Ideal Boilers LOGIC COMBI C24 Installation & Servicing

Also see for LOGIC COMBI C24: User guide

37Installation and ServicingSECTION 2 - INSTALLATIONWATER CIRCULATION SYSTEM1. With the system COLD, check that the initial pressure iscorrect to the system design requirements.For pre-pressurised systems, this should be 1.0 bar.2. With the system HOT, examine all water connectionsfor soundness. The system pressure will increase withtemperature rise but should not exceed 2.5 bar.3. With the system still hot, turn off the gas, water andelectricity supplies to the boiler and drain down to completethe flushing process.Note: A flushing solution should be used during the flushingprocedure. Flushing solutions: Fernox Superfloc,Sentinel X300 (new systems) or X400 (existingsystems). Refer to Section 1.19.4. Refill and vent the system, add inhibitor (refer to section1.19), clear all air locks and again check for watersoundness.5. Reset the system initial pressure to the designrequirement.6. Balance the system. Refer to Section 1.18.7. Check the condensate drain for leaks and check that it isdischarging correctly.8. Finally, set the controls to the User’s requirements.Note: The pump will operate briefly as a self-check once every24 hours in the absence of any system demand.WATER TEMPERATURESTemperatures can be selected using the CH and DHW thermostats.Knob Setting CH Flow Temp DHW Outlet TempoC oCMax 80 65Min 30 402.24 GENERAL CHECKS1. Fully open all DHW taps in turn and ensure that water flowsfreely from them.The display should show‘ ’ then‘ ’ ‘ ’ when the burner lights2. Close all taps except the furthest one from the boiler and checkthat the boiler is firing at maximum rate.This is factory set to give a DHW temperature rise ofapproximately 35 oC at the flow rate stated on page 10 under“operation”.3. Reduce the DHW draw-off rate to about 3 l/min (0.7gpm) andcheck that the boiler modulates to deliver DHW at approximately65 o C.4. Close the DHW tap and check that the main burner extinguishes.The pump should overrun for 60 seconds.When the pump stops the display sequence should read:Note. On systems in excess of 2 bar inlet pressure a waterpressure governor may be required to prevent water noise.CENTRAL HEATING (CH)& DOMESTIC HOT WATER (DHW) MODE.1. Ensure that the CH external controls are calling for heat.The display should show:‘ ’‘ ’2. Fully open a DHW tap and check that hot water is delivered.The display should show‘ ’ ‘ ’3. Gas RateCheck the boiler gas rate when the boiler is at full DHWoutput.Check at the gas meter, with no other appliance in use.Refer to Tables 2 & 3 for gas rates.4. Close the DHW tap.5. Set the central heating external controls to OFF. The burnershould go off and the pump continue to run for two minutes.The display should read:6. Check the correct operation of the timer (if fitted) and allother system controls. Operate each control separately andcheck that the main burner responds.Make the following checks for correct operation in:Due to system variations and seasonal temperaturefluctuations DHW flow rates/temperature rise will vary, requiringadjustment at the draw off tap : the lower the rate the higher thetemperature, and vice versa.INSTALLATION