Munchkin VWH High Efficiency Hot Water Supply Boiler - Manual (Page 4)

GENERAL INFORMATION
4
RECOMMENDED SERVICE CLEARANCES
PART 1. GENERAL INFORMATION
A. HOW IT OPERATES
The Munchkin VWH is a hot water supply boiler designed to operate in conjuction with a hot water
storage tank. Each Munchkin VWH is equipped with a high velocity pump to keep the unit running
efficiently for many years of service. A flow switch monitors the water flow through the heat exchanger
to make sure that the unit has an adequate flow rate during operation. The Munchkin VWH Controller
accurately monitors the return and supply temperature that controls the output range of the Munchkin
When the system has sensed a temperature drop below the set point and minus the differential set
point, The Munchkin VWH will activate the blower motor for a pre-purge of 5 seconds before going
into operation. Once in operation, the Munchkin controller will now start to modulate the pre-mix
burner based on analyzing the return, supply, differential and operating set point temperatures. By
compiling this information, the controller utilizes an algorithm to fully adjust the firing rate while
maintaining the desired output temperature. The pre-mix burner fan has direct drive current, low-
voltage motor with pulse relay counting. This system allows precise control over the fan speed and
combustion air volumes. Coupled with the fuel and air mixing system which are set to provide a one
to one ratio of precisely measured volumes of fuel to air, an accurate and instant burner output is
achieved. This keeps the Munchkin VWH running at the highest efficiency.
RECOMMENDED SERVICE CLEARANCES
Figure 1-1