PVI Industries PV500-34 User's Manual
Contents
1. INSTALLATION amp MAINTENANCE MANUAL FOR SEMI INSTANTANEOUS QuickDraw ENERGY STEAM TO WATER U TUBE SINGLE WALL amp DOUBLE WALL HEAT EXCHANGERS U tube Heat Exchanger Steam Inlet Shutoff Valve Y Strainer Steam Pressure Gauge Steam Valve Condensate Drain Main Steam Trap Thermostatic Trap OOAN Oar onw gt ia a Typical Construction Figure 34 1 10 11 12 13 14 15 16 Potable Water Inlet Check Valve Intratank Circulator Potable Water Outlet Tank Drain Valve Relief Valve Control Enclosure Optional Not supplied by PVI shown with dashed lines CAUTION TEMPERATURES HIGHER THAN 125 F INCREASE THE RISK OF SCALD INJURY IMPORTANT Clearances for servicing and inspection are 18 at top sides and rear and a minimum of one tank diameter in front PVI Industries LLC P O Box 7124 Fort Worth TX 76111 800 433 5654 e www pvi com PV500 34 05 03 1 Section 34 QuickDraw STEAM WITH SINGLE WALL DOUBLE WALL WARNING Setting the temperature selector to higher settings provides hotter water which increases the risk of scald injury Households with small children or invalids may require a 125 F or lower temperature setting to reduce the risk of scald injury Allow a few days of operation at your selected setting t2. ance instructions are shipped with the unit Refer to these instructions during start up and file for future referencing on maintenance CAUTION Most valve problems are caused by dirt or trash in the steam line This is most likely to occur during installation Teflon pipe tape pipe joint compounds metal particles and dirt will clog up strainers and orifices and prevent valve seats from closing Clean all pipe line strainers at start up and check the valves again after a few days operation as recommended by the valve manufacturer Inspection of strainers and blowdown piping should be part of the normal maintenance routine on this equipment OPTIONAL SAFETY SYSTEMS 1 This heater may be supplied with a pressure gradient monitoring PGM system consisting of a differential pressure switch a delay timer and a steam purge valve It serves as a safety system to prevent the contamination of potable water with steam The pressure switch monitors both steam and potable water system pressure If the potable water pressure falls to a point slightly above the steam pressure and stays there for a short period of time then the heater shuts down closes the steam valve and opens a steam purge valve to quickly reduce the steam pressure in the heat ex changer The system requires a manual reset to begin operation again Note that the system does not necessarily detect a leak but it prevents steam from entering the potable water if there
3. ectrical shock injury or death on control systems using 120 volt external power be certain switch is off and power disconnected before work is performed on this heater Section 34 QuickDraw STEAM WITH SINGLE WALL DOUBLE WALL con t TROUBLESHOOTING NOTES Problem 1 No hot water at even low flow a Cause Steam valve s not opening Solution Check that electrical coils are energized If not trace wiring problem If so the valve may be faulty the steam pressure inadequate to open the valve lt 5 psi depending on the valve or the linkage if applicable is out of adjustment Cause Condensate flow is blocked Solution Float type traps will not open if the inlet steam pressure exceeds the trap rating Check steam pressure against the rating stamped on the trap Check that there are no valves or clogged strainers between the heat exchanger and the condensate receiver Cause PGM system tripped Solution The pressure gradient monitoring option prevents the steam valve from opening if the water pressure in the tank is within 10 psi of the steam pressure Correct water pressure problem Problem 2 Heater recovery is slow or outlet temperature is below setpoint a Cause Steam supply insufficient Solution Loss of steam delivery pressure see below b Cause Condensate not draining Solution Check that there is not excessive condensate lift For low pressure steam any lift at all may affect performance C
4. essary corrections PV500 34 05 03 6 Section 34 QuickDraw STEAM WITH SINGLE WALL DOUBLE WALL con t b Cause Steam valve s not fully opening Solution Check steam pressure before and after steam valve The pressure drop should not be more than half of the inlet pressure Check valve for blockage Check linkage for adjustment Check modulating signal if applicable Check the supplied voltage to the valve coil c Cause Piping flow restricted Solution Calculate the flow velocity and expected friction loss If excessive larger inlet and outlet piping are necessary d Cause Main valve malfunction Solution Refer to the valve manual for instructions on main valve repair e Cause Main valve undersized Solution Check steam pressure before and after steam valve Check valve capacity against the load If insufficient increase trim or valve size Problem 4 Outlet water temperature not constant a Cause Insufficient recovery Solution If the thermostat or controller is always open then the outlet temperature will vary with load See above for causes of insufficient recovery b Cause Malfunctioning thermostat Solution Measure the tank temperature near the thermostat and compare to setpoint The thermostat should turn on and off within 5 F of setpoint Problem 5 Unusual noises coming from heater a Cause Flashing condensate Solution Pinging rattling or banging noises are usually the result of condensate f
