Lochinvar 402 - 2072 Boiler bypass requirements, Temperature / pressure gauge, DHW installation

Installation & Service Manual

4 Water connections

TABLE - 4C

SYSTEM TEMPERATURE RISE CHART

Temperature Rise and Head Loss Based on Boiler Output in Btu/hr

Btu/hr		30°F ΔT		35°F ΔT		40°F ΔT		45°F ΔT		50°F ΔT		55°F ΔT		60°F ΔT
Input	Output	GPM	Ft/hd	GPM	Ft/hd	GPM	Ft/hd	GPM	Ft/hd	GPM	Ft/hd	GPM	Ft/hd	GPM	Ft/hd
399,999	339,999	23	1.1	19	0.7	--	--	--	--	--	--	--	--	--	--
500,000	425,000	28	1.6	24	1.2	21	0.7	19	0.7	--	--	--	--	--	--
650,000	552,500	37	3.0	31	2.2	28	1.6	24	1.2	22	0.9	20	0.7	18	0.6
750,000	637,500	42	4.1	36	2.8	32	2.3	28	1.6	25	1.3	23	1.1	21	0.7
990,000	841,500	55	2.6	48	2.3	42	1.5	37	1.4	33	1.0	30	0.9	28	0.9
1,260,000	1,071,000	71	4.4	61	3.6	53	2.7	48	2.3	42	1.7	39	1.5	35	1.2
1,440,000	1,224,000	81	6.3	70	5.0	61	3.8	54	2.7	48	2.3	44	2.0	40	1.8
1,800,000	1,530,000	102*	11.8	87	9.0	76	6.6	68	5.6	61	4.4	55	2.6	50	3.0
2,070,000	1,759,500	--	--	100*	10.1	87	9.0	78	7.6	70	6.2	64	5.4	58	4.6

*Cupro-Nickel Heat Exchanger Required at Flows Above 55 GPM on Models 402 - 752 and above 90 GPM on Models 992 - 2072.

TABLE - 4D

BOILER TEMPERATURE RISE AT MAXIMUM FLOW Temperature Rise at Full Rate Fire, 55 and 90 GPM Maximum Flow

Model	Temperature Rise °F
402	12 @ 55 GPM
502	15 @ 55 GPM
652	20 @ 55 GPM
752	23 @ 55 GPM
992	19 @ 90 GPM
1262	24 @ 90 GPM
1442	27 @ 90 GPM
1802	34 @ 90 GPM
2072	39 @ 90 GPM

Boiler bypass requirements

The installer must ensure that the boiler is supplied with adequate flow without excessive temperature rise. It is recommended that this boiler be installed with a bypass in the piping if the maximum recommended flow rate is exceeded. The bypass will help to ensure that the boiler can be supplied with adequate water flow. Flow rates exceeding the maximum recommended flow will result in erosion of the boiler tubes. A typical bypass with a valve as shown in FIG. 4-5 will allow control of boiler flow.

Temperature / pressure gauge

This boiler is equipped with a dial type temperature / pressure gauge. This gauge is factory installed in the outlet side of the boiler piping. The gauge has one scale to read system pressure and a separate scale to read water temperature in degrees Fahrenheit. The temperature / pressure gauge is provided to meet code requirements. Water temperatures can be more accurately monitored from the data provided in the digital display in the Operator Interface.

38

Typical heating boiler installations

General plumbing rules:

1.Check all local codes.

2.For serviceability of boiler, always install unions.

3.Always pipe pressure relief valve to an open drain.

4.Locate system air vents at highest point of system.

5.Expansion tank must be installed near the boiler and on the suction side of the system pump.

6.Support all water piping.

Installation with a chilled water system

Pipe refrigeration systems in parallel. Install duct coil downstream at cooling coil. Where the hot water heating boiler is connected to a heating coil located in the air handling units which may be exposed to refrigeration air circulation, the boiler piping system must be equipped with flow control valves or other automatic means to prevent gravity circulation of the boiler water during the cooling cycle.

The coil must be vented at the high point and hot water from the boiler must enter the coil at this point. Due to the fast heating capacity of the boiler, it is not necessary to provide a ductstat to delay circulator operation. Also, omit thermostat flow checks as the boiler is cold when heating thermostat is satisfied. This provides greater economy over maintaining standby heat.

DHW installation

Boilers may be utilized with a Hot Water Generator tank for domestic hot water. When used for DHW, either a tank thermostat or sensor must be installed in a bulbwell within the tank and connected back to the unit in order for the controller to regulate water temperature and a pump for DHW. Pumps used for DHW purposes should be sized to provide adequate flow to the boiler when in DHW Mode. Reference FIG. 4-3 shown with a Hot Water Generator for DHW on page 39 for a typical DHW piping scheme.