Laars JVS Installation And Operation Instructions Manual

Laars JVS Installation And Operation Instructions Manual Manual pdf 12 page image

LAARS Heating SystemsPage 12A full sized, 1¼" bypass with balancing valves isstrongly recommended for all systems, and requiredwhen: 1) the boiler is installed without primary-secondary piping in a multiple zone system; 2) whenthe return water temperature can be expected to belower than 120°F (44°C); or 3) whenever the systempiping on the outlet side of the boiler may allowreduced flow through the heat exchanger, causingexcessive temperature rise (see Section 5.2).Note: Laars strongly recommends a primary/secondary piping system for all installations,especially sizes 125, 160 and 225. In this system, acirculator is dedicated to pumping the boiler only. Thiscirculator should be sized for the boiler head loss andflow rate.All precautions must be taken by the installer toinsure that a maximum temperature rise through theboiler does not exceed 30°F (17°C). The temperaturerise on boilers installed in multi-zone systems usingzone valves must be taken when the zone of thelongest length and/or the zone of the highest head lossis open.A full size, 1¼" diameter by-pass withbalancing valve must be installed if a return watertemperature below 120°F (44°C) is expected underoperating conditions regardless of boiler size. Thismay be expected in many systems, including in-floor radiant and snow melt systems.Adjusting the bypass:Refer to figure 7. Provide a means of measuringtemperature on the inlet pipe to the boiler such asusing a strap on or infrared themometer. Starting withboth balancing valves fully open, start the boiler.Adjust the balancing valve on the return to the systemslowly to provide 120°F (44°C) water at the inlet tothe boiler, leaving the bypass balancing valve fullyopen. As the system warms up, this valve may need tobe adjusted open. In rare cases, this valve will have tobe kept fully open, and the bypass balancing valveadjusted toward closed to prevent heated bypass waterfrom satisfying the call for heat when the system is upto temperature.5.2 Alternate Auto-Bypass OperationUse of the Laars themostatic union, p/n 2400-030, can provide automatic bypass operation inprimary - secondary piped systems (but cannot beused when primary - secondary piping is not used).The thermostatic union is installed on the outletpiping, after the bypass assembly. It can be used iinplace of a balancing valve. It opens fully at 140°F (seeFigure 6). Contact the factory for more information.SECTION 5.Water Connections5.1 Water PipingFigure 6 shows ‘typical’ plumbing installations.Be sure to provide unions and isolation valves at theboiler inlet and outlet so it can be isolated for service.Check local codes for specific plumbing requirementsbefore beginning the installation.An ASME pressure relief valve is supplied on allJV boilers, and is pre-set at 30 PSI. The valve outletpiping must discharge to a drain. Under nocircumstances should the relief valve piping be aclosed circuit.A pressure reducing valve (automatic feed) mustbe used to maintain system at constant proper pressure(see Figure 6). Supply properly installed purge valvesto eliminate air from each circuit.A drain valve is supplied with the boiler, and canbe found in the plastic bag shipped with each boiler.This valve is to be installed on the lower right side ofthe boiler, see Figure 1, and is used for draining theunit. To drain the boiler completely, open the drainvalve and remove the two drain plugs located onthe lower left side of the boiler.Be sure to include air vent devices located at thehighest point in the system to eliminate trapped air,and an air elimination device near the outlet side ofthe JV boiler. Manual vent valves are recommended.Hot water piping should be supported by suitablehangers or floor stands, NOT by the boiler. Due toexpansion and contraction of copper pipe,consideration should be given to the type of hangersused. Rigid hangers could transmit noise through thesystem caused by the piping sliding in the hangers. Itis recommended that padding be used when rigidhangers are installed.Gas piping should also be supported by suitablehangers or floor stands, not the boiler.A properly sized expansion tank must beincluded in the system. Laars offers an airchargeddiaphragm-type expansion tank, with an automaticfeed valve, which includes a pressure regulator set at12 psig. The part numbers are:Less Than 20 Gallons in System A006680020 to 45 Gallons in System A00669005.1.1 By-pass PipingThe following information and suggestions aremade on by-pass piping as it affects the temperaturerise at the boiler. A boiler temperature rise must betaken on all JV boiler installations. If the temperaturerise exceeds 30°F (17°C) at full rate, it is an indicationthat the boiler is not receiving adequate water flow.Check the pump for any obstruction, replace the pumpwith a larger size where necessary, or install a systemby-pass as indicated in Figures 6 and 7.