5. fe for the water heater Scale will normally form in the tank during operation and will accumulate on the bottom of the tank The scale is formed from the natural chemicals in the water that precipitate out during the heating cycles Some water supplies contain more of these chemicals than others and the scale buildup will occur more rapidly Other factors affecting the scale buildup are the amount of hot water used and the temperature of the water The more hot water used the more fresh water containing the scale forming chemicals is brought into the tank As the temperature of the water increases the rate of scale deposited will be increased The unit should be inspected and cleaned as required by local water conditions PV500 34 04 03 CAUTION The relief valve is a primary safety device 3 It is required for safe practice to operate the temperature and pressure relief valve once a year by lifting the lever briefly If the valve does not open and close properly when testing it must be replaced The temperature limiting device and thermostat temperature sensors that extend into the water in the tank may become coated with scale depending on the type of water in your area This coating will affect accuracy of sensors and can allow water temperature to exceed the desired limits These controls should be removed from tank and inspected at necessary intervals Remove scale if present WARNING To reduce the risk of el
6. heck the sizing of the trap Check that the condensate receiver is not pressurized Check that there is no blockage in the condensate line from the trap to the receiver Unclog any strainers in the system c Cause Condensate trap not operating Solution If the condensate temperature near the heat exchanger is considerably less than the steam temperature then condensate is being backed up into the heat exchanger Check that the supply steam pressure does not exceed the trap pressure rating Check the trap for blockage or mechanical failure Check that the trap is sized sufficiently for the load d Cause Heat exchanger is breached Solution If excessive condensate is draining the heat exchanger may have a leak and be filling with water e Cause Heat exchanger is fouled Solution Inspect the heat exchanger for excessive scaling or fouling on the water side f Cause Abnormal operating conditions Solution The water temperature has a significant effect on the efficiency of the heat exchanger Check if the setpoint is higher than specified Confirm the measured flow rate with meters or by volume and rate Check that there are no other loads on the heater Problem 3 Steam delivery pressure to heat exchanger is low or drops off a Cause Low supply steam pressure Solution Unclog strainer Check for blockage or restrictions in the line between the boiler and the water heater Check for low boiler output or upstream blockage and make nec
7. ing diagram provided with this unit when installing or troubleshooting the electrical components of this heater 2 All wiring must be in accordance with all local state or federal codes 3 Provide proper overload protection for the system s circulating pump NOTE Use only copper wire of proper sizing for incoming service Damage resulting from use of aluminum wiring will be excluded from coverage under the warranty of this unit PV500 34 05 03 Section 34 QuickDraw STEAM WITH SINGLE WALL DOUBLE WALL con t RELIEF VALVE PIPING The water heater is supplied with a pressure and temperature relief valve sized in accordance with ASME requirements Each relief valve should be piped to a suitable floor drain No reducing coupling or other restriction can be installed in the discharge line It is strongly recommended that this valve should be manually operated at least once a year WARNING Make sure the safety relief valve is piped to a proper drain per instructions Scalding STEAM amp CONDENSATE CONNECTIONS 1 The condensate trap controls the discharge of condensate based on the load on the heat exchanger thus preventing the discharge of live steam through the unit Appropriately sized traps are available from your PVI representative The steam trap must have a pressure rating equal or more than the maximum steam pressure supplied to the water heater The trap must also be sized according to the steam flo
8. is a leak 2 Another safety option is the tank purge system sometimes called a double solenoid safety system The tank temperature is monitored and if it exceeds an adjustable limit the heater is shut down and a valve opens to dump the overheated water This allows cold make up water to enter the tank and quickly reduce the tank temperature START UP OPERATION 1 After all the steam condensate and water lines are installed and inspected the steam supply source and the condensate receiver should be checked for correct operation Steam supply pressure to the heater must be equal to or less than the supply pressure on the heater decal A pressure reducing valve can be installed in the supply line to meet this requirement 2 Steam is directed to the heat exchanger through a header and steam control valves The steam control valves are normally closed on off electric valves and solenoid operated PV500 34 05 03 Should an electrical power failure occur steam valves will close and stop steam flow to the unit WARNING Excessive steam pressure can cause the steam valve s and condensate trap to malfunction and can cause the heat transfer rate to exceed the relief valve capacity which can result in an explosion causing damage injury or death Section 34 1 QuickDraw STEAM WITH SINGLE WALL DOUBLE WALL con t START UP PROCEDURE Fill tank with water open relief valve to purge air from top of tank Check f
9. lashing to steam Condensate not draining properly Check that there is not excessive condensate lift Check the sizing of the trap Check that the condensate receiver is not pressurized Check that there is no blockage in the condensate line from the trap to the receiver Unclog any strainers in the system Problem 6 Heat exchanger visibly leaking a Cause Plumbing connection loose Solution Check and tighten plumbing connection b Cause Double wall heat exchanger tube leak Solution If one of the tube walls is breached a double wall heat exchanger will leak at the joint between the tubesheets Isolate the heater and replace the heat exchanger Since PVI cannot control the use of the water heater water conditions or maintenance the warranty on the water heater does not cover poor performance structural failure or leaking due to an excessive accumulation of scale PV500 34 05 03 7 Section 34
