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MUA-SVX005B-EN
NNOOTTIICCEE
HHeeaatt EExxcchhaannggeerr DDaammaaggee!!
FFaaiilluurree ttoo ffoollllooww iinnssttrruuccttiioonnss bbeellooww ccoouulldd rreessuulltt iinn hheeaatt eexxcchhaannggeerr ddaammaaggee..
HHeeaatt ccoonntteenntt ooff ggaass vvaarriieess bbyy llooccaalliittyy;; cchheecckk tthhee ggaass iinnppuutt aafftteerr iinnssttaallllaattiioonn ooff tthhee uunniitt ttoo
eennssuurree pprrooppeerr iinnppuutt.. NNeevveerr eexxcceeeedd tthhee iinnppuutt oonn tthhee rraattiinngg ppllaattee..
For an accurate input rate measurement, the following meter method should be used to
determine unit input rate. If the meter method is not possible, a manifold pressure check should
be made.
MMeetteerr MMeetthhoodd ooff CChheecckkiinngg IInnppuutt RRaattee
1. Obtain the heating value of the gas from the local utility or gas dealer. This should be in units
of Btu/ft
3
(MJ/m
3
).
2. Determine the gas flow rate as shown in the following example. EXAMPLE: Assume this unit
has a input rate of 250,000 Btu/hr (73.2 kW) and the heating value of the gas is 1000 Btu/ft
3
(37.3 MJ/m
3
).
Gas Flow Rate =
250,000 Btu/hr
1000 Btu/ft
3
x 60 min/hr
=
4.17 ft
3
/min
3. Before determining the gas flow rate to the unit, all other gas appliances connected to the
same meter must be turned off.
4. Fire unit according to instructions.
5. After approximately 15 minutes of unit operation, determine volume of gas used in five
minutes of unit operation. For the Example above the unit should use 4.17 ft
3
/min x 5 minor
20.8 ft
3
(1.97 L/s x 5 min x 60 s/min = 591L) of gas. Minor input adjustments can be made by
removing pressure regulator cap and turning regulator clockwise to increase input or counter
clockwise to decrease input. Any appreciable adjustment in input rate should be made by
reorificing.
MMeetthhoodd ttoo CChheecckk MMaanniiffoolldd PPrreessssuurree
1. Close the manual valve of unit gas valve.
2. Install a 1/8" pipe connection in the tapped hole provided in the gas valve body near outlet of
the valve.
3. Attach manometer to 1/8" pipe connection by means of a rubber hose.
4. Fire unit according to instructions and observe the pressure and confirm it matches the unit
manifold pressure from the unit rating plate.
5. Small variations in the manifold pressure can be made by means of the gas valve pressure
regulator. Remove pressure regulator cap and turn regulator clockwise to increase pressure
or counter-clockwise to decrease pressure.
Pilot Adjustment
1. Disconnect wire from terminal marked MV at gas valve.
2. Provide call for heat.
3. Pilot adjustment is found on the gas valve. Remove pilot adjustment cap.
4. Adjust the pilot screw to provide properly sized flame.
5. A proper pilot burner flame is a soft steady flame that envelopes 3/8 to 1/2 inch (9.5 to
12.7mm) of the flame sense probe tip.
6. Replace the pilot adjustment cap.
7. Reconnect wire to terminal MV.
OOppeerraattiioonn
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