Maintenance - Honeywell V4730C Operating Instructions Manual

7.1 Adjust gas/air 1:1 regulation
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Incorrect adjustment
High inlet pressures as used for gas G30 or G31,
can cause oscillation. This is dependent on type of
appliance. If oscillation occurs:
– The oscillation shall not exceed 10 % of the
outlet pressure, with a stable air pressure signal.
– The oscillation has to be verified for the
complete modulation band of the appliance.
– Please contact your Honeywell representative if
the maximum of 10 % is exceeded.
The 1:1 gas/air regulator assembly has an air pres-
sure connection and an offset adjustment screw.
The 1:1 gas/air regulator equals the gas pressure to
the supplied air pressure. With the offset adjustment
screw it is possible to adjust the offset. (Offset =
P - P )
gas air
2
1 Cap screw
2 Offset adjustment screw
3 M5 pressure feedback connection
1 With the valve in the final mounting position,
adjust the venturi fan for the lowest burner firing
rate.
2 Remove cap screw with a torque bit (or slotted
screwdriver) to expose offset adjustment screw.
3 Using a torque bit T40 or a 5 mm hex wrench,
carefully adjust the low fire gas setting for proper
combustion.
4 After proper low fire offset adjustment has been
made, replace cap screw and tighten pressure
taps.
5 Before commissioning the burner, check for
proper lightoff and verify correct fuel/air mix and
combustion quality through out the entire firing
range (from lowest to highest fan speeds used).
Checkout of adjustment
6 After any adjustment check pressure taps and
gas connections with an approved leak
detection fluid for gas leakage.
7 After any adjustment set appliance in operation
and observe several complete cycles to ensure
that all burner components function correctly.
7.1.1 specify application parameters (gas/air
1:1)
Define maximum allowable deviation on ΔP
at minimum ΔP air in new appliance for reliability
reasons.
The application parameters can effect the Offset
Adjustment accuracy during cycling and life cycling
of the control system.
These parameters are (in sequence of importance):
1
3
gas
– Start pressure (the lower the better)
– Ambient temperature (the lower the better)
It is therefore advisable to verify the offset adjust-
ment at service interval by CO
ΔP (burner orifice pressure drop) at minimum
gas
ΔP (pressure drop over air restriction).
air
ΔP measured on pressure tap of combination
gas
gas control (highest pressure) can deviate from
real ΔP (burner orifice pressure drop) due to gas
turbulence and/or restrictions in the application. The
deviation should be defined and documented. The
measurement accuracy should be +/- 1 Pa.

8 MAIntenAnCe

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Explosion hazard and electrical shock hazard!
Can cause severe injury, death of property dam-
age.
– Turn off gas supply and disconnect all electrical
power to the valve before servicing.
– Only trained, experienced, flame safeguard
technicians should attempt to service or repair
flame safeguard controls and burner assem-
blies.
scheduled Inspection and Maintenance
➔ Set up and follow a schedule for periodic inspec-
tion and maintenance, including the burner, all
other controls and the valves.
➔ It is recommended that the valve leak test in the
Checkout section be included in this schedule.
Refer to the instructions for the primary safety
control (s) 0 for more inspection and mainte-
nance information.
1 Make sure the gas supply is turned off and all
electrical power has been removed.
2 Remove bolts/nuts from flange/valve.
3 Remove flange from gas supply pipe.
4 Remove old screen/strainer
5 Clean the strainer by using compressed air, or
replace the strainer.
6 Install the cleaned strainer or new strainer.
7 Make sure O-ring sealing surface is clean on the
flange.
8 Using general purpose lithium grease, grease the
Oring.
9 Apply a moderate amount of good quality pipe
dope, resistant to the action of LP gas, only on
the pipe threads.
10 Install the O-ring in the O-ring groove provided
on the flange/valve body (one O-ring per groove).
11 Screw the flange onto the pipe.
12 Mount the gas valve to the flange, using the
bolts and nuts for each flange.
13 Apply power to the valve.
14 Turn on the main gas supply.
15 Complete the valve leak test.
16 Return the valve to service.
EN-8
measurement or
2