10. nsate receiver and pump or vacuum return to the condensate return header b Plumb to a pneumatic electric actuated condensate pump trap for return to the condensate return header c Drain to atmosphere would require constant make up of boiler water Inadequate drainage of condensate can adversely affect heat transfer and limit the performance of the water heater Please note damage to the water heater attributed to poor condensate drainage is not covered in the product warranty On the Quickdraw semi instantaneous steam heater the 3 4 thermostatic trap must be plumbed in parallel with the main steam trap for optimal operation of the heater It speeds the removal of air from the heat exchanger when the steam valve opens It also serves the second purpose of a vacuum breaker to protect the heat exchanger and allow proper drainage of condensate See Figure 34 1 Locate the thermostatic trap in a tee six inches above the main condensate line between the heat exchanger and the main trap Plumb its outlet to a point downstream of the main trap Section 34 QuickDraw STEAM WITH SINGLE WALL DOUBLE WALL con t STEAM VALVES 1 One or more two position on off electric valves are used to control the flow of steam The valves will return to the closed position when power is off This feature will prevent an excessive temperature buildup in the event of a power failure The valve manufacturer s operation and mainten
11. o determine the correct temperature setting consistent with your needs er temperature over 125 F can cause severe burns instantly or death from scalds Children disabled and elderly are at highest risk of being scalded See instruction manual before setting temperature at water heater Feel water before bathing or showering If this appliance is used to produce water that could scald if too hot such as domestic hot water use adjust the outlet control limit or use temperature limiting valves to obtain a maximum water temperature of 125 F CONNECTING UNIT CAUTION All steam and water supply lines should be flushed before connecting the unit 1 Use backup wrenches on all screwed pipe connections to prevent damage to brazed ELECTRICAL joints or studded connections Shutoff valves and dielectric unions should be installed in steam and water lines to allow maintenance on the unit Steam supply water supply and condensate lines must be supported before connecting the unit The heater is wired for 120 volts and must be electrically grounded in accordance with local codes or in the absence of local codes with the latest edition of the National Electrical Code ANSI NFPA When unit is installed in Canada it must conform to the CSA C22 1 Canadian Electrical Code Part 1 and or local electrical codes 1 Branch circuit protection and disconnecting means must be furnished by the installer Refer to the wir
12. or plumbing leaks Push control switch located on the control box to activate the steam valve and thermostats Check steam valve for operation the valve solenoid should click to open valves when operating switch is pushed on The tank circulating pump if present should also operate Check thermostat settings The temperature limiting device is set at 200 F Temperature setting The operating thermostat is set at the factory at approximately 130 F and the upper operating thermostat is set at approximately 125 F Adjustment may be made by turning the operating thermostat dial to the desired temperature Push the operating switch located on the control box to off before opening manual main steam supply valve This will allow condensate that has collected in the supply line to drain through the trap installed in front of the steam valve When the steam supply line is free of condensate push operating switch to on opening the electric on off steam valves allowing steam to flow through the heat exchanger Open nearby hot water tap to maintain a flow of water through tank when starting up units Observe condensate flow at the receiver or other collection site to verify satisfactory flow Regulate flow of water through tank to allow steam valve to cycle off and on and check operation of unit MAINTENANCE 1 A preventive maintenance program should be established to assure a long trouble free li
13. w shown on the heater decal Connect the steam supply to the steam inlet fitting on the unit as shown in Figure 34 1 A Y strainer 100 mesh recommended must be installed ahead of and near the unit to prevent particles of scale and other solids from damaging the seats of the steam valve It is good practice to install a blowdown valve on the Y strainer piped to a suitable location that can be opened at intervals to clean the strainer screen A condensate trap may be located upstream of the steam valve This trap will drain the condensate that collects in the piping and must be plumbed to a suitable drain or the condensate receiver plumbing Connect condensate trap inlet at or below the outlet of the heat exchanger The ability to lift condensate via steam pressure cannot be assured on Quickdraw products due to the possible use of a modulating steam valve or multiple solenoid steam control system The PV500 34 05 03 4 5 injury and or water damage can occur from either the manual lifting of the lever or the normal operation of the valve if it is not piped to a proper drain Insure that the safety relief valve piping is of the proper material and rating for the temperature and pressure of the system and that it is secured to prevent possible injury If valve fails to flow water or reseat consult the factory The relief valve is a primary safety device recommended methods of condensate distribution are a Plumb to a conde
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