detect flow and start providing heat in 15 seconds, and be up to capacity by 25 seconds. Once running, the unit can
provide an endless amount of hot water. If the flow is momentarily turned off for whatever reason, the unit will turn off.
Once off, the unit must relight, and not provide heat for 45-75 seconds. This will cause cold unheated water to pass
through the unit, and advance through the domestic plumbing between the previously heated (hot) water, and the new
(hot) water. This can be mistaken for an inability to adequately heat the water.
“Storage”Feature (St0) –
For improved domestic hot water comfort, the Combi incorporates a “Storage” feature. This storage
feature, when enabled, will keep the boiler water hot for a period of 1 to 24 hours following a call for domestic hot water (See
Section 12.0 for further information of setting control). When the boiler water drops below 140°F the boiler will fire and bring the
boiler to 180°F before shutting off. This “Storage” feature helps in reducing the wait time associated with a tankless hot water
system. In systems where a storage tank is used (See Figure 10-2), this feature should be disabled, e.g. set to OFF.
Procedure for Setting up Domestic Hot Water –
If the Combi is being installed in an application that uses municipal water,
often the pressure is high enough to generate flow rates at the faucets that will exceed the appliances capacity to heat it. See the
following tables to determine what flow can be expected at various inlet and outlet water temperatures.
