Reznor, RHC21 4000 Installation EN May 2021 D301334 Issue 0 Page No 39 of 56
4. Before fitting new venturi, ensure throttle
screw is fully closed (turn throttle clockwise
for all RHC21 4000 models except 4100-12
and anticlockwise for RHC21 model 4100-
12. Do not overtighten.
5. Replace cork gasket all RHC21 4000
models except 4100-12 or o-ring on RHC21
model 4100-12, 8175M21 (1 off valve)
and 8200M24 (2 off valves)) between
combustion fan and venturi.
RHC21 4000 all models except 4100-12
combustion fan
RHC21 model 4100-12 combustion fan
6. Refit remaining items in reverse order.
7. Follow start up and commissioning
procedure.
7.3 Combustion fan cleaning and
replacement
1. Follow steps 1 to 4 from gas valve
replacement and step 3 from venturi
replacement.
2. Clean fan body with a lint free cloth and
blow any dirt out of the wheel using
compressed air (air should not exceed 1.5
bar).
3. Check condition of fan wheel. If damaged
replace fan.
4. On RHC21 4000 all models except 4100-12
there is a mounting plate that will need to
be transferred across to the new fan. There
is no mounting plate fitted to the 4100-12.
5. To remove unscrew the 8mm nuts.
6. Attach new gasket to fan outlet flange (all
models). Fit mounting plate to all RHC21
4000 models except RHC21 4100-12, where
there is no mounting plate.
7. Refit remaining items in reverse order.
8. Follow start up and commissioning
procedure.
O-ring
Gasket
4 off 8mm
nuts
Fan outlet
flange gasket
