Eco Heating Systems CB 105 HW, Installation, Service And User Manual

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E93.1803.901 HW 86
Demand for Domestic Hot water
13.1.18 DHW S
TORAGE WITH BULB AND STRAP
-
ON SENSOR
; DHW
MODE
1
Only use DHW mode 1 for a standalone water heater and for a Cascade water heater. Don’t use another DHW
mode because the water heater will not work properly. Also, the heater is programmed as managing (Master)
heater and a system sensor is needed next to a DHW sensor. The system sensor is a strap-on sensor connected
to the supply pipe close to the storage vessel and the DHW sensor is an adhesive sensor or bulb on or in the
storage vessel.
When installing the water heater always check what the local water hardness is. Default the water heater is set for
a water harness between 4 and 11 °dH the temperature difference between flow and return of the heater should
be maximum 16,5 °C.
Our Water heater will be standard delivered with a modulating pump, and the pump will modulate on a delta T
setpoint of 16,5
⁰
C. This feature shall give the water heater extra efficiency because the water heater stays in
condensing zone of the heat-exchanger if the setpoint storage vessel is below 65
⁰
C.
Principles to design water heater system:
•
If the water hardness is between 4 and 11 °dH the temperature difference between flow and return of
the heater should be maximum 16,5 °C
•
If the water hardness is between 11 and 14 °dH the temperature difference between flow and return
should be maximum 12,5 °C
•
If the water hardness is above 14 °dH use a water softener . Also above 11 °dH a water softener could
be considered, since an installation at 12,5 °C temperature difference will need bigger pipes and pumps.
After softening, the water hardness should be minimum 4 °dH.
Its possible to check If the flow over the heat-exchanger is according to this principles:
1.
This can be done by changing parameter (136) “Mod. Pump Mode” from “Modulating” to “Fixed 100%” the
pump will run now at 100% speed.
2. Open a tapping point for hot water and be sure that the heater is running at 100% power, now the delta T
should be 16,5 °C or lower for water hardness below 11 °dH and 12,5 °C or lower for above 11 °dH. For
determining the delta T read out in the Information menu by selecting heater
status now check the “Flow
temperature” minus the “Return Temperature”.
3.
If the delta T is within limits change back parameter 136 to “Modulating” if it is not within limit’s replace pump
by a bigger pump or check if there are any obstructions between the water heater and the storage vessel.
Or use a water softener when having a water hardness above 11 °dH.
4.
When using a delta T below 12,5 °C also change parameter (133) “Mod. Pump dT” from 16,5°C to 12°C.
Also change parameter (137) “Mod. Pump Min Pwr” from 45% to 75%.
5. Check if the water heater is working correctly by opening a tapping point on large and small amount of water.
6. When using a (115) DHW store setpoint above 70°C use a fixed setpoint for the pump because the water
heater will not condensate at high temperatures. Repeat point 1 and 2 and lower the % until your above the
16,5°C or 12,5°C now increase the fixed setpoint by one step (10%). The delta T should be 16,5°C or 12,5°C
or smaller depending on water hardness below or above 11°dH.
DHW Mode 1 is also used cascading water heaters set the cascade parameters according to paragraph
“
16 cas-
cade
“ Connect the Depending water heater and the managing water heater. Attach the strap on sensor (system
sensor) to the combined supply of the water heaters and connect this to the managing water heater, also connect
the DHW sensor which measures the temperature in the tank to the managing heater.
The DHW temperature in the tank is measured with sensor T_Store and set with parameter (115) DHW_Store_Set-
point. When this sensor drops below DHW_Store_Setpoint minus (36) DHW_Store_Hyst_Down the control detects
a demand for the store and starts the DHW circulator.
If the supply temperature T_Supply is below (115) DHW_Store_Setpoint plus (38) DHW_Store_Supply_Extra
minus DHW_Supp_Hyst_Down the heater is started as well.
Fac
tory set: 60⁰C + 0⁰C - 5⁰C = 55⁰C
(38) DHW_Store_Supply_Extra this parameter is default set to 0⁰C because the supply temperature of the water
is almost the same as the tank temperature.
When one of the water heaters in the cascade is ON, the power is PID-modulated so T_System is regulated
towards the DHW_Setpoint plus DHW_Store_Supply_Extra.
Warning: the warranty will void if these design requirements are not met.