Page No 42 of 56 Reznor, RHC21 4000 Installation EN May 2021 D301334 Issue 0
15. Refit burner probes. Check condition
of probe bracket gasket and replace if
necessary.
16. Replace the burner gasket if necessary.
17. Refit in reverse order.
18. Follow start up and commissioning
procedure.
7.6 Cleaning and replacement of
burner probes
1. Disconnect the spark and flame sense cables
from the ignition transformer and ignition
controller.
2. Unscrew 4 fixings with 10mm socket to
remove the probe access panel.
3. Once removed unscrew the 2 fixings with a
10mm socket to release the probe mounting
bracket.
4. Pull probe mounting bracket away from
the burner chamber to extract the burner
probes.
5. The burner probe assembly can now be
removed from the heater.
6. Review the condition of the probes. Light
oxidation can be removed with a fine
abrasive paper.
7. Measure the length of each probe and
check against the dimensions given below. If
probes are corroded or damaged in any way,
they will need to be replaced.
No gap
between
tube
insert and
chamber
insulation
Flame sense
probe
Spark probe
Probe access
panel fittings x4
Probe mounting
bracket fittings x2
Withdraw
probe mounting
bracket from
chamber
Flame probe
Length of probe =
46.55mm overall
32.95mm to angle
13.79 mm angle to tip
Tip deflection away from 0°
= 27°
