HTP MC120 - Manual (Page 70)

70
LP-171 Rev. 4.10.14
o Visually inspect the primary pressure relief valve and discharge pipe for signs of weeping or leakage.
o If the pressure relief valve often weeps, the expansion tank may not be operating properly. Immediately contact a
qualified service technician to inspect the unit and system.

Check the condensate drain system.
o While the unit is running, check the discharge end of the condensate drain tubing. Ensure no clue gas is leaking from
the condensate drain tubing by holding your fingers near the opening.
o If you notice flue gas leaking from the opening, this indicates a dry condensate drain trap. Fill the condensate trap
assembly with water. If problem persists regularly, contact a qualified service technician to inspect the unit and
condensate line.
o The service technician must ensure the condensate drain line is not blocked by pouring water through the plug port
on the condensate drain assembly. The water should flow out of the end of the drain line. If water does not appear at
the end of the drain line, the qualified service technician must clean the condensate line.
o To fill the condensate drain assembly, remove the cup from the assembly. Slowly pour water into the cup until water
appears at the end of the drain line. Stop filling and replace the cup.
You must ensure that the condensate cup is securely fastened before restarting heater. Do a final check to ensure proper condensate
flow.
Every 6 Months

Check heater piping and gas supply piping for corrosion or signs of potential leakage.
o Remove the heater cover and perform a gas leak inspection following Gas Valve Operating Instructions, p. 2 in this
manual. If gas or odor leak is detected, immediately shut down the unit following To Turn Off Gas To Appliance
procedures on p. 2. Call a qualified service technician.
o Visually inspect for leaks around the internal heater water connections and around the heat exchanger. Visually
inspect the external system piping, circulators, and system components and fittings. Immediately call a qualified
service technician to repair any leaks.
Have gas leaks fixed at once by a qualified service technician. Failure to comply could result in substantial property damage, severe
personal injury, or death.

Operate pressure relief valve.
o Before proceeding, verify that the relief valve outlet has been piped to a safe place of discharge, avoiding any
possibility of scalding from hot water.
To avoid water damage or scalding due to relief valve operation, a discharge line must be connected to the valve outlet and directed to
a safe place of disposal. This discharge line must be installed by a qualified service technician or heating/plumbing installer in
accordance with this manual. The discharge line must be terminated so as to eliminate possibility of severe burns or property damage
should the valve discharge.
o Read the temperature and pressure gauge to ensure the system is pressurized. Minimum is 10 psi. Maximum is 25
psi. Lift the relief valve top lever slightly, allowing water to relieve through the valve and discharge piping.
o If water flows freely, release the lever and allow the valve to seat. Watch the end of the relief valve discharge pipe to
ensure that the valve does not weep after the line has had time to drain. If the valve weeps, lift the lever again to
attempt to clean the valve seat. If the valve does not properly seat and continues to weep, contact a qualified service
technician to inspect the valve and system.
o If water does not flow from the valve when you completely lift the lever, the valve or discharge line may be blocked.
Immediately shut the unit down per instructions on p. 2 in this manual and call a qualified service technician to inspect
the valve and system.