Poor Hot Water Checklist - Grant Vortex Series Installation And Servicing Instructions

C BURNER NOT OPERATING
First, set either hot water or heating to ON
NO
Is the 'BURNER' indicator
lit?
NO
YES
Is the 'BURNER' indicator
flashing?
Fast or slow flash.
Slow flash
If the 'BURNER' indicator (once every 2 seconds):
continues flashing.
Indicates a possible fault
with the PCB (relay).
YES
Is the 'BURNER' indicator
PCB is supplying voltage to
lit?
the burner - but the burner
is not working.

12.3 POOR HOT WATER CHECKLIST

Always check the basics before changing parts.
If heat energy input is
incorrect: heat energy
output will be incorrect.
Burner
Poor heat input = poor hot
water.
Plate heat exchanger
requires water circulation
DHW pump
from primary store to
operate.
DHW 'store' and CH 'flow'
Thermistors thermistors must detect
temperatures correctly.
Excessive flow rate
exceeds heat input from
burner.
Water flow rate at hot tap
Excessive flow rate = poor
hot water.
Excessive pressure has a
Water pressure
major influence on flow rate.
Scale forming in the plate
heat exchanger = poor heat
Water condition
transfer in plate = poor hot
water temperature.
Must be correctly set to
Thermostatic blending valve
provide optimum hot water.
! NOTE !
For an overview of the fault diagnostic capabilities built
into the circulating pumps that come installed in all Vortex
Pro Combi models, please refer to Appendix A1 or A2,
as required, at the back of this installation and servicing
manual.
Page 46
Refer to 'initial checklist' for guidance.
Continue to next check.
First, set boiler 'ON/OFF' switch to 'OFF'.
Wait 5 seconds
Then set 'ON/OFF' switch back to 'ON'.
Replace PCB
Check all electrical connections to burner control box.
Check for 230V at L and N terminals in control box.
Is 'lockout' button (on control box) lit?
If yes: press 'lockout' button to reset burner.
If burner does not fire, refer to Section 12.4 (burner fault finding).
Check nozzle is correct size.
Check oil pump pressure is correct.
Check combustion is correctly set.
Check pump speed setting: it must be maximum.
Check pump valves are fully open.
Check both are fully inserted in their pockets.
Check flow rate at tap.
Combi 21 = 12 litres/minute maximum.
Combi 26 = 15 litres/minute maximum.
Combi 36 = 18 litres/minute maximum.
Check standing and operating water pressure.
2 bar minimum standing pressure required.
8 bar maximum standing pressure.
If greater than 8 bar; fit a pressure reducing valve on the cold supply to the boiler.
1 bar minimum dynamic pressure required.
Check for scale in the plate heat exchanger.
Replace plate heat exchanger if necessary.
In hard water areas some form of anti-scale device or water softener must be fitted.
NOTE: Faults due to hard water scaling are not covered by the product guarantee.
Check if blending valve is scaled up (refer to 'water condition' above).
Clean or replace as necessary.
Section 12: Fault Finding