Manifold Pressure Connections; Water Temperature Regulation - A.O. Smith 100 Series Service Handbook

MANIFOLD PRESSURE CONNECTIONS

Check the manifold pressure (refer to Table 2 on Page 19) by removing the pipe plug (located on the back of the boiler/water heater near
the main gas shutoff valve) and inserting a suitable 1/8" NPT hose barb for connection to the manometer/pressure gauge. Upon completion
of measurements and adjustments, remove the hose barb and replace the pipe plug. Check for gas leaks and insure all connections are
gas tight. The draft pressures can range in between 0.05" - 1.5" W.C. And the static to dynamic pressures may vary in the range of 2" - 5"
W.C. depending on the boiler/water heater models.

WATER TEMPERATURE REGULATION

HOT WATER CAN SCALD: Boilers/water heaters are intended to produce hot water. Water heated to a temperature which will
satisfy space heating, clothes washing, dish washing and other sanitizing needs can scald and permanently injure you upon contact.
Some people are more likely to be permanently injured by hot water than others. These include the elderly, children, the infirm or
physically/mentally disabled. If anyone using hot water in your home fits into one of theses groups or if there is a local code or state
law requiring a specific temperature water at the hot water tap, then you must take special precautions. In addition to using the lowest
possible temperature setting that satisfies your hot water needs, a means such as a mixing valve should be used at the hot water taps
used by these people or at the hot water supply tank. Mixing valves are available at plumbing supply or hardware stores. Follow the
manufacturer's instructions for installation of the valves. Before changing the thermostat setting on the hot water system controller,
refer to Table 5.
Hot water temperatures required for automatic dishwasher and laundry use can cause scald burns resulting in serious personal injury
and/or death. The temperature at which injury occurs varies with the person's age and time of exposure. The slower response time of
children, aged or disabled persons increases the hazards to them. Never allow small children to use a hot water tap, or to draw their
own bath water. Never leave a child or disabled person unattended in a bathtub or shower. The boiler/water heater should be located
in an area that is inaccessible to the general public.
Water Temperature
Should overheating occur or the gas supply fail to shut off, turn off the main manual gas shutoff valve to the boiler/water heater.
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TABLE 5. RISK OF SCALDS
Time for 1st Degree Burns
ºF
(Less Severe Burns)
110 (normal shower temp.)
116 (pain threshold)
116
122
131
140
149
154
(U.S. Government Memorandum, C.P.S.C., Peter L. Armstrong, Sept. 15,1978)
Servicing should only be performed by a Qualified Service Agent
35 minutes
1 minute
5 seconds
2 seconds
1 second
instantaneous
Time for Permanent Burns
2nd & 3rd
(Most Severe Burns)
45 minutes
5 minutes
25 seconds
5 seconds
2 seconds
1 second